• Authors:
    • Heddadj, D.
    • Cloarec, M.
  • Source: Options Mediterraneennes. Serie A, Seminaires Mediterraneens
  • Issue: 96
  • Year: 2011
  • Summary: An experimental device has been set up for ten years at the Kerguehennec Experimental Station (Chambre Regionale d'Agriculture de Bretagne) located in Brittany (western France) on the basis of a corn/wheat/rape/wheat rotation. The study, in the western context of France, compares three tillage practices (moldboard plowing, surface tillage and no-tillage) and two nutrient sources (mineral and poultry manure), each management systems repeated three times. The aim of this study was to evaluate the effect of reduced tillage and manure fertilization on the evolution of soil characteristics: porosity, aggregate stability, organic carbon, hydraulic conductivity and earthworm populations. The results show that treatments without plowing know a decline of global porosity on the layer 0-25 cm, particularly in the case of the no-till. Although the abundance and biomass of earthworms are increased in reduced tillage, the decrease of porosity is not compensated. The consequence is the decline of hydraulic conductivity, in the case of the no-till. Surface tillage seems to constitute the best compromise, because it maintains or improves the infiltrability thanks to the improvement of aggregate stability in the surface layer and the protection of soil surface by the presence of a mulch.
  • Authors:
    • Schwartz, R. C.
    • MacDonald, J. C.
    • Tolk, J. A.
    • Baumhardt, R. L.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 3
  • Year: 2011
  • Summary: Cattle (Bos taurus) grazing intensifies production of the dryland wheat (Triticum aestivum L.)-sorghum [Sorghum bicolor (L.) Moench]-fallow (WSF) rotation in the U. S. Southern High Plains. Stubble-mulch (SM) tillage controls weeds and counteracts soil compaction. No-till (NT) increases soil water at planting and dryland crop yields, but added grazing effects are unknown. Our objectives were to quantify dryland winter wheat and sorghum yield responses to grazing and tillage practices. At the USDA-ARS Conservation and Production Research Laboratory, Bushland, TX, we established all WSF rotation phases in triplicate ungrazed and grazed paddocks beginning 1999 on a Pullman clay loam (fine, mixed, superactive, thermic Torrertic Paleustoll) using SM tillage. During spring 2004, NT or SM tillage were superimposed within grazing main plots. Cattle gain, soil water aft er fallow, and crop yield were compared during 2005 to 2009 using a split-plot randomized complete block design. Cattle, stocked at 1.8 Mg ha(-1), grazed sorghum stover and growing wheat an average of 29 d for a mean gain of 147 kg ha(-1). Soil water at planting was unaffected by grazing, but increased from 14 to 28 mm with NT. Although grazing seldom reduced yield of wheat or sorghum, NT in ungrazed plots increased crop yields sufficiently (0.96-2.6 Mg ha(-1)) in 2008 and 2009 to off set any value added by grazing. We conclude that cumulative grazing effects in NT plots reduced soil water storage and depressed yield. We recommend post-wheat-harvest SM tillage to disrupt soil compaction and restore grazed soil productivity.
  • Authors:
    • Adetunji, M.
    • Makinde, E.
    • Akande, M.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 42
  • Issue: 9
  • Year: 2011
  • Summary: Field trials were conducted at the Institute of Agricultural Research and Training Ibadan in 2000 and 2001 cropping seasons to evaluate the efficiency of some phosphorus (P) sources, rates, and frequency of application on grain yields of maize and cowpea grown sequentially. The experiment was laid out in a split-split plot arrangement using randomized complete block design, with three replications. The main plot was frequency of fertilizer application (seasonal and annual). Source of P [single superphosphate (SSP: 18% P 2O 5)]; Ogun rock phosphate (OPR: 20.21% P 2O 5), and crystallizer super (CS: 31.4% P 2O 5) constituted the subplots. The P rates (0, 20, 40, and 60 kg P ha -1) were the sub-subplots. An early maize cropping followed by a late-season cowpea was the sequential cropping, while an early maize followed by a late-season maize was the continuous cropping. The croppings were repeated the second year. Frequency of P application and source of P were significantly different while rates of application were not. Maize and cowpea grain yields from the control treatment were significantly less than yields from P-treated plots. Maize grain yields were slightly greater in plots alternated with cowpea, compared to continuous maize. Relative agronomic efficiency (RAE) values of OPR and CS were 67% and 75%, respectively, in annual application and 140% and 134% in seasonal applications, respectively, in 2000. In 2001, the trend was almost similar to 2000 except that there was a decline in RAE values of cowpea. Each Naira invested in the annual application returned about Naira 3.12 while about Naira 2.13 was returned with the seasonal application (Naira 125.00 is the equivalent of USD$1.00). The OPR and CS can serve as alternatives to water-soluble sources such as SSP.
