• Authors:
    • Muchaonyerwa, P.
    • Chiduza, C.
    • Dube, E.
  • Source: Soil & Tillage Research
  • Volume: 123
  • Year: 2012
  • Summary: A study was conducted to determine the effects of oat (Avena sativa) and grazing vetch (Vicia dasycapa) winter cover crops and fertilization regimes on soil organic matter (SOM) in an irrigated maize-based (Zea mays L.) conservation agriculture (CA) system following four years of continuous practice. Separate plots of oat and grazing vetch cover crops were grown in winter and then maize was planted in all plots in the following summer season. The four fertilization regimes used were: (i) fertilizer applied to the cover crops and the maize crop (F1), (ii) fertilizer applied to cover crops only (F2), (iii) fertilizer applied to the maize crop only (F3) and (iv) no fertilizer applied (F4). Control plots (weedy fallows) were included and the treatments were laid out in a randomized complete block design with three replications. Soil samples from 0-5, 5-20 and 20-50 cm depths were analyzed for total SOM, particulate organic matter (POM) fractions, hot water soluble C (HWC) and C-associated with water stable macro- and micro-aggregates (WSAC). While total SOM was more concentrated in the 0-5 cm soil depth across treatments, a lack of maize fertilization (F2 and F4 regimes) significantly (P
  • Authors:
    • Haghighi, B. J.
    • Miri, H. R.
    • Ebrahimi, S. M.
  • Source: Advances in Environmental Biology
  • Volume: 6
  • Issue: 4
  • Year: 2012
  • Summary: The purpose of this study was evaluating the growth and compare yield and water consumption of corn under treatments of conventional tillage, reduced tillage and no tillage during the different irrigation intervals. This study was conducted at Arsanjan city, southern Iran in 2009. The experiment was split plot in randomized completely blocks design with three tillage methods (conventional tillage without residues, minimum tillage and conservation residues, and no tillage and reserve residues) as main factor and irrigation intervals (8 days, 11 days and 14 days intervals) as sub factor with four replication. Result of this study showed that 8 days irrigation interval and conventional tillage produced the highest grain yield, biological yield, ear number, seed number and seed weight in comparison with other treatments. But, by increasing irrigation interval to 14 days and decreasing water usage, no tillage and reserve residue treatment could prevent reduction in grain yield. In general results showed that residues management by reserving residue as a surface cover and improves tillage method to minimum and no tillage can increase corn yield through improvement soil organic carbon which is the main goal in conservation agriculture. We can reach to economic corn yield by reducing irrigation times and saving water usage in warm and dry regions, so it is possible to plant corn in this area directly in residue of previous crop.
  • 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:
    • Kadyampakeni, D.
    • Fandika, I. R.
    • Zingore, S.
  • Source: Irrigation Science
  • Volume: 30
  • Issue: 1
  • Year: 2012
  • Summary: The performance of a bucket drip irrigation system (BDI) powered by treadle pump was evaluated on tomato and intercropped maize/bean crops, between 2005 and 2007 in Malawi. It was a split plot experiment with three replicates. The BDI system consisted of a 1,300-l tank mounted 1.5 m above ground and connected with a 32-mm mainline and 15-mm lateral lines spaced at 1 m by 0.6 m. A treadle pump was used to uplift water to the tank. Tomato and intercropped maize/bean were irrigated every 4 days. The system reduced labour and water by >25% and it showed high uniform application depth and wetted diameter. Yields were significantly different between tomato varieties ( P
  • Authors:
    • Samar, S. M.
    • Shahabian, M.
    • Talaie, A.
    • Emdad, M. R.
  • Source: Archives of Agronomy and Soil Science
  • Volume: 58
  • Issue: 3
  • Year: 2012
  • Summary: This work examines the effects of two deficit irrigation strategies, conventional deficit irrigation (DI) and partial root-zone drying (PRD), on mature navel orange trees. The study carried out during two consecutive years (2008 and 2009) in a semi-arid climate on a silty-clay-loam soil in the north of Iran. Both DI and PRD trees were irrigated at two levels, 75 and 50% (DI75, PRD75, DI50 and PRD50) of the full irrigation (FI). In DI, irrigation water was applied to both sides of the tree rows, similar to FI. In PRD, irrigation water was applied alternately to only one side, at each irrigation event. Results showed that DI treatments reduced fruit yield by ~30% compared with FI, but PRD treatments caused no reduction in fruit yield. No negative impact was detected in fruit quality after applying DI and PRD treatments. Shoot growth decreased in all DI and PRD treatments in both years. In DI, stomatal resistance was higher (50%) than in FI, but it was not significantly affected in PRD. The irrigation water use efficiency of PRD trees increased to nearly twice that of FI. According to these two years' results, we recommend PRD as an acceptable deficit irrigation strategy in the region.
  • Authors:
    • Mexal, J. G.
    • Steiner, R. L.
    • Sammis, T. W.
    • Shukla, M. K.
    • Sharma, P.
