Improving the Growth and Productivity of Macrotyloma uniflorum Medicinal Plant by the Co-inoculation of P, Zn and K-Solubilizing Fungi Under Field Conditions

The presence of small amount of soluble forms of Phosphorus (P), Potassium (K) and Zinc (Zn) in most soils is one of the limiting factors for agronomic crop production. The current study focuses on Macrotyloma uniflorum (horse gram or gahat), the most commonly cultivated crop in Uttarakhand. The current initiative and study were started, because there is a little information available on the impact of co-inoculation of beneficial fungi on crops in agricultural fields. Aspergillus niger K7 and Penicillium chrysogenum K4 were isolated and selected for the study on the basis of in vitro P, K and Zn-solubilizing activity. The solubilizing efficiency of K4 strain was 140% and K7 was 173.9% for P. However, the solubilizing efficiencies of K4 and K7 were 160% and 138.46% for Zn and 160% and 466% for K, respectively. The field trials were performed for two consecutive years, and growth and yield related parameters were measured for evaluation of the effect of P, K and Zn-solubilizing fungal strains on the crop. All the treatments showed a significant (P < 0.05) increase in growth and yield of M. uniflorum plants over uninoculated control; however, the best treatment was found to be soil inoculated with P. chrysogenum K4 + A. niger K7 in which the yield was enhanced by 71% over control. Thus, the co-inoculation of K4 and K7 strains showed a great potential to improve the growth and yield of plants. Both the fungal strains simultaneously solubilized three important nutritional elements in soil, which is a rare trait. Moreover, the capacity of these fungal strains to enhance the plant root nodulation and microbial count in soil makes the co-inoculation practice quite beneficial for sustainable agriculture.