Increasing Yield of Upland Rice by Applications of Silicate, Phosphate and Inoculation of Arbuscular Mycorrhizal Fungi in Ultisol

Abstract

Low soil phosphorus (P) availability and P fertilization efficiency were, among others, recognized as the main production constraints of acid upland soils. Laboratory, glasshouse and field experiments conducted with Typic Hapludult from Jasinga region. The objectives of laboratory experiment was to study the effect of Si on available of P, sorption of P, Al and Fe-P, soil charges, pH, exchangeable Al and Fe, amorphous Al and Fe, and effective CEC. Glasshouse experiment was to study the effect of Si (Na2SiO3), P and inoculation of AMF on unhulled rice yield and P, N, K, Ca and Mg leaf flag content. While, field experiment was to study the effect of Si (basic slag and Na2SiO3), P, and AMF inoculation to rice yield and the uptake of P, N, K, Ca, Mg and Fe content of rice straw. Our laboratory experiment showed that: At Si treatment at rate 1 x exchangeable Al, the soil-P increased about 6.67% (from 9.0 to 9.6 ìg P/g), pH value (from 4.85 to 5.51), and exchangeable-Al decreased (from 8.87 to 5.83 me/100 g of soil). Increasing in soil-P was related to the decreasing in P sorption energy (from 632.23 to 20.31 ml/ìg) or the increase in net negative charges as confirmed by the increase in ÄpH value (from 1.02 to 1.71). At 98 ìg/g P treatment (0.2 ìg/ml P in soil solution) the available of P increased 91% but followed by increasing in Al-P and Fe-P by 160 and 65 %. The availability of P fertilizer due to formerly Si addition higher than if Si added after phosphate.