Showing papers in "The Journal of Agricultural Science in 2015"

The soybean yield gap in Brazil – magnitude, causes and possible solutions for sustainable production

Abstract: Brazil is one of the most important soybean producers in the world. Soybean is a very important crop for the country as it is used for several purposes, from food to biodiesel production. The levels of soybean yield in the different growing regions of the country vary substantially, which results in yield gaps of considerable magnitude. The present study aimed to investigate the soybean yield gaps in Brazil, their magnitude and causes, as well as possible solutions for a more sustainable production. The concepts of yield gaps were reviewed and their values for the soybean crop determined in 15 locations across Brazil. Yield gaps were determined using potential and attainable yields, estimated by a crop simulation model for the main maturity groups of each region, as well as the average actual famers’ yield, obtained from national surveys provided by the Brazilian Government for a period of 32 years (1980–2011). The results showed that the main part of the yield gap was caused by water deficit, followed by sub-optimal crop management. The highest yield gaps caused by water deficit were observed mainly in the south of Brazil, with gaps higher than 1600 kg/ha, whereas the lowest were observed in Tapurah, Jatai, Santana do Araguaia and Uberaba, between 500 and 1050 kg/ha. The yield gaps caused by crop management were mainly concentrated in South-central Brazil. In the soybean locations in the mid-west, north and north-east regions, the yield gap caused by crop management was 2000 kg/ha. For reducing the present soybean yield gaps observed in Brazil, several solutions should be adopted by growers, which can be summarized as irrigation, crop rotation and precision agriculture. Improved dissemination of agricultural knowledge and the use of crop simulation models as a tool for improving crop management could further contribute to reduce the Brazilian soybean yield gap.

Carbon footprint of crop production in China: an analysis of National Statistics data

Abstract: Assessing carbon footprint (CF) of crop production in a whole crop life-cycle could provide insights into the contribution of crop production to climate change and help to identify possible greenhouse gas (GHG) mitigation options. In the current study, data for the major crops of China were collected from the national statistical archive on cultivation area, yield, application rates of fertilizer, pesticide, diesel, plastic film, irrigated water, etc. The CF of direct and indirect carbon emissions associated with or caused by these agricultural inputs was quantified with published emission factors. In general, paddy rice, wheat, maize and soybean of China had mean CFs of 2472, 794, 781 and 222 kg carbon equivalent (CE)/ha, and 0·37, 0·14, 0·12 and 0·10 kg CE/kg product, respectively. For dry crops (i.e. those grown without flooding the fields: wheat, maize and soybean), 0·78 of the total CFs was contributed by nitrogen (N) fertilizer use, including both direct soil nitrous oxide (N2O) emission and indirect emissions from N fertilizer manufacture. Meanwhile, direct methane (CH4) emissions contributed 0·69 on average to the total CFs of flooded paddy rice. Moreover, the difference in N fertilizer application rates explained 0·86–0·93 of the provincial variations of dry crop CFs while that in CH4 emissions could explain 0·85 of the provincial variation of paddy rice CFs. When a 30% reduction in N fertilization was considered, a potential reduction in GHGs of 60 megatonne (Mt) carbon dioxide equivalent from production of these crops was projected. The current work highlights opportunities to gain GHG emission reduction in production of crops associated with good management practices in China.

Chlorophyll estimation in field crops: an assessment of handheld leaf meters and spectral reflectance measurements

Abstract: The widespread adoption by agronomists and researchers of handheld leaf chlorophyll meters stimulates enquiries on instrumental calibration issues, given the necessity, for some applications, of inferring actual chlorophyll concentrations from the readings provided. This is especially required for recently developed and more innovative devices such as the Dualex (Force-A, France), which unlike the more common SPAD-502 (Minolta, Japan) has not undergone extensive (published) calibration tests. Additionally, devices for spectral reflectance measurements are also becoming increasingly available. In the present paper, the calibration of SPAD on maize (Zea mays L.) and of Dualex on winter wheat (Triticum aestivum L.), durum wheat (Triticum durum Desf.), horse bean (Vicia faba L.) and maize, was compared to spectral reflectance indices and full spectral information (400–2500 nm) acquired by a spectroradiometer (ASD FieldSpec) equipped with a contact probe and leaf clip. Full spectral data were exploited using partial least squares regression (PLSR). The measurements were performed in the field at Maccarese (Central Italy) in 2012, gathering a specific experimental dataset. The calibration models obtained on experimental data for SPAD (on maize) and Dualex (on four crops) showed intermediate or high estimation accuracy with root-mean-square error (RMSE) values ranging between 7 and 11 μg/cm2 depending on the species. These results were slightly better than those achieved using spectral reflectance indices, which were inferior though to those provided by PLSR using full spectral resolution. A synthetic database, generated by the physically based PROSPECT model, simulating hemispherical leaf reflectance and transmittance, was used to compare the performances of the reflectance indices and the chlorophyll meters for a wider range of leaf properties. The results confirmed the substantial equivalence of reflectance-based and transmittance-based (i.e. simulated SPAD and Dualex) indices and the advantage of exploiting the full spectral information, e.g. through PLSR, if available.

