• Authors:
    • Fasinmirin, J. T.
    • Reichert, J. M.
  • Source: Soil & Tillage Research
  • Volume: 113
  • Issue: 1
  • Year: 2011
  • Summary: Cassava ( Manihot esculenta crantz) is often cultivated on tilled plots, traditionally on mounds and ridges with the use of hand hoes or tractor driven implements. These two conditions alter the soil structural parameters and most times increase the vulnerability of soil to erosion or compaction as a result of frequent machine movement under the conventional tillage system. A review of the effects of tillage systems on soil bulk density, total porosity and penetration resistance was conducted to investigate the effectiveness of soil conservation for the optimum production of cassava in the tropics. Tillage treatments under review were: conventional tillage (CT), no-till (NT), minimum tillage (MT) and soil compaction (CP). Our review indicated that the bulk density (BD) in plots under CT was not significantly different ( p<0.05) from the value of BD in plots under minimum tillage (MT) within the 0-5 cm soil layer, but was highest in soils under compaction due to traffic passes of heavy duty equipment. Soils under no-till were characterized with lowest bulk density within the 0-5 cm layer, but gradually increased in BD within the 10-20 cm soil layer, which offers the soil some structural stability. However, the difference in bulk densities between plots under NT and CP treatments were highly significant at p<0.05, with CP plots having the highest bulk density within the 0-30 cm soil layer. Total porosity was highest in soils under conventional tillage (CT) comparatively with other tillage systems. Organic matter accumulation in NT treatment resulted to higher total porosity compared with other systems except CT at the surface soil (0-5 cm) but with reduced porosity at the sub-surface soil. Total porosity was least in plots under traffic passes (compacted plots). Statistically, there were no significant differences in total porosity among plots under conventional tillage with mulch residues, conventional tillage without mulch residues and minimum tillage with mouldboard at the p<0.05. However, plots under minimum tillage without mouldboard had lower total porosity. Penetration resistance was higher in NT plots when compared with plots under CT system, except from compacted plots (CP), which offered highest resistance to penetration. A long term experiment showed that cassava root yield was highest under NT with mulch residues, with or without fertilizer application. The reviewed work further confirmed that cassava can be grown successfully under no-till (NT) to give the optimum growth and yield required of the crop, while conserving the soil physical properties.
  • Authors:
    • Feng, G.
    • Sharratt, B.
    • Young, F.
  • Source: Journal of Soil and Water Conservation
  • Volume: 66
  • Issue: 4
  • Year: 2011
  • Summary: In the low precipitation zone (<0.3 m [11.8 in] annual precipitation) of the Inland Pacific Northwest, no-tillage continuous spring cereal and no-tillage spring cereal-chemical fallow rotations are being examined as alternatives to the traditional winter wheat-summer fallow rotation for soil conservation. There is limited information, however, regarding the long-term effects of no-tillage cropping systems on soil hydraulic properties in this semiarid region. The objective of this study was therefore to characterize infiltration, water retention, saturated hydraulic conductivity and bulk density of a silt loam that had been subject to various tillage and crop rotations in east-central Washington. Treatments examined included no-tillage spring barley-spring wheat (NTSB-SW), no-tillage spring wheat-chemical fallow (NTSW-ChF), and traditional winter wheat-summer fallow (WW-SF). Soil properties were measured in spring and late summer 2006 due to the vulnerability of the soil to rapidly dry and erode during these seasons. Saturated hydraulic conductivity was determined by the falling-head method, infiltration was measured using a double-ring infiltrometer, and water retention characteristics was assessed by examining the temporal variation of in situ soil water content. NTSB-SW resulted in higher infiltration and saturated hydraulic conductivity, lower bulk density, and larger and/or more continuous pores in the upper soil profile (<0.1 in [<3.9 in] depth) than WW-SF and NTSW-ChE Infiltration and saturated hydraulic conductivity were lower for chemical fallow than for traditional fallow in spring whereas hydraulic conductivity was lower for summer fallow than chemical fallow in late summer. Soil hydrologic properties appeared more favorable for no-tillage continuous spring cereal rotations. These results arc useful for soil and water management and conservation planning in the low precipitation zone of the Inland Pacific Northwest.
  • Authors:
    • Fernandez, M. R.
    • Ulrich, D.
    • Brandt, S. A.
    • Zentner, R. P.
    • Wang, H.
    • Thomas, A. G.
