• Authors:
    • Burmester, C.
    • Reeves, D. W.
    • Motta, A. C. V.
    • Feng, Y.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 38
  • Issue: 19-20
  • Year: 2007
  • Summary: The impact of conservation tillage, crop rotation, and cover cropping on soil-quality indicators was evaluated in a long-term experiment for cotton. Compared to conventional-tillage cotton, other treatments had 3.4 to 7.7 Mg ha(-1) more carbon (C) over all soil depths. The particulate organic matter C (POMc) accounts for 29 to 48 and 16 to 22% of soil organic C (SOC) for the 0- to 3- and 3- to 6-cm depths, respectively. Tillage had a strongth influence on POMc within the 0- to 3-cm depth, but cropping intensity and cover crop did not affect POW A large stratification for microbial biomass was observed varing from 221 to 434 and 63 to 110 mg kg(-1) within depth of 0-3 and 12-24 cm respectively. The microbial biomass is a more sensitive indicator (compared to SOC) of management impacts, showing clear effect of tillage, rotation, and cropping intensity. The no-tillage cotton double-cropped wheat/soybean system that combined high cropping intensity and crop rotation provided the best soil quality.
  • Authors:
    • Odebode, S. O.
    • Akinbile, L. A.
  • Source: American-Eurasian Journal of Sustainable Agriculture
  • Volume: 1
  • Issue: 1
  • Year: 2007
  • Summary: Sustainability, which involves the ability to use a resource in ways that ensure little or no damage to guarantee continuous use of the resources, was the focus of the study. A focus group discussion was employed using farms to take inventory of the soil conservation practices they consider to be sustainable, from which 15 practices were validated. The study identified the determinants of the farmers' use of the practices in the study area. Quantitative data were gathered from 112 respondents sampled though systematic technique from five communities with the use of questionnaire. The results of the study shows that the farmers are aware of most of the practices. The soil conversation practices they often make use of multiple cropping, use of cover crops, crop rotation and the use of fallow system. They also plant multipurpose tree species for erosion control, and use organic manure with inorganic fertilizer at varying degrees to enhance productivity and ensure sustainability. Correlation test at P<0.05 shows that farm size, income, labour use, their other income generating activities and there level of awareness had significant relationship with respondents use of the sustainable soil conservation practices. Multiple regression analysis shows that factors that determine farmers use of those soil conservation practices are their level of awareness of the practices, farm size, income, labour use of their income generating activities in which they are involved. The factors determined 72% of the variation in respondents' use of conservation practices. Farmers should therefore be assisted with respect to those factors to ensure the sustainable use of the soil, which is very important in their income generating activities as farmers.
  • Authors:
    • USDA
  • Year: 2006
  • Authors:
    • Jung, Y. S.
    • Meek, D. W.
    • Cambardella, C. A.
    • Jaynes, D. B.
    • Parkin, T. B.
    • Kaspar, T. C.
  • Source: Soil Science Society of America Journal
  • Volume: 70
  • Issue: 4
  • Year: 2006
  • Summary: Winter cover crops have the potential to increase soil organic C in the corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] rotation in the upper Midwest. Management effects on soil C, however, are often difficult to measure because of the spatial variation of soil C across the landscape. The objective of this study was to determine the effect of oat (Avena sativa L.), rye (Secale cereale L.), and a mixture of oat and rye used as winter cover crops following soybean on soil C levels over 3 yr and both phases of a corn-soybean rotation using terrain attributes as covariates to account for the spatial variability in soil C. A field experiment was initiated in 1996 with cover crop treatments, both phases of a corn-soybean rotation, and a controlled-traffic no-till system. Oat, rye, and oat-rye mixture cover crop treatments were overseeded into the soybean phase of the rotation in late August each year. Cover crop treatments were not planted into or after the corn phase of the rotation. Soil C concentration was measured on 450 samples taken across both rotation phases in a 7.62-m grid pattern in the late spring of 2000, 2001, and 2002. Slope, relative elevation, and wetness index (WI) were used as covariates in the analysis of variance to remove 77% of the variation of soil C caused by landscape driven patterns of soil C. Soil C concentrations were 0.0023 g C g soil -1 higher in 2001 and 0.0016 g C g soil-1 higher in 2002 than in 2000. The main effects of cover crops were not significant, but the interaction of cover crops and rotation phase was significant. The rye cover crop treatment had 0.0010 g C g soil-1 higher soil C concentration than the no-cover- crop control in the soybean phase of the rotation, which included cover crops, but had 0.0016 g C g soil -1 lower C concentrations than the control in the corn phase of the rotation, which did not have cover crops. Using terrain covariates allowed us to remove most of the spatial variability of soil C, but oat and rye cover crops planted every other year after soybean did not increase soil C concentrations averaged over years and rotation phases.
