M. Yousefifard, A. Jalalian, H. Khademi,
Volume 11, Issue 40 (summer 2007)
Abstract
Improper use of natural resources, especially soil, causes its degradation and severe soil erosion. Water erosion is an important factor causing soil degradation. Land use change of pasture would result in severe soil erosion mainly due to the reduction of vegetation cover and also surface soil disturbance. The objectives of this study were to estimate the amount of sediment, runoff and nutrient loss in four different land uses including a pasture with good vegetation cover (> 20%), a pasture with poor vegetation cover (< 10%), a currently being used dryland farm and a degraded dryland farm which is not used. Soil samples were taken from the depth of 0–10 cm in a completely randomized design with four replications. A rainfall simulator was run for two hours to estimate the amount of sediment, runoff and nutrient loss. Organic matter, total N, available P and distribution of particles size in soil and sediment were measured. The results showed that a very high degradation has occurred in the area mostly due to water erosion created as a result of overgrazing in pasture, susceptibility of geological formations and more importantly, the change of land use pasture to inefficient dryland farming. Maximum and minimum runoff was observed in the abandoned dry landfarm and pasture with good vegetation cover, respectively. Maximum sediment content was observed in dryland farm. Sediment content in dryland farm, abandoned dry landfarm and pasture with poor vegetation cover were 54.5, 21 and 10.4 times more than that in the pasture with good vegetation cover, respectively. Enrichment ratio (ER) of soil particles in sediment was highest for fine silt (2-5µm), followed by clay. A minimum of ER was obtained for sand fraction. Percentages of organic matter, total N and available P in sediment were higher in the first hour as compared to the second one. This is mainly due to the fact that fine particles are removed at the beginnings of the rainfall event. Total removal of these chemical factors was highest in dryland, intermediate in pasture with poor vegetation cover and abandoned dryland and lowest in pasture with good vegetation cover. In general, cultivation and disturbance of the pasture in the area land have caused a great decrease in soil quality and made the surface very sensitive to erosion.
V. Dorostkar, M. Yousefifard, Z. Jajarmi,
Volume 23, Issue 2 (Summer 2019)
Abstract
A significant amount of the oil meal is produced annually in the oil industry. Oil meal addition into the soil can improve the soil organic matter and micronutrients concentration. This study was conducted to investigate the effect of olive, sesame and black cumin meal (0, 2 and 5 g 100g-1 soil) on the soil Cu, Zn and Fe concentration in saline and non-saline soils by a greenhouse experiment. The soil basal respiration, organic carbon, carbohydrate and DTPA extractable Cu, Zn and Fe concentration were measured after 60 days of incubation. The results showed that the greatest organic carbon and carbohydrate content were observed in olive and black cumin treatments and the lowest was observed in the sesame treatment. Using oil meal in the soil improved the micronutrient concentration, as compared to the control treatment. Sesame meal had the greatest effect on the DTPA extractable Cu and Zn concentration increment. The DTPA extractable Fe concentration was the highest in the sesame treatment and the lowest in the black cumin one. In addition, salinity decreased the DTPA extractable Fe and Zn concentration, as compared to the non-saline soil. As the conclusion, oil meal incorporation in to the soil improved the soil organic carbon and micronutrient concentration. However, their effect depends on the meal quality and soil salinity.
