19602015
  • Authors:
    • Abera, Y.
    • Beyene, S.
    • Kebede, M.
  • Source: Journal of Environment and Earth Science
  • Volume: 2
  • Issue: 2
  • Year: 2012
  • Summary: Floriculture is one of the booming sectors in Ethiopia. With its expansion, there is a growing concern as to its adverse effect on the environment. The objectives of this study were therefore, to provide concrete information on the influence of floriculture effluents on soil quality and crop productivity. Two permanent greenhouse experiments were conducted at Debre Zeit Agricultural Research Center on soils samples collected from farmer's field using wheat as a test crop. The soil samples were divided into two equal parts as sterilized and non-sterilized. Seven rates of floriculture effluents (0, 15.0, 30.0, 45.0, 60.0, 75.0 and 90.0 ml pot -1) were used as treatment in CRD with four replications. The effluent was characterized by high pH, EC, N, P, S and basic cations (K, Ca, Mg and Na), low in micronutrients (Cu, Fe, Mn and Zn) and very low in heavy metals (Mo, Ni, Cd and Cr). Accordingly, its application did not significantly influence the texture and water holding capacity (WHC) of the soil, though decreasing values of FC, PWP and WHC were obtained both from sterilized and non-sterilized soils. Chemical properties were highly influenced by effluent additions. The pH, EC, exchangeable bases and micronutrients of the soil were significantly raised after first and second harvest. Organic carbon and Total Nitrogen increased with increasing volume of effluent, but decreased at high levels. Shoot dry weight of the wheat was also significantly affected by increasing volume of effluent. In non-sterilized soils, addition of low volume effluent increased shoot dry weight which later followed the same trends as sterilized soils. The decreasing trend in shoot dry weight was in line with that of soil organic matter, whereas continuous increments in pH, CEC and ESP resulted in changing the neutral soil to saline. Hence, floriculture effluent was found to affect the performance of wheat and soil quality parameters, where the effect was pronounced for sterilized soil. Future research should focus on long-term effects of floriculture effluents on physical, chemical and biological properties of soil and crop productivity.
  • Authors:
    • Hellin, J.
    • Wall, P.
    • Sayre, K.
    • Erenstein, O.
    • Dixon, J.
  • Source: Journal of Sustainable Agriculture
  • Volume: 36
  • Issue: 1-2
  • Year: 2012
  • Summary: Conservation agriculture's underlying principles-minimal soil disturbance, soil cover and crop rotation-are increasingly recognized as essential for sustainable agriculture. This article summarizes three contrasting cases of adapting conservation agriculture (CA) to smallholder conditions in the (sub)tropics: a) irrigated rice-wheat systems in South Asia; b) rainfed maize/wheat and irrigated wheat systems in Mexico; and c) rainfed maize in Southern Africa. In the South Asia case, farm surveys show rapid and widespread adoption of zero tillage wheat-primarily due to a substantial cost saving (15-16%). In the other cases, uptake so far has been limited-although long-term trials show continuously higher and more stable yields both for maize and wheat. Under marginal conditions CA can generate substantial yield increases-averaging some 50% over conventional smallholder maize yields of 1 ton per ha over 6 years in on-farm trails in Southern Africa. The diverse experiences attest to the wide adaptability of CA systems, which can generate clear economic and potentially enormous environmental benefits. The case studies and wider literature however also reiterate the substantial challenges in terms of targeting, adapting and adopting CA-particularly for smallholders in the (sub)tropics. CA systems are best developed in situ through a multi-stakeholder adaptive learning process to create viable CA-based options that are technically sound, economically attractive, and socially acceptable.
  • Authors:
    • Ward, P. R.
    • Cordingley, N.
    • Flower, K. C.
    • Weeks, C.
