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Showing papers in "The Journal of Agricultural Science in 2011"


Journal ArticleDOI
TL;DR: In this paper, the authors employed the Heckman sample selection model to analyse the two-step process of adaptation to climate change, which initially requires farmers' perception that climate is changing prior to responding to changes through adaptation.
Abstract: The present study employed the Heckman sample selection model to analyse the two- step process of adaptation to climate change, which initially requires farmers' perception that climate is changing prior to responding to changes through adaptation. Farmers' perception of climate change was significantly related to the age of the head of the household, wealth, knowledge of climate change, social capital and agro-ecological settings. Factors significantly affecting adaptation to climate change were: education of the head of the household, household size, whether the head of the household was male, whether livestock were owned, the use of extension services on crop and livestock production, the availability of credit and the environmental temperature.

708 citations


Journal ArticleDOI
TL;DR: In this paper, the authors compare and contrast postharvest food losses (PHLs) and waste in developed countries (especially the USA and the UK) with those in less-developed countries (LDCs), especially the case of cereals in sub-Saharan Africa.
Abstract: This review compares and contrasts postharvest food losses (PHLs) and waste in developed countries (especially the USA and the UK) with those in less developed countries (LDCs), especially the case of cereals in sub-Saharan Africa. Reducing food losses offers an important way of increasing food availability without requiring additional production resources, and in LDCs it can contribute to rural development and poverty reduction by improving agribusiness livelihoods. The critical factors governing PHLs and food waste are mostly after the farm gate in developed countries but before the farm gate in LDCs. In the foreseeable future (e.g. up to 2030), the main drivers for reducing PHLs differ: in the developed world, they include consumer education campaigns, carefully targeted taxation and private and public sector partnerships sharing the responsibility for loss reduction. The LDCs’ drivers include more widespread education of farmers in the causes of PHLs; better infrastructure to connect smallholders to markets; more effective value chains that provide sufficient financial incentives at the producer level; opportunities to adopt collective marketing and better technologies supported by access to microcredit; and the public and private sectors sharing the investment costs and risks in market-orientated interventions.

613 citations


Journal ArticleDOI
TL;DR: Replacement of heat-sensitive cultivars with heat-tolerant ones, adjustment of sowing time, choice of varieties with a growth duration allowing avoidance of peak stress periods, and exogenous application of plant hormones are some of the adaptive measures that will help in the mitigation of forecast yield reduction due to global warming.
Abstract: The predicted 2–4°C increment in temperature by the end of the 21st Century poses a threat to rice production. The impact of high temperatures at night is more devastating than day-time or mean daily temperatures. Booting and flowering are the stages most sensitive to high temperature, which may sometimes lead to complete sterility. Humidity also plays a vital role in increasing the spikelet sterility at increased temperature. Significant variation exists among rice germplasms in response to temperature stress. Flowering at cooler times of day, more pollen viability, larger anthers, longer basal dehiscence and presence of long basal pores are some of the phenotypic markers for high-temperature tolerance. Protection of structural proteins, enzymes and membranes and expression of heat shock proteins (HSPs) are some of the biochemical processes that can impart thermo-tolerance. All these traits should be actively exploited in future breeding programmes for developing heat-resistant cultivars. Replacement of heat-sensitive cultivars with heat-tolerant ones, adjustment of sowing time, choice of varieties with a growth duration allowing avoidance of peak stress periods, and exogenous application of plant hormones are some of the adaptive measures that will help in the mitigation of forecast yield reduction due to global warming.

281 citations


Journal ArticleDOI
TL;DR: In this article, the authors summarized the available evidence regarding the potential of urban agriculture to respond to a number of key urban challenges and reviewed the perspectives on urban agriculture applied by local and national authorities.
Abstract: The current paper briefly summarizes the available evidence regarding the potential of urban agriculture to respond to a number of key urban challenges and reviews the perspectives on urban agriculture applied by local and national authorities. The last section of the paper briefly presents the authors’ views on the development of urban agriculture as an integral part of sustainable city development.

174 citations


Journal ArticleDOI
TL;DR: Differences from other current protein evaluation systems, viz. the Cornell Net Carbohydrate and Protein system and the Feed into Milk system, are discussed.
Abstract: In the current Dutch protein evaluation system (the DVE/OEB1991 system), two characteristics are calculated for each feed: true protein digested in the intestine (DVE) and the rumen degradable protein balance (OEB). Of these, DVE represents the protein value of a feed, while OEB is the difference between the potential microbial protein synthesis (MPS) on the basis of available rumen degradable protein and that on the basis of available rumen degradable energy. DVE can be separated into three components: (i) feed crude protein undegraded in the rumen but digested in the small intestine, (ii) microbial true protein synthesized in the rumen and digested in the small intestine, and (iii) endogenous protein lost in the digestive processes. Based on new research findings, the DVE/OEB1991 system has recently been updated to the DVE/OEB2010 system. More detail and differentiation is included concerning the representation of chemical components in feed, the rumen degradation characteristics of these components, the efficiency of MPS and the fractional passage rates. For each chemical component, the soluble, washout, potentially degradable and truly non-degradable fractions are defined with separate fractional degradation rates. Similarly, fractional passage rates for each of these fractions were identified and partly expressed as a function of fractional degradation rate. Efficiency of MPS is related to the various fractions of the chemical components and their associated fractional passage rates. Only minor changes were made with respect to the amount of DVE required for maintenance and production purposes of the animal. Differences from other current protein evaluation systems, viz. the Cornell Net Carbohydrate and Protein system and the Feed into Milk system, are discussed.

