a1 Department of Microbial Technology, Central Institute of Medicinal and Aromatic Plants (CIMAP-CSIR), PO CIMAP, 226015, Lucknow, India.
Trials in farmers' field(s) were conducted to study the usefulness of vermicompost (VC) produced from distillation waste of menthol mint (Mentha arvensis L. cv. Kushal) using earthworms (Eisenia foetida) in reducing the inputs of chemical fertilizers and improving soil health in menthol mint-based cropping systems. Results of the first trial conducted on menthol mint (sole crop) in the fields of 45 farmers clearly indicated that 75% of the chemical fertilizer inputs can be reduced by supplementing the fields with 5tha−1 of menthol mint VC leading to higher levels of profits to the farmers by significantly improving herb and oil yield (6.7 and 8.4%, respectively) compared to the full recommended dose of chemical fertilizers (NPK 75:60:60kgha−1). The second trial was conducted in the fields of six farmers adopting a menthol mint cropping system (mint–rice–wheat–mint) where significantly higher yields were recorded in plots supplemented with 5tha−1 of menthol mint VC+25% of the recommended dose of chemical fertilizers; an increase of 5.6–7.2% in mint oil and 6.6% in wheat yield over the plots receiving the full recommended dose of chemical fertilizers (NPK 75:60:60kgha−1). However, in the case of rice, the highest grain yield was observed within plots receiving the full recommended dose of chemical fertilizers. Data obtained on soil properties clearly showed that apart from enhancing the yields of crops, the integration of VC with chemical fertilizers considerably improved the soil fertility/sustainability status in terms of organic carbon, available N, P and K.
(Accepted February 20 2012)
(Online publication April 04 2012)