    • Olfert, O.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 3
  • Year: 2011
  • Summary: The impact of cropping system management on root and crown rot of spring wheat ( Triticum aestivum L.) was examined on a Dark Brown Chernozem (Typic Boroll) soil in the Canadian Prairies. This systems approach tried to reflect the most common practices of organic and conventional producers in this region. The study consisted of a factorial combination of three input levels (high, with tillage, fertilizer and pesticides; reduced [RED], with conservation tillage, targeted fertilizer and weed control; and organic [ORG] with tillage and N-fixing legumes); and three levels of cropping diversity (low diversity with wheat and summerfallow or legume green manure fallow; diversified using annual grain crops; and diversified using annual grain crops and perennial forages). All rotations were 6 yr long. Subcrown internodes and crowns/lower culms of wheat plants were scored for discoloration, and fungi in discolored tissue were identified and quantified. Overall, input level had a greater impact on disease levels and fungal frequency than cropping diversity. Discoloration severity was lowest in the RED systems, which was attributed to lower percentage isolation of Cochliobolus sativus, the most common pathogen. Fusarium species varied with input level. The pathogens F. avenaceum and F. culmorum were most associated with RED and/or least associated with ORG systems, whereas the weak pathogen/saprophyte F. equiseti was most associated with ORG systems. Thus, ORG management helped to reduce populations of F. avenaceum and F. culmorum, two of the most important Fusarium pathogens in the Canadian Prairies.
  • Authors:
    • Franzluebbers, A. J.
    • Causarano, H. J.
    • Norfleet, M. L.
  • Source: Plant and Soil
  • Volume: 338
  • Issue: 1-2
  • Year: 2011
  • Summary: Prediction of soil organic C sequestration with adoption of various conservation agricultural management approaches is needed to meet the emerging market for environmental services provided by agricultural land stewardship. The soil conditioning index (SCI) is a relatively simple model used by the USDA-Natural Resources Conservation Service to predict qualitative changes in soil organic matter. Our objective was to develop a quantitative relationship between soil organic C derived from published field studies in the southeastern USA and SCI scores predicted from matching management conditions. We found that soil organic C sequestration (at 20 +/- 5 cm depth) could be reliably related to SCI across a diversity of studies in the region using the regression slope: 1.65 Mg C ha(-1) SCI(-1) [which translated into a rate of 0.25 +/- 0.04 Mg C ha(-1) yr(-1) SCI(-1) (mean +/- standard error of 31 slope estimates)]. The calibration of soil organic C on SCI scores will allow SCI to become a quantitative tool for natural resource professionals to predict soil organic C sequestration for farmers wanting to adopt conservation practices.
  • Authors:
    • Rangel, D.
    • Jacobson, A. R.
    • Laba, M.
    • Darnault, C.
    • Otten, W.
    • Radulovich, R.
    • Camargo, F. A. O.
    • Baveye, P. C.
  • Source: Soil Science Society of American Journal
  • Volume: 75
  • Issue: 6
  • Year: 2011
  • Summary: When the Soil Science Society of America was created, 75 yr ago, the USA was suffering from major dust storms, causing the loss of enormous amounts of topsoil as well as human lives. These catastrophic events reminded public officials that soils are essential to society's well-being. The Soil Conservation Service was founded and farmers were encouraged to implement erosion mitigation practices. Still, many questions about soil processes remained poorly understood and controversial. In this article, we argue that the current status of soils worldwide parallels that in the USA at the beginning of the 20th century. Dust bowls and large-scale soil degradation occur over vast regions in a number of countries. Perhaps more so even than in the past, soils currently have the potential to affect populations critically in several other ways as well, from their effect on global climate change, to the toxicity of brownfield soils in urban settings. Even though our collective understanding of soil processes has experienced significant advances since 1936, many basic questions still remain unanswered, for example whether or not a switch to no-till agriculture promotes C sequestration in soils, or how to account for microscale heterogeneity in the modeling of soil organic matter transformation. Given the enormity of the challenges raised by our (ab)uses of soils, one may consider that if we do not address them rapidly, and in the process heed the example of U.S. public officials in the 1930s who took swift action, humanity may not get a chance to explore other frontiers of science in the future. From this perspective, insistence on the fact that soils are critical to life on earth, and indeed to the survival of humans, may again stimulate interest in soils among the public, generate support for soil research, and attract new generations of students to study soils.
  • Authors:
    • Hontoria, C.
    • Lammerding, D.
    • Tenorio, J.
    • Walter, I.
  • Source: Agronomy Journal
  • Volume: 103
  • Issue: 2
  • Year: 2011
  • Summary: It is widely accepted that conservation tillage management affords benefits to soil properties and reduces production costs; therefore these practices could be attractive to farmers from semiarid regions. The objective of this study was to assess the long-term effects of different tillage practices under semiarid conditions on macroaggregate stability (water stable aggregates, WSA), soil organic carbon (SOC), and particulate organic carbon (C-POM) content of an Alfisol from Spain. The experimental design involved a split plot and four randomized blocks in which tillage was the main factor and crop rotation (fallow-wheat-pea-barley) the secondary factor. Three tillage systems were compared: no tillage (NT), minimum tillage (MT), and conventional tillage (CT). Soil samples were collected on November 2006 and October 2007. In November 2006 no significant differences in WSA were found among the tillage treatments. In October 2007, however, the mean WSA in the upper soil layer for the NT was significantly higher, 24%, that in the CT. No significant differences were seen for the subsurface layer. Under NT, the SOC and C-POM values for the surface soil layer were significantly higher than those for the other treatments on both sampling dates. At the subsurface depth, no significant differences were seen in either of these variables. The SOC and C-POM values were more homogeneous throughout the soil profile in the plowed soil than in the NT for which the corresponding values were more stratified. The results show that NT will help improve soil structure and soil fertility, which is particularly relevant to semiarid conditions like the area studied.
