• Authors:
    • Fernandes, C.
    • Cora, J. E.
    • Marcelo, A. V.
    • Martins, M. dos R.
    • Jorge, R. F.
  • Source: Revista Brasileira de Ciência do Solo
  • Volume: 33
  • Issue: 2
  • Year: 2009
  • Summary: Decomposing crop residues in no-tillage system can alter soil chemical properties, which may consequently influence the productivity of succession crops. The objective of this study was to evaluate soil chemical properties and soyabean, maize and rice yield, grown in the summer, after winter crops in a no-tillage system. The experiment was carried out in Jaboticabal, Sao Paulo, Brazil on a Red Latosol (Oxisol), in a completely randomized block design, in strip plots with three replications. The treatments consisted of four summer crop sequences (maize monocrop, soyabean monocrop, soyabean/maize rotation and rice/bean/cotton rotation) combined with seven winter crops (maize, sunflower, oilseed radish, pearl millet, pigeon pea, grain sorghum and sunn hemp). The experiment began in September 2002. After the winter crops in the 2005/2006 growing season and before the sowing of summer crops in the 2006/2007 season, soil samples were collected in the layers 0-2.5; 2.5-5.0; 5-10; 10-20; and 20-30 cm. Organic matter, pH, P, K +, Ca 2+, Mg 2+, and H+Al were determined in each soil sample. In the summer soyabean/maize rotation and in maize the organic matter contents and P levels were lower, in the layers 0-10 cm and 0-20 cm, respectively. Summer rice/bean/cotton rotation increased soil K levels at 0-10 cm depth when sunn hemp and oilseed radish had previously been grown in the winter, and in the 0-2.5 cm layer for millet. Sunn hemp, millet, oilseed radish and sorghum grown in the winter increased organic matter contents in the soil down to 30 cm. Higher P levels were found at the depths 0-2.5 cm and 0-5 cm, respectively, when sunn hemp and oilseed radish were grown in the winter. Highest grain yields for soyabean in monoculture were obtained in succession to winter oilseed radish and sunn hemp and in rotation with maize, after oilseed radish, sunn hemp and millet. Maize yields were highest in succession to winter oilseed radish, millet and pigeon pea. Rice yields were lowest when grown after sorghum.
  • Authors:
    • Rosculete, E.
    • Gheorghe, D.
    • Matei, G.
    • Imbrea, F.
    • Cojocaru, I.
  • Source: Research Journal of Agricultural Science
  • Volume: 41
  • Issue: 1
  • Year: 2009
  • Summary: Field studies were conducted in Romania, from 2006 to 2008, to determine the effect of rotations and fertilizer applications on the yield and quality of maize in irrigated sandy soils. The treatments comprised 3 years rotation (wheat, maize and soyabeans), 4 years rotation (wheat, lucerne, maize and soyabeans), wheat monoculture, maize monoculture, 2 years rotation (maize and wheat), 5 years rotation (wheat, lucerne, potato, maize and wheat), 3 years rotation (wheat, maize and groundnut), 6 years rotation (maize, groundnuts, wheat, sunflower, potato and wheat) and 4 years rotation (bean, wheat, maize and wheat) and fertilizer applications, i.e. 160 kg N and 80 kg P/ha, 80 kg N and 80 kg P/ha and control. Results showed that maize gave good seed yields, which varied between 4.5 q/ha on unfertilized variant and 38.5 q/ha in the 6 years rotation on 160 kg N and 80 kg P/ha. The most valuable rotations for maize were beans, soyabean, groundnuts or lucerne. Applying fertilizers in monoculture resulted only in small increases in production. The best variant with fertilizers was the 80 kg N and 80 kg P/ha, which increased the yields of all rotations used compared to the control. On all the rotations studied, the nitrogen fertilizer application improved the N content of maize seeds and directly increased the protein content, while other macro- and microelements in maize seeds registered small fluctuations, some of which were considered as constant no matter what kind of rotation was used.
  • Authors:
    • Tom, C. T.
    • Ngwuta, A. A.
    • Ibeawuchi, I. I.
    • Ogoke, I. J.
    • Onweremadu, E. U.
