Planning of cropping pattern for paddy, corn, and soybean with 60 percent rainfall opportunity in Tenggarong, Kutai Kartanegara district (Indonesia)

English. Field evaluation was conducted in Tenggarong Regency, Kutai District about 4 months (July through October 2000). The planning of growing pattern for paddy, corn, and soybean cultivation based on the analyzed in order to examine land water balanced with 60 percent rainfall opportunity and growing season potential. The length growing season's potential is determined through the counting of the areas water balance with book keeping method, considering the aspects of soil water availability in the effective rooting depth of the plantation. Monthly land water balanced indicated that in Tenggarong area, there haven't monthly water surplus, while water deficits occurred during 1 month (September), it was 47.2 mm/year. Optimally, at Tenggarong Regency, there was growing season of 30 days, and with assumption that danger of pest and pathogen can be overcame, paddy growing and second crops (corn or soybean) can be planted once time a year

unknown. Penelitian ini dilaksanakan selama 4 bulan (Juli - Oktober 2000) di Kec. Tenggarong Kab. Kutai dengan tujuan menentukan perencanaan pola penanaman padi, jagung dan kedelai berdasarkan potensi masa tanam dan analisis neraca air lahan pada peluang hujan 60 persen. Potensi panjangnya musim tanam ditentukan dengan menggunakan perhitungan neraca air lahan, yang memperhitungkan aspek kandungan air tanah pada kedalaman perakaran efektif tanaman. Neraca air lahan kumulatif bulanan pada peluang hujan 60 persen menunjukkan bahwa daerah Tenggarong tidak mengalami surplus air sepanjang tahun, dan juga hanya mengalami difisit air selama 1 bulan (bulan September), secara kumulatif mengalami defisit sebanyak 47,2 mm/tahun. Meskipun demikian secara otimal Kecamatan Tenggarong mempunyai panjang musim tanam 30 hari, dengan asumsi bahwa serangan hama dan penyakit dapat ditanggulangi, maka penanaman padi, jagung atau kedelai dapat dilakukan masing-masing sekali dalam setahun