Land suitability assessment to achieve optimal field rice yield

Abstract

Shifting cultivation of dryland rice is still practiced by indigenous Kalimantan people to fulfill their own needs for rice. The selected locations are mainly young secondary forest land cover with a fallow period of 10-15 years for easier work and higher biomass. The stage of shifting cultivation that most determines the ease of subsequent activities, growth and yield is the amount of biomass burned (>70%) to ash, except for parts of trees >15cm in diameter. Ash contains available macro and micro nutrients that can increase nutrient retention (nr), namely CEC, base saturation and pH and available nutrients (na) N, P and K. Assessment of land suitability to the requirements of growing field rice with the matching method, that the minimum land characteristics are the heaviest constraints that determine the class and sub-class land suitability. The evaluation results obtained actual land suitability sub-class S3nr,na, the heaviest limiting factors of nutrient retention and nutrient availability. Improvement of biomass ash after land burning occurs naturally starting with rain. Improvement of limiting factors is naturally limited, farmers must add N and P nutrients from Urea and Super Phosphate-36 (SP-36) fertilizers at doses of N 25-40 kg.ha-1 and P 30-50 kg.ha-1. Fertilizers are applied by sowing at 21 days of age and 45 days of age at a dose of 50% each. After the improvement efforts were made, the growth of field rice was better so that production increased. The sub-class of suitability increased one level to S2eh,nr, the limiting factors are slope class (eh) and nr.