19892015
  • Authors:
    • Buzetti, S.
    • Bergamaschine, A. F.
    • Ulian, N. de A.
    • Pariz, C. M.
    • Furlan, L. C.
    • Andreotti, M.
    • Meirelles, P. R. de L.
    • Cavasano, F. A.
  • Source: Revista Brasileira de Ciência do Solo
  • Volume: 35
  • Issue: 6
  • Year: 2011
  • Summary: The greatest limitation to the sustainability of no-till systems in Cerrado environments is the low quantity and rapid decomposition of straw left on the soil surface between fall and spring, due to water deficit and high temperatures. In the 2008/2009 growing season, in an area under center pivot irrigation in Selviria, State of Mato Grosso do Sul, Brazil, this study evaluated the lignin/total N ratio of grass dry matter, and N, P and K deposition on the soil surface and decomposition of straw of Panicum maximum cv. Tanzania, P. maximum cv. Mombaca, Brachiaria brizantha cv. Marandu and B. ruziziensis, and the influence of N fertilization in winter/spring grown intercropped with maize, on a dystroferric Red Latosol (Oxisol). The experiment was arranged in a randomized block design in split-plots; the plots were represented by eight maize intercropping systems with grasses (sown together with maize or at the time of N side dressing). Subplots consisted of N rates (0, 200, 400 and 800 kg ha -1 year -1) sidedressed as urea (rates split in four applications at harvests in winter/spring), as well as evaluation of the straw decomposition time by the litter bag method (15, 30, 60, 90, 120, and 180 days after straw chopping). Nitrogen fertilization in winter/spring of P. maximum cv. Tanzania, P. maximum cv. Mombaca, B. brizantha cv. Marandu and B. ruziziensis after intercropping with irrigated maize in an integrated crop-livestock system under no-tillage proved to be a technically feasible alternative to increase the input of straw and N, P and K left on the soil surface, required for the sustainability of the system, since the low lignin/N ratio of straw combined with high temperatures accelerated straw decomposition, reaching approximately 30% of the initial amount, 90 days after straw chopping.
  • Authors:
    • Sarker, S. C.
    • Patra, P. S.
    • Mula, G.
    • Paramanik, B.
  • Source: Journal of Crop and Weed
  • Volume: 7
  • Issue: 1
  • Year: 2011
  • Summary: Zero tillage saves tillage and irrigation costs, results in yield gains through a possible improvement in sowing time and enhanced fertilizer and water use efficiencies. The present study was conducted to explore the possibilities of saving critical inputs and to enhance the profit margin of the rural farmers of Uttar Dinajpur, Dakshin Dinajpur, Malda and Murshidabad districts of West Bengal through National Agricultural Innovation Project. Mean grain yield of 10 villages showed that zero tillage practices produced 8.004% more grain yield than conventional tillage method. On an average zero tillage method save total cost of Rs. 4449.67 ha -1 and increase profit margin of Rs. 7056.25 ha -1. Zero till field also recorded higher B:C ratio of 0.923 as compared to conventional tillage method (0.432).
  • Authors:
    • Carneiro, P. T.
    • Melo, A. S. de
    • Soares Filho, W. dos S.
    • Gheyi, H. R.
    • Brito, M. E. B.
    • Fernandes, P. D.
  • Source: Acta Scientiarum Agronomy
  • Volume: 33
  • Issue: 2
  • Year: 2011
  • Summary: Water and soil salinity affects the growth, development and production of fructiferous species, such as citrus. The use of tolerant rootstocks can guarantee the agribusiness of citrus under such conditions. Thus, the sensibility to salinity during the phase of rootstock formation of varieties and selected hybrids was studied. The experiment was carried out in a greenhouse, with five levels of irrigation water salinity [control, tap water with electrical conductivity (EC w) of 0.41 dS m -1, and water with EC w of 1.0, 2.0, 3.0 and 4.0 dS m -1] and seven genotypes, in a randomized block design and five replications each consisting of four plants, during 150 day period. Growth and physiologic variables were evaluated. Significant effects of genotypes and salinity in the variables were observed. The most expressive reduction was found for total dry matter with unit increase of EC w. A linear reduction was observed in hybrids LVK * LVA-009 and TSK * TRENG-256. Among the evaluated genotypes 'Volkamer' lemon was the least sensitive to saline stress.
