Özet:

Bamboo-based agroforestry is suitable for soils which are poor in nutrient. The characteristics of bamboo and the rapid closure of  its canopy improve soil cover, soil nutrient availability and soil moisture  content,  and  prevent  erosion  by reducing surface runoff. The  research was aimed at determining the factors that influenced surface runoff and the availability of soil organic matter (SOM) in the bamboo-based agroforestry in East Lombok. Research was done from March 2010 to March 2011 in Lenek Daya village, Aikmel sub-district, East Lombok district. The research plots were located on slopes of 0-15o, 30-45o, and 45-65o; with bamboo canopy closures of 0-25%, 25-50%, 50-75%, and over 75%. The research involving 12 plots, each in 4 x 12 m size. Measurements included surface runoff, bamboo canopy closure, weeds and bamboo leaves litter weight, rainfall depth and duration, dissolved sediment, and soil physical and chemical properties as well as SOM. Correlation and multiple linear regression tests were used in data analysis. The results of the regression tests showed a change in surface runoff which was influenced by changes in bamboo canopy closure, rain duration, rain intensity and soil sand fraction, each by -0.019, 0.418, 0.049 and -0.065 respectively. Rain duration was the highest influencing variable, whereas bamboo canopy closure significantly decreased surface runoff. Bamboo canopy closure had no correlation with the increase of SOM. But, the increase of SOM had correlation with the increase of  soil cation exchange capacity (CEC). The positive impact of  bamboo canopy closure  on  Regosol soil fertility in  bamboo-based  agroforestry land  was determined  by  land management intensity which could increase the availability of SOM and decrease phosphorus element loss due to leaching of nutrient.

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