Pores and organic matter take a multitude of forms in soil and their characteristics change in space and time following a change in tillage practices as a new “steady state” is approached. Information on the variation with depth (stratification) in the characteristics of pores and organic matter and the rates of changes in these characteristics are vital to interpreting the short- and long-term impacts of the reduction of using conventional tillage on the productivity and hydrology of agricultural soils. This information is also of value in estimating the effect of a reduction in tillage on the sequestration of carbon in agricultural soils. The influence of tillage on bulk density, macro porosity and organic matter content was found to be documented more extensively than the effects on pore size distribution, soil organic matter fractions and their interactions at different soil depths. Many of the reports documenting tillage-induced changes in soil porosity and organic matter were based on measurements at a specific time after initiating the tillage trial. The potential advantages of conservation tillage in organic farming are reduced erosion, greater macro porosity in the soil surface due to larger number of earthworms, more microbial activity and carbon storage, less run-off and leaching of nutrients, reduced fuel use and faster tillage. Conversion from conventional (CT) to no-tillage (NT) resulted in an immediate change in the placement of aboveground crop residue and the reduced fragmentation of the soil matrix may also slow the mineralization of SOC.
کلید واژگان :Conservation tillage, Soil organic matter, SOC
ارزش ریالی : 300000 ریال
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