No abstract

Soil management practices can have negative or positive effects on soil quality. Our objective was to assess the effect of long-term agricultural practices by evaluating selected soil physical and chemical properties. Soil samples were collected from two depths (0 to 15 and 15 to 30 cm) within a native pasture and an adjacent agricultural field that was being used for three different crop rotations. Soil quality was quantified using aggregate stability, bulk density, soil texture and available water content as physical properties and pH, electrical conductivity, organic matter and available phosphorus as chemical properties. The farmland soils were functioning at 71 and 70 per cent of their full potential at the 0-to 15-and 15 to 30-cm-depth increments, respectively, whereas those from the pasture were functioning at 73 and 69 per cent, respectively. The assessment showed substantial loss in soil organic carbon following 50 years of farmland cultivation. Tillage and fertilizer applications were presumably the primary reasons for weaker spatial dependence within farmland at the 0-to 15-cm depth. Grazing was postulated as the main reason for weaker spatial dependence within the pasture soils at the 15-to 30-cm depth. Overall, we conclude that 50 years of cultivation has not caused soil quality to decline to a point that threatens sustainability of the agricultural fields.Notes: CV, coefficient of variation; ns, not significant; TOC, total organic carbon; BD, bulk density; EC, electrical conductivity; SQI, soil quality index. a Significant at the 0·01 level. b Significant at the 0·05 level.

No abstract

Abstract:A diverse topography along with deforestation, changing climatic conditions, long-term human settlement, overuse of agricultural lands without sustainable planning, cultural difficulties in accepting conservative land management practices, and wrong political decisions have increased the vulnerability of many soils to degradation and resulted in a serious decline in their functional capacity. A progressive reduction in the capacity of soils to support plant productivity is not only a threat in the African continent and its large desert zone, but also in several parts of Central and Southeastern Europe (CASEE). The loss of soil functions throughout CASEE is mainly related to the human activities that have profound influence on soil dynamic characteristics. Improper management of soils has made them more vulnerable to degradation through water and wind erosion, organic matter depletion, salinity, acidification, crusting and sealing, and OPEN ACCESSSustainability 2015, 7 2162 compaction. Unmitigated degradation has substantial implications for long term sustainability of the soils' capability to support human communities and resist desertification. If sustainable agricultural and land management practices are not identified, well understood and implemented, the decline in soil quality will continue and probably accelerate. The lack of uniform criteria for the assessment and evaluation of soil quality in CASEE countries prevents scientific assessments to determine if existing management practices are leading to soil quality improvement, or if not, what management practices should be recommended to mitigate and reverse the loss of soil health.

No abstract

No abstract

Soil compaction affects crop yield in many ways. Knowing its spatial variability provides possibilities for site-specific soil treatments that can increase the profitability and sustainability of crop production. The purposes of this study were (1) to investigate the spatial variability of particle size distribution, gravimetric water content, bulk density, and penetration resistance using classical and geostatistical methods in a field in which conventional soil tillage methods and a particular crop rotation were applied, and (2) to evaluate the spatial relations among soil properties in the field studied. Topsoil (0 to 20 cm) and subsoil (20 to 40 cm) were separately sampled at each of 94 predetermined sampling points based on an irregular grid design in a 45 ha areaypic Ustifluvents). Bulk density showed the lowest variability (CV = 9.09% for topsoil and 6.00% for subsoil), and the penetration resistance showed the highest variability among the soil properties investigated (CV = 64.08% and 42.69%, for topsoil and subsoil, respectively). Gravimetric water content and bulk density showed high correlation particularly with clay and sand content, whereas no significant correlation occurred between penetration resistance and any of the textural components. Spatial correlation ranges varied from 72 to 510 m. Clay content had strong spatial dependence in topsoil, whereas, only moderate spatial dependence occurred in subsoil. Spatial dependence classes of other soil properties evaluated did not change with depth. Strong spatial dependence occurred for penetration resistance and sand content, and Long Term Conventional Tillage Effect 143 a moderate spatial dependence occurred for bulk density, gravimetric water content, and silt content. Comparisons of kriged maps of bulk density, penetration resistance, and textural components revealed that greater penetration resistance and bulk density were associated with greater sand content. However, most of the soils of study area had a clayey texture. Therefore, farmers need to be careful in application of soil tillage and other management practices that could cause compaction.

Bu çalışma, Mustafa Güzel tarafindan hazırlanan 'Sivas-Gürün şartlarında aspir üretiminde farklı toprak işleme sistemlerinin enerji kullanım etkinliği açısından karşılaştırılması' konulu yüksek lisans tezinin bir bölümüdür.