Showing papers in "The Journal of Agricultural Science in 2010"

Plant breeding and climate changes

Abstract: Climate change is now unequivocal, particularly in terms of increasing temperature, increasing CO 2 concentration, widespread melting of snow and ice and rising global average sea level, while the increase in the frequency of drought is very probable but not as certain. However, climate changes are not new and some of them have had dramatic impacts, such as the appearance of leaves about 400 million years ago as a response to a drastic decrease in CO 2 concentration, the birth of agriculture due to the end of the last ice age about 11 000 years ago and the collapse of civilizations due to the late Holocene droughts between 5000 and 1000 years ago. The climate changes that are occurring at present will have – and are already having – an adverse effect on food production and food quality with the poorest farmers and the poorest countries most at risk. The adverse effect is a consequence of the expected or probable increased frequency of some abiotic stresses such as heat and drought, and of the increased frequency of biotic stresses (pests and diseases). In addition, climate change is also expected to cause losses of biodiversity, mainly in more marginal environments. Plant breeding has addressed both abiotic and biotic stresses. Strategies of adaptation to climate changes may include a more accurate matching of phenology to moisture availability using photoperiod-temperature response, increased access to a suite of varieties with different duration to escape or avoid predictable occurrences of stress at critical periods in crop life cycles, improved water use efficiency and a re-emphasis on population breeding in the form of evolutionary participatory plant breeding to provide a buffer against increasing unpredictability. ICARDA, in collaboration with scientists in Iran, Algeria, Jordan, Eritrea and Morocco, has recently started evolutionary participatory programmes for barley and durum wheat. These measures will go hand in hand with breeding for resistance to biotic stresses and with an efficient system of variety delivery to farmers.

Synergies between the mitigation of, and adaptation to, climate change in agriculture

Abstract: There is a very significant, cost effective greenhouse gas (GHG) mitigation potential in agriculture. The annual mitigation potential in agriculture is estimated to be 4200, 2600 and 1600 Mt CO 2 equiv/yr at C prices of 100, 50 and 20 US$/t CO 2 equiv, respectively. The value of GHG mitigated each year is equivalent to 420000, 130000 and 32000 million US$/yr for C prices of 100, 50 and 20 US$/t CO 2 equiv, respectively. From both the mitigation and economic perspectives, we cannot afford to miss out on this mitigation potential. The challenge of agriculture within the climate change context is two-fold, both to reduce emissions and to adapt to a changing and more variable climate. The primary aim of the mitigation options is to reduce emissions of methane or nitrous oxide or to increase soil carbon storage. All the mitigation options, therefore, affect the carbon and/or nitrogen cycle of the agroecosystem in some way. This often not only affects the GHG emissions but also the soil properties and nutrient cycling. Adaptation to increased variability of temperature and rainfall involves increasing the resilience of the production systems. This may be done by improving soil water holding capacities through adding crop residues and manure to arable soils or by adding diversity to the crop rotations. Though some mitigation measures may have negative impacts on the adaptive capacity of farming systems, most categories of adaptation options for climate change have positive impacts on mitigation. These include: (1) measures that reduce soil erosion, (2) measures that reduce leaching of nitrogen and phosphorus, (3) measures for conserving soil moisture, (4) increasing the diversity of crop rotations by choices of species or varieties, (5) modification of microclimate to reduce temperature extremes and provide shelter, (6) land use change involving abandonment or extensification of existing agricultural land, or avoidance of the cultivation of new land. These adaptation measures will in general, if properly applied, reduce GHG emissions, by improving nitrogen use efficiencies and improving soil carbon storage. There appears to be a large potential for synergies between mitigation and adaptation within agriculture. This needs to be incorporated into economic analyses of the mitigation costs. The inter-linkages between mitigation and adaptation are, however, not very well explored and further studies are warranted to better quantify short- and long-term effects on suitability for mitigation and adaptation to climate change. In order to realize the full potential for agriculture in a climate change context, new agricultural production systems need to be developed that integrate bioenergy and food and feed production systems. This may possibly be obtained with perennial crops having low-environmental impacts, and deliver feedstocks for biorefineries for the production of biofuels, biomaterials and feed for livestock.

Rice Husk Biochar for Rice Based Cropping System in Acid Soil 1. The Characteristics of Rice Husk Biochar and Its Influence on the Properties of Acid Sulfate Soils and Rice Growth in West Kalimantan, Indonesia

Abstract: The experiments were carried out to study the characteristics of biochar made from rice husk and its potential as a soil amendment in acid soils. Biochar was produced by pyrolysis; after which it was applied as a soil amendment. The soil was incubated for 30 days, and then it was planted with rice. For comparison, soil was applied with: rice straw, rice husk, rice husk ash, Chromolaena odorata biomass, and no soil amendment. The characteristics of biochar were: water content 4.96%, pH 8.70, C 18.72%, P 0.12%, CEC 17.57cmol kg-1, K 0.20%, Ca 0.41%, Mg 0.62%, and Na 1.40%. Application of biochar decreased soil bulk density, soil strength, exchangeable Al, and soluble Fe and increased porosity, available soil water content, C-organic, soil pH, available P, CEC, exchangeable K, and Ca. Out of these improvements, only soil carbon, phosphorus, exchangeable Al, soluble Fe, and soil strength significantly influenced rice biomass.

Modified Starches and Their Usages in Selected Food Products: A Review Study

Abstract: Modified starches have been developed for a very long time and it applications in food industry are really significant nowadays. This paper will elaborate more about the definition and classifications of modified starches by considering several modification techniques such as physical, chemical, and enzymatic treatment. Review on journal’s papers of current decade has been done so as to observe the latest applications of modified starches in the food industry. In order to organize the findings, they have been divided into several sub-groups according to its functional applications, as fat replacer/fat mimetic, as texture improver, for high nutritional claim, for high shear and temperature stability, and for flavor oil encapsulation. Examples on its recent applications of specific foods products were also included. Hopefully this paper will assist anyone especially students who wants to get information about the latest applications of modified starch in the food industry.

