• Authors:
    • Li, Z.
    • Liu, W. Z.
    • Zhang, X. C.
    • Chen, J.
  • Source: Agricultural and Forest Meteorology
  • Volume: 151
  • Issue: 10
  • Year: 2011
  • Summary: Trends and uncertainty of the climate change impacts on hydrology, soil erosion, and wheat production during 2010-2039 at El Reno in central Oklahoma, USA, were evaluated for 12 climate change scenarios projected by four GCMs (CCSR/NIES, CGCM2, CSIRO-Mk2, and HadCM3) under three emissions scenarios (A2, B2, and GGa). Compared with the present climate, overall t-tests ( n=12) show that it is almost certain that mean precipitation will decline by some 6% (>98.5% probability), daily precipitation variance increase by 12% (>99%), and maximum and minimum temperature increase by 1.46 and 1.26 degrees C (>99%), respectively. Compared with the present climate under the same tillage systems, it is very likely (>90%) that evapotranpiration and long-term soil water storage will decease, but runoff and soil loss will increase despite the projected declines in precipitation. There will be no significant changes in wheat grain yield. Paired t-tests show that daily precipitation variance projected under GGa is greater than those under A2 and B2 ( P=0.1), resulting in greater runoff and soil loss under GGa ( P=0.1). HadCM3 projected greater mean annual precipitation than CGCM2 and CSIRO ( P=0.1). Consequently, greater runoff, grain yield, transpiration, soil evaporation, and soil water storage were simulated for HadCM3 ( P=0.1). The inconsistency among GCMs and differential impact responses between emission scenarios underscore the necessity of using multi-GCMs and multi-emission scenarios for impact assessments. Overall results show that no-till and conservation tillage systems will need to be adopted for better soil and water conservation and environmental protection in the region during the next several decades.
  • Authors:
    • Pelissari, A.
    • Moraes, A.
    • Balbinot Junior, A.
    • Veiga, M.
    • Dieckow, J.
  • Source: Revista Brasileira de Agrociencia
  • Volume: 17
  • Issue: 1
  • Year: 2011
  • Summary: The objective of this study was to evaluate the effect of winter soil use on reminiscent straw on the soil, physical characteristic in superficial soil layer and maize performance cultivated in succession. One experiment was carried out in three places in the North Plateau of Santa Catarina State, Brazil, during 2006/07 crop season. Five alternatives of soil use in the winter were investigated: (1) multicropping with black oat+ryegrass+vetch+arrow leaf clover without grazing and nitrogen fertilization (multicropping cover); (2) the same multicropping, with grazing and nitrogen fertilization, 100 kg ha -1 of N (pasture with N); (3) the same multicropping, 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). Higher straw dry mass was verified in multicropping cover. The winter annual pasture in crop-livestock system, cover crops and fallow did not affect the bulk density in 0,02 to 0,07 m of soil layer and maize performance in succession.
  • Authors:
    • Arbugeri, F.
    • Kaminski, J.
    • Casali, C.
    • Piccin, R.
    • Doneda, A.
  • Source: Informacoes Agronomicas
  • Volume: 21-24
  • Issue: 135
  • Year: 2011
  • Summary: This study evaluated the forms of phosphorus accumulated in plant tissue cover crops and their release from the mineralization of their residues. The field work was conducted in the agricultural year 2008/2009, in the town of Mantiqueira, in the municipality of Touch-Me-Not, RS, Brazil. The treatments were: black oats ( Avena nuda), rye ( Secale cereale), pea ( Pisum sativum subsp. arvense) and radish ( Raphanus sativus var. oleferus). Observations showed that the chemical fractionation of P in plant tissue used in this study is a reliable method that aids in understanding the dynamics of the release of P. The cover crops accumulate different forms of P in plant tissue, which interferes with the dynamics of release of this element. It was also observed that rye is a plant that releases the P tissue with greater speed to the ground, while the pea tissue P releases more slowly.
