EXPERIMENTAL MODEL TO INCREASE WATER HOLDING CAPACITY IN DRY LAND IRRIGATION I Wayan Yasa, Ismail Hoesain M, I Dewa Gede Jaya Negara, Ida Bagus Giri Putra
University of Mataram
Abstract
As one of the provinces in Eastern Indonesia, West Nusa Tenggara Province has a very wide dry land potential of almost 161874 ha spread over the southern, eastern and northern parts of Lombok Island, while on Sumbawa Island it is spread in all districts. In general, the very basic problems in the management of dry land irrigation are limited rain and soil texture. The texture of dry land irrigated soil on the island of Lombok is generally sandy, so the productivity is very high. The ability of the soil to hold water is very low and the time to bind soil moisture is very short. Likewise, the intensity of rain in dry land irrigation on Lombok Island is very short, causing the success rate of dry land irrigation agricultural production is very low.
In an effort to increase the ability of porous soils to increase their resistance to irrigation water and rainwater, efforts were made to improve soil texture by replacing the sandy porous soil layer by replacing or mixing the porous soil in the root zone with fine-grained soil. The research design was carried out in a laboratory with experimental modeling. Modeling is done by mixing porous soil with fine grained soil in several portions of the mixture. Furthermore, rainfall modeling was carried out with several variations of rain intensity and measurements of soil moisture and runoff were carried out both through the surface and below the surface. The composition of the soil mixture used is 25% and 50%. The tool used is a rain simulator model. Rain is simulated with a rain duration of 20 minutes, 40 minutes and 60 minutes.
Based on the modeling results show that by mixing porous soil with fine-grained soil can increase soil moisture and water binding time in the root zone is longer. For the percentage of fine textured soil 25% with a rain duration of 20 minutes the humidity can be increased to 48.25%, for a duration of 40 minutes the humidity increases to 52.50% and at a rain duration of 60 minutes the humidity increases to
