• Authors:
    • Counce, P. C.
    • Gordon, E. C.
    • Keisling, T. C.
    • Oliver, L. R.
    • Manning, P. M.
    • Popp, M. P.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 34
  • Issue: 19/20
  • Year: 2003
  • Summary: Clay soils are difficult to manage to obtain a soyabean [ Glycine max (L.) Merr.] stand, especially when dry. A novel production system, recently observed on several farms in Arkansas, consists of bedding the dry clayey soil with disk-bedders, broadcasting the soyabean seed over the surface, re-bedding the seedbed to cover the seed, rolling the beds to flatten the tops and finally furrow irrigating immediately thereafter. Typically this planting system provides a stand of soyabean within 4 to 6 days after irrigation and is designated as "hipped" after the common reference of a disk-bedder as a hipper. Studies were conducted on Sharkey soil at Keiser, AR from 1998 to 2000 for comparing this "hipped" system to more widely used planting methods. On dry clayey soils, a randomized complete block design with three replications was used to compare full-season soyabean under a conventional 96-cm row system, drilled-planting into a stale seedbed, and the "hipped" system. A similar study for double-cropped wheat-soybean involved straw management (burn or leave) coupled with no-till drill, tilled drill, and "hipped" systems. Other small studies on the "hipped" system were conducted to investigate the sensitivity to planting depth, soyabean plant population, and suitability for obtaining a stand on other crops such as cotton [ Gossypium hirsutum (L.)] and grain sorghum [ Sorghum bicolor (L.) Moench]. The "hipped" system worked well for obtaining stands of soyabean, cotton, and grain sorghum. In essence the "hipped" system (1) provides insurance against poor planting conditions; (2) allows for a reduction in the uncertainty of planting and stand establishment time required; (3) can be used to achieve high plant populations; (4) requires a relatively higher seeding rate in double-crop than full-season systems; (5) shows promise for situations when wheat stubble burning becomes curtailed especially if planting can occur early to lead to improved canopy coverage and (6) leads to yield reductions in fields where depth of seed placement cannot be controlled easily.
  • Authors:
    • Tope, K. L.
    • Gaddis, S. E.
    • Petersen, B. E.
    • Sterner, R. T.
    • Poss, D. J.
  • Source: Crop Protection
  • Volume: 22
  • Issue: 4
  • Year: 2003
  • Summary: During 2000-2001, small mammals, birds, and potential corn/soybean damage were studied at a low-tillage, non-irrigated agricultural research site in the Colorado Piedmont. A small mammal survey involved four trapping sessions and 18, 12-live-trap grids each. Within years, two grids each were placed at random, fixed locations in experimental corn, fallow, millet, pea, soyabean, sunflower, and wheat plots at the site; two off-plot grids each were set at random, fixed locations
  • Authors:
    • Huang, D. L.
    • Dai, Z. Y.
    • Liang, G. W.
    • Pang, X. F.
    • Yang, Y. Z.
  • Source: Journal of Yangzhou University, Agricultural and Life Sciences Edition Issue: 2
  • Volume: 24
  • Issue: 2
  • Year: 2003
  • Summary: The development of cotton bollworm (H. armigera) fed with different host foods was investigated. Higher values for pupal weight and eggs per female were recorded for the cotton bollworms fed with pea and soyabean leaves, compared with those fed with aubergine fruit and groundnut leaf. The rate larval development was highest with pea leaf, followed by maize fruits, and lowest for cotton leaf, flower, bud and boll. Based on values of the index of population trend, the preference of the cotton bollworm to different host foods were as follows: pea > soyabean > maize > Chinese sorghum > cotton > groundnut > aubergine. The results of a study of the dynamics of the cotton bollworm population in a cotton field in China are presented.
  • Authors:
    • Beghin, J. C.
    • Fang, C.
  • Source: Agricultural trade and policy in China: issues, analysis and implications
  • Year: 2003
  • Summary: This chapter assesses the protection and comparative advantage of China's major agricultural crops in six regions, using a modified Policy Analysis Matrix and 1997-2000 data. The following commodities are considered: early indica rice, late indica rice, japonica rice, wheat, maize, sorghum, soyabean, rapeseed, cotton, tobacco, sugarcane, and a subset of fruits and vegetables. The results suggest that, with the exception of high quality rice, the production of grains and oilseeds tends to suffer from a lack of comparative advantage over other crops in China, such as fruit and vegetables, tobacco and cotton. Further, it is concluded that grain self-sufficiency policies reduce allocative efficiency several-fold.
  • Authors:
    • Anand, K. V.
    • Katyal, V.
    • Gangwar, B.
  • Source: Indian Journal of Agricultural Science
  • Volume: 73
  • Issue: 9
  • Year: 2003
  • Summary: An experiment was conducted in Akola, Parbhani and Rahuri, Maharashtra, India to evaluate the productivity of various cropping sequences. In Akola (1987-88 to 1997-98) representing Vidharbha zone, the cropping sequence involving upland cotton ( Gossypium hirsutum)-groundnut ( Arachis hypogaea) was the most suitable and efficient, resulting in the highest grain-equivalent yield (10 079 kg ha -1 year -1), productivity (43.82 kg day -1 ha -1 wheat grain equivalent), profitability (49 539 rupees ha -1 year -1), economic efficiency (135.7 rupees day -1 ha -1) and land use efficiency (90.0%), and good benefit:cost ratio (16.57) and stability (0.68). However, in terms of energetics, soyabean ( Glycine max)-groundnut sequence was superior. In Central Maharashtra Plateaux Zone, cotton-groundnut sequence was also identified as the most efficient based on an 8-year study at Parbhani (1990-91 to 1997-98). This sequence gave the highest yield (12 060 kg ha -1 year -1 wheat grain equivalent), productivity (50.04 kg day -1 ha -1), profitability (62 053 rupees ha -1 year -1), economic efficiency (170.0 rupees day -1 ha -1) and land use efficiency (85%), with moderate system stability (0.59). In terms of energetics, soyabean-Indian mustard ( Brassica juncea) was superior. At Rahuri, representing western Maharashtra scarcity zone, sole sugarcane recorded the highest net return (93 429 rupees ha -1 year -1), economic efficiency (255.9 rupees ha -1 day -1) and benefit:cost ratio (19.96). Sorghum ( Sorghum bicolor)-cabbage ( Brassica oleracea var. capitata)-cowpea ( Vigna unguiculata) was equally profitable for fodder, resulting in a wheat grain yield equivalent of 22 793 kg ha -1 year -1, productivity of 94.2 kg day -1 ha -1, profitability of 81 733 rupees ha -1 year -1, economic efficiency of 223.9 rupees day -1 ha -1, and carbohydrate production of 4.69 g 10 6/ha.
