• Authors:
    • Shakir, A. S.
    • Rehman, H. U.
    • Sharif, M. B.
    • Hameed, A.
    • Qazi, A. U.
    • Khan, N. M.
    • Afzal, M.
  • Source: Pakistan Journal of Science
  • Volume: 63
  • Issue: 3
  • Year: 2011
  • Summary: Global demands for food & fiber are increasing, necessitating efficient management of the irrigated water. Vast-uncultivated but otherwise fertile lands in Baluchistan, Pakistan attract the authorities to develop the land for agriculture through irrigation. Kachhi plains are one of such areas that will be provided canal water through a gravity canal system off-taking from Indus river at Taunsa Barrage. Efficient use of water especially in arid climates requires good estimates of crop water requirements (CWR). Physical based methods of estimating crop water requirement including the Radiation-Resistance based methods take into account the energy radiated from various sources and the atmospheric resistance depending on air circulation and humidity. This study employs a radiation-resistance based Penman Monteith Equation (Allen et al., 1998) through a spread sheet based tool and CROPWAT software to estimate the crop water requirements in Kachhi Plains, the study area. The study compares the reference crop evapotranspiration with four other well known methods. Meteorological data namely rainfall, temperature, humidity, actual sunshine hours of the closest meteorological station i.e. Jacobabad station is used for the study. Crop coefficients are calculated using FAO guidelines. Total water requirement for Wheat is estimated as 380 mm, while that for Cotton is 928 mm. Crop water requirement calculated by the spreadsheet matches well with that from CROPWAT. The result differs by 3% from the crop water requirements estimated/used by the feasibility report of the Kachhi Canal. Staggering of major crops (wheat, cotton) have been incorporated while computing the CWR. The study can be used for optimization of the cropping pattern and can further be extended by estimation of crop water requirement using lysimeter in the study area. It can also be used to study the impact analysis of meteorological data on the crop water requirement.
  • Authors:
    • Kugbei, S.
  • Source: Journal of Crop Improvement
  • Volume: 25
  • Issue: 3
  • Year: 2011
  • Summary: Production figures in 2008 showed that new private seed enterprises in Afghanistan produced and sold about 12,000 tons of certified wheat seed, which accounted for 95% of the total certified seed produced in the country. At a retail price of about US$1,200 per ton, the enterprises earned an average margin of 20%. When interviewed, the farmers ranked high yield as by far the most important characteristic they sought in improved varieties. Besides yield, the next important attributes were earliness, disease resistance, grain color, and bread making quality. Estimates of on-farm productivity showed that use of improved wheat varieties alone could contribute up to 33% incremental yield under irrigated conditions, whereas the use of quality seed could enhance yield further by 28%. These estimates were obtained under recommended fertilizer rates, in the absence of which yield levels would have declined substantially. Apart from wheat, other major crops the farmers grew varied by regions but in broad terms included rice, vegetables, maize, potato, cotton, barley, watermelon, and alfalfa.
  • Authors:
    • Bacalan, G. E.
    • Kaman, H.
    • Uz, I.
    • Sonmez, N. K.
    • Uz, B. Y.
    • Ersahin, S.
    • Kurunc, A.
    • Emekli, Y.
  • Source: Agricultural Water Management
  • Volume: 98
  • Issue: 6
  • Year: 2011
  • Summary: Identification of nitrate (NO 3) leaching hot spots is important in mitigating environmental effect of NO 3. Once identified, the hot spots can be further analyzed in detail for evaluating appropriate alternative management techniques to reduce impact of nitrate on groundwater. This study was conducted to identify NO 3 leaching hot spots in an approximately 36,000 ha area in Serik plain, which is used intensively for agriculture in the Antalya region of Southern Turkey. Geo-referenced water samples were taken from 161 wells and from the representative soils around the wells during the period from late May to early June of 2009. The data were analyzed by classical statistics and geostatistics. Both soil and groundwater NO 3-N concentrations demonstrated a considerably high variation, with a mean of 10.2 mg kg -1 and 2.1 mg L -1 NO 3-N for soil and groundwater, respectively. The NO 3-N concentrations ranged from 0.01 to 102.5 mg L -1 in well waters and from 1.89 to 106.4 mg kg -1 in soils. Nitrate leaching was spatially dependent in the study area. Six hot spots were identified in the plain, and in general, the hot spots coincided with high water table, high sand content, and irrigated wheat and cotton. The adverse effects of NO 3 can be mitigated by switching the surface and furrow irrigation methods to sprinkler irrigation, which results in a more efficient N and water use. Computer models such as NLEAP can be used to analyze alternative management practices together with soil, aquifer, and climate characteristics to determine a set of management alternatives to mitigate NO 3 effect in these hot spot areas.
