Influence of tree leaf litters and paddy straw on the nutrient availability in two paddy soils of South Karnataka, India

Abstract

Growth response of rice (Oryza sativa L.) was measured in terms of total dry matter production, grain yield and nutrient uptake (nitrogen [N], phosphorus [P], potassium [K] and sulphur [S]) in a pot experiment against the nutrient release patterns of a cereal crop residue (paddy straw) and four types of tree litters, namely, neem litter (Azadirachta indica Adr. Juss.), pongamia litter (Pongamia pinnata[L.] Pierre and Glabra), gliricidia litter (Gliricidia sepium[Jacq.] Kunth ex Walp.), mixed forest litter in two soils (Mandya Paddy Soil and Brahmavara Paddy Soil) of Karnataka, India, varying in physico-chemical properties. Then, the nutrient release pattern of the litters and paddy straw was evaluated under submergence, at periodic intervals in an incubation study and correlated to the crop growth observed in the pot culture. Soil electrochemical properties fluctuated temporally and depended significantly, on the type of the carbon (C) sources used and its rate of application. Gliricidia leaf litter contained much more N and K than other nutrient sources used. Influence of different leaf litters on the nutrient availability during the initial stages of incubation followed the sequence K > N > P > S. Use of nutrient sources at 5% C levels, significantly decreased the grain yield and nutrient uptake despite the fact that more nutrients were in available state at 5% C treatments. Pongamia litter application at 2.5% C is more attractive than other treatments for it gives significantly higher grain yields and total dry matter.