145 citations


Journal ArticleDOI
TL;DR: A 4-year study was conducted on the Lincoln University Dairy Farm (LUDF), Canterbury, New Zealand, from 2003 to 2007 as mentioned in this paper, where a new technique using GPS technology was developed to precisely measure the paddock spatial area coverage, diversity and distribution of dairy cattle urine patches in grazed paddocks over time.
Abstract: SUMMARY Accurate field data on the paddock area affected by cow urine depositions are critical to the estimation and modelling of nitrogen (N) losses and N management in grazed pasture systems. A new technique using survey-grade global positioning system (GPS) technology was developed to precisely measure the paddock spatial area coverage, diversity and distribution of dairy cattle urine patches in grazed paddocks over time. A 4-year study was conducted on the Lincoln University Dairy Farm (LUDF), Canterbury, New Zealand, from 2003 to 2007. Twelve field plots, each 100 m 2 in area, were established on typical grazing areas of the farm. All urine and dung deposits within the plots were visually identified, the pasture response area (radius) measured and position marked with survey-grade GPS. The plots were grazed as part of the normal grazing rotation of the farm and urine and dung deposits measured at 12-week intervals. The data were collated using spatial (GIS) software and an assessment of annual urine patch coverage and spatial distribution was made. Grazing intensities ranged from 17645 to 30295 cow grazing h/ha/yr. Mean annual areas of urine patches ranged from 0·34 to 0·40 m 2 (4-year mean 0·37±0·009 m 2 ), with small but significant variation between years and seasons. Mean annual urine patch numbers were 6240±124 patches/ha/yr. The mean proportional area coverage for a single sampling event or season was 0·058 and the mean proportional annual urine patch coverage was 0·232±0·0071. There was a strong linear relationship between annual cow grazing h/ha and urine patch numbers/ha (R 2 =0·69) and also annual urine patch area coverage (R 2 =0·77). Within the stocking densities observed in this study, an annual increase of 10000 cow grazing h/ha increased urine patch numbers by 1800 urine patches/ha/yr and annual urine patch area coverage by 0·07. This study presents new quantitative data on urine patch size, numbers and the spatial coverage of patches on a temporal basis.

138 citations


Journal ArticleDOI
TL;DR: In this article, the authors used nine agroclimatic indices (i.e., average temperature, radiation and precipitation during winter, spring and summer) to predict the wheat grain yield under five climate change scenarios (a baseline for 1985 and two climate change projections for 2020 and 2040) for two soil types and two locations in Denmark.
Abstract: Data on grain yield from field trials on winter wheat under conventional farming, harvested between 1992 and 2008, were combined with daily weather data available for 44 grids covering Denmark. Nine agroclimatic indices were calculated and used for describing the relation between weather data and grain yield. These indices were calculated as average temperature, radiation and precipitation during winter (1 October–31 March), spring (1 April–15 June) and summer (16 June–31 July), and they were included as linear and quadratic covariates in a mixed regression model. The model also included an effect of year to describe the change in yield caused by unrecorded variables such as management changes. The final model included all effects that were significant for at least one of the two soil types (sandy and loamy soils). Seven of the nine agroclimatic indices were included in the final model that was used to predict the wheat grain yield under five climate scenarios (a baseline for 1985 and two climate change projections for 2020 and 2040) for two soil types and two locations in Denmark.The agroclimatic index for summer temperature showed the strongest effect causing lower yields with increasing temperature, whereas yield increased with increasing radiation during summer and spring. Winter precipitation and spring temperature did not affect grain yield significantly. Grain yield responded non-linearly to mean winter temperature with the highest yield at 4·4°C and lower yields both below and above this inflection point.The application of the model predicted that the average yield would decrease under projected climate change. The average decrease varied between 0·1 and 0·8 t/ha (comparable to a relative reduction of 1·6–12.3%) depending on the climate projection, location and soil type. On average, the grain yield decreased by about 0·25 t/ha (c. 3.6%) from 1985 to 2020 and by about 0·55 t/ha (c. 8·0%) from 1985 to 2040. The predicted yield decrease depended on climate projection and was larger for wheat grown in West Zealand than in Central Jutland and in most cases also larger for loamy soils than for sandy soils.The inter-annual variation in grain yield varied greatly between climate projections. The coefficient of variation (CV) varied between 0·16 and 0·46 and was smallest for wheat grown on loamy soils in Central Jutland in the baseline climate and largest for winter wheat grown under one of the 2040 climate projections. The increase in CV is not so much an effect of increased climatic variability under the climate change projections, but more an effect of increased winter temperature, where more extreme winter temperatures (lower or higher than the inflection point at 4·4°C) increased the effect of winter temperatures.

136 citations


Journal ArticleDOI
TL;DR: At elevated temperatures, yields generally declined in these relatively cool growing conditions of northern Europe, except for pea, which was probably associated with reduced water availability, which limited yield determination, especially in early growth phases.
Abstract: Global warming has accelerated in recent decades and the years 1995–2006 were the warmest ever recorded. Also, in Finland, the last decade has been exceptionally warm. Hence, this study examines how current field crop cultivars, adapted to northern long-day conditions and short growing seasons, have responded to the elevated temperatures, especially with regard to determination of yield potential and quality. These comparisons were carried out with spring and winter wheat (Triticum aestivum L.), oats (Avena sativa L.), barley (Hordeum vulgare L.), winter rye (Secale cereale L.), pea (Pisum sativum L.) and rapeseed (turnip rape, Brassica rapa L. and oilseed rape, B. napus L.). Long-term data sets of MTT Official Variety Trials and the Finnish Meteorological Institute were used to study crop responses to precipitation and elevated temperatures at different growth phases. The MTT data sets were also grouped into experiments that could be considered typical of the temperature conditions in the period 1971–2000 seasons (termed ‘1985’ conditions) or typical of the period 2010–39 (termed ‘2025’). At elevated temperatures, yields generally declined in these relatively cool growing conditions of northern Europe, except for pea. Elevated temperatures tended to have negative effects both in the pre- and post-anthesis phases, but the response depended on species. The response was probably associated with reduced water availability, which limited yield determination, especially in early growth phases. For example, in spring cereals a decrease in early summer precipitation by 10 mm decreased yields by 45–75 kg/ha. As warmer conditions also typically hastened development and growth in such generally cool growing conditions of Finland, it is essential that breeding programmes produce cultivars that are less sensitive to elevated temperatures, which are likely to become more frequent in future.

