• Authors:
    • Nagler, P. L.
    • Hunsaker, D. J.
    • Neale, C. M. U.
    • Glenn, E. P.
  • Source: Hydrological Processes
  • Volume: 25
  • Issue: 26
  • Year: 2011
  • Summary: Crop coefficients were developed to determine crop water needs based on the evapotranspiration (ET) of a reference crop under a given set of meteorological conditions. Starting in the 1980s, crop coefficients developed through lysimeter studies or set by expert opinion began to be supplemented by remotely sensed vegetation indices (VI) that measured the actual status of the crop on a field-by-field basis. VIs measure the density of green foliage based on the reflectance of visible and near infrared (NIR) light from the canopy, and are highly correlated with plant physiological processes that depend on light absorption by a canopy such as ET and photosynthesis. Reflectance-based crop coefficients have now been developed for numerous individual crops, including corn, wheat, alfalfa, cotton, potato, sugar beet, vegetables, grapes and orchard crops. Other research has shown that VIs can be used to predict ET over fields of mixed crops, allowing them to be used to monitor ET over entire irrigation districts. VI-based crop coefficients can help reduce agricultural water use by matching irrigation rates to the actual water needs of a crop as it grows instead of to a modeled crop growing under optimal conditions. Recently, the concept has been applied to natural ecosystems at the local, regional and continental scales of measurement, using time-series satellite data from the MODIS sensors on the Terra satellite. VIs or other visible-NIR band algorithms are combined with meteorological data to predict ET in numerous biome types, from deserts, to arctic tundra, to tropical rainforests. These methods often closely match ET measured on the ground at the global FluxNet array of eddy covariance moisture and carbon flux towers. The primary advantage of VI methods for estimating ET is that transpiration is closely related to radiation absorbed by the plant canopy, which is closely related to VIs. The primary disadvantage is that they cannot capture stress effects or soil evaporation. Copyright (C) 2011 John Wiley & Sons, Ltd.
  • Authors:
    • Zaidi, J. H.
    • Matiullah
    • Husaini, S. N.
    • Arif, M.
  • Source: Journal of Radioanalytical and Nuclear Chemistry
  • Volume: 290
  • Issue: 3
  • Year: 2011
  • Summary: Due to the inadequate water sources, usually sewerage water and industrial effluents are being use for irrigation of the agricultural land around the industrial areas in Pakistan wherein crops and vegetables are cultivated. As untreated effluents contain heavy elements, toxic metals and organic pollutants that may find its way through food chain to general public and may cause health hazards. It is, therefore, mandatory to assess the toxic metals in such crops and vegetables. In this regard, samples of corn, millet, cabbage, spinach and potato were collected within the vicinity of industrial areas of the Faisalabad and Gujranwala regions. The food samples were analyzed using neutron activation analysis (NAA) technique. The highest concentration values of Arsenic (1.90.1 g/g) and Cobalt (0.850.01 g/g) were found in cabbage whereas Manganese (91.60.2 g/g), Antimony (0.150.03 g/g) and Selenium (1.10.1 g/g) were observed in spinach and Chromium (9.631.3 g/g) was found in millet crop. The observed concentrations of all the toxic and heavy metals in crops and vegetables are higher than those reported in the literature.
  • Authors:
    • Dalgliesh, N. P.
    • Nelson, R.
    • Khan,I. A.
    • Carberry, P. S.
    • Kabir, M. J.
    • Poulton, P. L.
  • Source: ACIAR Technical Reporst No.78, Australian Centre for International Agricultural Research, Canberra, H. Rawson (ed), Canberra, ACT[Research Book Chapter]
  • Issue: 78
  • Year: 2011
  • Summary: Increased Rabi-season crop production in southern Bangladesh could help meet the country's growing food demand. This paper reports on an assessment of the economic viability of wheat and other Rabi-season crops based on farmer surveys of crop yields and economic performance. In addition, it considers the agroeconomic and socioeconomic factors that influence farmers' choice of Rabi-season crops. Current Rabi-season crops in southern Bangladesh include boro rice and vegetable production on lands with irrigation facilities. A range of other crops are grown, with and without irrigation, including chilli, potato, grasspea, chickpea, mungbean and soybean. Although farmers in some southern regions had grown wheat in the past, wheat is not a significant crop across the region. The recent increased interest in wheat in some villages corresponded to project activities of a development project, funded by the Australian Centre for International Agricultural Research (ACIAR) and specifically to the availability of newly released varieties with higher yield potential and disease resistance. In those villages where project trials were conducted, irrespective of seasonal conditions, wheat-based rotations provided higher gross margins than the alternative crops of chilli and cowpea. Even in a relatively poor season, wheat offered a significantly higher gross margin and thus lower risk than the other crops. However, the crop establishment costs of wheat are high and wheat requires at least one irrigation when many farmers lack any irrigation facilities. Formal education, off-farm income and farming experience are the socioeconomic factors that displayed significant positive correlation to the surveyed farmers' decision to adopt wheat production. This study confirmed the economic viability of Rabi cropping in southern Bangladesh. While the crops currently grown in the Rabi season are profitable under most seasonal conditions, this study confirmed that wheat offers farmers a profitable and low-risk option.
  • 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:
    • 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:
    • 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:
    • Stepannikov, V.