Opportunities for improving irrigation efficiency with quantitative models, soil water sensors and wireless technology.

Abstract: Increasingly serious shortages of water make it imperative to improve the efficiency of irrigation in agriculture, horticulture and in the maintenance of urban landscapes. The main aim of the current review is to identify ways of meeting this objective. After reviewing current irrigation practices, discussion is centred on the sensitivity of crops to water deficit, the finding that growth of many crops is unaffected by considerable lowering of soil water content and, on this basis, the creation of improved means of irrigation scheduling. Subsequently, attention is focused on irrigation problems associated with spatial variability in soil water and the often slow infiltration of water into soil, especially the subsoil. As monitoring of soil water is important for estimating irrigation requirements, the attributes of the two main types of soil water sensors and their most appropriate uses are described. Attention is also drawn to the contribution of wireless technology to the transmission of sensor outputs. Rapid progress is being made in transmitting sensor data, obtained from different depths down the soil profile across irrigated areas, to a PC that processes the data and on this basis automatically commands irrigation equipment to deliver amounts of water, according to need, across the field. To help interpret sensor outputs, and for many other reasons, principles of water processes in the soil–plant system are incorporated into simulation models that are calibrated and tested in field experiments. Finally, it is emphasized that the relative importance of the factors discussed in this review to any particular situation varies enormously.

Evaluation of Sorghum-Cowpea Intercrop Productivity in Savanna Agro-ecology using Competition Indices

Abstract: The competitive behaviour of sorghum-cowpea intercrops at different planting patterns were studied at the Abubakar Tafawa Balewa University Teaching and Research farm, Bauchi in the northern Guinea savanna of Nigeria during the 2005 and 2006 growing seasons. The treatments comprised of three row arrangements of sorghum/cowpea mixtures; one row of sorghum for one row of cowpea (1S:1C), two rows of sorghum for one row of cowpea (2S:1C) and one row of sorghum for two rows of cowpea (1S:2C), respectively. Sole crops of sorghum and cowpea were included as check to compare yields of intercropped mixtures. Results indicated that grain and straw yields of both sorghum and cowpea were higher in sole cropping than in the intercropping mixtures. However, the 2S:1C planting arrangement exhibited higher LER, competitive indices values, SPI and MAI (N7857.11) compared to the other planting arrangements and the sole crops. From this study, it is inferred that intercropping of sorghum with cowpea at 2S:1C planting pattern will give higher income, better land use efficiency and thus enhancing sustainability of crop production than sole culture of each crop species.

Climate change and agriculture: introductory editorial

Abstract: There seems to be little doubt that the global climate is changing, partly due to natural factors, and in part due to forcing by human activities. However, there are still uncertainties about the extent to which human activity (including agricultural activity) has contributed to the current changes and could influence the future climate. Inevitably, climate and its variability, including the ongoing current changes at various spatial and temporal scales, must impact on agricultural activities. A major challenge for the agricultural industry worldwide is to feed the world population that has been projected to increase by 50% from 6 billion in 2000 to 9 billion in 2050. Most of the increase occurred in the less developed countries, where the current food production is often low. But, although the proportion of hungry people in the world is far below that of 1970, FAO’s current estimate of the number of undernourished people in the world in 2008 was 915 million, the highest over the past 30–40 years (FAO 2009). History suggests that we can be optimistic about achieving appropriate increases in food production. Nevertheless, agriculture must adapt to a changing, and probably more variable, climate and simultaneously reduce emissions and other human impacts, which contribute to global warming. We need to develop and implement farming systems that produce more, from lower inputs, and that do not predjudice the future (i.e. are more sustainable) than the current systems. A key focus of much current research around the world is to predict future changes in climate and to suggest how these changes will curtail current agricultural systems at individual locations. Thus, the Journal of Agricultural Science, Cambridge has decided to inaugurate a ‘special topic’ of Climate Change and Agriculture. In this issue, we launch the series that will continue in future issues. The series will concentrate mainly on the effects of changing climate on agricultural activity but will also consider the impacts of agriculture on climate. One group of papers deals with estimating climate change and documenting or predicting its effects on current agricultural systems, activity and outputs as well as estimating or predicting agricultural impacts from future climate change. The variability in climate, i.e. changing weather conditions from season to season, has a significant impact on agricultural productivity. There are several seasonal climate variations, such as the El Nino Southern Oscillation or the North Atlantic Oscillation, which are important in determining seasonal weather patterns and can impact on crop yields. Studying how current climatic variability influences crop yields is not only important in providing a baseline for estimation of future impacts, but it can also give insights into potentially useful crop prediction methods. Climate factors represent one of the main inputs for plant growth and have a direct effect on many plant physiological processes such as the onset and duration of phenological stages. Over the past decades, temperatures have been increasing and this has led to earlier start dates of crop stages and even shortening the duration of stages for certain species. This has implications for determining which crop varieties farmers can best grow at a certain location. Varieties developed or adapted to a certain location over the past 30 years may not be the best varieties to grow in the future. Integrating cropmodels with climate change scenarios can provide important information on whether farmers could or should replace the current crops or crop varieties with ones grown elsewhere in a region or continent, whether more research is needed to develop new varieties or * To whom all correspondence should be addressed. Email: r.e.l.naylor@abdn.ac.uk Journal of Agricultural Science (2010), 148, 499–500. © Cambridge University Press 2010 doi:10.1017/S0021859610000481 499

The Effects of Temperature Stress on the Quality and Yield of Soya Bean [(Glycine max L.) Merrill.]

