Total Kjeldahl-N, Nitrate-N, C/N Ratio and pH Improvements in Chimato Composts Using Tithonia Diversifolia

Abstract

The study investigated improvements of composting blended feedstock of T. diversifolia and maize stalks on total Kjeldahl-N (TKN), nitrate-N, C/N ratios and pH of chimato Composts. In this study, T. diversifolia/maize stalks (Td: MS) ratios: 0:100, 25:80, 20:80, 40:60, 50:50, 60:40, 75:25, 80:20 and 100:0 (v/v) were prepared and then composted using chimato composting technology. The TKN and organic carbon, nitrate-N, C/N ratios and pH were determined using standard methods. Results showed significantly higher TKN and nitrate-N and lower final C/N ratios in chimato composts produced using T. diversifolia blending ratios of above 40% than those below (0% (p<0.001, a=0.01), 20% (p<0.018, a=0.05) and 25% (p<0.028, a=0.05)). Empirical models of the form Y=mX+C (where Y=T. diversifolia percentage and X=TKN or Nitrate-N percentage) were developed indicating significant effect of T. diversifolia on TKN and nitrate-N on resultant chimato composts. Results also showed significant improvement in TKN and nitrate-N content and C/N ratios in composts with blending ratios of Td:MS=40:60, Td:MS=50:50 and Td:MS=60:40 (v/v) hence judged optimal. The observed significance is attributed to optimal initial C/N ratios, moisture and porosity of the composite ingredients that enhanced active and rapid microbial aerobic activities that limited nitrogen volatilization. Blending composition of greater than 60% of T. diversifolia yielded reduced quantities of TKN and nitrate-N besides possessing greater quantities of nitrogen rich ingredients. The observations suggest occurrence of significant nitrogen volatilization. Thus, optimal Td:MS blending composition in the range of 50:50 to 60:40 (v/v) should be promoted as one strategy of improving quality of composts among smallholder farmers.