• Authors:
    • Smith, H. J.
    • Trytsman, G.
    • Bloem, J. F.
  • Source: Biological Nitrogen Fixation: Towards Poverty Alleviation through Sustainable Agriculture
  • Volume: 48
  • Issue: 1-3
  • Year: 2009
  • Summary: Farm lands of resource-poor communities in South Africa are depleted of nutrients due to continuous mono-cropping, limited use of fertilisers, and sometimes leaching caused by high rainfall. Despite the well-known advantages of biological nitrogen fixation (BNF) in cropping systems, less than 10% of the grain crops planted annually in these areas are legumes. Using a participatory research and development approach, resource-poor farmers were introduced to conservation agriculture (CA) practices, including BNF, that promoted zero (or reduced) tillage, increased retention of soil cover, as well as crop diversification. Because crop rotation and intercropping of legumes with cereals are known to contribute to soil fertility while enhancing food security, resource-poor fanners from various Provinces in South Africa were trained on the benefits of legume culture for eight years. As a result, these resource-poor farmers did not only get training in inoculation techniques, but were also supplied with inoculants for use on their farms. Data collected from Farmers Demonstration Trials at Belvedere, Dumbarton and Lusikisiki, showed that the grain and fodder yield of maize planted after legumes, and maize intercropped with legumes, were comparable to those of maize receiving high N fertilizer dose (i.e. 54 kg N at planting and 54 kg N as top-dressing). The same data further showed that Rhizobium inoculation, when combined with application of low levels of P and K. significantly increased crop yields within farmers' trial plots. BNF therefore offers a great opportunity for resource-poor farmers in South Africa to increase their crop yields and thus improve the quality of their livelihoods through the adoption of affordable and sustainable biological technologies that enhance soil fertility.
  • Authors:
    • Gathala, M. K.
    • Singh, K. K.
    • Sharma, S. K.
    • Saharawat, Y. S.
    • Tetarwal, J. P.
    • Ladha ,J. K.
    • Gupta, R. K.
    • Jat, M. L.
    • Singh, S.
  • Source: ACIAR PROCEEDINGS
  • Issue: 127
  • Year: 2008
  • Summary: Resource-conserving technologies with double no-till practices represent a major shift in production techniques for attaining optimal productivity, profitability and water use in rice-wheat (RW) systems in the Indo-Gangetic Plain. Permanent raised beds (PRB) and double no-till with flat layouts are under evaluation for RW systems for a range of soils, climate, cultivars and seeding/crop establishment techniques (dry seeding, transplanting). To date, results have been inconsistent and systematic information on trials with PRB is lacking. Four researcher- and farmer-managed experiments were conducted with various tillage and crop establishment techniques for RW on PRB and flat layouts. The yield of rice on PRB was significantly lower than that on double no-till flat layouts, whereas wheat yield was highest on PRB. The total RW system yield with PRB was similar to that of other tillage and crop establishment techniques. However, irrigation and input (irrigation plus rain) water productivity (kg grain/m 3 of water) of both rice and wheat was much higher on PRB. In farmer-managed trials of transplanted basmati rice on PRB, profitability was highest on PRB (US$684/ha) and lowest with traditional practices (US$531/ha). In a researcher-managed long-term experiment, the soil physical properties (bulk density, mean weight diameter of aggregates, cone index and infiltration rate) improved significantly on PRB compared with the conventional puddled transplanted rice-tilled wheat system.
  • Authors:
    • Pringle, H.
    • Ebelhar, M.
    • Martin, S.
  • Source: Journal of Cotton Science
  • Volume: 12
  • Issue: 4
  • Year: 2008
  • Summary: Increasing available soil water for a crop can be accomplished with both deep tillage and irrigation. Both have the potential to replace or complement the other due to their common function. The addition of a crop rotation may also enhance or diminish the response from irrigation and/or deep tillage. The major objective of this study was to determine long-term effects of different levels of furrow irrigation and in-row subsoil tillage on lint yield and economic returns for cotton grown on alluvial silty clay loam soils in a cotton/corn cropping sequence. A secondary objective was to determine the ability and efficiency of deep tillage and irrigation to replace and/or complement each other in the cropping system. Field experiments were conducted at Tribbett, MS on silty clay loam soils from 1999 through 2004. In-row subsoil tillage was performed with a low-till parabolic subsoiler. A roll-out pipe system was used to furrow water the irrigated plots. Production costs were calculated and include direct costs plus total specified costs excluding land rent, general farm overhead, and returns to management. Growing non-irrigated cotton without deep tillage in this cotton/corn sequence on these silty clay loam soils that were prone to backwater flooding gave the highest average net returns. It appears producers should neither subsoil, nor furrow irrigate and the two should never be combined, based on this study. These results emphasize the need for drainage and support the need for further research on these type soils in the absence of drainage problems.