  • Authors:
    • Hebbar, K. B.
    • Mayee, C. D.
  • Source: Current Science
  • Volume: 100
  • Issue: 11
  • Year: 2011
  • Summary: There are several reasons why plants wilt. Some of them are over-watering, lack of water, too much sun, not enough sun, too many/much fertilizers, diseases caused by infection, etc. Wilt due to lack of water or other environmental factors generally occurs gradually and hence, the cause of those can be studied and accordingly it can be controlled by devising appropriate management strategies. Moreover, plants recover with appropriate control measures and continue to yield. In this review, we discuss a typical wilt which is sudden and occurs within a few hours. Hence, understanding the cause and devising a control measure are difficult. Its sporadic distribution and untimely occurrence further complicate the effort to find the cause of this wilt. Unlike the wilt mentioned above which occurs due to lack of water, sudden wilt occurs when the soil is suddenly saturated by a downpour of rain and the sun later shines bright and hot. Paradoxically, the physiological responses, i.e. wilt symptoms to those induced by either drought or flooding are similar. However, the causal mechanism is different. Here, we demonstrate that the imbalance in uptake and loss of water under flooding is the cause of sudden/parawilt of cotton. We also discuss how plants with rapid growth rate and climate factors like bright sunshine and high temperature accentuate the problem of parawilt in cotton.
  • Authors:
    • Jansirani, R.
  • Source: Journal of Cotton Research and Development
  • Volume: 25
  • Issue: 2
  • Year: 2011
  • Summary: The study was conducted at Kovilpatti block of Tuticorin district of Tamil Nadu with the specific objective of studying extent of adoption of production technologies in Bt cotton by the growers. The area was selected based on the major cultivation of Bt areas and production of Bt cotton under irrigated condition. The selected respondents for this study were 90, who have adopted Bt cotton and non Bt cotton i.e 45 growers in each category by using simple random sampling method. The collected data were analyzed using percentage analysis. All the growers adopted Bt varieties and 95.55 per cent of the growers adopted appropriate time of planting. About 80.00 per cent of the growers adopted spacing. Three fourths (77.77%) of the growers adopted regular plucking intervals during harvest and 75.55 per cent of the growers adopted proper irrigation management followed by pest and diseases management (73.33%). More than fifty (66.66%) of the growers adopted preparation of fields to required tilth and formation of trenches followed by manures and fertilizers (62.22%) and number of split doses (57.77%). Out of ten technologies nine technologies were adopted more than fifty per cent by the growers due to the reasons that private firms have agreed to buy the produce from the farmers offering a minimum support prices. State Department of Agriculture has also introduced contract farming to assure remunerative prices to farmers.
  • Authors:
    • Krajewski, A. J.
    • Krajewski, S. A.
  • Source: Acta Horticulturae
  • Issue: 894
  • Year: 2011
  • Summary: Over the past 18 years, citrus canopy management strategies (CMS) were developed improving tree health, productivity, fruit quality and management efficiency of orchards in tropical Southern Africa and Australia. These CMS are based on understanding of knowledge of tree phenology and natural growth habit, recognition of fruiting habits of "strong" and "weak" bearing branch units (SBBU and WBBU respectively), tree physiology, floral biology, environmental physiology, effects of canopy illumination, branch sap flow patterns, and of effects on these of climate, weather, topography, altitude and local pest and disease cycles. Secondly, CMS were derived with an understanding of effects on tree physiology of specific pruning and regrowth management practices. Thirdly, cost-effective methods were developed of optimising growth, form and function of non-bearing trees, trees in full production, and old trees declining due to age and/or shading. The strategy is to create, after planting, strong, balanced tree frameworks, and to maintain these through the orchard's life by selectively pruning multiple light- and spray "channels" into the trees' canopies. As new "internal" growth arises and develops, fruiting is displaced to sheltered, well-lit and ventilated canopy interiors. Pruning specifically removes WBBU, and stimulates production of SBBU, directly subtended by scaffold branches in which sap flow is strong. These SBBU bear large, unblemished fruit of uniform high quality. Rejuvenation pruning of old trees is discussed, as is protection of leaf flush from the pests citrus leaf miner, thrips, leafhoppers and pathogens Citrus black spot (CBS), Asiatic citrus canker (ACC) and Huanglongbing (HLB). Also discussed are improvements observed to soil following additions of coarse, organic wood chip mulches derived from triturated prunings, and necessary adjustments in support of CMS to fertiliser practices, irrigation, pest-, disease- and orchard floor management.