  • Authors:
    • Jones, R. H.
    • Leonard, B. R.
    • Gore, J.
  • Source: Environmental Entomology
  • Volume: 32
  • Issue: 1
  • Year: 2003
  • Summary: Field and laboratory studies evaluated the influence of selected crop hosts on Helicoverpa zea population dynamics in relation to genetically engineered Bt (Bollgard) and non-Bt cottons. Host specific H. zea colonies were initiated with a colony originally collected from sweetcorn. The colony was allowed to complete one generation on meridic diet then split into cohorts and allowed to complete one generation on field maize, grain sorghum, soyabean, cotton, or meridic diet in individual 29.5 ml plastic cups. During the first part of the study, larval developmental times, pupal weights, and survival were measured. H. zea survival was higher on meridic diet and grain sorghum than on soyabean and cotton. The development of H. zea larvae was faster on field maize than the other larval diets. Also, H. zea required a longer period of time to complete development on cotton than on the other hosts. Pupal weights were higher on meridic diet than the plant hosts. Pupal weights of H. zea that completed larval stadia on cotton were lower than on the other larval diets. Neonates (F 1) from each of the host specific colonies (200 per colony) were exposed to Bt and non-Bt cottons. Mortality of second generation H. zea on non-Bt and Bt cottons was measured at 96 h. H. zea larvae from the cotton colony had higher mortality on non-Bt cotton than the other host specific colonies except the grain sorghum colony. On Bt cotton, larvae from the maize colony had a higher level of mortality than larvae from the soyabean and grain sorghum colonies. These data provide valuable information for evaluating the contribution of cultivated hosts as additional, alternative refugia in Bt-cotton resistance management plans.
  • 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:
    • Post, W. M.
    • West, T. O.
  • Source: Soil Science Society of America Journal
  • Volume: 66
  • Issue: 6
  • Year: 2002
  • Summary: Changes agricultural management can potentially increase the accumulation rate of soil organic C (SOC), thereby sequestering CO2 from the atmosphere. This study was conducted to quantify potential soil C sequestration rates for different crops in response to decreasing tillage intensity or enhancing rotation complexity, and to estimate the duration of time over which sequestration may occur. Analyses of C sequestration rates were completed using a global database of 67 long-term agricultural experiments, consisting of 276 paired treatments. Results indicate, on average, that a change from conventional tillage (CT) to no-till (NT) can sequester 57 +/- 14 g C m(-2) yr(-1), excluding wheat (Triticum aestivum L.)-fallow systems which may not result in SOC accumulation with a change from CT to NT. Enhancing rotation complexity can sequester an average 20 +/- 12 g C m(-2) yr(-1), excluding a change from continuous corn (Zea mays L.) to corn-soybean (Glycine mar L.) which may not result in a significant accumulation of SOC. Carbon sequestration rates, with a change from CT to NT, can be expected to peak in 5 to 10 yr with SOC reaching a new equilibrium in 15 to 20 yr. Following initiation of an enhancement in rotation complexity, SOC may reach a new equilibrium in approximately 40 to 60 yr. Carbon sequestration rates, estimated for a number of individual crops and crop rotations in this study, can be used in spatial modeling analyses to more accurately predict regional, national, and global C sequestration potentials.
  • Authors:
    • Albrecht, A.
    • Sa, J. C. D.
    • Ogle, S. M.
    • Denef, K.
    • Feller, C.
    • Six, J.
  • Source: Agronomie
  • Volume: 22
  • Issue: 7
  • Year: 2002
  • Summary: The long-term stabilization of soil organic matter (SOM) in tropical and temperate regions is mediated by soil biota (e. g. fungi, bacteria, roots and earthworms), soil structure (e. g. aggregation) and their interactions. On average, soil C turnover was twice as fast in tropical compared with temperate regions, but no major differences were observed in SOM quality between the two regions. Probably due to the soil mineralogy dominated by 1:1 clay minerals and oxides in tropical regions, we found a higher aggregate stability, but a lower correlation between C contents and aggregate stability in tropical soils. In addition, a smaller amount of C associated with clay and silt particles was observed in tropical versus temperate soils. In both tropical and temperate soils, a general increase in C levels (approximate to 325 +/- 113 kg C.ha(-1).yr(-1)) was observed under no-tillage compared with conventional tillage. On average, in temperate soils under no-tillage, compared with conventional tillage, CH4 uptake (approximate to0.42 +/- 0.10 kg C-CH4.ha(-1) yr(-1)) increased and N2O emissions increased (approximate to 1.95 +/- 0.45 kg N-N2O.ha(-1).yr(-1)). These increased N2O emissions lead to a negative global warming potential when expressed on a CO2 equivalent basis.