    • Popova, E.
    • Popov, N.
  • Source: Mezhdunarodnyi Sel'skokhozyaistvennyi Zhurnal
  • Issue: 4
  • Year: 2011
  • Summary: Problems associated with the organization and provision of irrigation in the arid regions of Astrakhan Province, Russia, for the efficient use of both water and land are discussed. Recommendations are made for modernizing the structures of irrigated land use on the basis of scientifically based crop rotations. Economic evaluations of the main indicators of irrigated farming efficiency allowed farming systems to be developed for the Province's various natural and climatic zones and according to farm type (for example, meat or dairy farms, and farms devoted to growing cereals, rice, vegetables, cucurbit crops, fodder crops or potatoes).
  • Authors:
    • Faridi, I. A.
    • Gillani, S. R.
    • Imran, M
    • Mahmood. Z.
    • Shaheen, Q.
  • Source: ASIAN JOURNAL OF CHEMISTRY
  • Volume: 23
  • Issue: 12
  • Year: 2011
  • Summary: This work evaluates the effects of water of irrigation in comparison with the source of water with special reference to chromium contamination in vegetables grown in various areas of Pakistan. Twenty samples of each vegetable, i.e., spinach ( Spinacia oleracea), lettuce ( Lactuca sativa), carrot ( Daucus cariota), capsicum ( Capsicum fistulosus), sweet pea ( Lathyrus odoratus), potato ( Solanum tuberosum) and cabbage ( Brassica oleracea), were collected during the year 2006 and replicated in 2007 and 2008. The range of concentration of chromium in vegetables irrigated with tube well water, canal water and municipal sewage water was in between 0.3-5.3, 1.01-13.09 and 1.11-29.89 ppm, respectively. Statistical analysis shows that the vegetables grown by tube well water and canal irrigation are quite safe and show less than 1% samples of vegetables showing chromium concentration more than that of permissible ambient levels. In case of vegetables irrigated by municipal sewage water more than 50% samples contained Cr more than that of permissible ambient levels. The results reflect that the uptake of chromium in vegetables is facilitated under the condition where the source of irrigation is sewage water.
  • Authors:
    • Moreno, M. F.
    • Diaz, M.
    • Roldan, J.
  • Source: Acta Horticulturae
  • Issue: 889
  • Year: 2011
  • Summary: Irrigation water management in the Genil-Cabra irrigation district, located in the province of Cordoba, southern Spain, was studied using three irrigation performance indicators: relative irrigation supply (RIS); relative water supply (RWS) and relative rainfall supply (RRS). All indicators have been calculated as in a global way as grouping data according to crop type, irrigation method and soil texture. All information of agronomic and hydraulic variables was incorporated in a Geographic Information System (GIS) to ease its management. Results show that applied irrigations are deficit irrigations because RIS values are relatively low. However, RWS values are greater and evaporative demand may be satisfied along crop development cycle. RRS indicator varies less than the other two and, together with RWS, permits to know the evapotranspiration fraction covers by rain water. Irrigation water management in four crops (olive, cotton, sunflower and maize) is considered to be adequate. In the case of sugar beet and asparagus, the deficit is larger. Wheat and garlic are the two crops that show inefficient management due to an excess supply of water. RWS and RIS values are higher for sprinkler irrigation than for drip irrigation. Soil type has little influence on irrigation management. In general, more water is applied to crops planted in sandy loam soils than in silty clay loam soils. The mean values of performance indicators we have calculated are very useful to know farmer's behaviour and the general trend, although the used sample is not significant to characterize the global irrigation district.
  • Authors:
    • Abubakar, M. M.
    • Kushwaha, S.
    • Sani, M. H.
    • Ayoola, G. B.
  • Source: Journal of Development and Agricultural Economics
  • Volume: 3
  • Issue: 9
  • Year: 2011
  • Summary: The application of modified compromise weighted multi-objective programming to Fadama farming in Dass Local Government Area of Bauchi State was the main focus of the study. Samples of 106 Fadama vegetable cultivars were randomly selected from 12 Fadama user's associations in the study area. The farm sizes were grouped and formed into three categories namely: below 1 ha, 1 to 2.99 ha and 3 to 4.99 ha farms, with sample size of 37, 39 and 30 farmers, respectively. It was assumed that farming could be optimized using four specific objectives (maximization of income, and employment; minimization of fertilizer and ground water use). Modified compromise weighted multi-objective programming technique was used to analyze the four objectives, which were optimized individually and combined. The results disclosed that the 3 to 4.99 ha farm size had the best maximum income level of N302,199.26 (+28.11%) and employment of 1125 man days (+33.61%) and minimum level of fertilizer use of 182 kg (-8.08%) and ground water use of 3962 mm (-17.25%) at their respective existing farm levels compared to the other categories of farms. This implied that the farmers were characterized by preponderance of high level of adoption of agricultural technology, resulting from intensive cropping, leading to a high level of chemical fertilizer and increased use of ground water for irrigation which consequently led to reduction of ground water table in the study area. It was therefore recommended that the farmers in the study area should concentrate in the cultivation of the major Fadama crops like onion, tomato, pepper, okro, cabbage and lettuce instead of spreading out their resources to grow potato, carrot and garden-egg.