Abstract: Reproductive development and growth by crops is especially important for human welfare because we depend on cropfruits and seeds, directly and indirectly, for most of our food. Seed production by crops depends on vegetativedevelopment and growth, development of pollen and egg, pollination, and fertilization. The final size of individualseeds generally hinges on cell division within the embryo, followed by seed filling and maturation process.Environmental conditions prior to the shift to reproductive development usually affect by influencing photosynthesisper unit of leaf area, canopy development and interception of solar radiation per unit of ground area, and initiation ofpotential fruiting site; a strong positive correlation between canopy photosynthesis per unit of ground area and seednumber exists for most crops. For many crops where they are now grown, an increase of just a few °C significantlyreduce yield. Dependence on soybeans for food and feed has increased rapidly in many countries during the last 30years. Nutritionists believe that utilization of soybeans should continue to increase in order to provide betternourishment for people throughout the world. For this goal to be realize, present production areas must produce moresoybeans and new production areas must be established.

Trends in Agriculturally-Relevant Rainfall Characteristics for Small-Scale Agriculture in Northern Ghana

Abstract: This study set out to investigate the trends of agriculturally-relevant rainfall characteristics among small-scale farmers in the rainfall-sensitive dry savanna agro-ecological zone of northern Ghana. Interviews are used to identify characteristics of rainfall which are deemed by the farmers as important in their food production. Time series daily rainfall data from 1960-2007 is then used to identify trends in these variables which include the amount and temporal distribution of rainfall, occurrence of extreme daily rainfall events, the onset of rains, risk of dry spells and coefficient of variability of rains. The risk of dry spells for varying number of days following the planting period is computed using first-order Markov chain modeling. We find that there is a significant increase in mean rainfall per rain day and the coefficient of variation or summer rainfall amounts. No significant change in the onset of rains, the annual rainfall amount or maximum rainfall days are established. However, a significant decrease in the number of rain days and the probability of dry spells of up to seven and eleven days in the first four weeks of the planting season is revealed. There is need for development of an agricultural policy framework designed to understand the growing risks associated with agricultural production among small-scale farmers, and to improve management practices to accommodate and adapt to the new challenges of varying rainfall.

Plant Growth Promoting Characteristics in Some Flavobacterium spp. Isolated from Soils of Iran

Abstract: Plant growth promoting rhizobacteria (PGPR) is referred to a heterogeneous group of beneficial rhizospherebacteria that could enhance plant yield through one or more mechanisms. Flavobacterium has been noted asPGPR in almost all review articles. However, there are a few studies regarding plant growth promotion imposedby them. Some of Plant growth promoting characteristics such as Phosphate solubilizing capacity, ability to useof 1-Amino Cyclopropan-1-Carboxylate (ACC) as sole nitrogen source and production of auxin, siderophore,salicylic acid, chitinase and hydrogen cyanide were evaluated in forty-four flavobacteria isolated fromrhizosphere of wheat. Results showed that none of the isolates were able to produce siderophore, salicylic acidand chitinase and they were not able to use ACC as well. Determining the siderophore showed that none isolatesdid not grow on Chrome Azurol S (CAS) Agar medium. The results of this part were further analyzed usingCAS Agar Diffusion (CASAD) method, but the results were also negative. HCN production was observed in allisolates, but in lowest limit. Thirty-four isolates were capable to solubilize insoluble inorganic Phosphate (P)sources. The average rate of P-solubilization was 3.54 ?g Pml-1, ranging from zero to 37.48 ?gPml-1. There wasa significant negative correlation (r = -0.81**) between solubilized P and the final pH of the growth medium. Inthis study, all the isolates were able to produce auxin, ranging from 0.27 to 12.03 ?gml-1 averaged by 2.03.Considering the ability of the isolates to produce auxin and for P-solubilization, it is necessary to evaluate theireffect on growth and yield of different crop plants.

Impact of climate change on soil erosion and the efficiency of soil conservation practices in Austria

Abstract: The goal of the present study was to assess the impact of selected soil protection measures on soil erosion and retention of rainwater in a 1·14 km2 watershed used for agriculture in the north-east of Austria. Watershed conditions under conventional tillage (CT), no-till (NT) and under grassland use were simulated using the Water Erosion Prediction Project (WEPP) soil erosion model. The period 1961–90 was used as a reference and results were compared to future Intergovernmental Panel on Climate Change (IPCC) scenarios A1B and A2 (2040–60).The simulations for the NT and grassland options suggested runoff would decrease by 38 and 75%, respectively, under the current climatic conditions. The simulation results suggest that, under future climate scenarios, the effectiveness of the selected soil conservation measures with respect to runoff will be similar, or decreased by 16–53%.The actual average net soil losses in the watershed varied from 2·57 t/ha/yr for conventional soil management systems to 0.01 t/ha/yr for grassland. This corresponds to a maximum average annual loss of about 0·2 mm, which is considered to be the average annual soil formation rate and therefore an acceptable soil loss. The current soil/land use does not exceed this limit, with most of the erosion occurring during spring time. Under future climate scenarios, the simulations suggested that CT would either decrease soil erosion by up to 55% or increase it by up to 56%. Under these conditions, the acceptable limits will partly be exceeded. The simulations of NT suggested this would reduce annual soil loss rates (compared to CT) to 0·2 and 1·4 t/ha, i.e. about the same or slightly higher than for NT under actual conditions. The simulation of conversion to grassland suggested soil erosion was almost completely prevented.The selected soil conservation methods maintain their protective effect on soil resources, independent of the climate scenario. Therefore, with small adaptations, they can also be recommended as sustainable soil/land management systems under future climatic conditions.However, based on the available climate scenarios, climate-induced changes in the frequency and intensity of heavy rainstorms were only considered in a limited way in the present work. As the general future trend indicates a strong increase of rainstorms with high intensity during summer months, the results of the present study may be too optimistic.

