Release of Plant Nutrients from Soils Amended with Poplar (Populus deltoides Bartr.) Leaf Litter

摘要

An incubation study was conducted to observe the release of nutrients from two soils (loamy sand and sandy loam) incorporated with poplar leaf litter inoculated with and without decomposing culture. Three levels of leaf litter on dry weight basis (0.15, 0.30 and 0.45%), without and with decomposing culture (Aspergillus awamori) @ 0.1 g lOmL~(-1) of 0.85 per cent NaCl along with nutrients @ 50 mg N kg~(-1) from urea and 11 mg P kg~(1-)0 from single superphosphate (SSP) and nutrients only in control treatment, were mixed thoroughly with the soil. Soil samples were drawn after 1, 2, 4, 8, 12, 16 and 20 weeks of incubation and analyzed for available nutrients. Available N content decreased significantly up to 2 and 4 weeks of incubation in loamy sand and sandy loam soil, respectively but increased thereafter. Release of P and K increased significantly with increase in incubation period in both the soils. The release of K was fastest during initial periods (4th to 8th week) of incubation. Available Ca content continued to increase up to 16 weeks of incubation and available Mg up to 20 weeks. Available S increased significantly till 12 weeks of incubation in both the soils but decreased thereafter in sandy loam soil. The available content of micronutrients was similar in various treatments during initial 8 (Zn and Cu) and 12 weeks (Fe and Mn) of incubation, but it increased thereafter at higher levels of leaf litter addition. The available macro and micronutrients increased with increasing level of uninoculated or inoculated leaf litter. Available contents of nutrients were generally higher in inoculated leaf litter treatments over the corresponding uninoculated treatments.