  • Source: Field Crops Research
  • Volume: 132
  • Year: 2012
  • Summary: Cover crops have been successfully integrated into conservation agriculture systems in many parts of the world. They are primarily used to provide surface cover as well as to improve soil fertility and suppress weeds. Black oat (Avena strigosa Schreb.) is a widely used cereal cover crop with a rapid growth and high biomass production. It is being trialled as a cover crop for conservation agriculture systems in southwestern Australia, which has a Mediterranean climate with a short winter growing season and where terminal drought is common. Only one crop can be grown in a year and, as such, the long term benefits of including a cover crop in this system must outweigh the loss in income by not growing a cash crop. This study, which was part of a larger conservation agriculture cropping systems trial, examined the effect of different crop sequences, which included oat cover crops and grass pasture, on soil nitrogen mineralisation and weed control. A related paper in this Special Issue examined the effect of cover crops on the soil water balance. We hypothesised that the inclusion of high-biomass oat cover crops in a cereal-dominated cropping system would (i) result in less immobilisation of soil nitrogen compared with that of harvested cereals, and (ii) significantly improve the weed control. We show that soil N mineralisation following oat cover crops was similar to that following wheat and barley. Therefore, cash crops grown after oat cover crops would require similar levels of nitrogen to those grown after harvested cereals. Oat cover crops and grass pasture were found to be very effective in controlling weeds, even in continuous cereal rotations. Two consecutive years of cover crop were required for good annual ryegrass (Lolium rigidum Gaud.) control in a predominantly cereal rotation. Timing of when the cover crops were killed by herbicide was crucial for good weed control, as failure to prevent weed seed set resulted in significantly reduced weed control. Also, late killing of the cover crop reduced soil water storage. The inclusion of an oat cover crop in the rotation reduced the three-year average gross margin; however, the profitability of these crops needs to be evaluated over a longer period. To date, managed pasture, with herbicide control of weed seed set, appears to be a better option than oat cover crops because of the relatively low cost and increased soil water storage. (C) 2011 Elsevier B.V. All rights reserved.
  • Authors:
    • Dahiya, S. S.
    • Pannu, R. K.
    • Singh, M.
    • Dhaka, A. K.
  • Source: Crop Research
  • Volume: 43
  • Issue: 1-3
  • Year: 2012
  • Summary: The survey was conducted in Haryana state during rabi season of 2005-06 on 972 farmers in 54 villages of 16 districts with respective cropping system i. e. pearl millet-wheat, cotton-wheat and rice-wheat. The 18 farmers from each village were selected randomly covering small (4.0 ha) group of land holders. Only those farmers were selected, who had grown PBW 343 variety of wheat. The sample sizes for pearl millet-wheat, cotton-wheat and rice-wheat of all three small, medium and large farm size groups were 90, 108 and 126, respectively. Yield reported in rice-wheat system was higher than cotton-wheat and pearl millet-wheat system. Maximum yield was observed with the use of more than five bags urea/ha. Numbers of irrigations above 4 and seed rate above 100 kg/ha were also reported to increase in yield. Protein content of wheat in pearl millet-wheat system was the highest. Protein content in late sown wheat in pearl millet-wheat system was higher than cotton-wheat and rice-wheat systems. Seed rate of 100 kg/ha and nitrogen dose of five bags of urea/ha gave significantly higher protein content. Quantitative production of wheat in rice-wheat and cotton-wheat cropping systems was higher than pearl millet-wheat system but quality in. terms of protein content was significantly superior to both the rice-wheat and cotton-wheat systems. Hence, export market should be developed in quality grain producing zone i. e. in pearl millet-wheat growing areas, where lower percentage of farmers use higher nitrogen doses and cultivation practices were numerically better than other cropping systems.
  • Authors:
    • Kabat, P.
    • Wolf, J.
    • Wit, A. J. W. de
    • Diepen, C. A. van
    • Supit, I.
    • Baruth, B.
    • Ludwig, F.
