• Authors:
    • Raundal, P. U.
    • Kambale, A. B.
    • Chaudhari, P. M.
    • Chitodkar, S. S.
  • Source: International Journal of Agricultural Sciences
  • Volume: 2
  • Issue: 2
  • Year: 2006
  • Summary: A study was conducted in Maharashtra, India during 2002, 2003 and 2004 under rainfed conditions to evaluate the effect of intercropping with pigeon pea (cv. BSMR-78), sorghum (cv. CHS-14) and cotton (cv. Y-1) on the productivity of soyabean (cultivars JS-335 and MACS-124). The spacings were 30 * 10, 65 * 20, 45 * 15 and 45 * 22.5 cm for soyabean, pigeon pea, sorghum and cotton, respectively, under soyabean intercropping, at 3:1 row proportion. Soyabean + pigeon pea produced the highest soyabean equivalent yield (24.06 q/ha), gross monetary returns (Rs. 30 322/ha), net monetary returns (Rs. 20 010/ha), land equivalent ratio (1.38) and benefit:cost ratio (2.92).
  • Authors:
    • Mohamed, A. E. M.
    • Arab, Y. A.
    • El-Shehaby, A. I.
  • Source: Egyptian Journal of Agricultural Research
  • Volume: 84
  • Issue: 1
  • Year: 2006
  • Summary: Growing some summer crops - preceding garlic - in heavily infested potted soil significantly reduced white rot disease (Sclerotium cepivorum) of garlic. Reductions in disease incidence obtained with sugarcane, roquette [ Eruca vesicaria] and sorghum as intercrops were 80.0, 73.3 and 66.7% of the control treatment, respectively. Reductions in disease incidence obtained with maize, squash, pepper, soyabean, cotton, sesame, cowpea and roselle ranged between 53.3 and 40.0%. Cauliflower, lucerne, broad bean, nigella, Egyptian clover, coriander and roquette grown in pots, as winter crops preceding garlic, exhibited 46.7-26.7% reduction in white rot disease. Intercropping cauliflower, coriander and roquette with garlic reduced the disease by 46.0-53.8%. Seedling root exudates of cauliflower, coriander and sorghum significantly reduced mycelial growth of S. cepivorum on PDA plates more than did radish and sugarcane. Cauliflower exhibited the highest reduction in mycelial growth, followed by sorghum and coriander. Ascending rates of cauliflower root exudates resulted in a higher reduction in fungus growth. Counts of fungi were significantly higher in soil of sorghum and roquette compared with sugarcane and coriander, while coriander rhizosphere yielded the highest density of fungi. Actinomycetes were detected in the rhizosphere at a highest count with coriander but were completely absent in the soil. Bacteria, in contrast, existed only in the soil where actinomycetes were completely absent. The highest count of bacteria was detected in sorghum soil. Actinomycetes inhabited soil only while bacteria and fungi existed in soil and rhizosphere of cauliflower, radish and garlic intercropped with the two crops. Cauliflower significantly increased counts of fungi and bacteria in rhizosphere when intercropped with garlic compared with those detected with garlic alone. Some recommendations are made.
  • Authors:
    • Kelly, K.
    • Baigent, R.
    • Eckard, R.
    • Weeks, I.
    • Leuning, R.
    • Phillips, F.
    • Barker-Reid, F.
    • Gates, W.
    • Grace, P.
    • Galbally, I.
    • Meyer, M.
    • Bentley, S.
  • Source: Environmental Sciences
  • Volume: 2
  • Issue: 2-3
  • Year: 2005
  • Authors:
    • De Janvry, A.
    • Qaim, M.
  • Source: Environment and Development Economics
  • Volume: 10
  • Issue: 2
  • Year: 2005
  • Summary: This article analyzes effects of insect-resistant Bt cotton on pesticide use and agricultural productivity in Argentina. Based on farm survey data, it is shown that the technology reduces application rates of toxic chemicals by 50 per cent, while significantly increasing yields. Using a damage control framework, the effectiveness of Bt versus chemical pesticides is estimated, and technological impacts are predicted for different farm types.Gross benefits could be highest for smallholder farmers, who are not currently using the technology. The durability of the advantages is analyzed by using biological models to simulate resistance development in pest populations. Rapid resistance buildup and associated pest outbreaks appear to be unlikely if minimum non-Bt refuge areas are maintained. Thus, promoting a more widespread diffusion of Bt cotton could amplify the efficiency, equity, and environmental gains. Conclusive statements about the technology's sustainability, however, require longer-term monitoring of possible secondary effects and farmers' behavior in maintaining refuges.
