جستجوی مقالات مرتبط با کلیدواژه « اصلاح کننده های خاک » در نشریات گروه « آبخیزداری، بیابان، محیط زیست، مرتع »

The soil of rangelands in mountainous areas has always been considered for changing to agricultural land due to its abundant organic matter. Research shows that changing the rangelands and implementing agricultural operations can increase soil erosion and generation of runoff. Therefore, using all kinds of modifiers as a suitable and desirable solution can control soil loss in these lands. This study was conducted with the aim of investigating and comparing the effect of land use change in rangeland and the effect of organic amendments on reducing sediment production, runoff and soil loss in one of the subbasins of Mereg river.

The present research was conducted in one of the sub-basins of Merg river, five kilometers away in Kermanshah province. This area is one of the main branches of the Karkhe River and one of the most important subbasin of the Qaresou River. The average annual rainfall is 458.59 mm and the average annual temperature is 13.89°C. Investigating the effect of land use change and organic modifiers (sheep manure and waste compost) on generation of sediment, runoff and carbon loss in both rangeland and agricultural uses, at erosion plots in dimensions of one in two square meters for two years (1398 and 1399) were evaluated. In the first year, samples were collected from undisturbed erosion plots, but in the second year, two modifiers (sheep manure and municipal waste compost) were added to agricultural plots in the amount of 1.5 kg. The modifiers were added  at the ended of July and until the first rain of the autumn season, there was enough time for chemical interactions and influence on the soil characteristics .The samples of runoff and sediment as well as soil samples were analyzed in the laboratory and the volume of runoff, the amount of suspended sediment, the organic carbon percentage of the sediments and the physical and chemical characteristics of the soil were measured.

The texture of the soil in both land use was the same (clay loam). But in terms of the amount of organic carbon, the two land uses have a significant difference (at 95 percent level) and this parameter is more than twice as much in the rangeland as in the agricultural use. Based on the results in the first year of sampling, the values ​​of runoff volume, sediment weight, carbon loss during five rainfall events in agricultural were 83, 90 and 87% higher than rangeland. In the second year of sampling, plots located on agricultural lands were treated with soil conditioners and their impact was investigated. Although the use of soil conditioners reduced runoff by 20% and reduced the amount and concentration of sediment in agricultural lands about 31.68 and 13.13%, but the amount of these parameters is still 67, 95, and 72% lower in rangeland use, respectively. The results also showed a 71% higher organic carbon loss in agricultural land use than rangeland. The results of this research showed that the modified wars were successful in reducing soil and water loss, and sheep manure treatment worked better than compost in controlling runoff and sediment.

In general, the results of this research showed that the amendments were able to reduce water and soil loss and sheep manure treatment worked better than compost in controlling runoff and sediment. But none of them have been able to reduce the effect of tillage destruction on this slope as much as rangeland. This shows the role and importance of protecting rangeland in reducing soil degradation and water wastage

 Nowadays, ths soil erosion is a serious threat for most societies and it causes the loss of water and soil. One of the most important factors of control of runoff and soil erosion is the application of soil conditioners. Therefore, the current research was conducted in order to performance evaluation of individually and combined effect of the bean straw mulch in three levels of 25, 50 and 75 percent and polyvinyl acetate in level of 3 percent on changes of runoff and soil erosion.

 the used soil at present study collected from rangelands at depth of 20 cm and after transportation to laboratory for relative stability of aggregates passed from sieve of 4 mm. For performance of the present study of the treatments of bean straw mulch as an organic soil conditioner and polyvinyl acetate as an inorganic conditioner used in individually and combined form. The conservation treatments applied at laboratory conditions using rainfall simulator for time priodes of 24 h, 2 and 4 months.

The results showed that the bean straw mulch and polyvinyl acetate at individually and combined various levels and applied time intervals could increase the time to runoff and end runoff and also decrease the runoff coefficient, soil erosion and sediemt concentration. The most affect on time to runoff related to combined treatment of bean straw mulch with level of 75 percent + polyvinyl acetate (MSP3) at time interval of 2 month (with rate of 74.68 percent). Also, the maximum changes of reduction of soil erosion related the application of bean straw mulch with level of 75 percent (MS3) at time level of 2 month with rate of 67.54 percent. The results showed that the bean straw mulch and polyvinyl acetate had significant effect on studied variables at level of 99 percent.

In general, it can be stated that the usage of bean straw mulch and polyvinyl acetate with form of individually and combined with other conditioners in order to investigation their effects on soil and water conservation can be a useful method. Finally, the usage of bean straw mulch and polyvinyl acetate in eroding or eroded lands and performance of new researches with other soil conditioners and in different conditions recommended with aim of soil and water conservation. Also Due to the different performance of individually and combined application of bean straw mulch and polyvinyl acetate, the correct usage of conditioners is necessity at the resources management of water and soil.

Soil erosion and nutrient loss threaten the soil and water resources worldwide. Application of soil conditioners, particularly organic amendments, is an effective way to mitigate this problem. This study was undertaken to assess the effect of application of two organic amendments, biochar and ship manure, under two rainfall intensities of 51 and 65 mm/h by using a rainfall simulator on intact soil. No significant difference was observed in the treatments at 51 mm/h, while with an increase in the intensity to 65 mm/h, the biochar amendment made a decrease of about 64% in the suspended load and runoff coefficient; sheep manure reduced the runoff coefficient and suspended load by about 76% and 74%, respectively at the 99% significance level.

In severely eroded areas, especially steep slopes, establishment of vegetation cover is not possible. The application of organic and inorganic amendments can therefore improve the conditions leading to establish vegetation cover through playing an effective role in runoff control. Accordingly, in the present study, woodchips as a soil organic amendment was applied to control runoff variables including time to runoff, runoff volume and coefficient. For this purpose, three levels of woodchips treatment of 0.5, 1.0 and 1.5 kgm-2 were used in three replications at in 1 m2- plot scale. The plots were located in 30% slope in accordance with field conditions under simulated rainfall of 60 mmh-1 and duration of 15 min. The results showed that application of woodchips in 0.5, 1.0 and 1.5 kgm-2, time to runoff increased 97.50, 192.38 and 203.31%, respectively. The runoff volume decreased 35.23, 55.11 and 60.43% and runoff coefficient also decreased 42.43, 67.40 and 72.14% in three levels of woodchips treatments, respectively. The results of GLM showed that woodchips treatment had a significant increasing effect on time to runoff (p≤0.01) as well as a significant decreasing effect on runoff volume and coefficient (p≤0.05). The application of woodchips as a conservation treatment on the soil surface showed that this amendment can be used for runoff control especially where large quantities of woodchips are simply available.