  • Authors:
    • Crusciol, C.
    • Calonego, J.
    • Castro, G.
  • Source: PESQUISA AGROPECUARIA BRASILEIRA
  • Volume: 46
  • Issue: 12
  • Year: 2011
  • Summary: The objective of this work was to evaluate the effects of crop rotation systems and liming materials on soil physical properties. The experiment was carried out from October 2006 to July 2008, in Botucatu, SP, Brazil, in a completely randomized block design in a split-plot arrangement with eight replicates. Main plots consisted of four crop rotation systems: soybean/fallow/maize/fallow, soybean/white-oat/maize/bean, soybean/millet/maize/pigeon pea and soybean/signal grass/maize/signal grass. Subplots consisted of the control treatment, without soil correction, and of the application of 3.8 Mg ha -1 of dolomitic lime (ECC=90%) or 4.1 Mg ha -1 of calcium-magnesium silicate (ECC=80%), on the surface of a clayed Rhodic Ferralsol. Aggregate stability, soil bulk density, total porosity, macro and microporosity, soil penetration resistance and moisture content were evaluated. Superficial application of the lime materials does not reduce soil aggregation and increases macroporosity down to 0.20 m, with calcium-magnesium silicate application, and to 0.10 m, when lime is applied. Soil under fallow in off-season decreases aggregate stability and increases soil penetration resistance in upper layers. The cultivation of Congo signal grass, between summer crops, increases aggregate stability down to 0.10-m depth.
  • Authors:
    • Orr, W.
    • Cooper, J.
    • Chataway, R.
    • Cowan, R.
  • Source: Animal Production Science
  • Volume: 51
  • Issue: 10
  • Year: 2011
  • Summary: Dairy farms located in the subtropical cereal belt of Australia rely on winter and summer cereal crops, rather than pastures, for their forage base. Crops are mostly established in tilled seedbeds and the system is vulnerable to fertility decline and water erosion, particularly over summer fallows. Field studies were conducted over 5 years on contrasting soil types, a Vertosol and Sodosol, in the 650-mm annual-rainfall zone to evaluate the benefits of a modified cropping program on forage productivity and the soil-resource base. Growing forage sorghum as a double-crop with oats increased total mean annual production over that of winter sole-crop systems by 40% and 100% on the Vertosol and Sodosol sites respectively. However, mean annual winter crop yield was halved and overall forage quality was lower. Ninety per cent of the variation in winter crop yield was attributable to fallow and in-crop rainfall. Replacing forage sorghum with the annual legume lablab reduced fertiliser nitrogen (N) requirements and increased forage N concentration, but reduced overall annual yield. Compared with sole-cropped oats, double-cropping reduced the risk of erosion by extending the duration of soil water deficits and increasing the time ground was under plant cover. When grown as a sole-crop, well fertilised forage sorghum achieved a mean annual cumulative yield of 9.64 and 6.05 t DM/ha on the Vertosol and Sodosol, respectively, being about twice that of sole-cropped oats. Forage sorghum established using zero-tillage practices and fertilised at 175 kg N/ha.crop achieved a significantly higher yield and forage N concentration than did the industry-standard forage sorghum (conventional tillage and 55 kg N/ha.crop) on the Vertosol but not on the Sodosol. On the Vertosol, mean annual yield increased from 5.65 to 9.64 t DM/ha (33 kg DM/kg N fertiliser applied above the base rate); the difference in the response between the two sites was attributed to soil type and fertiliser history. Changing both tillage practices and N-fertiliser rate had no affect on fallow water-storage efficiency but did improve fallow ground cover. When forage sorghum, grown as a sole crop, was replaced with lablab in 3 of the 5 years, overall forage N concentration increased significantly, and on the Vertosol, yield and soil nitrate-N reserves also increased significantly relative to industry-standard sorghum. All forage systems maintained or increased the concentration of soil nitrate-N (0-1.2-m soil layer) over the course of the study. Relative to sole-crop oats, alternative forage systems were generally beneficial to the concentration of surface-soil (0-0.1 m) organic carbon and systems that included sorghum showed most promise for increasing soil organic carbon concentration. We conclude that an emphasis on double- or summer sole-cropping rather than winter sole-cropping will advantage both farm productivity and the soil-resource base.
