• Authors:
    • Pringle, H. C.,III
    • Martin, S. W.
  • Source: Journal of Cotton Science
  • Volume: 7
  • Issue: 4
  • Year: 2003
  • Summary: Deep tillage at a 45 angle has been a recommended practice since the mid-1970s on most Mississippi Delta cotton soils. This practice disrupts hard pans and allows deeper wetting of the soil profile with winter rainfall. The newest deep tillage "subsoiler" designs (Paratill, low-till parabolic) have the shank extending through the soil at an angle, thereby reducing soil surface disturbance and allowing the subsoiler to run under the row in the direction of the row, without the shank passing directly through the drill. Both centre pivot and furrow irrigation of cotton has expanded since the early 1980s. With intermittent rainfall, irrigation is supplemental and represents a type of insurance against yield uncertainty during extended periods of water deficit. Field experiments were conducted at Stoneville, Mississippi, USA, during 1994-2001, to determine the long-term effects of sprinkler irrigation and in-row subsoil tillage on cotton yield and economic return of cotton cultivars DES119 (1994-95), SG125 (1996-99) and SG747 (2000-01) on silt loam soil from 1994 to 2001. In-row subsoil tillage was performed with a low-till parabolic subsoiler and irrigation was applied with an overhead lateral-move sprinkler irrigation system. Production costs were calculated for direct costs and total specified costs excluding land rent, general farm overheads and returns to management. Average net returns were calculated as the difference between income at the cotton loan rate of $1.15 per kg of lint and total specified costs. Returns were maximized with either the irrigated, non-subsoiled or the non-irrigated, subsoiled environments. Lower returns occurred in the irrigated, subsoiled environment due to the higher costs and lack of yield increase.
  • Authors:
    • Mundra, M. C.
    • Singh, B. P.
    • Gupta, S. C.
  • Source: Crop Research (Hisar)
  • Volume: 25
  • Issue: 3
  • Year: 2003
  • Summary: Field experiments were conducted in Haryana, India, on sandy loam soil to investigate the suitability of various cropping systems under irrigated conditions in an semi-arid environment. Thirteen kharif-rabi-summer cropping systems were tested and recommended rates of NPK fertilizers were applied to each crop. Among the cropping systems, pearl millet-potato-tomato, pearl millet-potato-green gram, cotton-wheat and soyabean-wheat-fodder cowpea produced yields of 13 948, 10 374, 8965 and 8316 kg/ha, respectively, on an equivalent basis. The lowest yield (6065 kg/ha) was obtained in the pearl millet-Indian mustard system. The maximum net return of Rs. 42 462/ha, benefit:cost ratio of 2.43, system productivity of 42.26 kg/ha per day, land use efficiency of 90.41% and total energy of 48 521 Cal * 100 calories were obtained from the pearl millet-potato-tomato system. The maximum stability indices of 0.98, 0.96 and 0.79 for kharif, rabi and summer seasons, respectively, were obtained in the pearl millet-mustard and pearl millet-mustard-fodder maize systems. The maximum system index of 0.90 was obtained in the fodder sorghum-wheat system followed by soyabean-wheat-fodder cowpea with 0.83. Pearl millet-potato-greengram showed the maximum risk of Rs. 10 915/ha, while the lowest risk of Rs. 3847/ha was obtained in the pigeon pea-wheat system.
  • Authors:
    • Zhou, R. L.
    • Zhang, T. H.
    • Zhao, H. L.
  • Source: Acta Pedologica Sinica
  • Volume: 40
  • Issue: 2
  • Year: 2003
  • Summary: Results are presented of a field experiment conducted on soil environment and productivity formation process of maize in 5 major types of farmlands of Horqin, Nei Menggu, China. The 5 main types of cropland are irrigated sandy loam, irrigated loam sandy soil, dry slope land of sandy loam, dryland of sandy loam, and dryland of sandy soil. The average soil water content, soil temperature, integrated index of soil nutrients, and height and biomass of maize are determined. The correlation coefficients between biomass and soil indexes, in terms of N, P, K, soil moisture and soil organic matter are also determined.
  • Authors:
    • Featherstone, A. M.
    • Langemeier, M. R.
    • Abdulkadri, A. O.
  • Source: Applied Economics
  • Volume: 35
  • Issue: 7
  • Year: 2003
  • Summary: The risk attitudes of dryland wheat, irrigated maize, and dairy producers in Kansas, USA, are examined using the nonlinear mean-standard deviation approach. Observations on farm characteristics, obtained from 1993-97, and the statewide market year average prices for wheat and maize from 1950-97, are used. Results of analyses indicated that dryland wheat and dairy producers are characterized by increasing absolute and increasing relative risk aversion while irrigated maize producers are characterized by constant absolute and increasing relative risk aversion. Both crop enterprises exhibited constant returns to scale technology while the dairy enterprise exhibited decreasing returns to scale. Gross farm income was significant and positively related to relative risk aversion.
  • Authors:
    • Bacon, R. K.
    • Gibbons, J.
    • Moldenhauer, K. A. K.
    • Windham, T. E.
    • Anders, M. M.
    • McNew, R. W.