Maize yield forecasting by linear regression and artificial neural networks in Jilin, China

Abstract: Forecasting the maize yield of China's Jilin province from 1962 to 2004, with climate conditions and fertilizer as predictors, was investigated using multiple linear regression (MLR) and non-linear artificial neural network (ANN) models. Yield was set to be a function of precipitation from July to August, precipitation in September and the amount of fertilizer used. Fertilizer emerged as the dominant predictor and was non-linearly related to yield in the ANN model. Given the difficulty of acquiring fertilizer data for maize, the current study was also tested using the previous year's yield in the place of fertilizer data. Forecast skill scores computed under both cross-validation and retroactive validation showed ANN models to significantly outperform MLR and persistence (i.e. forecast yield is identical to last year's observed yield). As the data were non-stationary, cross-validation was found to be less reliable than retroactive validation in assessing the forecast skill.

Influence of exogenous enzymes in presence of Salix babylonica extract on digestibility, microbial protein synthesis and performance of lambs fed maize silage

Abstract: Sixteen Suffolk lambs with 29 ± 2·0 kg body weight were housed in individual cages for 60 days and allotted to four treatments in a completely randomized design to determine the effect of administration of Salix babylonica (SB) extract and/or exogenous enzymes (ZADO®) on lamb performance. Lambs were fed with 300 g/kg concentrate (160 g crude protein (CP)/kg, 13·4 MJ metabolizable energy (ME)/kg dry matter (DM)) and 700 g/kg maize silage (80 g/kg CP, 11·7 MJ ME/kg DM) as a basal diet (control). Another three treatments were tested; the SB extract was administered at 30 ml/day (SB) and exogenous enzymes ZADO® (i.e. an exogenous enzyme cocktail in a powder form) directly fed at 10 g/day (EZ), while the last treatment contained ZADO® at 10 g/day + SB extract at 30 ml/day (EZSB). Lambs of the treatment EZSB had the greatest average daily weight gain (ADG) and feed conversion throughout the period of the experiment. However, during the first 30 days SB was more effective for ADG than EZ and vice versa during the last 30 days of the experiment. Water consumption was greater for SB, followed by EZ and EZSB compared to the control. Intakes of DM and organic matter (OM) were the highest in EZSB followed by EZ, which had the greatest neutral detergent fibre, acid detergent fibre (ADF) and nitrogen (N) intakes. The EZSB treatment had the greatest DM and OM digestibilities compared to the other treatments; however, SB had the greatest ADF digestibility. Combination of EZ and SB had the best N balance. Allantoin, total purine derivatives (PD), allantoin : -creatinine ratio, and PD : creatinine ratio were increased in EZSB compared to the other treatments. However, EZ supplementation increased uric acid concentration, whereas the microbial N (g N/day) and metabolizable protein (g N/day) were increased in EZSB versus the other treatments. It can be concluded that addition of 10 g ZADO® in combination with S. babylonica extract at 30 ml/day in the diet of lambs increased feed intake, nutrient digestibility and daily gain, with a positive impact on the use of N and microbial protein synthesis.

Adapting to the Impacts of Drought by Smallholder Farmers in Sekhukhune District in Limpopo Province, South Africa

Abstract: Smallholder farmers have been affected by drought impacts for several years. Sekhukhune district is characterized by poor and unreliable rainfall, frequent droughts and periodic flooding most of the time. Due to low and unreliable rainfall the smallholder farmers in the Sekhukhune district are finding it difficult to obtain high crop yields. As result of unreliable rainfall the majority of the households in the district are food insecure. The drought impacts in the Sekhukhune district has affected smallholder farmers in different ways including economically, socially and the production. Sekhukhune district has been receiving lower rainfall due to the effects of high extreme climatic events, climate variability and change. The impact of lower rainfall has negative effects on the agricultural sector, resulting in decrease in agricultural activities, loss of livestock, shortage of drinking water, low yields and shortage of seeds for subsequent cultivation in the district. The lowest average annual rainfall recorded was 438 mm in 1992. Limpopo Province including the Sekhukhune district has been characterised by low rainfall and recurrent drought problems especially in 1981/1984, 1988/1989, 1991/92 and in the 2004 and these hinder agricultural production in the province. The majority of farmers in the Sekhukhune district in 1992 lost high volumes of crops and livestock due to shortages of water and because of drought problems during that year. It was highlighted by several experts that the drought impacts in the Sekhukhune district are not only affecting the crop and the livestock smallholders, it is also affecting the vegetation status in the district. The quality and status of vegetation can be severely impacted by drought periods. The combination of these factors, for example low rainfall, poor vegetation condition and a range of other constraints, heightened during droughts, unfortunately produces a range of additional stressors for farmers in the Sekhukhune district. Poor vegetation usually means poor grazing and therefore poor cattle condition. This can further translate into loss of livelihoods as poor cattle often receive poor market prices.