  • Authors:
    • Bandyopadhyay, P.
    • Nath, R.
    • Jena, S.
    • Dutta, S. K.
    • Dutta, A.
    • Chakraborty, P. K.
  • Source: Journal of Crop and Weed
  • Volume: 7
  • Issue: 1
  • Year: 2011
  • Summary: Temperature is an important weather parameter affecting the growth and development of the crop. The growing degree days (GDD) indicate the thermal index required for the onset of phenophases in crop. A two-year (2008-09 and 2009-10) field experiment was conducted at the B.C.K.V Instructional Farm to investigate the effect of GDD on leaf growth rate (LGR), crop growth rate (CGR) and leaf area indices (LAI) of wheat and mustard grown under sole (T 1 and T 2) and intercrop situations, [2 wheat:6 mustard (T 3), 4 wheat:4 mustard (T 4) and 6 wheat:2 mustard (T 5)]. The experiment was laid out in a RBD design with 6 replications having a plot size of 50 m 2. The experimental soil has pH of 6.92, organic carbon 0.63%, total N 0.06%, available P 2O 5 18.47 kg/ha and available K 2O 127.22 kg/ha. The experimental site is under tropical humid climate. From the results, leaf growth rate, crop growth rate and leaf area index were found to be polynomial function of GDD. The results also suggested that the effect of GDD on different growth indices of wheat and mustard were strongly expressed in 4 wheat:4 mustard row ratios which might be adopted in the Gangetic Plains of New Alluvial zone of West Bengal.
  • Authors:
    • Ferrari, J. V.
    • Furlani Junior, E.
    • Ferrari, S.
    • Pereira, G. A.
  • Source: SEMINA-CIENCIAS AGRARIAS
  • Volume: 32
  • Issue: 4
  • Year: 2011
  • Summary: Nitrogen application on the cover and the maintenance of straw, conducted by direct seeding, should meet the needs of agriculture and promote soil conservation. This study evaluates the effect of pre-sowing nitrogen application in cotton crops and cover crops by direct seeding, on the development and yield of cotton. It was conducted in the municipality of Selviria-MS during the agricultural years 2005/06, 2006/07 and 2007/08. The experimental design used was a randomized block design consisting of three cover crops (forage turnip, black oat and white oat) and four nitrogen doses (0, 30, 60 and 90 kg of N ha -1) in pre-sowing of cotton. In April 2006, April 2007 and April 2008, the assessments of plant development and also harvesting of the experimental plots of cotton cultivars were conducted. The results showed that after planting the cover crops, the yield and development and the heights of cotton plants increased with the use of pre-sowing N of 90 kg ha -1, also showing that the forage turnip is a coverage plant that provides increased cotton.
  • Authors:
    • Bergonci, J. I.
    • Bergamaschi, H.
    • Rosa, L. M. G.
    • Mielniczuk, J.
    • Franca, S.