116 citations


Journal ArticleDOI
TL;DR: In this paper, the potential exploitation of novel drought stress biology in both crop improvement programs and via changed crop management practices is discussed, and it is concluded that an interdisciplinary approach is needed involving new genetic opportunities and plant breeding.
Abstract: Globally, agriculture accounts for 0·80–0·90 of all freshwater used by humans and, in many crop production systems, this water use is unsustainable. The current paper focuses on the potential exploitation of novel drought stress biology in both crop improvement programmes and via changed crop management practices. The aim is to deliver ‘more crop per drop’. In order to respond to the challenge of feeding a world population of seven billion and growing, it is concluded that an interdisciplinary approach is needed involving new genetic opportunities and plant breeding. It is also shown how crop management can exploit the drought stress physiology of plants to deliver improved water productivity without sacrificing crop yield.

114 citations


Journal ArticleDOI
TL;DR: To reduce the present high rate of malnutrition in the area, the study suggests the targeting of women with education programmes and provision of clean water, including the enforcement of healthy environment in the rural areas.
Abstract: Prevalence of malnutrition among under-five children is very high in many developing countries of the World. As a step towards reducing the prevalence, there is need to identify the important determinants of malnutrition in the specific context. This study examined the prevalence and determinants of malnutrition among under-five children of farming households in Kwara State, Nigeria. Descriptive and regression analyses were used to analyze anthropometrics data collected from 127 children selected randomly from 40 rural villages in the State. Descriptive results indicate that 23.6%, 22.0% and 14.2% of the sample children were stunted, underweight and wasted respectively. Regression analysis shows that the significant determinants of malnutrition were gender and age of child, education and body mass index of mother, calorie intake of the households, access to clean water and presence of toilet in the households. To reduce the present high rate of malnutrition in the area, the study suggests the targeting of women with education programmes and provision of clean water, including the enforcement of healthy environment in the rural areas.

110 citations


Journal ArticleDOI
TL;DR: The results showed that the starch concentration of grains given a heat-shock treatment above 30°C were lower than those developing at normal temperature in both cultivars, indicating the differences in resistance to high temperature between cultivars.
Abstract: The effect of high temperatures (above 25°C) on starch concentration and the morphology of starch granules in the grains of wheat (Triticum aestivum L.) were studied. Wheat plants of cultivars Yangmai 9 (weak-gluten) and Yangmai 12 (medium-gluten) were treated with high temperatures for 3 days at different times after anthesis. The results showed that the starch concentration of grains given a heat-shock treatment above 30°C were lower than those developing at normal temperature in both cultivars. High temperature lowered starch concentration due to the decrease of amylopectin. Under the same temperature, the effect of heat shock from 6 to 8 days after anthesis (DAA) was the greatest, whereas from 36 to 38 DAA the effect was the least. The effects of high temperatures after anthesis on starch-pasting properties were similar to those on starch concentration, especially after 35–40°C treatments. The size, shape and structure of starch granules in wheat grains (determined by electron microscopy) after heat shock were visibly different from the control. When given heat shock during development, the starch granules in mature wheat grains were ellipsoid in shape and bound loosely with a protein sheath in Yangmai 9, while they were damaged and compressed with fissures in Yangmai 12, indicating the differences in resistance to high temperature between cultivars. Ratios of large (type-A) and small (type-B) starch granules significantly decreased under heat shock, which limited the potential sink size for dry matter deposition in the grain.