Screening Flavonoids for Inhibition of Acetylcholinesterase Identified Baicalein as the Most Potent Inhibitor

Abstract: Screening phenolic and polyphenolic compounds for inhibitory activity against electric eels acetylcholinesterase (AChE) identified baicalein, a major flavone derived from the roots of Scutellaria baicalensis, as the most potent inhibitor with IC50 (concentration required for 50% inhibition) of 0.61 µM. None of the hydroxybenzoic and hydroxycinnamic acids screened showed inhibitory activity measured at 100 µM. Structure-activity relationships based on IC50 values of the active flavonoids showed that inhibitory activity (a) required the unsaturated 2-phenyl-chroman structure, (b) has strong requirement for the A-ring A5-OH, A6-OH and A7-OH groups (b) does not depend on B-ring hydroxyl groups, and (d) was reduced by bulky sugar substitution of the saturated C-ring C3-OH. Enzyme kinetic analysis showed that baicalein is a mixed inhibitor of AChE with K1 (equilibrium constant of dissociation of the inhibitor bound enzyme complex) and K2 (equilibrium constant of dissociation of the inhibitor bound enzyme-substrate complex) of 0.91 and 1.98 µM, respectively.

Assessment of Multiple Tolerance Indices for Salinity Stress in Bread Wheat (Triticum aestivum L.)

Abstract: Salinity is one of the major factors reducing plant growth and productivity worldwide and affects about 7% of world’s total land area. In India about 6.73 million hectare of land area is salt affected. Wheat is the second most important crop after rice in India and occupies approximately 28.5 million hectare area. Several tolerance indices comprising of mean productivity (MP), geometric mean productivity (GMP), stress tolerance index (STI), stress stability index (SSI), tolerance index (TOL), yield index (YI) and yield stability index (YSI) were calculated in this investigation for salinity and its ability to understand which one or more predictor among studied indices based on correlation, principal component analysis and cluster analysis. Ten wheat genotypes were evaluated in two successive growing seasons (2012-2014), with complete randomized design with three replications under both salinity stress and non-salinity to identify salt tolerant genotypes to the target environment. Multiple indices for salt tolerance were calculated based on the potential yield (Yp) under non-stress and yield (Ys) under stress conditions. The Ys and Yp showed highest significant and positive correlations with GMP, MP and STI among indices studied. Therefore, these indices were considered as a better predictor of Ys and Yp than TOL, SSI and YSI. Principal component analysis classified the genotypes into two groups. The first two PCs with eigen values >1 contributed 99.74% of the variability amongst genotypes. PC1 accounted for about 5.24% of the variation in salt tolerance indices and PC2 for 3.74%. The first PC was related to Ys, Yp, MP, GMP, STI and YI whereas the second PC related to Yp, TOL and SSI. The cluster analysis sequestrated ten genotypes into two clusters based on Ward’s method. According to results, salinity significantly reduced the yield of some genotypes while some were found tolerant to stress indicating sufficient genetic variability for salinity tolerance among the studied genotypes. It could be implicated in selection of salinity tolerant wheat genotypes for the development of bread wheat varieties.

Relative Efficiency of Zinc-Coated Urea and Soil and Foliar Application of Zinc Sulphate on Yield, Nitrogen, Phosphorus, Potassium, Zinc and Iron Biofortification in Grains and Uptake by Basmati Rice (Oryza sativa L.)

Abstract: Two on-farm trials conducted one each in Aligarh and Meerut districts of the state of Uttar Pradesh, India on zinc (Zn) deficient soils during the rainy season (July-October) showed that Zn application increased not only Zn concentration and uptake by rice but also increased protein content of rice kernels and concentrations of Fe, N, P and K due to the overall improvement in crop growth. Foliar application of Zn was better from the viewpoint of Zn biofortification of rice kernels; nevertheless much of the foliar applied Zn was retained in husk. Since, foliar application of Zn is made at a late stage of crop growth, hence it was not as effective as soil application in increasing yield attributes, yield and concentration and uptake of Fe, N, P and K in rice. This study brought out that adequate soil application of Zn sulphate followed by its foliar application is the best approach. Zn coated urea applying less than half the amount of Zn as applied through soil + foliar application was very close to it and is quite promising.

Distribution and analysis of the mechanisms of resistance of barnyardgrass ( Echinochloa crus-galli ) to imidazolinone and quinclorac herbicides

Abstract: SUMMARY The lack of control of barnyardgrass in flooded rice cultivated with imidazolinone-resistant rice cultivars is challenging the utilization of this system, which is continuously expanding for new rice areas worldwide. The objectives of the present study were to evaluate the frequency, distribution and mechanisms of imidazolinone resistance in barnyardgrass to establish the best practices to control and prevent this problem. The distribution of resistance was evaluated in 624 populations collected in Southern Brazil. The frequency of imidazolinoneherbicide resistance was 0·81, broadly distributed in all sampled regions. Resistance to quinclorac was also found in0·19ofthe populations, butalloftheevaluatedpopulationsweresusceptible tocyhalofop-butyl. Further studies were conducted in six populations. The enhanced metabolism was assessed with the metabolic inhibitors that reversed the resistance to quinclorac from 0·54 to 1·00 in two populations and the resistance to imazethapyr from 0·15 to 0·41 in three populations. The acetolactase synthase (ALS) enzyme activity also indicated the occurrence of altered target site resistance in two populations caused by the ALS gene mutations Trp574Leu and Ser653Asn, which is a novel finding in this species. The herbicide resistance in barnyardgrass in Southern Brazil presented a complex basis of resistance because it is associated with resistance to multiple herbicides due to multiple mechanisms and with multiple mutations of the ALS gene. This indicates that it is necessary to adopt specific measures to prevent and control the evolution of multiple herbicide resistance in this species.