  • Authors:
    • Fiorin, J.
    • Nicoloso, R.
    • Tornquist, C.
    • Amado, T.
    • Campos, B.
  • Source: Revista Brasileira de Ciencia do Solo
  • Volume: 35
  • Issue: 3
  • Year: 2011
  • Summary: Soil C-CO 2 emissions are sensitive indicators of management system impacts on soil organic matter (SOM). The main soil C-CO 2 sources at the soil-plant interface are the decomposition of crop residues, SOM turnover, and respiration of roots and soil biota. The objectives of this study were to evaluate the impacts of tillage and cropping systems on long-term soil C-CO 2 emissions and their relationship with carbon (C) mineralization of crop residues. A long-term experiment was conducted in a Red Oxisol in Cruz Alta, RS, Brazil, with subtropical climate Cfa (Koppen classification), mean annual precipitation of 1,774 mm and mean annual temperature of 19.2degreesC. Treatments consisted of two tillage systems: (a) conventional tillage (CT) and (b) no tillage (NT) in combination with three cropping systems: (a) R0 - monoculture system (soybean/wheat), (b) R1 - winter crop rotation (soybean/wheat/soybean/black oat), and (c) R2 - intensive crop rotation (soybean/black oat/soybean/black oat+common vetch/maize/oilseed radish/wheat). The soil C-CO 2 efflux was measured every 14 days for two years (48 measurements), by trapping the CO 2 in an alkaline solution. The soil gravimetric moisture in the 0-0.05 m layer was determined concomitantly with the C-CO 2 efflux measurements. The crop residue C mineralization was evaluated with the mesh-bag method, with sampling 14, 28, 56, 84, 112, and 140 days after the beginning of the evaluation period for C measurements. Four C conservation indexes were used to assess the relation between C-CO 2 efflux and soil C stock and its compartments. The crop residue C mineralization fit an exponential model in time. For black oat, wheat and maize residues, C mineralization was higher in CT than NT, while for soybean it was similar. Soil moisture was higher in NT than CT, mainly in the second year of evaluation. There was no difference in tillage systems for annual average C-CO 2 emissions, but in some individual evaluations, differences between tillage systems were noticed for C-CO 2 evolution. Soil C-CO 2 effluxes followed a bi-modal pattern, with peaks in October/November and February/March. The highest emission was recorded in the summer and the lowest in the winter. The C-CO 2 effluxes were weakly correlated to air temperature and not correlated to soil moisture. Based on the soil C conservation indexes investigated, NT associated to intensive crop rotation was more C conserving than CT with monoculture.
  • Authors:
    • Baranova, B.
    • Balazs, P.
    • Kotorova, D.
    • Fazekasova, D.
    • Bobul'ska, L.