Journal ArticleDOI
TL;DR: Understanding the natural ecology of pests and pathogens will improve the authors' ability to manipulate behaviour, or exploit natural enemies or other antagonists of pest species, and Harnessing new technologies and knowledge to create more durable resistant crops and sustainable disease and pest management systems.
Abstract: Pests and diseases impact on crop yield and quality, and also reduce resource-use efficiency. Improved crop protection strategies to prevent such damage and loss can increase production and make a substantial contribution to food security. DNA-based technologies are likely to greatly increase the speed, sensitivity and accuracy of pest and pathogen detection and diagnosis. Rapid sequencing of nucleic acids from infected plants will aid identification of novel disease agents. Biomarkers of disease or crop damage such as volatile chemicals or blends may also be used to detect pest outbreaks. Biosensors coupled to information networks will provide real-time monitoring and surveillance of crops or stored produce and hence early warning of emerging problems and new invasive species. Challenges remain in the dissemination of new technologies and information to resource poor farmers in developing countries, although the rapid extension of the internet, mobile phones and other communication networks will provide new opportunities. Defining the genetic and molecular basis of innate plant immunity has been a major advance in plant biology with the potential to identify new targets for intervention via novel chemistry or genetic modification (GM). Identification of regulatory genes, signal molecules, pathways and networks controlling induced plant defence should lead to the development of a new generation of defence modulators, delivered either as crop protection products, or via biological agents on seeds or in the root zone. There should also be opportunities to select more responsive crop genotypes, or to develop transgenic crops tailored to respond to specific chemical cues or molecular patterns diagnostic for particular biotic threats. Sequencing of the genomes of the major crop species and their wild relatives will expand enormously the known gene pool and diversity of genetic resources available for plant breeders to access. It should be possible to identify genomic regions and genes conferring more durable, quantitative resistance to pathogens. The breeding cycle will be accelerated by high-throughput phenotyping and more efficient selection of resistance traits using within-gene markers. GM approaches will facilitate pyramiding (combining) resistance genes with different specificities and modes of action, thereby reducing the risk of directional selection for virulence. Analysis of the genomes of plant pathogens and invertebrate pests is already providing new information on genes, gene families and processes involved in host colonization and pathogenicity. Comparative genomics of species with diverse host ranges, contrasting feeding habits and different pathogenic lifestyles will identify new targets for inhibiting pest attack and aid the development of novel antimicrobial drugs and pesticides. Understanding the natural ecology of pests and pathogens, such as the factors determining host location, resource exploitation and interactions with other organisms, will improve our ability to manipulate behaviour, or exploit natural enemies or other antagonists of pest species. Volatile signals, either from natural plant sources, or engineered in transgenic crops, will be more widely used to modify pest behaviour. It may also be possible to manipulate microbial communities regulating pathogen populations and activity, and thereby recruit and retain more effective biocontrol agents. Insights into the natural diversity and activity of soil and microbial populations in the zones surrounding roots and seeds will provide new information on mechanisms of suppression regulating pest species. Fully effective interventions are unlikely, due to the complexity and diversity of the soil system, but there should be progress towards integrated control regimes combining more resistant crop genotypes (either selected or GM) with targeted management of natural suppressive processes. Harnessing new technologies and knowledge to create more durable resistant crops and sustainable disease and pest management systems will require improved understanding of the factors driving pest and pathogen adaptation and evolution. There must also be an increased emphasis on translational research and delivery, and developing strategies appropriate for lower-input production systems, if the second ‘green revolution’ is to become a reality.

Journal ArticleDOI
TL;DR: Wang et al. as mentioned in this paper described of saponins compound in Binahong, one of medicinal plant investigated from these plant probably contribute to the effectiveness the above plant for treatment several diseases.
Abstract: Saponin has various types; it can be bond with glycosides that form soapy lathers when mixed and agitated with water, and have been used to treat diabetes; liver, hepatitis, cardiovascular as high blood pressure, high cholesterol, and physical stress. In this study describe of saponins compound in Binahong, one of medicinal plant investigated from these plant probably contribute to the effectiveness the above plant for treatment several diseases. The sample were dried by oven (60 o C) to be powder and extracted with solvents. After that used qualitative and quantitative test. The result of Binahong plant contains saponins compound on all a part of the Binahong plant, are positive indicate of presence of saponins triterpenoid and steroid. . Moreover crude of saponins substances from Leaves (28.14±0.22), Stems (3.65±011) and Tubers (43.15±0.10) of mg/g. The research showed of the Binahong plant, importance of the distribution of determination of saponins compound from plant, has a potential to treatment for several diseases

Journal ArticleDOI
TL;DR: The results proved that Chlorophyll content, MSI, RWC and Fv/Fm are good physiological indices of drought tolerance and can be used for improvement drought tolerance in wheat.
Abstract: Tolerant and susceptible durum wheat varieties were grown in the 1 st and 2 nd settlement zone under rainfed conditions inDaraa province-Syria, In order to expose plants to different level of water regime, since the two zones differ in total amount of rainfall during the growing season. Plants were suffered from terminal drought stress in both zones, however, the drought was more sever in the 2 nd settlement zone. All measured parameters: chlorophyll content, MSI, RWC, Fv/Fm decreased significantly in the 2 nd compared to the 1 st zone at all growth stages, however more reduction was recorded in drought susceptible varieties. Yield all yield components also affected negatively and drought tolerant varieties have maintained good performance in the 2 nd zone. Our results proved that Chlorophyll content, MSI, RWC and Fv/Fm are good physiological indices of drought tolerance and can be used for improvement drought tolerance in wheat.

Journal ArticleDOI
TL;DR: In this article, the effect of organic fertilizer on growth and yield components in rice was studied in 2008 and 2009, in randomized block design based on 4 replications, where chicken manure, cow manure and paddy rice were mixed together in 1:1:0.5 ratio to from organic fertilizer.
Abstract: In order to study the effect of organic fertilizer on growth and yield components in rice, an experiment was carried out in 2008 and 2009, in randomized block design based on 4 replications. The chicken manure, cow manure and paddy rice were mixed together in 1:1:0.5 ratio to from organic fertilizer. The treatments of organic fertilizer were given in 5 levels (0.5, 1.0, 1.5, 2.0 and 2.5 ton/ha). At one level organic fertilizer 1.5 ton/ha was mixed with inorganic fertilizers (N-50, P-25, K-25 kg / ha) and recommended dose of inorganic fertilizer-NPK (N=100, P=50, K=50 kg/ha) was used as check. The plants without treatments were served as control. Grain yield and its components were significantly increased in all the treatments over control. The maximum grain yield in 2008 (4335.88 kg/ha) was noted in plants treated with 2 ton/ha organic fertilizer and it was (4662.71 kg/ha) for 2009 for plant treated with combination of chemical fertilizer + 1.5 ton/ha organic fertilizer. An increase in the grain yield at the abovementioned treatments was may be due to the increase of 1000-seed weight, panicle number, number of fertile tiller, flag leaf length, number of spikelet, panicle length and decrease number of hollow spikelet per panicle.

