Back U. R. Sangakkara and P. Weerasekera
University of Peradeniya, Peradeniya 20400. Sri Lanka
Full Paper (PDF File: 130KB)
Abstract
Organic farming utilises different crop residues to maintain soil fertility and sustainability. However, the effectiveness of different crop residues to supply required nutrients to crops is determined by their C:N ratios. Studies using microbial solutions, including Effective Micro-organisms (EM) have illustrated greater nutrient use efficiencies of crops with the addition of such inoculants to organic matter. This enhancement could result from crops absorbing nutrients from organic matter or soil. Hence a study was conducted using 15N labelled crop residues of corn and mungbean to determine the influence of two types of microbial inoculants, EM and a slurry of cattle manure on N use efficiencies of cowpea (Vigna unguiculata Walp) grown in an organic system.
Application of microbial inoculants enhanced 15N enrichment of cowpea,
confirming the usefulness of inoculants in promoting nutrient availability
from organic matter. A comparison of the inoculants clearly provided evidence
of greater 15N enrichment in cowpea grown with EM. The impact was greater
with mungbean residue, which has a lower C:N ratio. The effects of dilutions
was also observed and maximum uptake was observed at a dilution ratio of
1:500. Germination and plant growth was also promoted by EM at a dilution
of 1:500, when compared to plants grown with a slurry of cattle manure.
The prospects of using EM as an inoculant for enhanced N utilisation from
organic matter, which is a problem in most tropical organic farming systems
is presented.