  • Source: Journal of Sustainable Agriculture
  • Volume: 33
  • Issue: 8
  • Year: 2009
  • Summary: Soil nutrient and physical status in small holder farms in southeastern Nigeria are subjected to debilitating effects of continuous cropping without adequate efforts towards replenishment and conservation to ensure sustainability of soil resources. Although inorganic fertilizers are quick acting for soil nutrient enhancement, to guarantee soil health they must be used within the context of integrated soil fertility management relative to soil type and other climatic conditions. On the other hand, apart from maintaining required nutrient levels, the use of appropriate crop combinations and arrangements in farmers' fields can improve soil health. Leguminous plants including tree, shrub and annual species have been determined to be useful components in such systems. These species can contribute immensely to soil carbon and other mineral contents in addition to improving soil physical properties. Apart from their high edible protein content, some leguminous seeds also have high phytate content, which should enhance the bioavailability of Zn, making them good nutrient sources in human and animal nutrition. However, indigenous leguminous tree, shrub, and grain legume species are currently underutilized in the common cropping systems on smallholder farms. While tree species are lost through logging, with very limited research toward their improvement, research on grain legumes has been limited in this zone resulting in the loss of indigenous grain species. Low available soil P is another constraint to legume cultivation in this region that has to be addressed through well coordinated agronomic research. Increased and sustainable food production on small holder farms in southeastern Nigeria is possible with improved practices within the prevailing cropping systems. This is achievable with intensive breeding, agronomic and utilization studies on legume species in the cropping systems.
  • Authors:
    • Buchroithner, M. F.
    • Sulieman, H. M.
  • Source: Land Degradation & Development
  • Volume: 20
  • Issue: 2
  • Year: 2009
  • Summary: In the Gadarif Region of Sudan, destruction of the natural vegetation for agricultural expansion is one of the major causes of the degradation of renewable resources and the environment. This Study identifies and analyses the farmers' attitudes and perceptions towards agricultural land degradation and abandonment. The cross-sectional data collected from ten key informants and 41 large-scale farmers focussed on the degradation and abandonment of mechanized agricultural land. The results of the Study show that the respondents are well aware that soil degradation is in various forms are taking place on their cultivated agricultural land. This is based on their perception and interpretation of indicators such as weed infestation, poor soil fertility and soil compaction. Continuous cropping, mono-cropping, rainfall shortage and the use of interior seeds are the main reasons of land degradation as indicated by fanners. The main Measures acknowledged to maintain and improve land productivity are repeated Soil Ploughing, abandonment/fallow periods and crop rotation. The study adduces evidence of widespread land degradation. The mitigation Measures followed by the farmers may though not be sufficient to restore the soil fertility. The application of appropriate chemical fertilizers, Sound crop rotation and long fallow periods can be recommended, Any management and research intervention regarding the problem of land degradation should; however, be concerted with the farmers knowledge. Copyright (C) 2009 John Wiley & Sons, Ltd.
  • Authors:
    • Suyker, A. E.
    • Verma, S. B.
  • Source: Agricultural and Forest Meteorology
  • Volume: 149
  • Issue: 3/4
  • Year: 2009
  • Summary: We have been making year-round measurements of mass and energy exchange in three cropping systems: (a) irrigated continuous maize, (b) irrigated maize-soybean rotation, and (c) rainfed maize-soybean rotation in eastern Nebraska since 2001. In this paper, we present results on evapotranspiration (ET) of these crops for the first 5 years of our study. Growing season ET in the irrigated and rainfed maize averaged 548 and 482 mm, respectively. In irrigated and rainfed soybean, the average growing season ET was 452 and 431 mm, respectively. On average, the maize ET was higher than the soybean ET by 18% for irrigated crops and by 11% for rainfed crops. The mid-season crop coefficient Kc (=ET/ET 0 and ET 0 is the reference ET) for irrigated maize was 1.030.07. For rainfed maize, significant dry-down conditions prevailed and mid-season Kc was 0.840.20. For irrigated soybean, the mid-season Kc was 0.980.02. The mid-season dry down in rainfed soybean years was not severe and the Kc (0.900.13) was only slightly lower than the values for the irrigated fields. Non-growing season evaporation ranged from 100 to 172 mm and contributed about 16-28% of the annual ET in irrigated/rainfed maize and 24-26% in irrigated/rainfed soybean. The amount of surface mulch biomass explained 71% of the variability in non-growing season evaporation totals. Water use efficiency (or biomass transpiration efficiency), defined as the ratio of total plant biomass ( YDM) to growing season transpiration ( T) was 5.200.34 and 5.220.36 g kg -1, respectively for irrigated and rainfed maize crops. Similarly, the biomass transpiration efficiency for irrigated and rainfed soybean crops was 3.210.35 and 2.960.30 g kg -1. Thus, the respective biomass transpiration efficiency of these crops was nearly constant regardless of rainfall and irrigation.