Analysis of the relationships between climate variability and grapevine phenology in the Nobile di Montepulciano wine production area

Abstract: Climate represents one of the main inputs necessary for plants to complete their vegetative–productive cycle, having a direct effect on the onset and duration of phenological stages and development of crops. Equally important are its indirect effects, affecting field operations such as the application of fertilizer, pruning and crop protection, finally determining the yield.In the present study, phenological stages of the Sangiovese grapevine for the production of Nobile di Montepulciano wine were analysed and related to historical series of meteorological information (since 1970 in Tuscany, Italy). Weather conditions were described through large-scale meteorological information; in particular geopotential height at the 500 hPa level (500 hPa GPH) and North Atlantic Oscillation (NAO) index were considered. All data were provided by the National Oceanic and Atmospheric Administration-Cooperative Institute for Research in Environmental Sciences (NOAA-CIRES) Climate Diagnostics Center, Boulder, Colorado, USA, available from the NOAA-CIRES website (http://www.cdc.noaa.gov/) and processed by the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) Reanalysis Project. Conventional meteorological data, such as air temperature and cumulated rainfall, from ground weather stations were also used.The effects of meteorological parameters on crop phenology (bud-break, flowering and harvest time) were investigated by means of regression analysis, while teleconnections between phenological data and large-scale meteo-climatological data were analysed through correlation maps created using the interactive plotting and analysis link from the NOAA-CIRES website (http://www.cdc.noaa.gov). All correlations were calculated on a monthly to a multi-monthly basis, and also in relation to the different physiological stages of the crop, from 1970 to 2006.The climate change and variability impact on the crop was investigated by trend analysis of meteorological information and its effect on the onset of grapevine phenological stages.The results demonstrated that large-scale meteorological information has a significant effect on the onset of the phenological stages of grapevine. In particular, winter NAO was negatively correlated with bud-break and flowering dates, while GPH of February–March, March–May and May–September were negatively correlated with bud-break, flowering and harvest dates, respectively. The trend analysis demonstrated that the change and variability of climate, due to global warming, directly affects the development of grapevine leading to an anticipation of all considered phenophases.

Effects of Treated Municipal Wastewater on Soil Chemical Properties and Heavy Metal Uptake by Sorghum (sorghum bicolor L.)

Abstract: In order to investigate the effect of treated municipal wastewater on soil chemical properties and heavy metal uptake by sorghum an experiment was carried out in the Institute of Agriculture at Zabol University, Iran 2007 in a randomized complete block design with four replications. The treatments were managed for irrigation; with well water during entire period of growing season as control (T1); wastewater during the first half of growing season (T2); wastewater during the second half of growing season (T3); wastewater and well water alternately (T4) and wastewater during entire period of growing season (T5). The results have indicated that irrigation with wastewater lead to significant increase in N, P, K, Ca, Na, Mg, SAR, EC, O.C% than control treatment (p ≤ 0.05). In addition, the increases of Zn, Fe, Mo in soil, and Cu, Fe in sorghum plant were statistically significant in comparison with control treatment (p≤0.01). The highest transfer coefficient was observed for Mo and Pb (1.28, 1.02), and the lowest for Cu (0.077) which highlight the high absorption power of sorghum toward these elements.

An assessment of greenhouse gas emissions: implications for the Australian cotton industry

Abstract: The majority of cotton produced in Australia is exported. The Australian cotton industry must maintain product quality in order to remain globally competitive. In addition, carbon-conscious consumers need reassurance that the system used to grow the product is environmentally sustainable. The aim of the present study was to estimate greenhouse gas (GHG) emissions due to various farm inputs in three common types of cotton farming systems on the Darling Downs region, southern Queensland. Analysis revealed that GHG emissions for dryland solid-plant and dryland double-skip cotton farming systems are similar, but emissions are much higher for irrigated solid-plant cotton farming (1367, 1274 and 4841 kg CO2e/ha, respectively). However, if comparisons of GHG emissions are based on yield (per tonne), the positions of dryland double-skip farming and dryland solid-plant farming are reversed, but the position of irrigated cotton farming still remains as the highest GHG emitter. If the cotton industry comes under the Australian Government Carbon Pollution Reduction Scheme (CPRS) without any subsidies and preconditions, and with a carbon price of A$25/t CO2e, the costs borne by each system would be A$66.8/t for the irrigated cotton industry, A$39.7/t for the dryland solid-plant cotton industry and A$43.6/t for the dryland double-skip cotton industry. This suggests that irrigated cotton would be more profitable in financial terms but with heavy environmental sustainability costs.

Growth and yield response of winter wheat to soil warming and rainfall patterns

Abstract: It is predicted that climate change will increase not only seasonal air and soil temperatures in northern Europe but also the variability of rainfall patterns. This may influence temporal soil moisture regimes and the growth and yield of winter wheat. A lysimeter experiment was carried out in 2008/09 with three factors: rainfall amount, rainfall frequency and soil warming (two levels in each factor), on sandy loam soil in Denmark. The soil warming treatment included non-heated as the control and an increase in soil temperature by 5 °C at 100 mm depth as heated. The rainfall treatment included the site mean for 1961-90 as the control and the projected monthly mean change for 2071-2100 under the International Panel on Climate Change (IPCC) A2 scenario for the climate change treatment. Projected monthly mean changes in rainfall compared to the reference period 1961-90 show, on average, 31 % increase during winter (November-March) and 24% decrease during summer (July-September) with no changes during spring (April-June). The rainfall frequency treatment included mean monthly rainy days for 1961-90 as the control and a reduced frequency treatment with only half the number of rainy days of the control treatment, without altering the monthly mean rainfall amount. Mobile rain-out shelters, automated irrigation system and insulated heating cables were used to impose the treatments. Soil warming hastened crop development during early stages (until stem elongation) and shortened the total crop growing season by 12 days without reducing the period taken for later development stages. Soil warming increased green leaf area index (GLAI) and above-ground biomass during early growth, which was accompanied by an increased amount of nitrogen (N) in plants. However, the plant N concentration and its dilution pattern during later developmental stages followed the same pattern in both heated and control plots. Increased soil moisture deficit was observed only during the period when crop growth was significantly enhanced by soil warming. However, soil warming reduced N concentration in above-ground biomass during the entire growing period, except at harvest, by advancing crop development. Soil warming had no effect on the number of tillers, but reduced ear number and increased 1000 grain weight. This did not affect grain yield and total above-ground biomass compared with control. This suggests that genotypes with a longer vegetative period would probably be better adapted to future warmer conditions. The rainfall pattern treatments imposed in the present study did not influence either soil moisture regimes or performance of winter wheat, though the crop receiving future rainfall amount tended to retain more green leaf area. There was no significant interaction between the soil warming and rainfall treatments on crop growth.

