Effect of soil tillage and drowning of organic matter on soil water holding capacity

anglais. Soil water holding capacity can be improved by increasing rooting depth and soil organic matter. Research aimed at improving soil conservation techniques by increasing soil water holding capacity was carried out on Regosol soil at IP2TP Mojosari, during the dry season of 1997. The treatments were arranged in split plot design, replicated three times. Soil tillage was assigned as main plot, consisted of (A) without tillage (B) shallow tillage (10-20 cm) (C) deep tillage (25-35 cm). As sub plot was drowning of organic matter, covering (1) crotalaria compost (2) paddy husk compost (3) dry paddy stalk compost (4) manure, each 10 t/ha and (5) control (without organic matter). Mungbean variety of Sriti was grown with planting distance of 40 cm x 10 cm, 2 plants per hill. The plants were fertilizer with 50 kg Urea + 57.5 kg SP36 + 50 kg KCl per ha. Observations were done on soil bulk density, soil water holding capacity, soil water content at field capacity and soil water content during plant growth. The results indicated that shallow tillage did not improve soil physic is indicated by low (4 percent) soil bulk density that decreased. Soil bulk density decreased 14 percent on the deep tillage treatment. Soil bulk density decrease was also observed on organic matter drowning treatments. Among the four organic matter studied, the paddy husk compost was the most effective in decreasing soil bulk density, it decreased the density about 31-42 percent. The decrease of soil bulk density on deep tillage followed by paddy husk compost drowning treatments increased soil water holding capacity 11.2-28.8 percent and soil water content at field capacity 46-64 percent. However this treatment did not improve soil moisture to support optimal plant growth at dry condition. It is suggested to further study the conservation of soil moisture

indonésien. Kapasitas tanah menahan air dapat ditingkatkan dengan memperdalam lapisan perakaran dan meningkatkan kadar bahan organik tanah. Penelitian ini bertujuan untuk mendapatkan cara meningkatkan kapasitas tanah menahan air guna memperbaiki teknik konservasi lengas tanah. Penelitian dilaksanakan di tanah Regosol IP2TP Mojosari, pada MK 1997. Rancangan penelitian yang digunakan adalah rancangan petak terbagi dengan 3 ulangan. Sebagai petak utama adalah pengolahan tanah, meliputi (A) tanpa olah tanah, (B) pengolahan tanah dangkal (10-20) dan (C) pengolahan tanah dalam (25-35 cm). Sedangkan anak petak adalah pembenaman bahan organik, meliputi (1) kompos crotalaria, (2) kompos sekam, (3) kompos jerami padi, (4) pupuk kandang, masing-masing 10 t/ha dan (5) kontrol, tanpa bahan organik. Kacang hijau varietas Sriti ditanam dengan jarak 40 cm x 10 cm, 2 tanaman/rumpun dengan diberi pupuk dasar 50 kg Urea + 57,5 kg SP36 + 50 kg KCl per ha. Pengamatan dilakukan terhadap berat isi tanah, kapasitas tanah menahan air, kadar air tanah pada kapasitas lapang, kadar air tanah selama pertumbuhan tanaman kacang hijau. Hasil penelitian menunjukkan bahwa pengolahan tanah dangkal tidak cukup memperbaiki sifat fisik tanah dan hanya menurunkan berat isi tanah rata-rata 4 persen sedangkan pengolahan tanah dalam dapat menurunkan berat isi tanah rata-rata 14 persen. Pembenaman bahan organik dapat pula menurunkan berat isi tanah. Di antara 4 macam bahan organik yang dikaji, kompos sekam terlihat paling efektif dan dapat menurunkan berat isi tanah 31-42 persen. Dengan berkurangnya berat isi tanah, pengolahan tanah dalam dan pembenaman kompos sekam dapat meningkatkan kapasitas tanah menahan air 11,2-28,8 persen serta meningkatkan kadar air tanah pada kapasitas lapang sekitar 46-64 persen. Keadaan ini ternyata belum mampu memperbaiki kadar lengas tanah pada keadaan kering, sehingga masih diperlukan upaya lain untuk pengawetan lengas tanah ini