  • Authors:
    • Reddy, K. C.
    • Reddy, S. S.
    • Nyakatawa, E. Z.
    • Raper, R. L.
    • Reeves, D. W.
    • Lemunyon, J.
    • Roberson, T.
  • Source: Journal of Environmental Quality
  • Volume: 37
  • Issue: 2
  • Year: 2008
  • Summary: Increased CO2 release from soils resulting from agricultural practices such as tillage has generated concerns about contributions to global warming, Maintaining current levels of soil C and/or sequestering additional C in soils are important mechanisms to reduce CO2 in the atmosphere through production agriculture. We conducted a study in northern Alabama from 2003 to 2006 to measure CO2 efflux and C storage in long-term tilled and non-tilled cotton (Gossypium hirsutum L.) plots receiving poultry litter or ammonium nitrate (AN). Treatments were established in 1996 on a Decatur silt loam (clayey, kaolinitic thermic, Typic Paleudults) and consisted of conventional-tillage (CT), mulch-tillage (MT), and no-tillage (NT) systems with winter rye [Secale cereale (L.)] cover cropping and AN and poultry litter (PL) as nitrogen sources. Cotton was planted in 2003, 2004, and 2006. Corti was planted in 2005 as a rotation crop using a no-till planter in all plots, and no fertilizer was applied. Poultry litter application resulted in higher CO2 emission from soil compared with AN application regardless of tillage system. In 2003 and 2006, CT (4.39 and 3.40 mu mol m(-2) s(-1), respectively) and MT (4.17 and 3.39 mu mol m(-2) s(-1), respectively) with, PL at 100 kg N ha(-1) (100 PLN) recorded significantly higher CO2 efflux compared with NT with 100 PLN (2.84 and 2.47 mu mol m(-2) s(-1), respectively). Total soil C at 0- to 15-cm depth was not affected by tillage but significantly increased with PL application and winter rye cover cropping. In general, cotton, produced with NT conservation tillage in conjunction with PL and winter rye cover cropping reduced CO2 emissions and sequestered more soil C compared with control treatments.
  • Authors:
    • Dhuyvetter, K. C.
    • Staggenborg, S. A.
    • Gordon, W. B.
  • Source: Agronomy Journal
  • Volume: 100
  • Issue: 6
  • Year: 2008
  • Summary: Grain sorghum [ Sorghum bicolor (L.) Moench] is often grown where water stress is expected. But, improved drought tolerance in corn ( Zea mays L.) hybrids has resulted in increased dryland corn production in preference to grain sorghum. However, grain sorghum may still have a yield advantage over corn in drought prone environments. This study was conducted to determine if grain sorghum has either a yield or economic advantage over corn when drought or temperature stress occurs. Yield and weather data from crop performance testing programs in Kansas and Nebraska (1992-2005) were analyzed. Grain sorghum produced higher yields than corn in environments where corn yields were <6.4 Mg ha -1. When net returns ($ ha -1) were considered for grain sorghum prices that were set at 70, 87, 100, and 117% of corn prices, grain sorghum net returns were higher than corn net returns when corn yields were ≤4.4, 6.6, 8.8, and 13.6 Mg ha -1, respectively. Both corn and grain sorghum yields were positively correlated to June through August precipitation and negatively correlated to June through August maximum temperatures. The yield difference (grain sorghum minus corn) increased as July and August maximum temperatures increased. Monthly minimum temperatures affected corn yield less than grain sorghum yield. Producers in this region likely can minimize production risks by considering this historical yield information. At locations in this region where corn yields are consistently <6.4 Mg ha -1, producers should consider producing grain sorghum.
  • Authors:
    • Parvender, S.
    • Sukhvinder, S.