The Moisture Content Effect on Some Physical and Mechanical Properties of Corn (Sc 704)

Abstract: Physical and mechanical properties of grains are necessary for the designing the facility of storage, handling and processing of agricultural products. Physical and mechanical properties of corn grains were determined as a function of moisture content in the range of 4.73-22% w.b. (wet basis) using standard techniques. The average length, width, thickness, geometric mean diameter, equivalent diameter, arithmetic diameter, sphericity, angle of repose, grain volume, surface area and aspect ratio ranged from 11.62 to 12.60 mm, 7.27 to 7.98 mm, 4.47 to 4.71 mm, 7.20 to 7.77 mm and 7.63 to 7.96 mm, 7.77 to 8.43 mm, 62.31% to 62.00%, 49° to 58°, 209.66 to 265.00 mm3, 137.69 to 160.09 mm2 and 63.05% to 63.77% as the moisture content increased from 4.73-22% w.b. With increase in moisture content, the bulk density was found to decrease from 710 to 649 kgm-3 whereas true density and porosity increased from 1250 to 1325 kgm-3 and 43.2% to 51.02%. In the moisture range from 4.73% to 22% w.b., studies on rewetted corn grains showed that the thousand grain weight (TGW) increased linearly from 271.0 to 321.4 g. The static coefficient of friction of corn grains increased linearly against surfaces of three materials, namely, plastic (0.32–0.51), plywood (0.48–0.60) and galvanized iron (0.38–0.65) and the static angle of repose increased from 49o to 58o when the moisture content increased from 4.73% to 22% w.b. The mechanical properties of corn were determined in terms of average rupture force and rupture energy. Rupture energy of the corn grains generally increased in magnitude with an increase in moisture content, while rupture force decreased for compression.

A Comparison of the Antioxidant Properties and Total Phenolic Content in a Diatom, Chaetoceros sp. and a Green Microalga, Nannochloropsis sp.

Abstract: The aquaculture industry commonly makes use of microalgae as live feed. Chaetoceros sp., a diatom, and Nannochloropsis sp., a unicellular green microalga, have both been reported to contain a substantial amount of polyunsaturated fatty acids and carotenoids. Their potential as natural sources of antioxidants has gained recent attention. This study focuses on determining the antioxidant properties of the different solvent extracts, namely hexane, dichloromethane, chloroform and methanol, from both microalgae. The evaluation of antioxidant capacities was done by Folin-ciocalteu, 1,1-diphenyl-2-picrylhydrazyl radical-scavenging, metal chelating, nitro-blue tetrazolium reduction and ferric-reducing antioxidant power assay. Results showed that the non-polar solvent extracts from the diatom were highest in antioxidant power, whereas both polar and non-polar solvent extracts of green microalgae showed good antioxidant potential. In general, Chaetoceros sp. had higher antioxidant capacities than Nannochloropsis sp. This study suggests that different solvent extracts contain different potential antioxidant compounds able to scavenge different types of free radicals.

Effect of different physiological traits on grain yield in barley grown under irrigated and terminal water deficit conditions

Abstract: Drought is the main factor limiting the productivity of crops in Mediterranean areas. The introduction of physiological traits into crops that improve their tolerance to drought is necessary if yields under these conditions are to be efficiently improved. The effect of drought on different gas exchange variables, i.e. net photosynthesis (A), stomatal conductance (gs) and leaf chlorophyll concentration (Chl), and the relationship of these variables with yield were studied in 12 barley genotypes grown under irrigated and terminal drought conditions. The variable most sensitive to water deficit was gs (mean reduction 43% with respect to control conditions), followed by A (mean reduction 34%). The mean reduction of yield by terminal drought was 27%. A significant correlation was seen between these physiological traits and yield. The effect of water deficit on A, gs and Chl was smaller in the breeding lines than in the traditional varieties assayed, in agreement with the results found for yield. These results suggest a potential indirect selection of physiological characteristics in these breeding lines that allow greater tolerance to drought. The response of the different genotypes examined was not homogeneous across all the variables analysed. This variability is important in programmes aiming to obtain drought-tolerant genotypes via the optimization of traits such as those above.