  • Authors:
    • Robles-Gonzalez, M. M.
    • Virgen-Calleros, G.
    • Vazquez-Garcia, M.
    • Medina-Urrutia, V. M.
  • Source: Acta Horticulturae
  • Issue: 894
  • Year: 2011
  • Summary: This work was carried out to determine the influence of seasons of vegetative shoots on the time of flowering and to known the intervals from flowering to fruit harvest of Mexican lime trees. Two experiments on a seven years old Mexican lime trees budded on Sour Orange rootstock were established. In experiment 1, the number of vegetative (VS) and reproductive shoots (RS) on each one of 10 trees were registered weekly during one year, using a metallic ring of one square meter area placed on the tree 1.75 m from the ground. Minimum temperature and rainfall data were also recorded every week. In experiment 2, monthly, ten new vegetative shoots on each one of ten trees were tagged. These shoots were observed every week until they bloom. During the most important periods of blooming, five flowering shoots per tree were chosen to determine interval to harvest. In experiment 1, four VS and two RS flushes were observed. The first period of VS and RS started in autumn and was associated to the initiation of irrigation. The second and more important was registered in January when temperatures were the lowest of the year. Half RS and half VS were recorded during this period. The third and four flushes were mainly VS and occurred during summer months with highest temperatures and the rainy season. In experiment 2, from the vegetative shoots emerging in January, 52% formed reproductive shoots 60-85 days later and 25% also flowered sparsely four to six months later. The remaining shoots (23%) repeated their vegetative activity during June and July. Most of the vegetative shoots initiated in February showed again a vegetative activity during May to July, and only 20% of them changed to reproductive. New vegetative shoots appeared from March to July showed a vegetative activity during the next two to six months. From the vegetative shoots emerged from July to September very few (15%) transformed to reproductive during November-December and the majority became vegetative again, however, most of them changed to reproductive from January to April. Fruits initiating during the winter time lasted 130 to 145 days until harvest. But those fruits emerged during the late spring and summer months reached complete development 90 to 120 days later. These combined phenological characteristics explain the long period of harvest showed by the MLT under tropical semiarid conditions.
  • Authors:
    • Murari, L.
  • Source: Regional Environmental Change
  • Volume: 11
  • Issue: Supplement 1
  • Year: 2011
  • Summary: One of the targets of the United Nations 'Millennium Development Goals' adopted in 2000 is to cut in half the number of people who are suffering from hunger between 1990 and 2015. However, crop yield growth has slowed down in much of the world because of declining investments in agricultural research, irrigation, and rural infrastructure and increasing water scarcity. New challenges to food security are posed by accelerated climatic change. Considerable uncertainties remain as to when, where and how climate change will affect agricultural production. Even less is known about how climate change might influence other aspects that determine food security, such as accessibility of food for various societal groups and the stability of food supply. This paper presents the likely impacts of thermal and hydrological stresses as a consequence of projected climate change in the future potential agriculture productivity in South Asia based on the crop simulation studies with a view to identify critical climate thresholds for sustained food productivity in the region. The study suggests that, on an aggregate level, there might not be a significant impact of global warming on food production of South Asia in the short term (
  • Authors:
    • Grace, P.
    • Barton, L.
    • Chen, D.
    • Eckard, R.
    • Kelly, K.
    • Officer, S.
    • Scheer, C.
    • Schwenke, G.
    • Wang, W.
  • Source: Soil Solutions for a Changing World
  • Year: 2011
  • Authors:
    • Grace, P.
    • Robertson, G. P.
    • Butterbach-Bahl, K.
  • Source: ASA-CSSA-SSSA Annual Meeting
  • Year: 2011