  • Authors:
    • Stevenson, F. C.
    • Legere, A.
    • Benoit, D. L.
  • Source: Weed Science
  • Volume: 59
  • Issue: 1
  • Year: 2011
  • Summary: A conservation tillage study provided the opportunity to test whether tillage effects on the germinable weed seedbank would be consistent across different crop rotations and to investigate the potential residual effects of herbicide treatments terminated 12 yr earlier. Our objective was to measure the effects of tillage (moldboard plow [MP] vs. chisel plow [CP] vs. no-till [NT]), crop rotation (2-yr barley-red clover followed by 4-yr barley-canola-wheat-soybean rotation, compared to a cereal monoculture), and of a prior weed management factor (three intensity levels of herbicide use) on the density, diversity, and community structure of weed seedbanks. Species richness, evenness (Shannon's E), and diversity (Shannon's H′) of spring seedbanks varied little across treatments and over time. Total seedbank density generally increased as tillage was reduced, with some variations due to weed management in 1993 and crop rotation in 2006. Crop rotations generally had smaller seedbanks with fewer species than the monoculture. In 1993, seedbanks with minimum weed management were twice as dense as those with intensive or moderate weed management (approximately 6,000 vs. 3,000 seed m -2). By 2006, seed density averaged 6,838 seed m -2 across intensive and moderate weed management regardless of tillage, but was nearly twice as large in NT (12,188 seed m -2) compared to MP (4,770 seed m -2) and CP (7,117 seed m -2) with minimum weed management (LSD 0.005=4488). Species with abundant seedbanks responded differently to treatments. Barnyardgrass and green foxtail had larger seedbanks in the monoculture than in the rotation. Common lambsquarters and pigweed species had large seedbanks in tilled treatments in the rotation, whereas yellow foxtail and field pennycress contributed to the large seedbanks observed in NT treatments. The latter two species were also associated with residual effects of weed management treatments (terminated 12 yr earlier) in NT. The differential seedbank response of weed species, attributed in part to contrasting weed emergence patterns and agronomic practice effects on seed rain, explained some of the weak treatment effects observed for total seedbank density and diversity. The large weed seedbanks observed in NT plots after 18 yr confirms the importance of seed rain and seedbank management for the sustainability of NT systems.
  • Authors:
    • Askegaard, M.
    • Olesen, J. E.
    • Kristensen, K.
    • Rasmussen, I. A.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 142
  • Issue: 3-4
  • Year: 2011
  • Summary: Two main challenges facing organic arable farming are the supply of nitrogen (N) to the crop and the control of perennial weeds. Nitrate leaching from different organic arable crop rotations was investigated over three consecutive four-year crop rotations in a field experiment at three locations in Denmark (12 years in total). The experimental treatments were: (i) crop rotation, (ii) catch crop and (iii) animal manure. Nitrate leaching was estimated from measured soil nitrate concentration in ceramic suction cells and modelled drainage. There were significant effects on annual N leaching of location (coarse sand > loamy sand > sandy loam) and catch crops (without > with). Including a grass-clover green manure on 25% of the area did not increase N leaching compared with crop rotations without green manure. Also the application of animal manure did not influence N leaching, probably because even in the manured treatments the application rate was lower than crop demand. The results identify management of crop and soil during autumn as the main determinant of N leaching. Nitrate leaching was lowest for a catch crop soil cover during autumn and winter (avg. 20 kg N ha -1), a soil cover of weeds/volunteers had on avg. 30 kg N ha -1, and the largest N leaching losses were found after stubble cultivation (avg. 55 kg N ha -1). The N leaching losses increased with increasing number of autumn soil cultivations.
  • Authors:
    • Chen, D.
    • Barton, L.
    • Li, Y.
  • Source: Journal of the Science of Food and Agriculture
  • Volume: (in press).
  • Year: 2011
  • Authors:
    • Jitareanu, G.
    • Bucur, D.
    • Ailincai, D.
    • Ailincai, C.