Crop Evapotranspiration (ET) Estimation Models: A Review and Discussion of the Applicability and Limitations of ET Methods

Abstract: This is a review paper on existing methodologies to calculate crop evapotranspiration (ETc). We have attempted to present all the important ET estimation procedures to date starting from the simple empirical Blaney Criddle method to the complex Shuttleworth model. The common approach to calculate ETc is to estimate a reference crop ET rate (ETref) using weather variables from nearby weather station, and multiplying it by an appropriate crop coefficient (Kc). Recently, there have been attempts to calculate actual crop ET (ETa) directly without using Kc. The latter method is still in the developmental phase. This study reviews the existing literature on ET estimation and identifies research needs in the current methods and technology. The extension of the Shuttleworth model for hourly time step and the validity of the Irmak and Mutibwaa model at field level for various crops would be a good milestone for the one step ET estimation. Furthermore, there are indications that the development of a new variable canopy surface resistance (rc) model, which can be applicable for different crops at different climatic conditions, would be a good contribution in this field.

Examining the potential for climate change mitigation from zero tillage

Abstract: The benefits of reduced and zero-tillage systems have been presented as reducing runoff, enhancing water retention and preventing soil erosion. There is also general agreement that the practice can conserve and enhance soil organic carbon (C) levels to some extent. However, their applicability in mitigating climate change has been debated extensively, especially when the whole profile of C in the soil is considered, along with a reported risk of enhanced nitrous oxide (N2O) emissions. The current paper presents a meta-analysis of existing literature to ascertain the climate change mitigation opportunities offered by minimizing tillage operations. Research suggests zero tillage is effective in sequestering C in both soil surface and sub-soil layers in tropical and temperate conditions. The C sequestration rate in tropical soils can be about five times higher than in temperate soils. In tropical soils, C accumulation is generally correlated with the duration of tillage. Reduced N2O emissions under long-term zero tillage have been reported in the literature but significant variability exists in the N2O flux information. Long-term, location-specific studies are needed urgently to determine the precise role of zero tillage in driving N2O fluxes. Considering the wide variety of crops utilized in zero-tillage studies, for example maize, barley, soybean and winter wheat, only soybean has been reported to show an increase in yield with zero tillage (7·7% over 10 years). In several cases yield reductions have been recorded e.g. c. 1–8% over 10 years under winter wheat and barley, respectively, suggesting zero tillage does not bring appreciable changes in yield but that the difference between the two approaches may be small. A key question that remains to be answered is: are any potential reductions in yield acceptable in the quest to mitigate climate change, given the importance of global food security?

Effects of Drought Stress on Seed Germination and Seedling Growth of Different Maize Varieties

Abstract: Maize is susceptible to drought stress, especially during germination. The experiment of seed germination and seedling growth of two maize varieties under different concentration of mannitol solution was carried out. Four mannitol concentrations were set: 0, 200, 400 and 600 mM, and the corresponding solution osmotic potential was: 0, -0.49, -0.99, and -1.49 Mpa. Results indicated that Zhengdan958 germinated more quickly and in greater numbers than Liansheng15. The germination rate, germination potential, shoot and root fresh weight, shoot and root length of two maize varieties both decreased under drought stress, but they decreased more in Liansheng15 than in Zhengdan958. However, the germination and vigor index of Zhengdan958 were obviously higher than that of Liansheng15 under the stress of 200, 400 and 600 mM mannitol. These results showed that the drought resistances of Zhengdan958 was higher than that of Liansheng15 by having more powerful root system and higher osmotic adjustment ability.

Influence of cellulase addition to dairy goat diets on digestion and fermentation, milk production and fatty acid content

Abstract: Twenty four French Alpine goats (39 ± 2·0 kg) were individually housed in a completely randomized design and fed a basal diet containing 146 g crude protein and 356 g neutral detergent fibre (NDF)/kg in the absence (control – CTRL) or presence (CELL) of 2 ml of cellulase/kg dry matter intake (DMI) for 70 days, which included a 10-day adaptation period. The feed was offered three times daily at 07·00, 13·00 and 19·00 h, but the single daily dose of cellulase was only fed at 07·00 h. Goats were hand-milked daily; milk production recorded and samples taken for compositional analysis. During the last 5 days of the experimental period, goats from each group were individually housed in stainless steel metabolic cages to enable separate and total collection of faeces and urine for nutrient digestibility and ruminal fermentation determinations. Goats fed CELL had greater DMI and greater digestibility of dry matter (DM), organic matter and NDF than CTRL goats. CELL goats had greater ruminal pH, concentration of acetic acid and concentration of propionic acid than CTRL goats. However, the concentration of ruminal butyric was lower in CELL goats compared with CTRL goats. CELL goats had greater milk yield, energy corrected milk, milk energy content, milk energy output and milk density than CTRL goats and the milk content for total solids, fat, protein and lactose were also greater for CELL goats than for the CTRL goats. The milk of CELL goats had greater palmitoleic acid, c is -10-heptadecanoic acid content and mono-saturated acids than the milk of CTRL goats and lower linoleic acid, linolenic acid contents and saturated fatty acids than the milk of CTRL goats. These results suggest that addition of 2 ml cellulase/kg DM of feed in the diet of lactating French Alpine goats elevated their milk production and improved its composition probably due to improved feed utilization.