  • Authors:
    • Pishbin, Y.
    • Lack, S. H.
    • Dadnia, M. R.
    • Modhej, A.
  • Source: Crop Research (Hisar)
  • Volume: 37
  • Issue: 1-3
  • Year: 2009
  • Summary: Diversification and continuous cropping have largely been a consequence of soil moisture saved through the adoption of conservation tillage. Consequently, weed communities have changed and, in some cases, become resistant to commonly used herbicides, thus increasing the complexity of managing weeds. The main plots contain cutivars in two levels and sub-plots contain rye grass and wild oat with 0, 25 and 50 density. Utilizing the principle of varying selection pressure to keep rye grass and wild oat communities off balance has reduced weed densities, minimized crop yield losses, and inhibited adverse community changes towards difficult-to-control species. Varied selection pressure was best achieved with a diverse cropping system where crop seeding date, perennation, and species and herbicide mode of action and use pattern were inherently varied. Approaches to cropping systems, including balancing rotations between cereal and broadleaf crops, reducing herbicide inputs, organic production, and the use of cover crops and perennial forages, are discussed in light of potential systems-level benefits for weed management.
  • Authors:
    • Sabau, N. C.
    • Domuta, C.
    • Borza, I.
    • Bandici, G.
    • Samuel, A.
    • Ciobanu, C.
    • Ardelean ,I.
    • Ciobanu, G.
    • Sandor, M.
    • Domuta, C.
    • Brejea, R.
    • Vuscan, A.
  • Source: Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Agriculture
  • Volume: 66
  • Issue: 1
  • Year: 2009
  • Summary: Field studies were conducted in Oradea, Romania, from 2003 to 2008, in a long term trial placed in 1990 on preluvosoils. The climate indicator de Martonne aridity index (IdM) was used for quantification of the correlation between climate and wheat yield in unirrigated and irrigated conditions and a new class called arid was used for climate index characterization. Maintaining the soil water reserve on 0-50 cm depth between easily available water content and field capacity using the irrigation determined the increase of the IdM values for period IV-VI with 79% in 2003, 73% in 2004, 36% in 2005, 16% in 2006, 162% in 2007 and with 131% in 2008. Using the irrigation and the improvement of the microclimate conditions determined to obtain the yield gains, showed very significant results every year and every crop rotation studied, both in unirrigated and irrigated conditions. The smallest wheat yields were obtained in monocrop and the biggest in the wheat-maize-soyabean rotation. In the all 3 rotations, the direct links statistically assured were registered between the values of the IdM and yields in unirrigated and irrigated wheat. These correlations sustained the need of the irrigation in wheat from Crisurilor Plain. Correlation between the IdM was stronger in the wheat-maize-soyabean rotation compared to the wheat-maize rotation and with wheat monocrop. As a consequence, rotation of wheat-maize-soyabean was recommended because the climate and microclimate conditions were better used.
  • Authors:
    • Clayton, G. W.
    • Turkington, T. K.
    • Irvine, R. B.
    • O'Donovan, J. T.
    • Harker, K. N.
  • Source: Weed Science
  • Volume: 57
  • Issue: 3
  • Year: 2009
  • Summary: Wild oat causes more crop yield losses and accounts for more herbicide expenditures than any other weed species on the Canadian Prairies. A Study was conducted from 2001 to 2005 at four Canadian Prairie locations to determine the influence of repeated cultural and herbicidal management practices on wild oat Population density, biomass, and seed production, and on barley biomass and seed yield. Short or tall cultivars of barley were combined with normal or double barley seeding rates in continuous barley or a barley-canola-barley-field-pea rotation under three herbicide rate regimes. The same herbicide rate regime was applied to the same plots in all crops each year. In barley, cultivar type and seeding rate were also repeated on the same plots year after year. Optimal Cultural practices (tall cultivars, double seeding rates, and crop rotation) reduced wild oat emergence, biomass, and seed production, and increased barley biomass and seed yield, especially at low herbicide rates. Wild oat seed production at the quarter herbicide rate was reduced by 91, 95, and 97% in 2001, 2003, and 2005, respectively, when call barley cultivars at double seeding rates were rotated with canola and field pea (high management) compared to short barley cultivars at normal seeding rates Continuously planted to barley (low management). Combinations of favorable cultural practices interacted synergistically to reduce wild oat emergence, biomass and seed production, and to increase barley yield. For example, at the quarter herbicide rate, wild oat biomass was reduced 2- to 3-, 6- to 7-, or 19-fold when optimal single, double, or triple treatments were combined, respectively. Barley yield reductions in the low-management scenario were somewhat compensated for by full herbicide rates. However, high management at low herbicide rates often produced more barley than low management in higher herbicide rate regimes.