  • Source: Cercetări Agronomice în Moldova
  • Volume: 44
  • Issue: 3
  • Year: 2011
  • Summary: The goal of the experiments carried out at the Podu-Iloaiei Agricultural Research Station, Iași County, was the study of water runoff and soil losses, caused by erosion, in different crops and the influence of water and soil erosion on the losses of organic matter and mineral elements from soil. The results on water runoff and soil losses in different crops from the Moldavian Plateau have shown that in the last seven years, of the total amount of 608.4 mm rainfall, 387.5 mm (63.7%) produced water runoff, which was between 8.5 mm in perennial grasses, in the second year of vegetation, and 34.9 - 36.8 mm, in maize and sunflower crops. The annual soil losses due to erosion, recorded at the same period, were between 0.190 t/ha/year in perennial grasses, and 4.079 - 4.451 t/ha/year in maize and sunflower crops. Erosion has affected soil fertility by removing once with eroded soil, high amounts of organic carbon and mineral elements, which reached 10.71 - 11.26 kg/ha nitrogen, 0.56 – 0.64 kg/ha phosphorus and 0.98 - 1.11 kg/ha potassium, in maize and sunflower crops. The crop structure, which determined the diminution in mean soil losses by erosion until 1.383 t/ha included 20 % straw cereals, 20% annual legumes, 20% row crops and 40 % perennial grasses and legumes. On land with a slope of 16%, lowering the percentage of weeding plants from 60% to 20% has reduced the amount of eroded soil by 49%.
  • Authors:
    • Booker, J.
    • Lascano, R.
    • Acosta-Martinez, V.
    • Calderon, F.
    • Zobeck, T.
    • Upchurch, D.
  • Source: Biology and Fertility of Soils
  • Volume: 47
  • Issue: 6
  • Year: 2011
  • Summary: In dryland agriculture in semiarid regions, crop establishment is not always possible because precipitation may not be sufficient. Modification of soil properties can improve the soil quality and functioning including soil water capture and storage capacity for crop production in dryland conditions. ARS scientists established a study near Lubbock, Texas in 2003 to compare the soil properties under different dryland cropping systems and tillage management. After only 3 years, this study detected increases in soil microbial community size and enzyme activities important for nutrient cycling under rotations with a winter cover crop such as cotton-rye-sorghum and haygrazer-rye compared to continuous cotton or sorghum-cotton at 0-10 cm soil depth. After 5 years, higher soil total C was found under Hay-Rye compared to the other systems. In addition, microbial properties were already impacted in all alternative systems (haygrazer-rye, cotton-rye-sorghum and cotton-sorghum) studied compared to continuous cotton. Several microbial properties indicative of increased soil water availability were also higher under the alternative rotations to continuous cotton. However, continuation of this study is vitally important for the long-term evaluation and confirmation of these trends, and their implications in water management, soil quality and crop productivity in dryland.
  • Authors:
    • Abdellaoui, Z.
    • Teskrat, H.
    • Belhadj, A.
    • Zaghouane, O.
  • Source: Options Mediterranennes
  • Issue: 96
  • Year: 2011
  • Summary: The comparative study of reduced tillage, zero tillage and conventional tillage conducted during 5 years in the sub-humid zone of Algeria showed a difference of the development of durum wheat and changes of some soil characteristics. In the first year experiment, the yield was higher in the conventional tillage compared with reduced tillage and no-tillage. After the 3rd year, better yields were obtained with no-till with a 10 q/ha rise compared with conventional tillage. This confirms that the production of wheat under no till is improved year by year. However, after the 5th year of experiment, the high soil moisture at the seeding has generated lower yields. The different tillage practices have generated differences in soil characteristics. In fact a better water retention and a better content in organic matter in the three studied layers, were observed with no till. The bulk density shows a clear variation at the surface layer (0-8 cm) with the highest density in the conventional tillage.
  • Authors:
    • Raman, A.
    • Ladha, J. K.
    • Kumar, V.
    • Sharma, S.
    • Piepho, H. P.
  • Source: Field Crops Research
  • Volume: 121
  • Issue: 3
  • Year: 2011
  • Summary: Normally, the data generated from farmer participatory trials (FPT) are highly unbalanced due to variation in the number of replicates of different treatments, the use of different varieties, farmers’ management of the trials, and their preferences for testing different treatments. The incomplete nature of the data makes mixed models the preferred class of models for the analysis. When assessing the relative performances of technologies, stability over a range of environments is an important attribute to consider. Most of the common models for stability may be fitted in a mixed-model framework where environments are a random factor and treatments are fixed. Data from on-farm trials conducted in the Indo-Gangetic Plain (IGP) of South Asia under the umbrella of Rice–Wheat Consortium (RWC) were analyzed for grain yield stability using different stability models. The objective was to compare improved resource management technologies with farmers’ practice. The variance components of an appropriate mixed model serve as measures of stability. Stability models were compared allowing for (i) heterogeneity of error variances and (ii) heterogeneity of variances between environments for farmers-within-environment effects. Mean comparisons of the treatments were made on the basis of the best fitting stability model. Reduced-till (non-puddled) transplanted rice (RT-TPR) and reduced-till drill-seeded wheat using a power tiller – operated seeder with integrated crop and resource management RTDSW(PTOS)ICRM ranked first in terms of both adjusted mean yield and stability.