| Popis: |
The field experiment was conducted on dry land in two location, that Jeneponto district and Gowa district, South Sulawesi regency by using single location approach. The aims of this research are (1) to determine the critical values of N, P and K for maize, and (2) to determine the rate of fertilizer on maize in the different classes of soil nutrient. Treatments were arrangement as a split-plot in randomized complete block design with three replications. Main plot were soil nutrient classes (low, moderate and high of N, P and K) and subplot were the rate of fertilizer of N, P and K. The results indicated that the critical values of total soil nitrogen for maize on Entisols ( Thypic Ustorthents ), Inceptisols ( Oxic Haplustepts ) and Vertisols ( Typic Haplusterts ) by using Cate-Nelson Method are 0.15, 0.15 and 0.11% N, respectively. Thus, the critical values of P and K for maize on Alfisols ( Typic Rhodustalfs ) are 0.32 ppm P, 85 mg P/100 g, 0.42 ppm P and 1.04 ppm P for each Mechlish, HCl 25 %, Bray-1 and Bray-2 extraction, respectively. 0.37 me K 100 g -1 , 0.55 me K 100/g, 178 ppm P, 213 ppm P for each NH 4 OAc pH 4.8, NH 4 OAc pH 7, Bray-1 and Olsen extractions, respectively. Rate of nitrogen fertilizer on Entisols, Inceptisols and Vertisols soil in Jeneponto district which gave the highest maize yield reached of fertilizer 180 kg N/ha for low class, 120 - 180 kg N/ha for moderate class, and 60 - 120 kg N/ha for high class of N total, while the rate of P fertlizer for the low and moderate P class of 160 kg P/haand 40-80 kg P/ha for high P class. While the rate fertilizer of K for low K class of 80 – 160 kg K/ha, moderate K class of 40 – 80 kg K/ha, and high K class of 20 – 40 kg K/ ha on Alfisols soil in Gowa district. |