    • Grantham, J.
    • Holzhauer, J.
  • Source: Research Series - Arkansas Agricultural Experiment Station
  • Issue: 504
  • Year: 2003
  • Summary: Rotation, tillage, and variety main effects on grain yield were all significant in 2002. Rice grain yield, over all treatment combinations, averaged 159 bu/acre, which was 22 bu/acre more than in 2001. Grain yields for the two 3-phase rotations were 180 bu/acre for the rice-corn-soybeans rotation and 177 bu/acre for the rice-corn (wheat)-soybean rotation. These yields were slightly better than the 174 bu/acre yield from the rice-soybean rotation and 165 bu/acre from the rice-corn rotation. Grain yield declined 13 bu/acre in the continuous rice treatments when compared to 2001 yields and 27 bu/acre from the 2000 yields. Plant growth was poor in all the continuous rice plots with leaf nitrogen (N) levels lower than in other rotations. Conventional tillage treatment combinations yielded 17 bu/acre more than the no-till combinations, but this difference varied between rotations. For the continuous rice rotation, the conventional-till yielded 37 bu/acre more than the no-till whereas the same difference was 14 bu/acre in the rice-soybean rotation. There was a non-significant 7 bu/acre increase in rice yield over all treatment combinations with the 'enhanced' fertility treatments when compared to the 'standard' fertility treatments. Wells yielded a non-significant 7 bu/acre better than LaGrue across all treatments. Rice grain yield from the two rotations where rice was planted after wheat averaged 144 bu/acre-significantly higher than any previous year. There was an overall yield loss of 12 bu/acre from no-till when compared to conventional tillage, a 4 bu/acre gain from increased fertility, and a 16 bu/acre gain from the variety XL-7 when compared to RU1093. Of all the treatment combinations in this comparison the no-till rice (wheat)-soybean (wheat) rotation using enhanced fertility and the variety XL-7 was the most productive with a rice yield of 181 bu/acre and a wheat yield of 77 bu/acre. Overall, irrigation-water use declined from the previous year with an average of 26 inches needed for the conventional till treatments and 24 inches for the no-till treatments. Continuous rice needed only 17 inches of irrigation while all other rotations required between 28 and 32 inches.
  • Authors:
    • Marland, G.
    • West, T. O.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 91
  • Issue: 1-3
  • Year: 2002
  • Summary: The atmospheric CO2 concentration is increasing, due primarily to fossil-fuel combustion and deforestation. Sequestering atmospheric C in agricultural soils is being advocated as a possibility to partially offset fossil-fuel emissions. Sequestering C in agriculture requires a change in management practices, i.e. efficient use of pesticides, irrigation, and farm machinery. The C emissions associated with a change in practices have not traditionally been incorporated comprehensively into C sequestration analyses. A full C cycle analysis has been completed for agricultural inputs, resulting in estimates of net C flux for three crop types across three tillage intensities. The full C cycle analysis includes estimates of energy use and C emissions for primary fuels, electricity, fertilizers, lime, pesticides, irrigation, seed production, and farm machinery. Total C emissions values were used in conjunction with C sequestration estimates to model net C flux to the atmosphere over time. Based on US average crop inputs, no-till emitted less CO2 from agricultural operations than did conventional tillage, with 137 and 168 kg C ha(-1) per year, respectively. Changing from conventional tillage to no-till is therefore estimated to both enhance C sequestration and decrease CO2 emissions. While the enhanced C sequestration will continue for a finite time, the reduction in net CO2 flux to the atmosphere, caused by the reduced fossil-fuel use, can continue indefinitely, as long as the alternative practice is continued. Estimates of net C flux, which are based on US average inputs, will vary across crop type and different climate regimes. The C coefficients calculated for agricultural inputs can be used to estimate C emissions and net C flux on a site-specific basis. Published by Elsevier Science B.V.
  • Authors:
    • Shewmaker, G. E.
    • Sojka, R. E.
    • Entry, J. A.
  • Source: Soil Science Society of America Journal
  • Volume: 66
  • Issue: 6
  • Year: 2002
  • Summary: Increasing the amount of C in soils may be one method to reduce the concentration of CO2 in the atmosphere. We measured organic C stored in southern Idaho soils having long term cropping histories that supported native sagebrush vegetation (NSB), irrigated mold-board plowed crops (IMP), irrigated conservation-chisel-tilled crops (ICT), and irrigated pasture systems (IP). The CO2 emitted as a result of fertilizer production, farm operations, and CO2 lost via dissolved carbonate in irrigation water, over a 30-yr period was included. Net organic C in ecosystems decreased in the order IP>ICT>NSB>IMP. In this study if NSB were converted to IMP, 0.15 g C m-2 would be emitted to the atmosphere, but if convered to IP 3.56 g C m-2 could be sequestered. If IMP land were converted to ICT, 0.95 g C m-2 could be sequestered in soil and if converted to IP 3.71 g C m-2 could be sequestered. There are 2.6 x 10 ^8 ha of land worldwide presently irrigated. If irrigated ariculture were expanded 10% and the same amount of rainfed land were converted back to native grassland, an increase of 3.4 x 10^9 Mg C (5.9% of the total C emitted in the next 30 yr) could potentially be sequestered. The total projected release of CO2 is 5.7x 10^10 Mg C worldwide during the next 30 yr/ Converting rainfed agriculture back to native vegetation while modestly increasing areas in irrigated agriculture could have a significant impact on CO2 atmospheric concentrations while maintaining or increasing food production.
