Quartz porphyry (Bakuhan-seki) as soil amendment in improving soil quality and yield of soybean (Glycine max (L.) Merr.)**

Author: Emelie Casayuran Ablaza ^1*, Noriko Takeda ² and Katsumi Ishikawa ²

Received 14 June 2006, accepted 22 August 2006.

Abstract

Production inputs such as fertilizers, pesticides and other chemicals are used to achieve maximum economic yield. Agricultural development strategy, however, must be focused on increasing soil productivity with reduced cost of production and higher efficiency of inputs with no harm to the environment. This study deals on the utilization of innovative techniques which is economically feasible while protecting and sustaining the environment. Bakuhan-seki stone is a mineral which had been distinct for its enormous porosity, high absorption capacity and has an additional negative charge. The objectives of this study were to determine the effects of different levels of Bakuhan-seki on soil quality and on growth and yield of soybean. Japan and China Bakuhan-seki were added into the soil at the rate of application as follows: 1.5 kg/m³, 3 kg/m³, 5 kg/m³ and control (no Bakuhan-seki). Soil samples were collected at the start of the experiment and after harvest and were analyzed for chemical properties. All levels of Bakuhan-seki control growth of soybean as shown in the prolonged harvest maturity date, increased seed diameter and 100-seed weight. Bakuhan-seki likewise retained nutrients in the soil as shown in the relative increase of CEC and moderately higher calcium and magnesium in soil. Addition of Bakuhan-seki also improved the soil environment and enhanced availability of NO3-N for plant uptake, thus resulting to increased yield.