abstract soil drying and rewetting (drw) cycles are considered as environmental stress that would affect the physical, chemical and biological properties of soil and nutrient cycles. the study of soil drying and rewetting effects on plant nutrition and soil fertility is very important and crucial specially their environmental effects. in this study, the effects of 1, 2, 3, 4 and 5 drying and re...

Root biomass is one of the most relevant root parameters for studies of plant response to environmental change, soil carbon modeling or estimations of soil carbon sequestration. A major source of error in root biomass quantification of agricultural crops in the field is the presence of extraneous organic matter in soil: dead roots from previous crops, weed roots, incorporated above ground plant...

Intensive forestry has resulted in considerable increases in aboveground stand productivity including foliar and belowground biomass which are the primary sources of soil organic matter. Soil organic matter is important for the maintenance of soil physical, chemical and biological quality. Additionally, sequestering carbon (C) in soils may provide a means of mitigating increasing atmospheric ca...

An understanding of the form and function of SOM in soil is essential to sustainable crop production. Various methods of SOM fractionation are used to study SOM forms and to gain an understanding of interaction between SOM and aggregate formation. Physical SOM fractionation techniques are based on the concept that SOM associated with particles of various sizes. differs in structure and function...

Radiocarbon data from soil organic matter and soil respiration provide powerful constraints for determining carbon dynamics and thereby the magnitude and timing of soil carbon response to global change. In this paper, data from three sites representing well-drained soils in boreal, temperate, and tropical forests are used to illustrate the methods for using radiocarbon to determine the turnover...

field study was conducted at five villages of botswana namely, tsabong, tshane, mathathane, motlhabaneng and tsetsejwe during the periods of june to august 1999 and june to august 2000. the objective of the study was to assess and compare the soil physicochemical properties of soils at the five villages and to study the effect of cultivation on some soil physical properties. parameters measured...

Sustainability of the rice–wheat rotation is important to Asia’s food security. Intensive cropping with no return of crop residues and other organic materials results in loss of soil organic matter and is not sustainable. We evaluated effect of eight treatments comprised of various combinations of green manure (GM), wheat straw (WS), rice straw (RS), farmyard manure (FYM) and urea alone (contro...