  • Authors:
    • Haqqani, A. M.
    • Munir, M.
    • Mann, R. A.
  • Source: Pakistan Journal of Agricultural Research
  • Volume: 18
  • Issue: 1
  • Year: 2002
  • Summary: Rice-wheat cropping system is the most important one in Pakistan. The system provides food and livelihood for more than 15 million people in the country. The productivity of the system is much lower than the potential yields of both rice and wheat crops. With the traditional methods, rice-wheat system is not a profitable one to many farmers. Hence, Cost of cultivation must be reduced and at the same time, efficiency of resources like irrigation water, fuel, and fertilizers must be improved to make the crop production system more viable and ecofriendly. Resource conserving technology (RCT) must figure highly in this equation, since they play a major role in achieving the above goals. The RCT include laser land leveling, zero-tillage, bed furrow irrigation method and crop residue management. These technologies were evaluated in irrigated areas of Punjab where rice follows wheat. The results showed that paddy yield was not affected by the new methods. Direct seeding of rice crop saved irrigation water by 13% over the conventionally planted crop. Weeds were the major problem indirect seeded crop, which could be eliminated through cultural, mechanical and chemical means. Wheat crop on beds produced the highest yield but cost of production was minimum in the zero-till wheat crop. Planting of wheat on raised beds in making headway in lowlying and poorly drained areas. Thus, resource conserving tillage technology provides a tool for making progress towards improving and sustaining wheat production system, helping with food security and poverty alleviation in Pakistan in the next few decades.
  • Authors:
    • Norsworthy, J. K.
    • Oliver, L. R.
  • Source: Weed Technology
  • Volume: 16
  • Issue: 1
  • Year: 2002
  • Summary: A field experiment was conducted in 1998 and 1999 at Keiser, AR, to evaluate glyphosate timing and soybean population in reducing hemp sesbania and pitted morningglory interference with dryland and irrigated glyphosate-resistant soybean under a narrow row, no-till production system. Soybean densities following emergence were 247,000, 475,000, and 729,000 plants/ha. Glyphosate was applied at 0.56 kg ai/ha at the V2; V4; V2 and V4; and V2, V4, and R2 stages of soybean. In dry portions of the growing season, glyphosate increased moisture availability for dryland soybean because of control of hemp sesbania and pitted morningglory. As soybean population increased from 247,000 to 729,000 plants/ha, pitted morningglory and hemp sesbania control increased from 60 to 91%, respectively, for the V2 glyphosate application. Control of both species at 14 wk after emergence was at least 90% following the V4 alone treatment and sequential applications, with no differences in control among soybean populations. Untreated, irrigated hemp sesbania produced up to 32 million seeds/ha in 1999. Irrigation did not influence pitted morningglory seed production either year, and untreated pitted morningglory produced a maximum of 1 million seeds/ha in 1998 at 247,000 soybean plants/ha. Three sequential applications of glyphosate reduced pitted morningglory seed production to 9,000 seeds/ha and eliminated hemp sesbania seed production. Soybean yielded 1,297 kg/ha greater under irrigated than dryland conditions, whereas increasing soybean density from 247,000 to 729,000 plants/ha resulted in 416 kg/ha improvement in seed yield. At the densities of pitted morningglory and hemp sesbania present in this study, seed yield of drill-seeded soybean can be maximized following a V4 alone treatment or sequential glyphosate applications.
  • Authors:
    • Krishnappan, B. G.
    • Stone, M.
  • Source: Water Research
  • Volume: 36
  • Issue: 14
  • Year: 2002
  • Summary: A field-scale no-till corn plot (120 m * 90 m) located on a tile drained silt loam soil near Kintore, Ontario was irrigated with 2.5 cm of water over a 3 h period to examine the effects of irrigation on tile sediment transport in a headwater stream. Flow characteristics and the composition, concentration and size distribution of suspended solids were measured at the tile outlet, an upstream reference site and three sites located downstream of the tile drain. Results show that tile sediments at the study site are fine-grained ( D50=5.0 m) and consist primarily of quartz, anorthite/albite, dolomite and calcite. Sediment concentrations in tile effluent increased from 8 to 57 mg L -1 after 1.5 h of irrigation and reached a maximum of 72 mg L -1. The sediment yield from the tile drain for the irrigation event was 4.6 kg ha -1. An unsteady, mobile boundary flow model (MOBED) was used to predict flow characteristics in the stream. According to the MOBED model, bed shear stress in the stream was approximately 6 N m -2. This value is significantly greater than the critical shear stress for complete suspension of 1 N m -2 for tile sediments as determined from laboratory experiments using a rotating circular flume. Grain size distributions of suspended solids in the stream were close to the dispersed size distribution because of the high shear stress in the receiving stream.