Economic Analysis of the Role of Farmer Organizations in Enhancing Smallholder Potato Farmers’ Income in Middle Guinea

Abstract: Farmers’ organizations are inclusive of the poor and are charged with the purpose of becoming a market outlet for smallholder farmers in Guinea. Improving farmers’ income earning capability and agricultural productivity has been an important strategy of Guinea’s agriculture development policy. However, despite their growing importance, empirical studies on how farmers’ organizations have impacted their members’ income are limited in Guinea. This paper investigates the determinants and effects on farm income of group membership, using the sample of 90 smallholder potato producers in Middle Guinea. A probit model was used as a selection equation to identify factors that influence group membership decision by smallholder potato farmers. The results revealed that the age of the potato farmers, land ownership, extension service, credit access and off-farm income are positively associated with group membership while gender and education level of the farmer negatively influenced their decision to join farmer groups. Results of the second stage outcome equation found positive farm income effects of group membership. Furthermore, results revealed that farm income is predominantly determined by labor used, the size of the cultivated potato area, share of potato sold and potato market price. Since farmers are resource-poor and that farmer organizations are constrained by various institutional, technical and investment constraints despite their potential, it is recommended that favorable polices should be geared toward smallholder agriculture in Guinea in order to ensure the success of farmer organizations. Our results show that farmer groups can be an important institution for the transformation of smallholder farming, increase productivity and incomes thereby reducing poverty. Agricultural policies in Guinea should therefore focus more on the intensification of agriculture and farmers’ organizations and increase the market orientation of the smallholder farm sector.

Evaluation of Growth Performance, Haematological and Serum Biochemical Response of Broiler Chickens to Aqueous Extract of Ginger and Garlic

Abstract: An experiment which lasted for 56 days was carried out to investigate the growth performance, haematological and serum biochemical response of broiler chickens to aqueous extract of ginger and garlic. Eighty day-old Marshal Strain broiler chickens were used for the experiment. The birds were randomly allotted into four treatment groups consisting of four replicates with five birds per replicate. The aqueous extract was obtained by infusing 14 g of each test ingredient in 1 litre of hot boiled water for 12 hours and 50 ml of the filtrate/litre of drinking water given to birds’ ad-libitum. T1 (control), T2, T3, and T4 contained 0, and 50 mls of ginger, garlic and a 1:1 ratio mixture of ginger and garlic in drinking water respectively. T2 gave the best performance (p 0.05) while there was significant increase in the total protein, albumin, and globulin of the treated birds (p < 0.01). Administration of ginger and garlic to broiler chickens increased their performance, boosted their immunity as well as improved their general well-being. It is, thus, recommended in broiler chicken production.

Farmer Preferences for Coffee Certification: A Conjoint Analysis of the Indonesian Smallholders

Abstract: Most coffee certification schemes are developed by Northern-based businesses and NGOs to regulate the production of coffee in the South. It is questionable whether these Northern-driven standards correspond to the preferences of coffee farmers in the South. Understanding farmer preferences and taking them into account when developing or improving certification schemes is believed to lead to more internalized, and therefore more effective standards. However, there is a lack of information on farmer’s preferences, both in the academic literature as well as with the certification programs themselves. Based on conjoint analysis and interviews, this paper investigates the preferences of coffee smallholder farmers in Indonesia. The smallholders surveyed include farmers registered with global certification schemes (i.e. Rainforest Alliance, Utz certified, and 4C), a local certification scheme (Inofice) and uncertified farmers. Results indicate that farmers in the different groups do not differ much in terms of their preferences. Moreover, although farmers value environmental conservation, their preferences regarding certification are mainly economically driven. This leads us to conclude that sustainability certification of coffee is only weakly institutionalized in the farmer’s context.

Pig slurry characteristics, nutrient balance and biogas production as affected by separation and acidification

Abstract: Animal slurry is separated in order to avoid excessive nitrogen, phosphorus and potassium (NPK) fertilization of crops in the field. To enhance fertilizer efficiency further, slurry and its separation products may be acidified, for instance in animal houses. The current study quantified the effects of these treatments, both individually and in combination, on fertilizer efficiency, energy production and heavy metal accumulation as a result of manure management. Acidification increased the availability of N to plants in the manure applied, and provided a better match between plant-available NPK in the manure and separation fraction applied to fields and crop need. Total biogas production was not affected by separation, whereas acidification reduced biogas production because the process was inhibited by a low pH and a high sulphur concentration. The amount of copper applied per hectare in the liquid manure to the wheat field was lower than the amount taken up and more zink and copper was applied in the solid fraction to maize field than taken up. The transportation and field application of solids and liquids did not increase management costs when compared to the transportation of slurry alone, but the investment and running costs of separators and manure acidification increased overall management costs.