  • Source: Indian Journal of Dryland Agricultural Research and Development
  • Volume: 23
  • Issue: 2
  • Year: 2008
  • Summary: To study the impact of different cultural and chemical weed management practices alone and in combination on maize under rainfed conditions, a field experiment was conducted during 1996 and 1997 at farmer's fields in Hoshiarpur, Punjab, India, as a part of All India Coordinated Operational Research Project for Dryland Agriculture. There were 8 weed control treatments, i.e. weedy control, one hoeing at 15 days after sowing (DAS) alone and in combination with cut grass as mulch, 2 hoeings at 15 and 30 DAS, pre-emergence application of atrazine at 0.63 kg/ha alone and in combination with one hoeing at 35 DAS, post-emergence application of atrazine at 0.63 kg/ha in combination with one hoeing at 35 DAS, pre-emergence application of alachlor at 2.50 kg/ha in combination with one hoeing at 35 DAS. The important weed species in the field were Echinochloa colonum [ E. colona], Cyperus rotundus, Eleusine aegyptiacum [ Dactyloctenium aegyptium], Digera arvensis, Commelina benghalensis and Sorghum halepense. The pre-emergence application of atrazine in combination with one hoeing at 35 DAS resulted in the lowest weed density, total weed dry weight and highest mean grain yield (31.34 q ha -1) and was statistically at par with pre-emergence application of alachlor in combination with one hoeing at 35 DAS (29.86 q ha -1) and post-emergence application of atrazine in combination with one hoeing at 35 DAS (28.86 q ha -1). Application of atrazine (pre or post emergence) in combination with one hoeing at 35 DAS resulted in 7.48% higher mean grain yield over application of atrazine alone, while the same recorded 20.46% yield increase over 2 hoeings at 15 and 30 DAS, indicating the beneficial effect of chemical weed control compared to hoeing in the initial stages of crop growth.
  • Authors:
    • Egbert, S. L.
    • Wardlow, B. D.
  • Source: Remote Sensing of Environment
  • Volume: 112
  • Issue: 3
  • Year: 2008
  • Summary: Improved and up-to-date land use/land cover (LULC) data sets that classify specific crop types and associated land use practices are needed over intensively cropped regions such as the U.S. Central Great Plains, to support science and policy applications focused on understanding the role and response of the agricultural sector to environmental change issues. The Moderate Resolution Imaging Spectroradiometer (MODIS) holds considerable promise for detailed, large-area crop-related LULC mapping in this region given its global coverage, unique combination of spatial, spectral, and temporal resolutions, and the cost-free status of its data. The objective of this research was to evaluate the applicability of time-series MODIS 250 m normalized difference vegetation index (NDVI) data for large-area crop-related LULC mapping over the U.S. Central Great Plains. A hierarchical crop mapping protocol, which applied a decision tree classifier to multi-temporal NDVI data collected over the growing season, was tested for the state of Kansas. The hierarchical classification approach produced a series of four crop-related LULC maps that progressively classified: (1) crop/non-crop, (2) general crop types (alfalfa, summer crops, winter wheat, and fallow), (3) specific summer crop types (corn, sorghum, and soybeans), and (4) irrigated/non-irrigated crops. A series of quantitative and qualitative assessments were made at the state and sub-state levels to evaluate the overall map quality and highlight areas of misclassification for each map. The series of MODIS NDVI-derived crop maps generally had classification accuracies greater than 80%. Overall accuracies ranged from 94% for the general crop map to 84% for the summer crop map. The state-level crop patterns classified in the maps were consistent with the general cropping patterns across Kansas. The classified crop areas were usually within 1-5% of the USDA reported crop area for most classes. Sub-state comparisons found the areal discrepancies for most classes to be relatively minor throughout the state. In eastern Kansas, some small cropland areas could not be resolved at MODIS' 250 m resolution and led to an underclassification of cropland in the crop/non-crop map, which was propagated to the subsequent crop classifications. Notable regional areal differences in crop area were also found for a few selected crop classes and locations that were related to climate factors (i.e., omission of marginal, dryland cropped areas and the underclassification of irrigated crops in western Kansas), localized precipitation patterns (overclassification of irrigated crops in northeast Kansas), and specific cropping practices (double cropping in southeast Kansas).
  • Authors:
    • Giacomini, S.
    • Aita, C.