  • Source: REVISTA BRASILEIRA DE ENGENHARIA AGRICOLA E AMBIENTAL
  • Volume: 15
  • Issue: 11
  • Year: 2011
  • Summary: This work aimed to quantify the available nitrogen (N) to a maize crop and evaluate its effects on leaf area index (LAI), shoot dry matter (SDM) production, N absorption by the above ground biomass, and grain yield. The evaluations were performed in a soil management experiment run since 1985, with three cropping systems (oat- Avena strigosa/maize, oat+vetch- Vicia sativa/maize and oat+vetch/maize+cowpea- Vigna unguiculata) and two rates of nitrogen (0 and 180 kg ha -1) applied to maize. In the 2000/2001 cropping year, four nitrogen rates were applied (0, 60, 120 and 180 kg ha -1). The estimated available N to the maize calculated from the contribution from the soil, cover crops and N fertilizer varied from 27 to 192 kg ha -1. All evaluated variables presented high dependence on available N, and reached its maximum level near to the highest level of available N (192 kg ha -1). With this level of availability, at the stage of pollination, the largest values of LAI (4.41) and the highest leaf N concentration were observed, however, the highest N accumulation in the above ground biomass was observed at the milk grain stage and the shoot dry matter accumulation at the dent stage. The maximum grain yield obtained was 8,920 kg ha -1, corresponding to 112 kg ha -1 of exported N by the grain.
  • Authors:
    • Schuh, R.
    • Loffaguen, J.
    • Epping, J.
    • Costa, M.
    • Kunze, A.
    • Lovato, P.
  • Source: REVISTA BRASILEIRA DE CIENCIA DO SOLO
  • Volume: 35
  • Issue: 3
  • Year: 2011
  • Summary: Cover crops may difffer in the way they affect rhizosphere microbiota nutrient dynamics. The purpose of this study was to evaluate the effect of mycorrhizal and non-mycorrhizal cover crops on soil phosphatase activity and its persistence in subsequent crops. A three-year experiment was carried out with a Typic Quartzipsamment. Treatments were winter species, either mycorrhizal black oat ( Avena strigosa Schreb) or the non-mycorrhizal species oilseed radish ( Raphanus sativus L. var. oleiferus Metzg) and corn spurry ( Spergula arvensis L.). The control treatment consisted of resident vegetation (fallow in the winter season). In the summer, a mixture of pearl millet ( Pennisetum americanum L.) with sunnhemp ( Crotalaria juncea L.) or with soybean ( Glycine max L.) was sown in all plots. Soil cores (0-10 cm) and root samples were collected in six growing seasons (winter and summer of each year). Microbial biomass P was determined by the fumigation-extraction method and phosphatase activity using p-nitrophenyl-phosphate as enzyme substrate. During the flowering stage of the winter cover crops, acid phosphatase activity was 30-35% higher in soils with the non-mycorrhizal species oilseed radish, than in the control plots, regardless of the amount of P immobilized in microbial biomass. The values of enzyme activity were intermediate in the plots with corn spurry and black oat. Alkaline phosphatase activity was 10-fold lower and less sensitive to the treatments, despite the significant relationship between the two phosphatase activities. The effect of plant species on the soil enzyme profile continued in the subsequent periods, during the growth of mycorrhizal summer crops, after completion of the life cycle of the cover crops.
  • Authors:
    • Carvalho, P. C. de F.
    • Sulc, R. M.
    • Moraes, A. de
    • Pelissari, A.
    • Lang, C. R.
    • Lopes, E. C. P.
  • Source: Scientia Agraria
  • Volume: 12
  • Issue: 1
  • Year: 2011
  • Summary: Producers seeking higher corn ( Zea mays) production efficiency have pursued more sustainable, integrated systems. The objective of this investigation was to determine the effect of nitrogen fertilization on corn yield and yield components in an integrated crop-livestock production system. The experiment was conducted on the experimental farm Fazenda Capao da Onca of the Universidade Estadual de Ponta Grossa, Brazil during the 2002/2003 harvest. Treatments were replicated four times in a split-plot randomization of a randomized complete block design. Whole plot treatments were two N rates (0, 150 kg ha -1) with and without grazing applied to a winter cover crop of black oat and Italian ryegrass established in April 2002 and desiccated prior to planting the corn in October 2002. Sequentially, treatments were four N rates (0, 75, 150, 225 kg ha -1) applied to the corn. The corn presented an increasing yield in relation to increasing N rates in plots without neither grazing nor N fertilization during winter; however, grazing allows for higher corn yields with lower N rates.