Effect of Gypsum Application and Irrigation Intervals on Clay Saline-Sodic Soil Characterization, Rice Water Use Efficiency, Growth, and Yield

Abstract: Saline-sodic soil is considered as a serious problem which could negatively affect rice water use efficiency, plant growth, and yield. Therefore, the objective of the current study was to investigate the effects of gypsum applied before sowing (i.e. gypsum and without gypsum) and irrigation interval treatments applied after anthesis (irrigation every 4, 6, 8 days) on chemical characterizations of clay saline-sodic soil. In addition, the effect of these treatments on rice growth, water use efficiency and related parameters and yield were investigated. A significant higher efficiency in reclamation of clay saline-sodic soil was obtained in terms of reducing SAR, Na + and EC when gypsum was applied and water was added every four or six days intervals in comparison to non-treated soil with gypsum and water added every eight days interval. The highest number of spikelets per panicle, ripened grains percent, grain and straw yields were obtained when rice plants were grown on soil treated with gypsum and irrigated every four and/or six days intervals compared to soil with no gypsum and irrigated every eight days interval. The highest water use efficiency was obtained from rice irrigated every six days interval. In conclusion, it may reduce the hazards of the saline-sodic soil due to application of gypsum which improved soil properties, rice growth and its productivity when plants were irrigated every four or six days intervals. This might be due to the valuable nutrient source of gypsum interns of Ca, which mitigated the toxicity caused by salts in saline soils. Gypsum can also be considered as an effective application for clay saline-sodic soil in the North Delta, Egypt.

The Effect of Heterogeneity Due to Inappropriate Tillage on Water Advance and Recession in Furrow Irrigation

Abstract: In surface irrigation, uniformity of longitudinal slope and depth of tillage are very important factors in advance duration time. Inappropriate tillage and land preparation can cause uneven surfaces and non-uniform slopes in fields which is especially important in furrow irrigation due to their influence on advance times. The purpose of this study is to evaluate the effect of non-uniform longitudinal slope due to inappropriate tillage on advance and recession phases in furrow irrigation system, which plays an important role in irrigation uniformity and application efficiency. For this purpose 12 furrows, each 42 m long were made with different longitudinal slopes and a width of 0.6 meter. The number of irrigation was 5 with irrigation interval of 4 days and input discharge of 0.8 lps. Results showed that advance times are very different in furrows especially in the first irrigation and varied from 19min up to 50min. The values for recession time were 9 to 29 min. The results of these five irrigation events indicate that non-uniform slope has significant effect on advance and recession time. Therefore with attention to the water crisis and the need to increase efficiency and uniformity of water distribution in surface irrigation, using modern machinery and paying more attention to accurate preparation of land are necessary in order to obtain uniform furrows in fields.

Quantitative characterization of five cover crop species

Abstract: The introduction of cover crops in the intercrop period may provide a broad range of ecosystem services derived from the multiple functions they can perform, such as erosion control, recycling of nutrients or forage source. However, the achievement of these services in a particular agrosystem is not always required at the same time or to the same degree. Thus, species selection and definition of targeted objectives is critical when growing cover crops. The goal of the current work was to describe the traits that determine the suitability of five species (barley, rye, triticale, mustard and vetch) for cover cropping. A field trial was established during two seasons (October to April) in Madrid (central Spain). Ground cover and biomass were monitored at regular intervals during each growing season. A Gompertz model characterized ground cover until the decay observed after frosts, while biomass was fitted to Gompertz, logistic and linear-exponential equations. At the end of the experiment, carbon (C), nitrogen (N), and fibre (neutral detergent, acid and lignin) contents, and the N fixed by the legume were determined. The grasses reached the highest ground cover (83–99%) and biomass (1226–1928 g/m2) at the end of the experiment. With the highest C:N ratio (27–39) and dietary fibre (527–600 mg/g) and the lowest residue quality (~680 mg/g), grasses were suitable for erosion control, catch crop and fodder. The vetch presented the lowest N uptake (2·4 and 0·7 g N/m2) due to N fixation (9·8 and 1·6 g N/m2) and low biomass accumulation. The mustard presented high N uptake in the warm year and could act as a catch crop, but low fodder capability in both years. The thermal time before reaching 30% ground cover was a good indicator of early coverage species. Variable quantification allowed finding variability among the species and provided information for further decisions involving cover crop selection and management.

Green Synthesis of Nano-Sized Sulfur and Its Effect on Plant Growth

Abstract: The major objective of this research paper is to synthesis sulfur nanoparticles (SNPs) by green route, which can improve plant’s growth and reduce the environmental pathogens. Sulfur nanoparticles (SNPs) were synthesized by a simple green procedure using Melia azedarach leaves aqueous extract and citric acid. The leaves of Melia azedarach aqueous extract act as a capping and stabilizing agent in the formation of sulfur nanoparticles. The synthesized sulfur nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FT-IR). The average particles diameter size was found to be 20 ± 4 nm. Analysis showed that the nanoparticles are crystalline in nature, with spherical shape. A preliminary field study was conducted to evaluate growth and development of Cucurbita pepo in response to sulfur nanoparticles.