Journal ArticleDOI
TL;DR: The availability of micronutrients in wheat grains and straw positively correlated with silt, clay, organic carbon and CEC and negatively correlated with sand, CaCO 3 and pH of soils.
Abstract: The aim of this study was to evaluate available micronutrient (Fe, Cu, Zn, Mn and B) status and their relationship with soil properties. To study this, there were seventy surface soil (0-30 cm depth) and plant samples, each collected from wheat growing fields of Jhunjhunu tehsil. The soils were analyzed for physico-chemical properties and status of available micronutrients. Grain and straw samples of wheat plant separately analyzed for micronutrient contents. The sand, silt and clay content of the soil ranges from 76.70 to 90.40, 1.30 to 7.50 and 5.20 to 12.90 per cent, respectively and these soils categorized as sandy, loamy sand and sandy loam. The soils were moderately calcareous in nature and having CaCO 3 content ranges from 3.90 to 12.00 per cent. The analyzed samples showing lower in organic carbon and CEC and their ranges from 0.06 to 0.43 per cent and 2.40 to 10.40 cmol (p + ) kg -1 , respectively. The pH (8.10 to 9.20) and EC (0.20 to 2.14 dSm -1 ) values indicated that soils were found to be moderately alkaline and non-saline in nature. The 90 per cent of analyzed soil samples were found to be deficient in iron and 70 per cent deficient in zinc and their values ranges from 1.22 to 5.87 and 0.12 to 1.30 mg kg -1 , respectively. While the remaining micronutrients (Cu, Mn and B) shown to be sufficient and their values ranges between 0.17 to 3.32, 2.03 to 5.67 and 0.37 to 1.51 mg kg -1 , respectively. The availability of micronutrients indicating positive and significantly correlated with silt, clay, organic carbon and CEC of soils, whereas, negative and significantly correlated with sand, calcium carbonate and pH of the soils. The availability of micronutrients in wheat grains and straw positively correlated with silt, clay, organic carbon and CEC and negatively correlated with sand, CaCO 3 and pH of soils.

Journal ArticleDOI
TL;DR: The challenge for the next 50 years is to increase the productivity of major livestock species to address the food needs of the world, while at the same time minimizing the environmental impact.
Abstract: The challenge for the next 50 years is to increase the productivity of major livestock species to address the food needs of the world, while at the same time minimizing the environmental impact. The present review presents an optimistic view of this challenge. The completion of genome sequences, and high-density analytical tools to map genetic markers, allows for whole-genome selection programmes based on linkage disequilibrium for a wide spectrum of traits, simultaneously. In turn, it will be possible to redefine genetic prediction based on allele sharing, rather than pedigree relationships and to make breeding value predictions early in the life of the peak sire. Selection will be applied to a much wider range of traits, including those that are directed towards environmental or adaptive outcomes. In parallel, reproductive technologies will continue to advance to allow acceleration of genetic selection, probably including recombination in vitro. Transgenesis and/or mutagenesis will be applied to introduce new genetic variation or desired phenotypes. Traditional livestock systems will continue to evolve towards more intensive integrated farming modes that control inputs and outputs to minimize the impact and improve efficiency. The challenges of the next 50 years can certainly be met, but only if governments reverse the long-term disinvestment in agricultural research.

Journal ArticleDOI
TL;DR: In this article, the authors examined the agronomic practices of smallholder conservation agriculture (CA) farmers in Zambia and found that weed management, crop residue retention, timely planting and soil fertility management were the most challenging for CA farmers especially those without reliable access to oxen.
Abstract: This study examined the agronomic practices of smallholder Conservation Agriculture (CA) farmers in Zambia. Questionnaire survey, focus group discussions, key informant interviews, field assessments, desk study and soil analyses were employed to collect data on tillage systems, crop rotations, weed control, soil fertility management, crop residue retention and crop yields. The results showed that weed management, crop residue retention, timely planting and soil fertility management were the most challenging for CA farmers especially those without reliable access to oxen. Crop residue retention conflicted with the socio-cultural practices of the communities and was hardly practised while crop rotation seemed difficult in light of the dominance of maize cultivation and the lack of markets for crop legumes. Possible options for improving smallholder CA systems were greater integration of livestock, correct herbicide application, market provision for crop legumes, farmer training in agri-business and better access to agricultural credit and subsidized inputs. CA promoters must incorporate the farmers’ local cultural contexts in order to better address the challenges associated with adopting CA.

Journal ArticleDOI
TL;DR: It was concluded that more fertile tiller number and number of kernels per main spike are major yield contributing factors in selecting high yielding barley cultivars.
Abstract: Eighty six promising new barley genotypes and three checks including one indigenous cultivar (Hordeum vulgare L. var Rum) were grown in two successive seasons of 2005 and 2006 to assess the presence of variability for desired traits and amount of variation for different parameters. Genetic parameters, correlations, and partial regressions were estimated for all the traits. Analysis of variance revealed significant differences among entries for all the characters. The estimates of genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) were high for grain yield per plant, biological yield and number of kernels per main spike. Broad sense heritability estimates for various traits ranged from 68 to 99.7%. Grain yield per plant showed high significant positive genetic and phenotypic correlation with only number of kernels per main spike. Multiple correlations of characters (0.36), via. fertile tiller number and number of kernels per main spike which were significant with grain yield were far from the multiple correlation of all characters (0.96). The total variability calculated through multiple correlation in the population for yield improvement accounted by fertile tiller number and number of kernels per main spike was 36 % compared to 96 % accounted by all other characters. It was concluded that more fertile tiller number and number of kernels per main spike are major yield contributing factors in selecting high yielding barley cultivars.