Seasonal influences on the litter size at birth of pigs are more pronounced in the gilt than sow litters

Abstract: The aim of the present study was to use data from herds to demonstrate the degree of seasonal influence on litter size at birth in gilts compared to sow parities 2, 3–5 and older (parities ⩾6) in a conventional, open-housing system for commercial pig herds in the northeastern part of Thailand. Data were obtained during a 3-year period from July 2005 to June 2008. The data analysed included observations on 25 835 litters from 8100 sows. Total number of piglets born per litter (TB), number of piglets born alive per litter (BA), proportion of stillborn piglets per litter (SB) and proportion of mummified fetuses per litter (MF) were analysed using a general linear mixed model procedure. The influence of temperature, relative humidity and temperature-humidity index (THI) on TB, BA, MF and SB were also analysed. The meteorological data were merged with the reproductive data and the means of temperature, relative humidity and THI during 115 days before farrowing were calculated and included in the statistical models. The results revealed that sows that farrowed in the hot season had a larger TB and BA than sows that farrowed in the rainy (P 0·05). In conclusion, inferior litter size at birth was observed in sows that farrowed in either rainy or cool seasons. High temperature, high relative humidity and/or high THI during gestation significantly reduced the number of total piglets born per litter. The influence of season, temperature, relative humidity and/or THI on litter size at birth was more evident in the gilts than the sows. These data indicated that various strategies to reduce temperature in the open-housing system for pregnant gilts and sows in Thailand are not adequate and the proper housing of pregnant gilts should be emphasized.

Simulating the effects of grassland management and grass ensiling on methane emission from lactating cows.

Abstract: A dynamic, mechanistic model of enteric fermentation was used to investigate the effect of type and quality of grass forage, dry matter intake (DMI) and proportion of concentrates in dietary dry matter (DM) on variation in methane (CH4) emission from enteric fermentation in dairy cows. The model represents substrate degradation and microbial fermentation processes in rumen and hindgut and, in particular, the effects of type of substrate fermented and of pH on the production of individual volatile fatty acids and CH4 as end-products of fermentation. Effects of type and quality of fresh and ensiled grass were evaluated by distinguishing two N fertilization rates of grassland and two stages of grass maturity. Simulation results indicated a strong impact of the amount and type of grass consumed on CH4 emission, with a maximum difference (across all forage types and all levels of DMI) of 49 and 77% in g CH4/kg fat and protein corrected milk (FCM) for diets with a proportion of concentrates in dietary DM of 0·1 and 0·4, respectively (values ranging from 10·2 to 19·5 g CH4/kg FCM). The lowest emission was established for early cut, high fertilized grass silage (GS) and high fertilized grass herbage (GH). The highest emission was found for late cut, low-fertilized GS. The N fertilization rate had the largest impact, followed by stage of grass maturity at harvesting and by the distinction between GH and GS. Emission expressed in g CH4/kg FCM declined on average 14% with an increase of DMI from 14 to 18 kg/day for grass forage diets with a proportion of concentrates of 0·1, and on average 29% with an increase of DMI from 14 to 23 kg/day for diets with a proportion of concentrates of 0·4. Simulation results indicated that a high proportion of concentrates in dietary DM may lead to a further reduction of CH4 emission per kg FCM mainly as a result of a higher DMI and milk yield, in comparison to low concentrate diets. Simulation results were evaluated against independent data obtained at three different laboratories in indirect calorimetry trials with cows consuming GH mainly. The model predicted the average of observed values reasonably, but systematic deviations remained between individual laboratories and root mean squared prediction error was a proportion of 0·12 of the observed mean. Both observed and predicted emission expressed in g CH4/kg DM intake decreased upon an increase in dietary N:organic matter (OM) ratio. The model reproduced reasonably well the variation in measured CH4 emission in cattle sheds on Dutch dairy farms and indicated that on average a fraction of 0·28 of the total emissions must have originated from manure under these circumstances

The Utilization of Insect-resources in Chinese Rural Area

Abstract: Human beings' uncontrolled exploitation leads to the rapid consumption and depletion of many natural resources. Mankind is facing an unprecedented dilemma in survival and development. Searching, development and utilization of new natural resources will be an important way to solve the current problems. Insects, as an important natural resource needing to be further exploited, have aroused wide concerns and may play an important role in tackling food crisis and natural resources depletion. In China, insects have been being utilized for a long time as an important natural resource and there were lots of practices and experiences in the use of insect, especially in the rural regions. In this paper, we presented the current situation of insect utilization in Chinese rural regions and introduced edible insects being used by ethnic people in Yunnan province of China, the place which is special for its diversity in ethnic culture and folkways. In addition, constraints and prospects in using insect resources were discussed and analyzed as well. It was expected that the experiences in using insect resources in China could be helpful for other countries to promote the utilization of insect resources in near future.

Medicinal Plant Diversity and Vegetation Analysis of Logged over Hill Forest of Tekai Tembeling Forest Reserve, Jerantut, Pahang

Abstract: The study was carried out to analyze the species diversity and study of quantitative analysis of medicinal plantsin logged over forest in Tekai Tembeling Forest Reserve (TTFR). Four plots of 1-hectare size each wereestablished within the forest area. A total of 6788 individual medicinal trees and non trees representing 231species, 179 genera and 87 families were recorded. The species area curve did not approach an asymptotecondition. The regression equation to estimate species richness waswith r2=0.95%. The most diverse species for trees was Cinnamomum porrectum and Lygodium circinnatum fornon trees. The most diverse plot was plot 2 with 7335 individuals and 188 species. Since the forest area was diversein medicinal species, it is necessary to begin conservation assessment that will improve medicinal plantsbiodiversity.

Studies on the potential ecological risk and homology correlation of heavy metal in the surface soil.

Abstract: The present paper was attempted to investigate the distribution, the potential ecological hazards and the homologous relativity of heavy metals in soil of Fujian agricultural protection area on the both side of 324 National Road in Xiang'an of Xiamen City. We analyzed the content of heavy metals in the surface of farming soil using ICP-MS and evaluated the potential ecological hazard of heavy metals in the soil of agricultural protection zone in Xiang'an and further investigated the relevance of heavy metals in the soil by the classical Lars Hakanson potential ecological risk index method. Results showed that the potential ecological risk levels (hazard index) of eight kinds of heavy metals in Xiang'an area were classified in the order Cd (94.4)> Hg (54.3)> As (46.7)> Pb (10.5)> Cu (4.3)> Ni (3.1)> Cr (2.3)> Zn (1.9), and the global potential ecological risk index (HI) of heavy metal was 216.8. The comprehensive evaluation of potential ecological risk of agricultural safety belonged to the moderate level. The major pollutants in this area were Cd and Pb, which attained the middle ecological hazard level. Through the correlation analysis of heavy metals, we found that the main external sources of pollution were the waste gas after the combustion of petrol and diesel, the excessive application of pesticides and so on. The internal source of pollution was the high background values of new cover soil.

