DETERMINATION OF PLANTING PATTERN BASED ON WATER BALANCE ANALYSIS FOR FARMING PLANNING AT DRYLANDS IN THE TROPIC (A CASE STUDY IN GUNUNG MAS DISTRICT, CENTRAL KALIMANTAN PROVINCE, INDONESIA)

The existence of water as a crop growth requirement is a prerequisite in tropical drylands. In addition, water balance, as an important part of climate change, is needed to be accessed under certain conditions. This study aimed to observe water availability and analyze water balance at drylands for farming planning purposes. The results of this study were then required to determine planting patterns and farming planning in the tropics, in which information related to hydrology is still lack. The Thornthwaite-Mather method approach was used in this study to analyze water balance in areas observed and. Because of its simplicity, this method can also be applied to areas with limited data. The water balance analysis that provides the information on water availability can be used as basic consideration for farming planning, especially at drylands in which water availability is a critical factor for farming activities. In tropical drylands, the cropping pattern of food crops – secondary crops – fallow – horticulture crops can be proposed within farming planning. Maize as a food crop can be planted for the early planting period in January, in which it can be harvested at the age of 80 days around March. In the following month, secondary crops such as soybeans can be planted and harvested at 135 days. Fallow periods during August and September, the lands cannot be optimally used because of water deficit. Entering the beginning of October, the land can be cultivated and prepared for the next crop, eggplant, as horticultural crops, harvested at 135 days in early February.