  • Authors:
    • Bullock, D. G.
    • Hao, X.
    • Robertson, G. P.
    • Kravchenko, A. N.
  • Source: Agronomy Journal
  • Volume: 98
  • Issue: 6
  • Year: 2006
  • Summary: Lack of information about the spatial variability of soil C in different management systems limits accurate extrapolation of C sequestration findings to large scales. The objectives of this study were to: (i) describe and quantify variability of total C in three management systems, chisel-plow (CT) and no-till (NT) with conventional chemical inputs and a chisel-plow organic management practice with cover crops (CT-cover) 15 yr after conversion from conventional management; (ii) assess the strengths of spatial correlation in the three studied systems; and (iii) evaluate contributions of topography and texture to the overall total C variability and its spatial components. The data were collected at 12 60 by 60 m plots at the Long Term Ecological Research site, Kellogg Biological Station, MI. The data consisted of elevation measurements taken on a 2 by 5 m grid and a total of 1160 measurements of total C, sand, silt, and clay contents taken from the 0- to 5-cm depth. Overall variability of total C in NT was more than four times greater than in CT, and in CT-cover the variability was more than two times greater than CT. Spatial correlation of total C was the strongest in NT, followed by CT-cover, and then by CT. Stronger spatial structures in NT and CT-cover were found to form in response to topographical and texture gradients. Effects of texture were largely associated with topographical effects; however, even when topography was controlled for, texture still substantially contributed to explaining total C variability.
  • Authors:
    • Wander, M.
    • Marriott, E. E.
  • Source: Soil Biology and Biochemistry
  • Volume: 38
  • Issue: 7
  • Year: 2006
  • Authors:
    • Gallagher, L.
    • Armentrout, D.
    • Kratochvil, R.
    • Sardanelli, S.
    • Everts, K.
  • Source: Plant Disease
  • Volume: 90
  • Issue: 4
  • Year: 2006
  • Summary: Experiments using soil-incorporated cover crops and amendments of poultry litter (PL) and PL compost to suppress root-knot (RKN) and root-lesion nematodes were conducted in response to increasing nematode populations in Maryland's potato production areas. Identical experiments were established in microplots infested with Meloidogyne incognita or Pratylenchus penetrans. Treatments consisted of 12 3-year rotational sequences comprising potato (year 1) and cucumber (year 2) followed by a moderately RKN-resistant or susceptible soyabean cultivar, castor bean, grain sorghum, or sorghum sudangrass; PL or PL compost were amended to some of the RKN-susceptible soyabean and sorghum sudangrass plots. In the third year of the rotation, potato followed by soyabean was planted in all 12 treatments. The RKN-resistant soyabean, castor bean, sorghum sudangrass, and fallow or tillage decreased the populations of M. incognita compared with microplots where RKN-susceptible soyabean had been grown. However, RKN populations quickly recovered. Root-lesion nematode was reduced in the spring of 2001 following application of high rates of PL and PL compost in 2000. In the fall of 2001, sorghum sudangrass alone or in combination with PL or PL compost, grain sorghum, or fallow or tillage reduced root-lesion nematodes compared with either soyabean cultivar. No treatment affected root-lesion nematode the following year. The use of cover crops and PL compost is an effective method to reduce nematode populations only if successively incorporated into rotational cropping sequences.
  • Authors:
    • Gamero, C.
