Sifat Kimia Tanah Sawah Dl Propinsi Kalimantan Selatan

ABSTRACT A number of 193 rice field soil samples from South Kalimantan, 162 samples from topsoil and 3 samples front soil profiles were subjected to chemical analysis. The analysis consisted of texture, organi carbon content, pH, potential phosphate (P pot)and potassium (K-pot). available phosphate (P-asp, phosphate retention (P-ret), exchangeable cation and cation exchange capacity (CEC). Results indicated that organic carbon content ranged between 1 to 3%. High organic carbo, content wcts found in rice fields from swamp, tidal flat and peat. Nitrogen (N) content was moderate, an, have an average of 0.34%. Soil acidity varies from very acid to slightly acid (mean 4.5). The lowest pH era. Punt! in rice fields from swamp and tidal ,flat. There was negative relationship between pH and organ carbon content. Generally, P-av (Bray) and P-pot (23% HC1) ranged from very low to very high, the P-a values were classified as moderate (26.4 ppm) and P-pot values were classified as high (44.3 mg per 100g) K-pot singes! front 10 to 20 mg per100g and )vere classified as very lour to lo-sv. Na and K, were classified a, /ow. while Ca and Mg were classified as moderate. Exchangeable AI is influenced by soil pH. Hig, exchangeable Al occured at pH values less than 5. C'EC was classified into moderate with a mean 21. cmolt+ ) per kg, and influenced by organic carbon content. The rice fields in South Kalimantan do not hay serious constraints, but attention should be given to ones in swamp and tidal flat areas which have rent� lot pH and high content of exchangeable Al. Flooding has potential as a constraint, especiall� in the alluvia c/epression. Ke�words.: rice field, soil chemical properties, South Kalimantan. 1NTISARI Sebanyak 193 sampel tanah lahan padi Kalimantan Selatan, 162 sampel berasal dari tanah lapis olal (topsoil) dan 31 sampel berasal dari profit tanah. dianalisis kandungan kimianya. Analisis dilakukan terhadal tekstur, kandungan bahan organik. pH, P dan K potensial, P tersedia, kation tertukarkan, dan kapasita: pertukaran kation (KPK). Hasil penelitian menunjukkan bahwa kandungan karbon organik antara 1-3 %. Rata-rata kandungar N berkisar 0,34% dengan pH rendah (rata-rata 4,5). Nilai pH terendah adalah pada sawah rawa (swamp) dal pasang surut (tidal flat). Hubungan negatif terjadi antara pH dan kandungan karbon. Secara umum reran kandungan P tersedia adalah 26,4 ppm dan P potensial sebesar 44,3 mg per 100 g. K potensial sangat rendal dan berkisar mulai 10 hingga 20 mg per 100g. Kandungan Na dan K sangat rendah, sedangkan Ca dan moderat. Nilai pH tanah sangat mempengaruhi kandungan Al tertukar dan pertukaran tertinggi terjadi pada pltanah di bawah 5. KPK tergolong moderat dengan rerata 21,1 cmol(÷) per kg dan dipengaruhi oleh kandungar karbon. Berdasarkan sifat-sifat kimia tanah. lahan sawah di Kalimantan Selatan tidak mempunyai permasalahar yang serius tetapi perhatian perlu diberikan bagi lahan sawah di daerah rawa dan pasang surut karena pH tanal sangat rendah dan pertukaran Al sangat tinggi. Banjir dapat menjadi kendala, khususnya pada tanah aluvial. Kata kunci: lahan padi, sifat kimia tanah, Kalimantan Selatan