  • Authors:
    • Degrande, P.
    • Soria, M.
  • Source: Revista Brasileira de Milho e Sorgo
  • Volume: 10
  • Issue: 2
  • Year: 2011
  • Summary: Pest species that are enhanced by cover crops used in no-tillage farming can cause damages to subsequent crops of economic importance planted into cover crops stubble. In the 2006/2007 growing season, in Dourados, MS, Brazil, a study was carried out to assess the arthropod fauna in three soybean no-tillage systems: unseeded vegetation-soybean, pearl millet-soybean and sorghum-soybean. During the soybean pre-planting season and the early soybean season, the incidence of pests and natural enemies was assessed in 1 m 2 of the cover crops and later on their respective stubble with soybean seedlings in development using a wood made frame square ("wood square" sampling method). The most abundant species at the soybean pre-planting season were caterpillars of Mythimna ( Pseudaletia) sequax and Mocis latipes (Lepidoptera: Noctuidae), and adults and nymphs of the predator Doru luteipes (Dermaptera: Forficulidae), showing a significant population increase on the pearl millet green cover crop. After the cover crops desiccation the incidence of Lagria villosa (Coleoptera: Lagriidae) species was significant on sorghum and pearl millet stubble and the genus Agrotis sp. (Lepidoptera: Noctuidae) on sorghum cover. Thus, the bioecology of pests and natural enemies associated with pearl millet as cover crop might be considered on the development of Integrated Pest Management (IPM) programs in conservation farming systems.
  • Authors:
    • Kitchen, N.
    • Lal, R.
    • Reicosky, D.
    • Goddard, T.
    • Nearing, M.
    • Groffman, P.
    • Delgado, J.
    • Rice, C.
    • Towery, D.
    • Salon, P.
  • Source: Journal of Soil and Water Conservation
  • Volume: 66
  • Issue: 4
  • Year: 2011
  • Summary: This paper presents an overview of the science on conservation practices that could potentially be used to mitigate and adapt to climate change. Following is a list that summarizes some basic principles based on a review of peer-reviewed scientific publications. Information is given on: the major world challenges related to soil and water conservation; soil and water conservation principles applied to climate change mitigation and adaptation; carbon and nitrogen cycles and agricultural influences on greenhouse gases; conservation practices to mitigate greenhouse gases emissions and adapt to climate change; and current mitigation and adaptation efforts and findings from research.
  • Authors:
    • Lenssen, A. W.
    • Sainju, U. M.
    • Jabro, J. D.
    • Evans, R. G.
  • Source: Communications in Soil Science and Plant Analysis
  • Volume: 42
  • Issue: 18
  • Year: 2011
  • Summary: We evaluated the effect of no tillage (NT) and conventional tillage (CT) on soil penetration resistance (PR), bulk density (BD), gravimetric moisture content (MC), and saturated hydraulic conductivity (Ks) during the fallow phase of a spring wheat-fallow rotation. The study was conducted on two soils mapped as Williams loam at the Froid and Sidney sites. Soil measurements were made on 19 May, 23 June, and 4 August 2005 at the Froid site and on 6 June and 8 July 2005 at the Sidney site. Tillage had no effect on either soil properties except on the PR at Sidney. However, soil PR, MC, and BD varied significantly with depth regardless of tillage and location. Further, soil PR and MC varied with the date of sampling at both locations, and PR generally increased with decreased MC at all soil depths. Soil Ks was slightly influenced by tillage at both locations.
  • Authors:
    • Sarauskis, E.
    • Karayel, D.
  • Source: Žemės Ūkio Inžinerija, Mokslo Darbai
  • Volume: 43
  • Issue: 3
  • Year: 2011
  • Summary: Seed placement uniformity and failure to establish a uniform plant stand are critical problems associated with no-tillage production of maize ( Zea mays L.) following wheat ( Triticum aestivum). The objective of this research was to evaluate the effect of different downforces (680, 880, 1150 and 1400 N) on performance of disc furrow openers and determine the optimum downforce for modified precision seeder equipped with single or double disc-type openers. The study was conducted in two different field conditions (field I and field II). The soil of field I and II were clay-loam and loamy, respectively. Seed spacing uniformity, sowing depth uniformity, mean emergence time and percentage of emergence were determined. Sowing depth and seed spacing uniformity, mean emergence time and percentage of emergence of both furrow openers were increased as a result of increasing downforce for both fields. The downforce of modified conventional precision seeder should be greater than 880 N for more precise no-till sowing using with single and double disc furrow openers for clay-loam and loamy soils.