Is rainfed crop production in central Europe at risk? Using a regional climate model to produce high resolution agroclimatic information for decision makers

Abstract: The reality of climate change has rarely been questioned in Europe in the last few years as a consensus has emerged amongst a wide range of national to local environmental and resource policy makers and stakeholders that climate change has been sufficiently demonstrated in a number of sectors. A number of site-based studies evaluating change of attainable yields of various crops have been conducted in Central Europe, but studies that evaluate agroclimatic potential across more countries in the region are rare. Therefore, the main aim of the present study was to develop and test a technique for a comprehensive evaluation of agroclimatic conditions under expected climate conditions over all of Central Europe with a high spatial resolution in order to answer the question posed in the title of the paper ‘Is rainfed crop production in central Europe at risk?’ The domain covers the entire area of Central Europe between latitudes 45° and 51·5°N and longitudes 8° and 27°E, including at least part of the territories of Austria, the Czech Republic, Germany, Hungary, Poland, Romania, Slovakia, Switzerland and Ukraine. The study is based on a range of agroclimatic indices that are designed to capture complex relations existing between climate and crops (their development and/or production) as well as the agrosystems as a whole. They provide information about various aspects of crop production, but they are not meant to compete with other and sometimes more suitable tools (e.g. process-based crop models, soil workability models, etc.). Instead, the selected indices can be seen as complementary to crop modelling tools that describe aspects not fully addressed or covered by crop models for an overall assessment of crop production conditions. The set of indices includes: sum of effective global radiation, number of effective growing days, Huglin index, water balance during the period from April to June (AMJ) and during the summer (JJA), proportion of days suitable for harvesting of field crops in June and July, and proportion of days suitable for sowing in early spring as well as during the autumn. The study concluded that while the uncertainties about future climate change impacts remain, the increase in the mean production potential of the domain as a whole (expressed in terms of effective global radiation and number of effective growing days) is likely a result of climate change, while inter-annual yield variability and risk may also increase. However, this is not true for the Pannonian (the lowlands between the Alps, the Carpathian Mountains and the Dinaric Alps) and Mediterranean parts of the domain, where increases in the water deficit will further limit rainfed agriculture but will probably lead to an increase in irrigation agriculture if local water resources are dwindling. Increases in the severity of the 20-year drought deficit and more substantial water deficits during the critical part of the growing season are very likely over the central and western part of the domain. Similarly, the inter-annual variability of water balance is likely to increase over the domain. There is also a chance of conditions for sowing during spring deteriorating due to unfavourable weather, which might increase the preference given to winter crops. This is already likely due to their ability to withstand spring drought stress events. Harvesting conditions in June (when harvest of some crops might take place in the future) are not improving beyond the present level, making the planning of the effective harvest time more challenging. Based on the evidence provided by the present study, it could be concluded that rainfed agriculture might indeed face more climate-related risks, but the overall conditions will probably allow for acceptable yield levels in most seasons. However, the evidence also suggests that the risk of extremely unfavourable years, resulting in poor economic returns, is likely to increase.

Effects of Nitrogen, Phosphorus and Potassium Levels on Kenaf (Hibiscus cannabinus L.) Growth and Photosynthesis under Nutrient Solution

Abstract: To date, little is known about the effect of levels of nitrogen, phosphorus and potassium on kenaf grown innutrient solution culture. The objective of the present study was to examine the effects of different nitrogen,phosphorus and potassium levels on kenaf growth such as diameter, plant height, leaf number, root dry weight,stem dry weight and leaf dry weight and physiology like chlorophyll content, photosynthesis and stomatalconductance. Treatment consisted of 5 different levels of nitrogen viz. 0, 50, 100, 200 and 400 mg/L and 5different levels of phosphorus and potassium viz. 0, 25, 50, 100 and 200 mg/L replicated thrice in a completelyrandomized design in a shade house. Growth (diameter, plant height and leaf number), chlorophyll content andphotosynthesis were measured once weekly and plant components biomass was measured, 28 DAT. Differentlevels of nitrogen, phosphorus and potassium had significant effects on all the parameters studied. The highestvalues for diameter, plant height, leaf number, root dry weight, stem dry weight, leaf dry weight, photosynthesisand stomatal conductance were obtained from 200N, 100P and 100K whereas values decreased with furtherincrease in levels of nutrient concentration. All the growth rates, chlorophyll content and photosynthesis declinedwith lower level of nitrogen, phosphorus and potassium. Among the plant components, leaf dry weight had thegreatest decrease while root/shoot ratio increased under N deficiency. The results of this study provide newknowledge to produce kenaf with better nutrient management in the field.

Combining Ability Studies for Development of New Hybrids in Rice over Environments

Abstract: Combining ability study on grain yield and its components from line x tester analysis over the locations of five well adapted CMS lines and twenty three testers of different eco-geographic origin revealed higher SCA variance than GCA variance for all the traits indicating the prevalence of non-additive gene action. The lines APMS 6A, PUSA 5A and CRMS 32A and testers 1096, 1005, IBL-57 and SC5 9-3 were the good general combiners for yield and its majority of the traits. IBL-57 was the only good general combiner among the male parents for earliness, dwarfness and grain yield per plant. The hybrids APMS 6A x SC5 9-3, APMS 6A x 1005 and APMS 6A x GQ 25 were identified as potential one for yield and desired traits based on sca effects.