  • Source: Agricultural and Forest Meteorology
  • Volume: 164
  • Year: 2012
  • Summary: Climate change impacts on potential and rainfed crop yields on the European continent were studied using output of three General Circulation Models and the Crop Growth Monitoring System in combination with a weather generator. Climate change impacts differ per crop type and per CO 2 emission scenario. Crops planted in autumn and winter (winter wheat) may benefit from the increasing CO 2 concentration. Rainfall is sufficient and if the CO 2 concentration increase is high, yields may increase up to 2090. If the CO 2 increase is less, increasing temperatures result in declining or stagnating yields after 2050. Crops planted in spring (potato, sugar beet) initially benefit from the CO 2 increase, however as time progresses the increasing temperatures reduce these positive effects. By the end of the century yields decline in southern Europe and production may only be possible if enough irrigation water is available. In northern Europe depending on the temperature and CO 2 concentration increase, yields either stagnate or decline. However in some of the cooler regions yield increase is still possible. Crops planted in late spring and summer (maize) may suffer from droughts and high temperature in summer. By the end of the century, depending on the temperature rise, crop yields decline almost everywhere. If the temperature increase is less only in north western Europe yields remain stable.
  • Authors:
    • Taalimoghaddam, A.
    • Karbasi, A.
  • Source: Annals of Biological Research
  • Volume: 3
  • Issue: 7
  • Year: 2012
  • Summary: In this study, two goals are pursued. The first, will be addressed the relationship between game theory and linear programming and then, the application of game theory is checked for crops Khorasan Razavi province. Actually, this is a theory that is related to decide when two or more than two competitors compete in a rational. In this study, game theory model is used for the province's major crops include irrigated wheat, rain fed wheat, irrigated barley, rain fed barley, irrigated sugar beet and irrigated cotton. The data included time series of gross product values of the investigated crops for the period 2000-2009. In this study, in game theory have been used the "Wald" decision-making criterion to determine the highest income under the worst conditions. The pattern results Show irrigated sugar beet cultivation is risky product for the period studied. Irrigated sugar beet is included in the optimization program since it will be the highest expected income in the worst conditions. On the other hand, it has the highest coefficient of variation compared to the other crops. As a result, the game theory model is a good indicator for selecting alternative management strategies for farmers.
  • Authors:
    • Luo,Y.
    • Zhou,C.
  • Source: Journal of Food, Agriculture and Environment
  • Volume: 10
  • Issue: 2
  • Year: 2012
  • Summary: Panzhuang Irrigation District is one of the Yellow River irrigation areas. The spatial and temporal distribution of water resources is severely uneven in the upper, middle and lower reaches of the irrigation district. In order to solve this problem, it is necessary to study the differences of crop water consumption (evapotranspiration-ET), irrigation amount, soil water and water use efficiency (WUE) of winter wheat, summer maize and cotton which are the main crops in the irrigation district. This paper improved calculating methods of the capillary rise and percolation of the established model. The model was then applied to the upper, middle and lower reaches of the irrigation district. Conclusions by the model simulation were as follows: (I) The model could simulate the dynamics of water balance components of wheat-maize and cotton relatively accurately in the irrigation district. (II) Winter wheat and summer maize (wheat-maize) had the highest ET in the upper reaches, followed by the middle reaches and then the lower reaches. There was almost no difference for cotton ET in the upper, middle and lower reaches. (III) Irrigation amount of wheat-maize was 225-300 mm in the upstream, 300 mm in the middle reaches, and 500 mm in the downstream. Cotton irrigation quantity was 60-150 mm in the upper and middle reaches, and 60-390 mm in the lower reaches. (IV) Soil water basically showed a decreasing trend in growth periods of wheat-maize and cotton in the middle and lower reaches, its recharge was primarily from irrigation of wheat. Combined with other references, there was a trend of soil drying in the North China Plain. (V) Mean values of water use efficiency (WUE) of winter wheat, summer maize and cotton were highest in the middle reaches and lowest in the upstream and downstream.
  • Authors:
    • Vazin, F.
    • Abbasi, M.