  • Source: Ekologia (Bratislava)
  • Volume: 30
  • Issue: 1
  • Year: 2011
  • Summary: In 2005-2009 the temporal and spatial dimensions in the six research sites were studied in order to assess the impact of environmental management on change of basic physical properties of the soil. Crop rotation was as follows: perennial fodder crops - perennial fodder crops - winter crops - root crops - spring crops - annual fodder crops. Soil sampling to determine bulk density, porosity and maximum capillary capacity was realised two times a year in spring and autumn at the six locations (I.-VI.) from the depth of 0.05 to 0.15 m. The results obtained were tested by statistical methods (analysis of variance, LSD-test). Soil bulk density is influenced by ecological farming in the five-year time series in comparison with 1996 and decreased its value in the interval ranging from 0.91 to 1.36 t m -3 in both samples. The porosity corresponded with bulk density, which in 2009 increased in all locations to the optimal levels for plant growth. The maximum capillary capacity in 1996 reached very low values (17.40 to 20.65%). In 2009 its value increased from 25.59 to 42.84%, which maybe associated with sum of precipitation and ecological farming, too. The positive change of soil bulk density and porosity and increasing the maximum capillary capacity was recorded in comparison with 1996. Test of obtained results confirmed a statistically significant effect of experimental year and localities on the bulk density, porosity and maximum capillary capacity. The date of sampling significantly influenced the values of porosity and the maximum capillary capacity.
  • Authors:
    • Halloran, J.
    • Larkin, R.
    • Olanya, O.
    • Honeycutt, C.
    • He, Z.
  • Source: Journal of Food Agriculture & Environment
  • Volume: 9
  • Issue: 1
  • Year: 2011
  • Summary: Appropriate evaluation of soil phosphorus (P) availability is a prerequisite for best P management in potato production systems. Consequently, we evaluated soil test P and microbial biomass P in 10 rainfed and irrigated potato field soils which had a three-year crop rotation. Ammonium oxalate extracted P was the highest with a level of >1400 mg kg -1. Olsen P was moderate and ranged from 100 to 120 mg kg -1. Modified Morgan inorganic P (MMPi) was lowest (
  • Authors:
    • Ewusi-Mensah, N.
    • Logah, V.
    • Tetteh, F.
  • Source: Journal of Plant Sciences
  • Volume: 6
  • Issue: 4
  • Year: 2011
  • Summary: A field experiment to evaluate Soil Organic Carbon (SOC) and maize grain yield under different soil amendments and cropping systems was conducted in 2006 and 2007 at the Soil Research Institute, Kwadaso, Kumasi. The experiment was a split plot with three replications. The main plot factor (cropping systems) consisted of continuous maize, maize/soybean intercropping and maize cowpea rotation systems, the sub-plot (amendments) comprised of Poultry Manure (PM) at 4 t ha -1, poultry manure+chemical fertilizer (PM+CF) at 2 t ha -1 (PM)+45-30-30 kg ha -1 (NPK 15-15-15), Chemical Fertilizer (CF) at 90-60-60 kg ha -1 NPK 15-15-15 and a control (no amendment). Soil samples were taken at 21 and 84 days after amendment (DAA). Generally, PM+CF produced the highest range of SOC (1.14-1.37%). The least (0.98-1.28%) was recorded on the control plots. Plots amended with chemical fertilizer alone or in combination with poultry manure out-yielded the control in maize grain yield. Positive correlations between SOC at 84 DAA and maize grain yield were recorded in the major (r=0.70*) and minor (r=0.89**) rainy seasons of 2006 which established crop yield a function of SOC at harvest. Land equivalent ratios of sole maize (maize grown under continuous maize system) and maize intercropped with soybean were
  • Authors:
    • Martiniello, P.