The impact of relative humidity, genotypes and fertilizer application rates on panicle, leaf temperature, fertility and seed setting of rice.

Abstract: A series of field and plant growth chamber experiments were conducted in 2006 and 2007 to study how relative humidity (RH), genotypes and nitrogen application rates affect organ temperatures and spikelet fertility rates in rice. It was observed that organ temperatures varied with air temperature, RH, genotype and nitrogen application rate. Increases in RH at constant air temperature and increasing air temperature with a constant RH both increased organ temperatures significantly. Cultivars also exhibited differences in organ temperatures; those cultivars with erect panicles recorded lower organ temperatures than those with droopy panicles under similar climatic conditions. Similarly, cultivars with panicles above the flag leaf had lower temperatures at the panicle when compared to those plants with the panicle below the flag leaf. It was also found that panicle temperature showed a significant negative correlation with both grain filling rate and seed setting rate. Spikelet fertility could be maintained by reducing spikelet temperature under decreasing RH in a high-temperature environment. Panicle fertilizer application rates had a significant effect on the organ and canopy temperatures. The canopy temperature of rice grown with an ample supply of nitrogen was generally cooler than the canopy temperature of a nitrogen-deficient treatment.

Wheat Production in India: Technologies to Face Future Challenges

Abstract: To meet the growing demands under the constrains of depleting natural resources, environmental fluctuation and increased risk of epidemic outbreak, the task of increasing wheat production has become daunting. The euphoria generated by first green revolution is very quickly subsiding and the second generation problems are becoming more intense with each passing year. The factors responsible for first green revolution seem to be exhausting rapidly and there is immediate need to develop the technologies which can not only increase the wheat production but also sustain at higher level without adversely affecting the natural resources. More investment on germplasm improvement, conservation agriculture including breeding for varieties adaptive to conservation agriculture, hybrid wheats, broadening the genetic base of the varieties at farmers level, wide scale utilization of alien translocations in the breeding programme along with integration of marker assisted selection and other innovative approaches with traditional breeding methods are some of the technologies which can yield dividend in the coming years.

Mineral Nitrogen and Microbial Biomass Dynamics under Different Acid Soil Management Practices for Maize Production

Abstract: Field and laboratory incubation studies were conducted to determine the effect of different acid soil managementpractices; liming (L), combined N and P fertilizers (NP), and goat manure (M) application, for maize production on thedynamics of mineral N, microbial biomass nitrogen (MBN) and microbial biomass carbon (MBC). A randomisedcomplete block design with a 23 factorial arrangement replicated thrice was used. The factors, each at two levels, were:NP fertilizers applied as triple superphosphate (0 and 75 kg ha-1), and urea (0 and 50 kg ha-1), L (0 and 2.5 t ha-1) and M(0 and 5 t ha-1) giving a total of eight treatments; L, M, NP, LM, LNP, MNP, LMNP and C (control). Soil samples fordetermination of mineral N, MBC and MBN were collected from the 0-15 and 15-30 cm depths at seedling, tasselling,and maturity stages of maize growth and after 0, 15, 30, 60, 120 and 240 days of laboratory incubation of soils obtainedfrom the same field.The NP treatment had significantly (P< 0.5) higher levels of mineral N in both depths at all stages of maize growth,followed by MNP and LMNP. The net mineralized N (?gN/g dry soil) for the incubated soil followed the order LMNP,MNP, LM, M, L, LNP, C and NP for the two depths. The MNP, LMNP and M treatments had significantly higher MBCand MBN for both field and incubated soils. The correlations between mineral N and MBN were positive butnon-significant at seedling and maturity stages of maize growth in the 0-15 cm depth and at seedling and tassellingstages in the 15-30 cm depth. The correlations between MBN and Mineral N for both depths and sampling periods werepositive and significant for the incubated soils, The maize grain yield increases (%) above control were 43, 36.4, 31.1,25.3, 21.9, 13.7 and 3.0 for LMNP, MNP, NP, M, LNP, LM and L treatments, respectively.Application of LMNP and MNP treatments enhanced mineral N, MBC and MBN and concomitantly soil quality andproductivity as gauged from the improved maize yields in the respective treatments. Combining manure, lime andchemical fertilizers and /or manure and chemical fertilizers is thus a promising alternative to developing a moresustainable acid soil management strategy for increased maize production in Molo district, Kenya.

Application of a model to assess aflatoxin risk in peanuts.

Abstract: When exposed to hot (22-35 degrees C) and dry climatic conditions in the field during the final 4-6 weeks of pod filling, peanuts (Arachis hypogaea L.) can accumulate highly carcinogenic and immuno-suppressing aflatoxins. Forecasting of the risk posed by these conditions can assist in minimizing pre-harvest contamination. A model was therefore developed as part of the Agricultural Production Systems Simulator (APSIM) peanut module, which calculated an aflatoxin risk index (ARI) using four temperature response functions when fractional available soil water was 15 mu g/kg) of peanuts in the Kingaroy region of Australia during the period between the 1998/99 and 2007/08 seasons. Simulation of ARI using historical climatic data from 1890 to 2007 indicated a three-fold increase in its value since 1980 compared to the entire previous period. The increase was associated with increases in ambient temperature and decreases in rainfall. To facilitate routine monitoring of aflatoxin risk by growers in near real time, a web interface of the model was also developed. The ARI predicted using this interface for eight growers correlated significantly with the level of contamination in crops (r=095, P <= 0.01). These results suggest that ARI simulated by the model is a reliable indicator of aflatoxin contamination that can be used in aflatoxin research as well as a decision-support tool to monitor pre-harvest aflatoxin risk in peanuts.