Effect of the chemical composition of green manure crops on humus formation in a Soddy-Podzolic soil

Abstract

The effects of different types of green manure (Trifolium pratense L., Dactylis glomerata L., and Secale cereale L.) and the time of its input into the soil (autumn and spring) on the contents of humus and labile humus substances in a soddypodzolic soil and the relationship between the formation of humus and the chemical composition of the applied biomass were studied. Green manure had a positive effect on the accumulation of humus in the soil. When the plants were plowed into the soil in the fall, the amount of humus formed in the soil in the first year was 0.1% higher in comparison with the spring application of green manure. The most active synthesis of new humus substances took place upon the following properties of the plant bio� mass: C : N = 15-25, the cellulose content of 20-28%, and the lignin content of 14-17%. The highest amount of labile humus substances was formed during the decomposition of the biomass with the C : N ratio above 20, the cellulose content of 19-20%, and the lignin content of 14-16%.