    • Rodrigues, J.
  • Source: Energia na Agricultura
  • Volume: 21
  • Issue: 4
  • Year: 2006
  • Summary: The present study aimed to evaluate the energy demand and the effective field capacity in different soil management systems, and three kinds of vegetal covering for soyabean cultivation. The experiment was carried out at the Lageado Experimental Farm, School of Agronomical Sciences, UNESP, Botucatu, SP, Brazil. The experimental area soil was classified as Red Dystroferric Nitosol. The experiment consisted of nine treatments combining three soil management systems (conventional, reduced and no-tillage) and three vegetal covering (black oats, sorghum and spontaneous vegetation). The experimental design was in randomized blocks, 3*3 factorial scheme with 4 replications, using Tukey's test at 5% to compare means. The soil management systems presented significant differences in the effective field capacity, fuel consumption per hour and operational consumption; the no-tillage system presented the best results, regardless of soil vegetal covering.
  • Authors:
    • Andrioli, I.
    • Pereira, M.
    • Fabian, A.
    • Torres, J.
  • Source: Revista Brasileira de Agrociencia
  • Volume: 12
  • Issue: 1
  • Year: 2006
  • Summary: To evaluate the influence of vegetation coverings on soil temperature and humidity, in a medium texture red distrophic latossol, a study was conducted at CEFET-Uberaba, Minas Gerais, Brazil from January to June 2000. A ramdomized complete split plot block design, with 3 replications was used. Eight vegetation covers were allocated to plots: pearl millet ( Pennisetum americanum [ P. glaucum] sin. tiphoides), braquiaria ( Brachiaria brizantha [ Urochloa brizantha]), sorghum ( Sorghum bicolor), pigeon pea ( Cajanus cajan), sun hemp ( Crotalaria juncea) and black oat ( Avena strigosa [ A. nuda]), fallow land and area under conventional system (control). In subplots, maize and soyabean were planted, after vegetation cover desiccation. No significant differences were found among vegetation coverings in relation to soil hydric regime but differences among months were observed. Effect of vegetation cover on soil temperature was shown effectively during the months of May and June, in terms of residues of cultivated crops, mainly maize. Higher values in thermal amplitude were detected under soyabean cropping. Temperatures were higher at 5 cm depth than at 10 cm, in afternoons, under maize and soyabean cultivation.
  • Authors:
    • Deen, W.
    • Janovicek, K.
    • Meyer-Aurich, A.
    • Weersink, A.
  • Source: Agronomy Journal
  • Volume: 98
  • Issue: 5
  • Year: 2006
  • Summary: The objective of our research was to identify economically efficient corn (Zea mays L.) based tillage-rotation combinations using a 20-yr data set from a long-term experiment in Ontario, Canada. Seven rotations in two tillage systems (moldboard and chisel plow) were analyzed. We found multiple benefits associated with diversifying rotations in both tillage systems The integration of soybean [Glycine mar (L.) Merr.] or soybean and wheat (Triticum aestivum L.) resulted in 7 to 11% higher corn yields in the chisel tillage system. In the plow tillage system corn yield in rotation with soybean and wheat increased by 5%, when wheat was underseeded with red clover (Trifolium pratense L.). These diversified rotations resulted in an increase in yearly net returns of $51 to $64 in the moldboard tillage system and $96 to $108 in the chisel tillage system. The diversification of rotations reduces variance of net return and thus makes the rotations attractive to risk averse producers. Furthermore diversified rotations showed less response to price changes. Diversified rotations evaluated in this study also proved to be less affected by increasing energy costs. Red clover seeded into wheat resulted in 5% higher yields for the following corn crop in the moldboard system. Rotations that included red clover cover lowered production risk but did not have higher net returns than comparable rotations without red clover. However, the potential for red clover to reduce N fertilization requirements for the following corn, was not considered in this study. Yield penalties due to chisel plowing with financial consequences were only observed in continuous corn. In all other rotations the effect of tillage was negligible. An increase in energy costs forces farmers to switch to crops with lower inputs rather than switch to reduced tillage.