Journal ArticleDOI
TL;DR: In this paper, one struvite from black water and another from urine were assessed for safety under Dutch regulations, and for effectiveness as P fertilizer in a maize field experiment and a literature review.
Abstract: To ensure food supply, phosphorus must be recycled, for which an appealing method is using struvite fertilizer from human excreta. One struvite from black water and another from urine were assessed for safety under Dutch regulations, and for effectiveness as P fertilizer in a maize field experiment and a literature review. Both struvites contained 12% P, 12% Mg, 6% N, and 0.5-1.5% of several micronutrients. Struvites did not exceed Dutch regulations for heavy metals or pathogens, and based on literature, organic toxins should be far below regulatory limits. In this study and 18 others, struvite appears to have similar effectiveness to soluble fertilizer. Early in the season, 200 kg P 2 O 5 ha -1 of black water struvite and soluble phosphorus improved maize performance (P<0.05), however at harvest, differences in yield and biomass P content were not significant. Problems of Mg accumulation in soil can be avoided by liming and accurate fertilization. Overall, the studied struvites are safe and effective fertilizers.

Journal ArticleDOI
TL;DR: In this paper, the effects of climate change on rice production systems in Africa have been discussed, and integrated weed management strategies are proposed to assist farmers in coping with the challenges of weed control in the future.
Abstract: SUMMARY Global changes including increases in temperature, atmospheric greenhouse gases, soil degradation and competition for land and water resources, will have multiple impacts on rice production systems in Africa. These changes will affect weed communities, and management approaches must be adapted to take this into account. Higher temperatures and limited water availability will generally advantage C4 over C3 plants (e.g. rice). Conversely, elevated carbon dioxide (CO2) levels will improve the competitiveness of rice relative to C4 weeds, which comprise many of the problem weeds of rice. Increased atmospheric CO2 levels may also improve tolerance of rice against parasitic weeds, while prevalence of parasitic species may be amplified by soil degradation and more frequent droughts or floods. Elevated CO2 levels tend to promote growth below-ground relative to above-ground, particularly in perennial (C3) species. This may render mechanical control of weeds within a cropping season less effective or even counterproductive. Increased CO2 levels, rainfall and temperature may also reduce the effectiveness of chemical control, while the implementation of adaptation technologies, such as water-saving irrigation regimes, will have negative consequences for rice–weed competition. Rain-fed production systems are prevalent throughout Africa and these are likely to be most vulnerable to direct effects of climate change (e.g. higher temperatures and changes in rainfall patterns). Effective weed management strategies in these environments could encompass off-season tillage, the use of well-adapted cultivars (i.e. those with drought and heat tolerance, high weed competitiveness and parasitic weed resistance or tolerance) and rotations, intercropping or short, off-season fallows with weed-suppressive legumes including those that suppress parasitic weeds. In irrigated, non-flooded rice systems, weeds are expected to become more serious. Specifically, perennial rhizomatous C3 weeds and species adapted to hydromorphic conditions are expected to increase in prevalence. By implementing an integrated weed management strategy primarily targeted at weed prevention, dependency on flood water, herbicides and mechanical control can be lessened. Off-season deep tillage, stale seed bed techniques, use of clean seeds and irrigation water, competitive cultivars, timely transplanting at optimum spacing and judicious fertilizer timings are suitable candidate components for such a strategy. Integrated, novel approaches must be developed to assist farmers in coping with the challenges of weed control in the future.

Journal ArticleDOI
TL;DR: A DREB2 transcription factor gene from sorghum was identified and cloned in binary vectors, such that it was driven either by a constitutive CaMV35S promoter or a stress-inducible rd29A promoter, leading to pleiotropic effects in rice and these transgenics did not set seed.
Abstract: Plant-specific transcription factors belonging to the dehydration response element binding (DREB)/C-repeat binding factor (CBF) subfamily of the AP2/EREBP family specifically interact with dehydration-responsive elements (DRE)/C-repeat (CRT) and control the expression of many stress-inducible genes in plants. Two major subgroups of DREB proteins are represented by DREB1 and DREB2, which are induced specifically under cold and drought/salt stress, respectively. A DREB2 transcription factor gene from sorghum, SbDREB2 was identified and cloned in binary vectors, such that it was driven either by a constitutive CaMV35S promoter or a stress-inducible rd29A promoter. These gene constructs were transferred into rice through Agrobacterium tumefaciens-mediated transformation. Expression patterns of the native DREB gene (OsDREB2) and the transgene (SbDREB2) were similar. Both genes showed induction at 1 h exposure to drought, after which expression gradually dropped to basal levels by 24 h. Constitutive expression of SbDREB2 led to pleiotropic effects in rice and these transgenics did not set seed. The rd29A: SbDREB2 rice plants set seed and the grains collected from primary transformants were sown to raise T1 plants. The drought-stressed rd29A: SbDREB2 transgenics showed a significantly higher number of panicles as compared to the wild-type rice plants. Other phenological and agronomic traits were not affected in wild-type and rd29A: SbDREB2 transgenic rice.

