Growth, yield and phosphorus (³²P) uptake by sweet corn (zea mays L. saccharate sturt) affected by biochar and SP-36

Studies on the effect of biochar combined with phosphorus chemical fertilizer on plant growth, plant yield, and nutrient uptake has not been widely reported, especially on the tropical soils. Phosphorus is one of the most limiting factors for plant production in tropical soils. Amount of available P in the soil rarely exceeds 0.01 % of the total P because most are not in available form to be up taken by plants. Most of P element in the soil is adsorbed and precipitated, so it can not be absorbed by plants that leading an inefficiency in the application of P fertilizer. A research was conducted to study the effect of biochar combined with SP-36 (superphosphate) on the production and P-uptake of sweet corn plants on Pasar Jumat latosol soil. This research was designed using factorial Randomized Block Design with factorial pattern was applied, contain of 2 treatments factor and 3 replications. The first factor was the rate of SP-36 fertilizer doses which divided into 4 levels treatment: without SP-36 fertilizer (1); 42 ppm P (2); 46 ppm P (3); 53 ppm P (4). The second factor was the rate of biochar doses which divided into 3 levels treatment: without biochar (1); 37.5 g/pot (2); 75 g/pot (3). Phosphorus uptake by plant was traced with ³²P isotopic technique. The results showed that the application of SP-36 fertilizer combined with biochar caused the percentage of SP-36 fertilizer absorption to be greater than 6.7 % - 8.8 % compared to without biochar addition, but not significant (P>0.05). It indicated that the addition of rate biochar 37.5 - 75 g/pot (equivalent to 2 - 4 ton/ha) increase of chemical fertilizers absorption by plant. However, the responses of plant growth, yield and P uptake in total plants are not significantly increased. The application of SP-36 fertilizer alone increase plant height, number of leaves, stem diameter, and plant dry matter significantly compared without SP-36 fertilization. The results of this study also showed that most of the P absorbed by plants derived from the soil, which were 188.4 - 199.4 mg/plant. P derived from fertilizers that are absorbed by plants were about 16.3 - 20.5 mg/plant. (author)