  • Source: European Journal of Agronomy
  • Volume: 35
  • Issue: 4
  • Year: 2011
  • Summary: Rotations experiment have been investigated from 1991 to 2008 under irrigated and rainfed condition in Mediterranean environment. The crops studied were: annual winter binary mixture (BM), perennial meadow (ME) and durum wheat (W) continuously rotated for 3 years and W rotated on itself for all period of experiment (CW). The forage rotations emphasized on the impact made on biochemical characteristics of topsoil and productivity of the crops. The 3 years continuous wheat rotation over forage crops assess the advantage of forage crops left in the soil on seed yield and on quality of kernel. The continuous wheat rotation (CW) reduced the soil biochemical parameters, seed yield and quality of kernel. The value of organic carbon, C/N and total nitrogen, under rainfed in comparison to the values present in the topsoil at the beginning of experiment were 6.4% and 2.48 higher and 11.2% lower in ME and lower 5.2% in organic carbon and 2.8% total nitrogen and 0.21 higher in C/N in BM. The agronomic advantages allowed by forage rotations expire their effect after 3 years of continuous wheat. Yearly yield W gain under rainfed was 11.3 kg (ha yr) -1 in BM and 62 kg (ha yr) -1 in ME. The qualitative traits of wheat kernel rotated on forage were higher than those of continuous wheat CW. Results of biochemical characteristics obtained at the end of experiment evidenced that W after BM and ME rotations sustained, under irrigated and rainfed condition, the content of organic carbon and total nitrogen and C/N in the topsoil of the cropping system while continuously CW allowed strong impact of the parameter values present at beginning of experiment (organic carbon, total nitrogen and C/N was reduced under rainfed by 23.5%, 18.2 and 0.32 and 30.3%, 15.4% and 1.72 under irrigated, respectively).
  • Authors:
    • Cabrera, D.
    • Liso, A.
    • Coelho, J.
    • Lopez-Pineiro, A.
    • Nunes, J.
    • Pena, D.
  • Source: Spanish Journal of Rural Development (SJRD)
  • Volume: 2
  • Issue: 1
  • Year: 2011
  • Summary: In order to determine the effect of different irrigated crop rotation (1. corn, 2. intensive olive grove (300-400 trees/ha), 3. Corn - barley/oat/wheat (1 or 2 years) sugar beet and 4. Tomato - barley/oat/wheat (1 or 2 years) - Beet) on the organic matter content, pH, electrical conductivity and soil sodicity, we collect and georeferenced 6280 samples from the surface layer of soils (0-20 cm) in the Caia Irrigation Perimeter (located in Elvas and Campo Maior Counties, Portalegre District, Portugal) occupied with those rotations. These samples were mixed in groups of 10, resulting 1 sample, corresponding to an area of 11.1 ha, the one was sent to the laboratory where we proceeded to examine the above parameters. With the use of appropriate software (Geographic Information Systems - GIS), it was possible to correlate these individual soil samples with crop rotations and with the group of soil present (Fluvisols, Luvisols and Calcisols). We found that the use of the abovementioned crop rotations, over about two decades, led to significant differences in soil characteristics, although not always significant from a statistical point of view. The crop rotations using larger water and fertilizers amounts in irrigated crop systems are the ones causing a more evident decrease in soil organic matter and pH and, at the same time, leading to an increase in soil electrical conductivity and exchangeable sodium content.
  • Authors:
    • Amarante, I.
    • Machado, J.
    • Fontaneli, R.
    • Santos, H.
  • Source: Pesquisa Agropecuaria Gaucha
  • Volume: 17
  • Issue: 1
  • Year: 2011
  • Summary: The effects of soil management systems and crop rotation on sorghum yield characteristics agronomic were evaluated during the period 2003/04 to 2010/11 at EmbrapaTrigo, Passo Fundo, RS, Brazil. Four soil management systems: (1) no tillage, (2) minimum tillage, conventional tillage using a disk plow and a disk harrow, and (4) conventional using a moldboard and a disk harrow; and three crop rotation system I (wheat/soybean), system II (wheat/soybean and common vetch/sorghum), and system III (wheat/soybean, white oats/soybean and common vetch/sorghum) were compared. An experimental design of blocks at random, with split-plots and three replications, was used. The main plot was formed by the soil management systems, while the split-plot constituted of the crop rotation systems. Minimum tillage and no-tillage presented higher yield of sorghum, while conventional tillage using a moldboard plow remained in intermediate position and tillage using disk plow the lowest yield of sorghum. The yield of sorghum grown after common vetch in system II was higher than yield obtained for sorghum after common vetch in system I. No significant differences were observed in sorghum characteristics agronomic as a result of soil management and crop rotation systems.