karakterisasi, Dinamika dan Optimasi Pemberian Undur Hara Serta Insektisida Pada Sistem Produksi Padi Bagi Pemanfaatan Lahan Sawah Berkelanjutan (Studi Kasus dik Sukamadi, Kabupaten Subang, Propinsi Jawa Barat)

Abstract

In Subang District, farmers are generally apply in-appropriate dosages of NPK fertilizers and carbofuran insecticide for their lowland rice (paddy) farming system. The dosages bring about lower productivity level and yield quality, and even pollute the lowland rice habitat. A research activity was conducted in experimental site of Indonesian Institute for Rice Research (Balitpa) during the dry season 2003 (March through August) on clayey textured and acidic soil which was low in total N and organic C, moderate in total K, and high in total P contents. The study aimed to formulate a recommendation for sustaining lowland rice management through optimizing nutrient and insecticide application. The experiment was arranged using split plot design with three replicates. The research results are: (1) ammonium content in the soil is determined by the interaction between intensity and frequency of observation; (2) soluble P in paddy water was controlled by dosage, intensity, and frequency of nutrient application, and also available P content was determined by the interaction between level of nutrient application and time, (3) concentration of available K in soil and K in lowland water are determined by intensity and frequency of observation; (4) residue of carbofuran in water-soil-plant system was determined by interaction among level of nutrient application, intensity and frequency of observation; (5) analysis on multi-purpose optimization considers optimal production factor and yield quality and minimizes nutrient and carbofuran pollutions on water-soil-crop system as low as possible. It shows that optimal dosage was achieved when applying nutrient and carbofuran as much as 98.03% of farmer's dosage (equal to 112.73 kg N/ha + 7.84 kg P2O5/ha + 29.41 kg K₂O/ha + 19.61 kg carbofuran per ha); (6) although productivity level between farmers and research result differs from 700 to 1,000 kg/ha, the B/C ratio and degree of adoption among the three tertiary areas were not significantly different; (7) adoption level of agricultural innovative technology by farmers was relatively low due to smaller land holding size (less than 0.5 ha), less educated, small capital, lack of information, and in-effective organization.