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TL;DR: Decomposing the variation in net margin performance between the most and least profitable groups, an approximate ratio of 65:23:12 is observed for higher yields: lower costs: higher milk price, indicating that yield differentials are the key performance driver in dairy profitability.
Abstract: The UK dairy sector has undergone considerable structural change in recent years, with a decrease in the number of producers accompanied by an increased average herd size and increased concentrate use and milk yields. One of the key drivers to producers remaining in the industry is the profitability of their herds. The current paper adopts a holistic approach to decomposing the variation in dairy profitability through an analysis of net margin data explained by physical input–output measures, milk price variation, labour utilization and managerial behaviours and characteristics. Data are drawn from the Farm Business Survey (FBS) for England in 2007/08 for 228 dairy enterprises. Average yields are 7100 litres/cow/yr, from a herd size of 110 cows that use 0·56 forage ha/cow/yr and 43·2 labour h/cow/yr. An average milk price of 22·57 pence per litre (ppl) produced milk output of £1602/cow/yr, which after accounting for calf sales, herd replacements and quota leasing costs, gave an average dairy output of £1516/cow/yr. After total costs of £1464/cow/yr this left an economic return of £52/cow/yr (0·73 ppl) net margin profit. There is wide variation in performance, with the most profitable (as measured by net margin per cow) quartile of producers achieving 2000 litres/cow/yr more than the least profitable quartile, returning a net margin of £335/cow/yr compared to a loss of £361/cow/yr for the least profitable. The most profitable producers operate larger, higher yielding herds and achieve a greater milk price for their output. In addition, a significantly greater number of the most profitable producers undertake financial benchmarking within their businesses and operate specialist dairy farms. When examining the full data set, the most profitable enterprises included significantly greater numbers of organic producers. The most profitable tend to have a greater reliance on independent technical advice, but this finding is not statistically significant. Decomposing the variation in net margin performance between the most and least profitable groups, an approximate ratio of 65:23:12 is observed for higher yields: lower costs: higher milk price. This result indicates that yield differentials are the key performance driver in dairy profitability. Lower costs per cow are dominated by the significantly lower cost of farmer and spouse labour per cow of the most profitable group, flowing directly from the upper quartile expending 37·7 labour h/cow/yr in comparison with 58·8 h/cow/yr for the lower quartile. The upper quartile's greater milk price is argued to be achieved through contract negotiations and higher milk quality, and this accounts for 0·12 of the variation in net margin performance. The average economic return to the sample of dairy enterprises in this survey year was less than £6000/farm/yr. However, the most profitable quartile returned an average economic return of approximately £50 000 per farm/yr. Structural change in the UK dairy sector is likely to continue with the least profitable and typically smaller dairy enterprises being replaced by a smaller number of expanding dairy production units.

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TL;DR: In this paper, the authors focused on the potential occurrence of the Colorado potato beetle (Leptinotarsa decemlineata, Say 1824), an important potato pest and the European corn borer (Ostrinia nubilalis, Hubner 1796), the most important maize pest, during climate change.
Abstract: The present study is focused on the potential occurrence of the Colorado potato beetle (Leptinotarsa decemlineata, Say 1824), an important potato pest, and the European corn borer (Ostrinia nubilalis, Hubner 1796), the most important maize pest, during climate change. Estimates of the current potential distribution of both pest species as well as their distribution in the expected climate conditions are based on the CLIMEX model. The study covers central Europe, including Austria, the Czech Republic, Hungary, and parts of Germany, Poland, Romania, Slovakia, Switzerland, Ukraine, Slovenia, the northern parts of Serbia, parts of Croatia and northern Italy. The validated model of the pests’ geographical distribution was applied within the domain of the regional climate model (RCM) ALADIN, at a resolution of 10 km. The weather series that was the input for the CLIMEX model was prepared by a weather generator (WG) which was calibrated with the RCM-simulated weather series (for the period of 1961–90). To generate a weather series for two future time periods (2021–50 and 2071–2100), the WG parameters were modified according to 12 climate change scenarios produced by the pattern scaling method. The standardized scenarios derived from three global climate models (HadCM, NCAR-PCM and ECHAM) were scaled by low, middle and high values of global temperature change estimated by the Model for the Assessment of Greenhouse-gas Induced Climate Change (MAGICC) model (assuming three combinations of climatic sensitivity and emission scenarios). The results of present study suggest the likely widening of the pests’ habitats and an increase in the number of generations per year. According to the HadCM-high scenario, the area of arable land affected by a third generation per season of Colorado potato beetle in 2050 is c. 45% higher, and by a second generation of the European corn borer is nearly 61% higher, compared to present levels.

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TL;DR: The soluble sugar content in the leaves went from high to low as the tuberous roots progressed from the setting stage to the ripening stage; starch accumulation in the root tubers followed the opposite pattern.
Abstract: The purpose of this study was to examine the relationships between the soluble sugar content in the leaves and stems and the starch accumulation in the tuberous roots of four cassava cultivars: FuXuan01, GR891, SC124, and SC201. The results showed that the highest leaf soluble sugar content was in September, and the highest stem sugar content was in October, which played an important role in starch accumulation in the tuberous roots. The leaf and stem soluble sugar content and the tuberous root starch accumulation were positively correlated in the setting and growth stages but negatively correlated in the ripening stage. The soluble sugar content in the leaves went from high to low as the tuberous roots progressed from the setting stage to the ripening stage; starch accumulation in the root tubers followed the opposite pattern.

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TL;DR: In this paper, a field trial was established on a common NORD Pallic soil (Timaru silt loam) to determine how land-use intensification affects indicators of soil quality (macroporosity, bulk density, structural condition score, total and mineralizable carbon and nitrogen and earthworms).
Abstract: Land-use intensification requires more farm inputs to sustain or increase farm product outputs. However, a common concern for land-use intensification is the potential deterioration of soil. The North Otago Rolling Downlands (NORD) region of New Zealand is drought prone, and although traditionally limited to extensive sheep farming, there are large-scale conversions to intensive cattle grazing operations such as dairy farming resulting from an irrigation scheme commissioned in 2006. Pallic soils (Aeric Fragiaqualf in US Soil Taxonomy) such as those in the NORD region are prone to soil compaction because of their ‘high’ structural vulnerability under intensive management. To address these concerns, a field trial was established on a common NORD Pallic soil (Timaru silt loam) to determine how land-use intensification affects indicators of soil quality (macroporosity, bulk density, structural condition score, total and mineralizable carbon and nitrogen and earthworms) and pasture production. The treatments compare irrigated v. dryland pasture and sheep v. cattle grazing on 16 plots. The findings show that soil physical quality responds more quickly to changes in land-use pressure than do biochemical and organic indicators. Both irrigation and cattle grazing, particularly in combination, increased soil compaction; macroporosity on irrigated plots grazed by cattle ranged from 9·1 to 13·3% v/v at a depth of 0–50 mm, compared to dryland plots with sheep grazing (18·9–23·0% v/v). Soil compaction/damage has implications for pasture production, soil hydrology and nutrient movement. Land management practices for intensive cattle grazing of irrigated soil prone to treading damage therefore need to implement high compaction risk strategies to avoid or ameliorate potential changes to soil quality.

