Field evaluation of commercial organic manuals and growth promoters in bush type vegetable cowpea (Vigna unguiculata subsp. sesquipedalis)

Abstract

In a field study conducted in the college of Agriculture, Vellayani, three commercial organic manures viz. Haritha Super (4.0: 4.4 : 2.0 NPK), Poabs Green (2.7 : 1.2 : 2.0 NPK) and Bharath Meal (1.5 : 2.2 : 2.5 NPK) were compared with FYM (1.0 : 0.4 : 0.5 NPK) and Enriched Vermicompost (2.0 : 1.25 : 1.0 NPK) as the organic component of integrated nutrient management in bush type vegetable cowpea in combination with and without two growth promoters viz. Panchagavyam and Vermiwash. Feasibility of using the commercial organic manures as an alternative for FYM was also looked into. All the organic manures tested in the field experiment (FYM, Haritha super, Poabs Green, Bharath Meal and Enriched Vermicompost) were applied on Nitrogen equivalent basis in accordance with Package of Practices (POP) recommendation of Kerala Agricultural University (KAU). The POP recommendation for bush type vegetable cowpea is 20 t FYM + 20 : 30 : 10 kg NPK ha-1. When FYM was substituted with other organic manures on nitrogen equivalent basis P and K supplied by these organic manures were accounted for while calculating the quantity of inorganic phosphatic and potassium fertilizers to be applied in each treatment. Germination percentage in the various treatments ranged between 97.66 to 99 per cent and it did not vary significantly. All the significantly influenced growth characters such as height of plant, number of primary branches per plant, LAI and dry matter production recorded maximum values in Enriched Vermicompost applied crop and least values in Haritha Super applied crop. Yield attributing characters in vegetable cowpea significantly influenced by organic manures include number of flowers and number of pods per plant, fresh weight of pod and length of pod. All the significantly influenced yield attributing characters recorded superior value for Enriched Vermicompost. Enriched Vermicompost was found to be significantly superior with respect to total and marketable crop yield. Among the quality parameters crude protein content of pod was significantly superior for Enriched Vermicompost. Haritha Super produced pods of lowest protein content. Shelf life of pods in Enriched Vermicompost and Bharat Meal were the same and was 14 per cent higher than that in FYM. N and P uptake were superior for Enriched Vermicompost where as K uptake in Enriched Vermicompost and Bharat Meal were on par and superior to other organic manure treatments. Post harvest available N and P2O5 content of soil was highest in Haritha Super treated plots which was significantly higher than all other organic manures. Post harvest available K2O status was the highest in Poabs Green compared to all other organic manures. Among the growth promoters, Panchagavyam was significantly superior to Vermiwash with respect to characters such as days to 50 per cent flowering, marketable yield, percentage pest incidence, post harvest N and organic carbon content of soil. Panchagavayam and Vermiwash were on par with respect to number of flowers per plant at 30 and 60 DAS, protein content of pods, crop uptake of N and K. Both the growth promoters were significantly superior to water spray in their influence on days to 50 per cent flowering, number of flowers per plant at 30 and 60 DAS, percentage pest incidence, protein content of pods, N and K uptake and post harvest soil organic carbon content. Significant interaction effects were obtained in the case of number of flowers per plant at 60 DAS, marketable yield, percentage pest incidence and organic carbon content of soil after the experiment All the organic manures, growth promoters and their interactions had significant influence on Benefit Cost Ratio (B: C). Among the organic manures B: C in Enriched Vermicompost was the maximum. Among the growth promoters B: C in Panchagavyam (1.04) was the maximum. Maximum B:C was recorded in the treatment combination M5G2 (Enriched Vermicompost + Panchagavyam) (1.68) which was on par with M5G3 (Enriched Vermicompost + Vermiwash) (1.48 ), M1G2 (FYM + Panchagavyam) ( 1.56) and M1G3 (FYM + Vermiwash) ( 1.51). The treatment combination M2G1 (Haritha Super + Water Spray) recorded the least B:C ( 0.39 ) From the growth and yield point, FYM can be substituted with the commercial manures such as Haritha Super, Poabs Green and Bharath Meal. But FYM is more desirable from the economic point. Among the five organic sources tested Enriched Vermicompost is the best organic component of integrated nutrient management both in terms of yield and economics of production. Panchagavyam is a better growth promoter than Vermiwash in regulating marketable yield of vegetable cowpea.