  • Authors:
    • Lal, R.
  • Source: Environment International
  • Volume: 31
  • Issue: 4
  • Year: 2005
  • Summary: Reducing and off-setting anthropogenic emissions of CO, and other greenhouse gases (GHGs) are important strategies of mitigating the greenhouse effect. Thus, the need for developing carbon (C) neutral and renewable sources of energy is more than ever before. Use of crop residue as a possible source of feedstock for bioenergy production must be critically and objectively assessed because of its positive impact on soil C sequestration.. soil quality maintenance and ecosystem functions. The amount of crop residue produced in the US is estimated at 367x10(6) Mg/year for 9 cereal crops, 450x10(6) Mg/year for 14 cereals and legumes, and 488x10(6) Mg/year for 21 crops. The amount of crop residue produced in the world is estimated at 2802x10(6) Mg/year for cereal crops, 3107x10(6) Mg/year for 17 cereals and legumes, and 3758x10(6) Mg/year for 27 food crops. The fuel value of the total annual residue produced is estimated at 1.5x10(15) kcal, about 1 billion barrels (bbl) of diesel equivalent, or about 8 quads for the US; and 11.3x10(15) kcal, about 7.5 billion bbl of diesel or 60 quads for the world. However, even a partial removal (30-40%) of crop residue from land can exacerbate soil erosion hazard, deplete the SOC pool, accentuate emission of CO, and other GHGs from soil to the atmosphere, and exacerbate the risks of global climate change. Therefore, establishing bioenergy plantations of site-specific species with potential of producing 10-15 Mg biomass/year is an option that needs to be considered. This option will require 40-60 million hectares of land in the US and about 250 million hectares worldwide to establish bioenergy plantations. (c) 2004 Elsevier Ltd. All rights reserved.
  • Authors:
    • Culpepper, A. S.
    • Young, B. G.
    • Mitchell, P. D.
    • Mueller, T. C.
  • Source: Weed Technology
  • Volume: 19
  • Issue: 4
  • Year: 2005
  • Summary: The value of glyphosate has been compromised in some fields where weed populations have developed resistance or tolerant species increased. Three case studies related to reduced control from glyphosate are: (1) a weed population that has become resistant to glyphosate, with horseweed in Tennessee as an example; (2) a weed population increases due to lack of control in ‘‘glyphosate only’’ systems, with tropical spiderwort in Georgia cotton used as an example; and (3) the hypothetical resistance of common waterhemp to glyphosate in Illinois. For each of these case studies, an economic analysis was performed using a partial budget approach. This economic analysis provides the cost of control to the farmer when glyphosate fails to control these weeds and gives a critical time in years to compare different glyphosate resistance management philosophies (applicable only before resistance has evolved). The cost of glyphosate-resistant horseweed in cotton-soybeancorn rotation in Western Tennessee was calculated to be $30.46/ha per year. The cost of tropical spiderwort in cotton in southern Georgia was calculated to be $35.07/ha per year. The projected cost if common waterhemp were to develop glyphosate resistance in a corn-soybean rotation in southern Illinois was projected to be $44.25/ha per year, and the critical time was determined to be greater than 20 yr, indicating that a resistance management strategy would extend the value of glyphosateresistant crops.
  • Authors:
    • Strickland, T. C.
    • Bednarz, C. W.
    • Truman, C. C.
    • Potter, T. L.
    • Bosch, D. D.