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TL;DR: There are many opportunities for the application of the cropping system model (CSM) of the Decision Support System for Agrotechnology Transfer (DSSAT) for carbon sequestration and resource management in Sub-Saharan Africa.
Abstract: In recent years, simulation models have been used as a complementary tool for research and for quantifying soil carbon sequestration under widely varying conditions. This has improved the understanding and prediction of soil organic carbon (SOC) dynamics and crop yield responses to soil and climate conditions and crop management scenarios. The goal of the present study was to estimate the changes in SOC for different cropping systems in West Africa using a simulation model. A crop rotation experiment conducted in Farako-Ba, Burkina Faso was used to evaluate the performance of the cropping system model (CSM) of the Decision Support System for Agrotechnology Transfer (DSSAT) for simulating yield of different crops. Eight crop rotations that included cotton, sorghum, peanut, maize and fallow, and three different management scenarios, one without N (control), one with chemical fertilizer (N) and one with manure applications, were studied. The CSM was able to simulate the yield trends of various crops, with inconsistencies for a few years. The simulated SOC increased slightly across the years for the sorghum–fallow rotation with manure application. However, SOC decreased for all other rotations except for the continuous fallow (native grassland), in which the SOC remained stable. The model simulated SOC for the continuous fallow system with a high degree of accuracy normalized root mean square error (RMSE)=0·001, while for the other crop rotations the simulated SOC values were generally within the standard deviation (s.d.) range of the observed data. The crop rotations that included a supplemental N-fertilizer or manure application showed an increase in the average simulated aboveground biomass for all crops. The incorporation of this biomass into the soil after harvest reduced the loss of SOC. In the present study, the observed SOC data were used for characterization of production systems with different SOC dynamics. Following careful evaluation of the CSM with observed soil organic matter (SOM) data similar to the study presented here, there are many opportunities for the application of the CSM for carbon sequestration and resource management in Sub-Saharan Africa.

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TL;DR: In this article, the extent of awareness of climate change by livestock farmers in the Eastern Cape Province of South Africa was investigated and the choice of adaptation measures that were followed and factors that affected adaption measures.
Abstract: This paper investigated the extent of awareness of climate change by livestock farmers in the Eastern Cape Province of South Africa. It further explored the choice of adaptation measures that were followed and factors that affected adaption measures. The results indicated that marital status, level of education, formal extension, temperatures and the way in which land was acquired, significantly affected awareness of climate change. Variables that significantly affected adaptation selections were gender, formal extension, information received about climate change, temperatures and the way in which land was acquired. The study suggested that the positive and significant variables that affected awareness and adaptation measures by livestock farmers be considered when awareness and adaptation strategies are implemented.

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TL;DR: This study used the Normalized Difference Vegetation Index (NDVI) of Landsat Enhanced Thematic Mapper plus (ETM+) images of rice plants to estimate rice yield based on field observation and showed that the rice yield could be estimated using the exponential equation of y = 0.3419e 4.1587x.
Abstract: Forecasting rice yield before harvest time is important to supporting planners and decision makers to predict the amount of rice that should be imported or exported and to enable governments to put in place strategic contingency plans for the redistribution of food during times of famine. This study used the Normalized Difference Vegetation Index (NDVI) of Landsat Enhanced Thematic Mapper plus (ETM+) images of rice plants to estimate rice yield based on field observation. The result showed that the rice yield could be estimated using the exponential equation of y = 0.3419e 4.1587x , where y and x are rice yield and NDVI, respectively. The R 2 and SE of the estimation were 0.852 and 0.077 ton/ha, respectively. An accuracy assessment of rice yield estimation using Landsat images was performed by comparing the rice yields from the estimation result and the reference data. The results show that the linear relationship with the R

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TL;DR: In this article, a conceptual framework is adapted to address the question of why CO2 effects on primary productivity vary so greatly among rangelands and among years for a given ecosystem, based on the premise that the influence of elevated CO2 on productivity is governed by a set of internal variables that interact dynamically with ecosystem processes.
Abstract: Plant productivity and other ecosystem processes vary widely in their responses to experimental increases in atmospheric carbon dioxide (CO2) concentration. A conceptual framework first suggested by Chapin et al. (1996) was adapted to address the question of why CO2 effects on primary productivity vary so greatly among rangelands and among years for a given ecosystem. The ‘interactive controls’ framework is based on the premise that the influence of elevated CO2 on productivity is governed by a set of internal variables that interact dynamically with ecosystem processes. These interactive controls, which include regional climate, soil resource supply, major functional groups of organisms and disturbance regimes, both regulate CO2 effects on ecosystems and respond to CO2 effects. Changes in interactive controls resulting from CO2 enrichment may feed back to dampen or amplify ecosystem responses to CO2. Most feedbacks from interactive controls will be negative and dampen CO2 effects on ecosystems. Negative feedbacks promote homeostasis in ecosystem processes and reduce the response of plant productivity to CO2. Positive feedbacks on CO2 responses are fewer, but can sustain or even increase benefits of CO2 enrichment for productivity. Positive feedbacks on CO2 responses occur most frequently through changes in plant species and functional group composition. Understanding positive and negative feedbacks on CO2 responses could be one key to predicting consequences of CO2 enrichment for rangeland productivity and other processes.