Assessment of the factors governing response to phosphorus in the rice soils of Kerala

Abstract

An attempt to asses the various factors and arrive at an integrated picture on response of rice to phosphorus application In rice soils of Kerala has teen made. To reach certain conclutions on some of the possible reasons for response of rice to phosphorus in the acid rice soils of Kerala, the following approaches have been resorted to. Categorising the rice soils with special reference to phosphorus and factors affecting them. Detailed studies on the various phosphorus fractions, both inorganic and organic as well as toe relationships between the p fractions and important soil parameters have been worked out. Elaborate studies have been undertaken on the p fixing capacity of rice soils and the factors governing it. Phosphorus transforation studies, both inorganic p fractions and available f due to waterlogging have also been conducted. Two rice varieties, a medium end a short duration have been tested under pot culture conditions -lO with graded levels of B and finally two p labelled sources of phosphorus, a water soluble monocalcium phosphate and water insoluble tricalcium phosphate have been evaluate in 7 soil types representing the major rice soil types of Kerala