Soil compaction was identified as the cause of ‘growth stunting disease’ in sultana grapes and ‘red death’ in cotton at the Lower Orange River and Vaalharts irrigation schemes. In an experiment growth stunting disease was eradicated completely and yields of sultanas increased substantially by deep cultivation, which eliminated compacted soil layers. Ripping increased the quality of tobacco, and...

Soil amendments can improve the sustainability of agricultural systems by building soil carbon and improving numerous other soil health indicators, including soil structure, water infiltration and retention, bulk density, nutrient availability, and microbial activity. This chapter covers some general considerations relevant to the use of soil amendments followed by a discussion of biosolids, an...

Measuring infiltration at the plot scale is difficult, especially for high hydraulic conductivity soils. At the plot scale, the infiltration rate is usually calculated by comparing surface runoff to rainfall. Direct measurement of infiltration beyond the point scale is typically limited to locations where land forming (e.g., infiltration pond) has been performed or fields with basin irrigation ...

Tillage-induced changes in soil properties are difficult to predict, yet can influence evaporation, infiltration and howwater is redistributedwithin the profile after precipitation.We evaluated the effects of sweep tillage (ST) on near surface soil water dynamics as compared with an untilled (UT) soil during a 7-month period. Plots were established in a fallow field devoid of residue under stub...

soil erosion by water is the main factor of land degradation, particularly in semi-arid regions where soil productivity is usually low and lowering soil quality can severely decrease crops yields. this study was done in an area of 900 km2 in the semi-arid agricultural region of hashtroud in northwestern iran to determine the relationship between soil productivity and soil erodibility. wheat gra...

with estimates increasing as much as a factor of 20 when the scale of measurement increased from 0.1 to 2 m (e.g., Estimates of saturated and unsaturated water flow in soil are imporGarbesi et al., 1996; Tidwell and Wilson, 1999). tant for predictions of infiltration, runoff, and solute transport. PreviMeasurement bias related to sample size has someous research indicates that ponded infiltrati...

Knowledge of soil hydraulic parameters for the van Genuchten function is important to characterize soil water movement for watershed management. Accurate and rapid prediction of soil water flow in heterogeneous gravel soil has become a hot topic in recent years. However, it is difficult to precisely estimate hydraulic parameters in a heterogeneous soil with rock fragments. In this study, the HY...

Film hole irrigation is an advanced low-cost and high-efficiency irrigation method, which can improve water conservation and water use efficiency. Given its various advantages and potential applications, we conducted a laboratory study to investigate the effects of soil texture, bulk density, initial soil moisture, irrigation depth, opening ratio (ρ), film hole diameter (D), and spacing on cumu...

infiltration process plays an important role in water cycle of the nature. conducting field experiments is necessary to determine the coefficients of infiltration equations due to the dependence of these coefficients to the soil type, soil surface conditions and the amount of initial soil moisture content. this study has been carried out in a field located in islamic azad university, marvdasht ...