Response of soybean (Glycine max (L.) Merr.) to interval water application in rainfed rice field

English. A field experiment was conducted in rainfed rice field at Pati, Central Java, during dry season 1991. The soil is Gray Brown Planosol with sandy loam in texture and known to be potassium deficient. The objectives of the study were: to understand response of high yielding soybean cultivars to interval water application, and to determine the level of interval water application which gives maximum water efficiency under limiting water supply. A split plot design with three replications was used. Main plot was soybean cultivars comprising of Orba, Lokon and Local Pati. Sub-plot was interval water application consisting of five levels: 7 days (farmer's practice), 10 days, 15 days, 20 days, and 25 days. Each plant was given 5 liters water in the late afternoon. Water was taken from a water reservoir located near the experiment plots. Water was applied after 10 days after seed emergence. The result showed that there was not interaction between cultivar and interval water application for all growth variables observed. The average yield of Orba under all interval water application treatments was higher than Lokon and Local Pati cultivars. Therefore, Orba was suitable for rainless areas. Watering beyond 7 days interval decreased plant growth, yield components as well as seed yield. To maximize water use or water productivity under limiting water condition for soybean planting, water could be applied at 10 days interval with can irrigation technique

Indonesian. Suatu penelitian lapangan telah dilakukan pada lahan sawah tadah hujan tepatnya di Kabupaten Pati, Jawa Tengah selama musim kemarau 1991. Tanah percobaan yaitu tipe Planosol Coklat Kelabu dengan tekstur lempung berpasir serta kahat kalium. Tujuan antara lain: a. mempelajari tanggap pertumbuhan dari hasil beberapa kultivar kedelai terhadap interval waktu pemberian air dan b. mengevaluasi selang waktu pemberian air yang efisien atau produktivitas air maksimal. Rancangan percobaan yang digunakan adalah Petak Terpisah dengan ulangan tiga kali. Petak utama adalah jenis kultivar terdiri atas tiga macam: Orba, Lokon dan Lokal Pati. Sedangkan anak petak adalah interval pemberian air yang meliputi lima taraf: tujuh hari; 10 hari; 15 hari; 20 hari dan 25 hari. Teknik pemberian air yaitu dengan cara kucuran pada tiap tanaman. Hasil percobaan menunjukkan bahwa tidak terjadi interaksi antara kultivar dengan interval pemberian air terhadap seluruh parameter tanaman yang diamati. Kedelai kultivar Orba memiliki keunggulan secara agronomis (hasil) lebih tinggi dibandingkan kultivar Lokon dan Lokal Pati pada kondisi suplai air minimal. Seluruh peubah pertumbuhan dan komponen hasil maupun hasil biji yang diamati menunjukkan penurunan bilangan interval pemberian air lebih dari tujuh hari. Pemberian air dengan interval 10 hari memberikan produktivitas air yang paling tinggi