  • Source: Advances in Environmental Biology
  • Volume: 6
  • Issue: 4
  • Year: 2012
  • Summary: In most areas of Isfahan Province, the maize is cultivated as a second crop after harvesting the wheat or barely and the farmers of this region are confronting with time-limit problems in performing correct yield of providing the soil bed, and the tillage is an expensive and energy-consuming yield. Thus, for examining the effect of tillage on the elimination of mechanical yield and saving the time and the expense of performing yield as well as the effect of appropriate date for planting the maize on the performance and its components, an experiment is conducted as a split plot design, 4 times in the agricultural year 2010 in Mourchekhort area of Isfahan. The factors including tillage in two levels (Current Tillage "CT" and Non-tillage "NT") on the main plot and the planting date in three levels (29 th June-15 th July-28 th July) with 15-day interval on the secondary plot were operated on the maize sort No. I704. The tillage system is not significantly effective on the biological performance. In tillage system, the performance of the grain, the number of corns in the maize row and the total number of corn in the maize showed respectively 10%, 12% and 22% increases, compared to those in nontillage system. On 29 th June, the weight of one-thousand corns was decreased 13% and the performance of the corn, the number of corns in the maize row and the total number of corns in the maize was respectively increased in 35%, 16% and 30% compared to those on 29 th July. Reciprocal effect of tillage system and planting dates didn't effect on the corn's performance and its components. Considering the results achieved, the best planting date for both tillage systems in this area is 29 th June.
  • Authors:
    • Armentano, G.
  • Source: L'Informatore Agrario
  • Volume: 68
  • Issue: 1
  • Year: 2012
  • Authors:
    • Dercon, G.
    • Kumar S.
    • Garg, A. K.
    • Manchanda, J. S.
    • Aulakh, M. S.
    • Nguyen, M. L.
  • Source: Soil & Tillage Research
  • Volume: 120
  • Year: 2012
  • Summary: Continuing cereal-based crop rotations such as rice-wheat, intensive cultivation and complete removal of postharvest crop residue (CR) for animal consumption and fuel, or its burning have reduced the organic matter content and productivity of irrigated semi-arid subtropical soils of South Asia. Identification of effective strategies for the management of tillage and CR could foster sustainable and environmentally sound agricultural systems. To this effect, a 4-year field experiment was established with annual soybean-wheat rotation under subtropical climate conditions in the Indo-Gangetic Plains of Northwestern India to evaluate the integrated effects of tillage, CR retainment, mineral fertilizers and farmyard manure (FYM) on crop production, nutrients uptake, soil moisture storage and temperature dynamics. The experimental soil was loamy sand, poor in organic C and low in available P. Sixteen treatment combinations involved recommended and 25% higher NP rates without or with 10 t FYM ha -1 and CR incorporated in conventional tillage (CT) and retained on the soil surface in conservation agriculture (CA) system. The results clearly revealed that (a) soybean yield was 2-6% higher in CA than CT in different treatments with and without CR, (b) significantly higher uptake of N and P by soybean from CR-amended treatments of both CT and CA, which reflected its effect in improving the soybean yield, (c) the current fertilizer NP recommendation of 20 kg N and 26 kg P ha -1 for soybean is not adequate and either application of 25% higher NP rate (25 kg N and 33 kg P ha -1) or additional 10 t FYM ha -1 is required for optimum crop production of ~2500 kg ha -1, (d) CA conserved more water in soil profile than CT, however, the differences in soil moisture storage in CT vis-a-vis CA were not reflected in soybean yield presumably due to frequent wetting of soil by heavy monsoonal rains, (e) the wheat yield was highest in both CT and CA systems when grown with the application of 150 kg N and 33 kg P ha -1 without CR and was 7% higher in CA (4140 kg ha -1) than CT (4048 kg ha -1), and (f) retention of CR on soil surface in winter-grown wheat under CA reduced wheat yield by 8-24% and N uptake by 3-5% as a consequence of mulching effects creating cooler environment in surface soil layer during initial 3 weeks after seeding, which led to the delayed germination and relatively poor crop growth during initial period.