  • Source: Agricultural Water Management
  • Volume: 109
  • Year: 2012
  • Summary: Nitrate leaching is a common problem in frequently fertilized agricultural crops in Southern New Mexico. The objectives of this study were to estimate the leaching depths, irrigation and plant uptake efficiencies for onion (Album cepa L), chile (Capsicum annuum), and cotton (Gossypium spp.) crops. The study aims to determine how existing best management practices for these three specialty crops could be improved. Soil samples collected monthly for two growing seasons starting April 2007 to June 2010 were analyzed for NO3-N and chloride concentrations. The NO3-N loadings below the rooting zone varied from 22 to 92 kg ha(-1) during growing season 1 and 18-90 kg ha(-1) during growing season 2 in all the three experimental fields. The leaching fractions (LFs) varied from 0.09 to 0.21 during growing season 1 and 0.08-0.22 during growing season 2 in the experimental fields. The irrigation efficiencies (1E = 1 - LF) ranged from 79 to 91% during growing season 1 and from 78 to 92% during growing season 2 in all the three fields. Nitrogen application efficiencies (NAEs) varied from 39 to 75% during growing season 1 and 40-76% during growing season 2 in all the experimental fields. Under the prevalent management conditions, cotton field showed higher irrigation efficiency as well as the NAE as compared to onion and chile fields. Based on the soil N content at the end of growing seasons, the results indicate that reducing fertilizer applications until bulb formation in onions and flower initiation in chile can decrease the amount of fertilizer applications to as much as half, thus can help in reducing the NO3-N leaching and improving nitrogen and water efficiencies. (C) 2012 Elsevier B.V. All rights reserved.
  • Authors:
    • Ribeiro, L.
    • Mendes, M. P.
    • Silva, E.
    • Cerejeira, M. J.
  • Source: Environmental Science & Pollution Research
  • Volume: 19
  • Issue: 7
  • Year: 2012
  • Summary: Purpose: To assess groundwater exposure to pesticides, in agricultural areas of 'Ribatejo' region (Portugal), and the influence of some key factors in that exposure, field, laboratory and modelling studies were carried out. Methods: The study was performed in maize, potato, sugar beet, tomato and vegetables agricultural areas, located in a shallow aquifer, with pesticides use and, in most cases, with irrigation practices. Pesticides used in the studied agricultural areas and having leaching potential were selected, being considered also other pesticides included in priority lists, defined in Europe. Evaluation of groundwater exposure to pesticides was carried out by successively: (1) groundwater sampling in seven campaigns over the period 2004-2006; (2) pesticide analysis [including isolation and concentration from the groundwater samples and further determination by gas chromatography-mass spectrometry (GC-MS) of 14 herbicides, four insecticides and two metabolites]; and (3) analysis and discussion of the results by applying joint correspondence analysis (JCA). Results: From the 20 pesticides and metabolites selected for the study, 11 were found in groundwater. Pesticides and metabolites most frequently detected were atrazine, alachlor, metolachlor, desethylatrazine, ethofumesate, alpha-endosulfan, metribuzine, lindane and beta-endosulfan. The results showed that groundwater exposure to pesticides is influenced by local factors - either environmental or agricultural, as precipitation, soil, geology, crops and irrigation practices. Spring and autumn were more associated with the detection of pesticides being more likely to observe mixtures of these compounds in a groundwater sample in these transition seasons. Conclusions: This work evidences the importance of models, which evaluate pesticides environmental behaviour, namely their water contamination potential (as Mackay multicompartimental fugacity model) and, specially, groundwater contamination potential (as GUS and Bacci and Gaggi leaching indices), in pesticide selection. Moreover, it reveals the importance to adapt proper statistical methods according to level of left-censored data. Using JCA was still possible to establish relations between pesticides and their temporal trend in a case study where there were more than 80% of data censored. This study will contribute to the Tagus river basin management plan with information on the patterns of pesticide occurrence in the alluvial aquifer system.
  • 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:
    • Soomro, B. A.
    • Markhand, G. S.
    • Soomro, M. H.
  • Source: Pakistan Journal of Botany
  • Volume: 44
  • Issue: 1
  • Year: 2012
  • Summary: The drought is one of the biggest abiotic stresses for crop production in arid and semi-arid agriculture. Thus it is a challenge for plant scientists to screen and develop the drought tolerant cotton lines. In this study, 31 cotton genotypes/cultivars were evaluated under two irrigation regimes i.e., seven irrigations (Control) and two irrigations (Stress), using split plot design with four replications. The crop growth, yield and some physiological parameters were studied. There were high inter-varietal differences for all the parameters under control as well as drought stress. Although all the varieties for all parameters were significantly affected by drought but however, CRIS-9, MARVI, CRIS-134, CRIS-126, CRIS-337, CRIS-355 and CRIS-377 maintained highest performance for all the parameters studied under high drought conditions.
  • Authors:
    • Srinivasan, G.
  • Source: Journal of Cotton Research and Development
  • Volume: 26
  • Issue: 1
  • Year: 2012
  • Summary: Field experiment was conducted at Cotton Research Station, Srivilliputtur during 2005-2008 to study the response of summer irrigated cotton to the preceding crop, residue management and INM practices. The results revealed that maize as a preceding crop was advantageous with its stalk incorporated with the highest seed cotton yield of 1573 kg/ha and was comparable with maize as a preceding crop with stalk removed. With regard to INM practices, application of 100 per cent RD of fertilizers+azophos registered the highest seed cotton yield and was comparable with 75 per cent RD of fertilizers+azophos, 100 per cent RD of fertilizers+FYM and 100 per cent RD of fertilizers alone indicating that 75 per cent RD of fertilizers+azophos was optimum to get economic yield.