  • Authors:
    • Griffis, T. J.
    • Baker, J. M.
  • Source: Agricultural and Forest Meteorology
  • Volume: 149
  • Issue: 12
  • Year: 2009
  • Summary: Climate change and economic concerns have motivated intense interest in the development of renewable energy sources, including fuels derived from plant biomass. However, the specter of massive biofuel production has raised other worries, specifically that by displacing food production it will lead to higher food prices, increased incidence of famine, and acceleration of undesirable land use change. One proposed solution is to increase the annual net primary productivity of the existing agricultural land base, so that it can sustainably produce both food and biofuel feedstocks. This might be possible in corn and soybean production regions through the use of winter cover crops, but the biophysical feasibility of this has not been systematically explored. We developed a model for this purpose that simulates the potential biomass production and water use of winter rye in continuous corn and corn-soybean rotations. The input data requirements represent an attempt to balance the demands of a physically and physiologically defensible simulation with the need for broad applicability in space and time. The necessary meteorological data are obtainable from standard agricultural weather stations, and the required management data are simply planting dates and harvest dates for corn and soybeans. Physiological parameters for rye were taken from the literature, supplemented by experimental data specifically collected for this project. The model was run for a number of growing seasons for 8 locations across the Midwestern USA. Results indicate potential rye biomass production of 1-8 Mg ha(-1), with the lowest yields at the more northern sites, where both PAR and degree-days are limited in the interval between fall corn harvest and spring corn or soybean planting. At all sites rye yields are substantially greater when the following crop is soybean rather than corn, since soybean is planted later. Not surprisingly, soil moisture depletion is most likely in years and sites where rye biomass production is greatest. Consistent production of both food and biomass from corn/winter rye/soybean systems will probably require irrigation in many areas and additional N fertilizer, creating possible environmental concerns. Rye growth limitations in the northern portion of the corn belt may be partially mitigated with aerial seeding of rye into standing corn. Published by Elsevier B.V.
  • Authors:
    • Wang, Z.
    • Hao, M.
    • Wang, L.
    • Li, S.
    • Li, X.
  • Source: Scientia Agricultura Sinica
  • Volume: 41
  • Issue: 9
  • Year: 2008
  • Summary: Objective: Research on effects of monocropping or rotation of different crops on water and different forms of soil organic nitrogen (N) and mineral N in dryland soils is recognized to be of great significance in determining dryland crop sequences, increasing soil fertility, and optimizing nutrients management. Method: Dryland soil samples were taken from 6 cropping systems: fallowing, continuous wheat monocropping, continuous maize monocropping, continuous alfalfa cropping with no-till, pea-wheat-wheat-millet rotation and maize-wheat-wheat-millet rotation, from a 23-year long-term experimental site on the Loess Plateau, to study the effects of cropping systems on soil water, organic N, light fraction organic N and mineral N. Result: Results obtained showed that continuous long-term fallowing system contained the lowest organic N, light fraction organic N and mineral N. Long-period alfalfa cropping with no-till system could promote water storage in topsoil layers, and accumulation of organic and light fraction organic N in 0-20 cm soil layers, but increased exhaustion of water and mineral N in deep soil layers. Continuous monocropping of wheat or maize could all significantly increase soil organic and light fraction organic N contents, and the organic N were increased more by monocropping of wheat. Organic N contents in soil layers of two rotation systems showed no obvious different to monocropping of wheat. Light fraction organic N contents also were not obvious different between two rotations in 0-20 cm soil layers, but they were all significantly higher than wheat or maize monocropping. The amount of soil mineral N was found to depend on the status of crop growing or N fertilizer application at sampling time. Conclusion: Although long term monocropping of legumes without tillage can enhance organic N accumulation by increase the light fraction organic N in soil, the exhaustion of soil water in deep layers is also increased. Rotations of legumes with cereal crops or the shallow and deep root crop rotations are proved to be feasible measures to optimize soil water utilization, increase organic N accumulation in soil, and synergize soil N supply capacity.