  • Source: Transactions of the ASAE
  • Volume: 48
  • Issue: 6
  • Year: 2005
  • Summary: Conservation tillage has significant potential as a water management tool for cotton production on sandy, drought-prone soils. Plant residue remaining at the soil surface from prior crops serves as a vapor barrier against water loss, reduces raindrop impact energy, slows surface runoff, and often increases infiltration. By increasing infiltration, the potential for greater plant-available water can be enhanced and irrigation requirements reduced. Five years of data were collected to quantify the hydrologic differences between strip till and conventional till production systems. Surface runoff and lateral subsurface flow were measured on six 0.2 ha plots in South Georgia in order to quantify the water-related effects of conservation tillage. Significant differences in surface and subsurface water losses were observed between the conventional and strip tilled plots. Surface runoff from the conventionally tilled plots exceeded that from the strip tilled plots, while subsurface losses were reversed. Surface runoff losses from the conventionally tilled plots exceeded those from the strip tilled plots by 81% (129 mm/year). Shallow lateral subsurface losses from the strip tilled plots exceeded those from the conventionally tilled plots by 73% (69 mm/year). Overall, a net annual gain of 60 mm of water was observed for the strip tilled plots.
  • Authors:
    • Mitchell, J. P.
    • Southard, R. J.
    • Baker, J. B.
  • Source: Journal of Environmental Quality
  • Volume: 34
  • Issue: 4
  • Year: 2005
  • Summary: The negative health effects of repeated dust exposure have been well documented. In California's San Joaquin Valley, agricultural operations may contribute substantially to airborne particulates. We evaluated four management systems to assess impacts on dust production and soil properties for a cotton (Gossypium hirsutum L.)-tomato (Lycopersicon esculentum Mill.) rotation: standard tillage with (STCC) and without (STNO) cover crop, and conservation tillage with (CTCC) and without (CTNO) cover crop. Gravimetric analysis of total dust (TD, < 100-mu m aerodynamic diameter) and respirable dust (RD, 4-mu m aerodynamic diameter) samples collected in the plume generated by field implements showed that dust concentrations for CTNO treatments were about one-third of their STNO counterparts for both cumulative TD and RD measured throughout the two-year rotation, primarily due to fewer in-field operations. The TD and RD production for STNO and STCC was comparable, whereas the CTCC system produced about twice as much TD and RD as CTNO. Energy dispersive spectroscopy (EDS) analyses showed absolute increases of 8 and 39% organic fragments in STCC and CTCC over STNO and CTNO, respectively, while organic fragments in the TD increased by 6% in both cover crop treatments. Soil C content was positively correlated with clay content and increased by an average of 0.12 and 0.07% in the cover crop and non-cover crop treatments, respectively, although soil C for each treatment showed a distinct response to a field texture gradient. While dust emissions show an immediate decrease due to fewer field operations for the conservation tillage treatments, long-term sampling is necessary to determine the effects that increased aggregation through organic matter additions may have on dust production.
  • Authors:
    • Blum, A.
  • Source: Australian Journal of Agricultural Research
  • Volume: 56
  • Issue: 11
  • Year: 2005
  • Authors:
    • Schulte, M.
  • Source: Gesunde Pflanzen
  • Volume: 57
  • Issue: 2/3
  • Year: 2005
  • Summary: Herbicide-resistant varieties currently play a key role among the genetically modified arable crops soyabean, cotton, oilseed rape, and maize grown worldwide. Reasons for the quick increase in areas cultivated by herbicide-resistant crops are, among others, shortcomings of existing chemical weed control solutions in these crops and an increase in cultivation methods using minimum tillage techniques. As a countermove, the minimum or no-till cropping area increased significantly, due to the introduction of herbicide-resistance technology, particularly in soybeans. Decision criteria during the past 8 years for choosing adequate weed control systems using herbicide-resistant or conventional varieties were: varietal performance, superior crop tolerance and application timing flexibility, efficacy of post-emergent weed control measures in dry areas, controlled weed spectrum, and duration of activity including control of resistant weed biotypes. Due to restrictive labelling instructions and lack of authorization in main overseas export markets, including European liability and coexistence rules, sales restrictions are essential decision parameters for individual farms. The technical progress of herbicide-resistance technology is achieved in the short and medium term by further development of spraying sequences and tank mixtures towards ready-formulated mixtures of complementary herbicides with conventional residual mixture partners. To control and prevent the spread of new herbicide-resistant weed biotypes, complementary herbicides are combined with other modes of action. Further developments are combinations of various other transgenic traits with transgenic herbicide resistance and herbicide-resistant varieties of (worldwide) less important minor crops without satisfying conventional chemical weed control solutions. For long-term developments, plastid transformation techniques to prevent the unwanted dissemination of transgenic features could gain importance.