Maize yield response to a phosphorus-solubilizing microbial inoculant in field trials

Abstract: Findings from multi-year, multi-site field trial experiments measuring maize yield response to inoculation with the phosphorus-solubilizing fungus, Penicillium bilaiae Chalabuda are presented. The main objective was to evaluate representative data on crop response to the inoculant across a broad set of different soil, agronomic management and climate conditions. A statistical analysis of crop yield response and its variability was conducted to guide further implementation of a stratified trial and sampling plan. Field trials, analysed in the present study, were conducted across the major maize producing agricultural cropland of the United States (2005–11) comprising 92 small (with sampling replication) and 369 large (without replication) trials. The multi-plot design enabled both a determination of how sampling area affects the estimation of maize yield and yield variance and an estimation of the ability of inoculation with P. bilaiae to increase maize yield. Inoculation increased maize yield in 66 of the 92 small and 295 of the 369 large field trials (within the small plots, yield increased significantly at the 95% confidence level, by 0·17 ± 0·044 t/ha or 1·8%, while in the larger plots, yield increases were higher and less variable (i.e., 0·33 ± 0·026 t/ha or 3·5%). There was considerable inter-annual variability in maize yield response attributed to inoculation compared to the un-inoculated control, with yield increases varying from 0·7 ± 0·75 up to 3·7 ± 0·73%. No significant correlation between yield response and soil acidity (i.e., pH) was detected, and it appears that pH reduction (through organic acid or proton efflux) was unlikely to be the primary pathway for better phosphorus availability measured as increased yield. Seed treatment and granular or dribble band formulations of the inoculant were found to be equally effective. Inoculation was most effective at increasing maize yield in fields that had low or very low soil phosphorus status for both small and large plots. At higher levels of soil phosphorus, yield in the large plots increased more with inoculation than in the small plots, which could be explained by phosphorus fertilization histories for the different field locations, as well as transient (e.g., rainfall) and topographic effects.

Genetic Variability, Coefficient of Variance, Heritability and Genetic Advance of Some Gossypium hirsutum L. Accessions

Abstract: The present study was conducted in central cotton research Institute Sakrand to analyze the genetic variability, phenotypic, genotypic and environmental coefficient of variation, heritability and genetic advance during summer 2014. In this experiment analysis of variance indicated that significant variation present among the accessions of the upland cotton for all the traits under study. The highest genotypic (GCV) and phenotypic coefficient of variation (PCV) were exhibited by the number of bolls per plant, lint index and seed cotton yield per plant. GCV had similar trend as PCV. High heritability and high genetic advance was observed in the lint index, number of bolls per plant and seed cotton yield per plant. The combination of the high heritability and high genetic advance provide the clear image of the trait in the selection process.

Characterization and Recycling of Organic Waste after Co-Composting - A Review

Abstract: Co-composting produces a valuable compost material that can be used as valuable soil amendment. The process of the co-composting and control of the composting factors are the current challenges for the researchers. There are different factors that govern the quality, stability and the maturity of the co-compost in terms of amount of plant nutrients and reduction of heavy metals. Among these, C:N ratio is a parameter that can affect the loss of plant nutrients. Different studies showed wide ranges of C:N ratios (14-40) for maturity of quality compost. Temperature, aeration and types of the bulking agents also regulate the process of co-composting. Most widely used co-composted materials are animal manures with agro-wastes (sawdust, wheat straw, rice straw, corn stalks etc.). This practice brought substantial loss of heavy metals and maximum retention of plant nutrients. Higher nutrients contents of the compost and favourable soil properties as a result of co-composting of the saw dust, cow dung and egg shells have been reported. The application of co-composted dairy manure with wheat straw and sawdust produced higher plant biomass. Co-compost of cattle manure with rice straw produced an organic matter, total N and C:N ratio contents suitable for soil amendment. Therefore, this review focuses on the characteristics and utilization of organic waste after a reasonable co-composting process.

A semi-quantitative approach for modelling crop response to soil fertility: evaluation of the AquaCrop procedure

Abstract: Most crop models make use of a nutrient-balance approach for modelling crop response to soil fertility. To counter the vast input data requirements that are typical of these models, the crop water productivity model AquaCrop adopts a semi-quantitative approach. Instead of providing nutrient levels, users of the model provide the soil fertility level as a model input. This level is expressed in terms of the expected impact on crop biomass production, which can be observed in the field or obtained from statistics of agricultural production. The present study is the first to describe extensively, and to calibrate and evaluate, the semi-quantitative approach of the AquaCrop model, which simulates the effect of soil fertility stress on crop production as a combination of slower canopy expansion, reduced maximum canopy cover, early decline in canopy cover and lower biomass water productivity. AquaCrop's fertility response algorithms are evaluated here against field experiments with tef (Eragrostis tef (Zucc.) Trotter) in Ethiopia, with maize (Zea mays L.) and wheat (Triticum aestivum L.) in Nepal, and with quinoa (Chenopodium quinoa Willd.) in Bolivia. It is demonstrated that AquaCrop is able to simulate the soil water content in the root zone, and the crop's canopy development, dry above-ground biomass development, final biomass and grain yield, under different soil fertility levels, for all four crops. Under combined soil water stress and soil fertility stress, the model predicts final grain yield with a relative root-mean-square error of only 11–13% for maize, wheat and quinoa, and 34% for tef. The present study shows that the semi-quantitative soil fertility approach of the AquaCrop model performs well and that the model can be applied, after case-specific calibration, to the simulation of crop production under different levels of soil fertility stress for various environmental conditions, without requiring detailed field observations on soil nutrient content.

