KETERSEDIAAN UNSUR HARA MAKRO PADA TAPAK TUMBUH TANAMAN (Acacia Crassicarpa A. Cunn EX.Bent) DI KAWASAN GAMBUT

The productivity of Acacia Crassicarpa A.Cunn Ex.Benn at PT. Daya Tani Kalbar Company experienced differences in growth in the RMBC155 plot. The difference is a 1-year-old stand, where in one plot there is a significant difference in growth. The characteristics of stands that experience poor growth are decreased growth, leaves turn yellow, many leaves fall and many stands die. The purpose of this study was to determine the effect and availability of macro nutrients on the growing site of A. Crassicarpa plants at the age of 1 year. This study was conducted in April - June 2025 at PT Daya Tani Kalbar and the BSIP Malang Laboratory. Sampling used the Purposive sampling method, where sample selection is based on criteria determined by the researcher. Analysis of the availability of macro nutrients used the Diagnosis and Recommendation Integrated System (DRIS) method, this method was chosen because it can determine the availability of a nutrient in the growing site and the results can be used as recommendations to solve the problem. The results of this study indicate that the macronutrients in the growing area of plot RMBC155 are N (4.84), P (17.35), K (56.87), Ca (-45.88) and Mg (-18.15). Based on these results, the excessive dominance of K nutrients causes the availability of Ca and Mg elements to be disrupted.