  • Source: Revista Brasileira de Ciencia do Solo
  • Volume: 32
  • Issue: 5
  • Year: 2008
  • Summary: This study was conducted to evaluate the accumulation and displacement of N-NO 3- in the soil after pig slurry application in no-tillage maize in southern Brazil. The doses of 0, 40 and 80 m 3/ha pig slurry were applied annually, for three years, on the mulch of cover crop of black oats [ Avena nuda] and of winter spontaneous vegetation, preceding maize sowing. The N-NO 3- concentration was evaluated in different soil layers to a depth of 60 cm and on six dates, from the slurry application until maize tasseling. The amount of N-NO 3- increased quickly in the soil surface layer with the pig slurry application, evidencing the high nitrification rates of ammoniacal N in the slurry. N-NO 3- produced in the surface layers moved down quickly in the soil profile. At a dose of 80 m 3/ha slurry the amounts of N-NO 3- in the 30-60 cm soil layer on the 30th day of the first year, 29th day in the second and 36th day in the third year were higher than the average of the treatments without slurry in 9, 21 and 32 kg N-NO 3-/ha, respectively. In the first two years the amount of soil N-NO 3- in the surface layer did not differ with slurry application on mulch of oats or spontaneous vegetation, indicating the low potential of grass mulch in promoting microbial N immobilization. The high rate of nitrification of ammoniacal N in the slurry and the fast displacement of N-NO 3- in the soil profile when maize N demand was still small indicate a greater susceptibility of N-NO 3- losses by leaching with slurry application, especially at a dose of 80 m 3/ha, where the average amount of total applied N in the three years was 244 kg/ha per year.
  • Authors:
    • Cargnin, R.
    • Inomoto, M.
    • Asmus, G.
  • Source: Tropical Plant Pathology
  • Volume: 33
  • Issue: 2
  • Year: 2008
  • Summary: Two greenhouse and one field experiment were carried out to evaluate the reaction of cover crops to reniform nematode, Rotylenchulus reniformis, and their effect on nematode populations in a naturally infested soil (2,359 nematodes/200 cm 3) and on cotton yield. Oil radish ( Raphanus sativus), Mulato grass ( Brachiaria ruziziensis * B. brizantha), forage sorghum ( Sorghum bicolor), tef ( Eragrostis tef), foxtail millet ( Setaria italica), Algerian ( Avena byzantina) and black ( A. strigosa) oats, pearl millet ( Pennisetum glaucum), and finger millet ( Eleusine coracana) were determined to be poor hosts for R. reniformis in greenhouse experiments. Grain amaranth ( Amaranthus cruentus) and quinoa ( Chenopodium quinoa) were good hosts to R. reniformis. In the field, lower nematode densities were observed after Mulato grass, oil radish and forage sorghum. Higher cotton fiber yields were obtained from plots cultivated with Mulato grass or sorghum during the winter compared to clean fallow. Cotton yield was inversely correlated with both reproduction factor (p
  • Authors:
    • Pelissari, A.
    • Moraes, A.
    • Balbinot Junior, A.
    • Dieckow, J.
    • Veiga, M.
  • Source: PLANTA DANINHA
  • Volume: 26
  • Issue: 3
  • Year: 2008
  • Summary: Economically viable alternatives for winter soil use in southern Brazil are scarce. During this period, pasture cultivated under crop-livestock system is an alternative. The objective of this study was to evaluate the effect of different winter soil uses on weed infestation in maize cultivated in succession. Two experiments were carried out from May, 2006 to April, 2007. Five alternatives of winter soil use were investigated: (1) multi-cropping with black oat+ryegrass+vetch+arrow leaf clover without grazing and nitrogen fertilization (multi-cropping cover); (2) the same multi-cropping, with grazing and nitrogen fertilization, 100 kg ha -1 of N (pasture with N); (3) the same multi-cropping, with grazing and without nitrogen fertilization (pasture without N); (4) oil seed radish, without grazing and nitrogen fertilization (oil seed radish); and (5) natural vegetation, without grazing and nitrogen fertilization (fallow). Cover crop in the winter, cultivated without grazing, produces a high amount of straw, reducing weed summer infestation. Under the experimental conditions, winter soil use with pasture allows high weed summer infestation, due to the low amount of straw that stays on the soil.