Influence of Extra Weight and Tire Pressure on Fuel Consumption at Normal Tractor Slippage

Abstract: Tire pressure and wheel load are both easily managed parameters which play a significant role in tillage operations for limiting slip which involves energy loss. To a great extent, this aspect affects the fuel consumption and the time required for soil tillage. The study was focused on the tire pressure and extra weight variation effect on fuel consumption and work productivity for soil tillage at normal tractor wheels slippage (7-15%). The experimental research unit composed of an 82.3 kW 4WD tractor and a reversible 4-bodies plough is presented. Tests were carried out on a stubble loam, where slip of tractor driving wheels was < 15%, tractor front ballast mass was varied in the range from 0 to 520 kg and inflation pressure in the tires from 240 kPa to 100 kPa. Dependences of tractor performance indicators on ballast mass and tires inflation pressure are presented. When tractor tire slip varies in the range from 7 to 15 percent (which is normal slip in the soil), reducing the tires inflation pressure decreases the driving wheel slip and fuel consumption, while increases work productivity. Increasing the additional mass of the tractor (adding ballast weights) decreases the driving wheel slip, increases work productivity, but also increases fuel consumption and soil compaction.

Honey Bees (Apis mellifera L.) and Pollination Issues: Current status, impacts and potential drivers of decline

Abstract: European honey bees (Apis mellifera L) are important pollinators of many fruits, nuts, vegetables and field crops Honey bees also pollinate different wild flowering plants and help to maintain the ecosystems Currently, these pollinators are facing a number of threats including habitat destruction, pesticides, mites, parasites and loss of genetic diversity Because of the decline in their number, there is a great loss of ecological services which impacts the world’s economy This review of honey bee and pollination issues highlights the need of protection and conservation of these important pollinators Research is required to quantify the synergistic effects of potential drivers for current colony loss and to identify the ecotypes and native species of honey bees which are more resistant to pests, pathogens and pesticides

Automatic discrimination of grapevine ( Vitis vinifera L.) clones using leaf hyperspectral imaging and partial least squares

Abstract: A worldwide innovative method to discriminate grapevine clones is presented. It is an alternative to ampelography, isozyme and DNA analysis. The spectra and their first and second derivatives of 201 bands in the visible and near-infrared wavelength range between 634 and 759 nm were used as inputs to a classifier created using partial least squares. The spectra were acquired in the laboratory for the adaxial side of the apical part of the main lobe of fully hydrated grapevine leaves. The classifier created allowed the separation of 100 leaves of the Cabernet Sauvignon (Vitis vinifera L.) variety into four clones, namely CS 15, CS 169, CS 685 and CS R5, comprising 25 leaves each. The percentages of leaves correctly classified for these clones were 98·2, 99·2, 100 and 97·8%, respectively, when the classifier input was the second derivative of the normalized spectra. These percentages were determined by Monte-Carlo cross-validation. With the new method proposed, each leaf of a given variety can be classified in a few seconds according to its clone in an environmentally friendly way.

Green Synthesis of Silver Nanoparticles Using Leaf Extract of Rosmarinus officinalis and Its Effect on Tomato and Wheat Plants

Abstract: Biological green synthesis of silver nanoparticles (AgNPs) from silver salts is a growing advanced approach to avoid the requirement of costly instruments and involvement of hazardous chemicals as well. However, increasing use of AgNPs raises potential toxicity level in the environment. In this investigation, leaf extract of rosemary (Rosmarinus officinalis) used as a reducing and stabilizing agent for biosynthesis of AgNPs. The biosynthesized AgNPs were authorized by UV-vis spectrophotometer and X-ray diffraction (XRD) analysis. The shape and size of the biosynthesized AgNPs were studied using high resolution transmission electron microscope (TEM). The toxicity of the biosynthesized silver nanoparticles on wheat and tomato plants was studied by soaking wheat grains and tomato seeds in 100 mg/L AgNPs and follow its effect on seedling growth of wheat (at 10 days) and on vegetative growth of tomato and wheat plants (at 35 days). Some physiological parameters as germination percentage of wheat seedling, length of seedling, dry weight, pigment fractions (chl.a, chl.b and caroteinoids), soluble proteins, lipid peroxidation (MDA) and antioxidant enzymes (catalase and peroxidase) of two plants were measured. AgNPs has a non-significant inhibitory effect on germination percentage of wheat, dry weight and pigment fractions. The biosynthesized AgNPs has a noticeable stress effect on tomato plant as reduced chlorophyll a and dry weight. Generally, AgNPs stimulate MDA accumulation in tomato and wheat plants. There was a noticeable different effect of AgNPs on soluble proteins and antioxidant enzymes as catalase and peroxidase among tomato and wheat plants.