MSc

The research work entitled “impact of organic farming practices on soil health, yield and quality of cowpea [Vigna unguiculata subsp. sesquipedalis (L.) Verdcort]” was conducted at the Instructional Farm, College of Agriculture, Vellayani. The study was undertaken to evaluate the effect of different nutrient sources (organic, inorganic and integrated) on soil health, yield and quality of cowpea using the variety Sharika.
The experiment was laid out in RBD with three replications. Vermicompost, poultry manure, farmyard manure, their combinations with PSM, POP recommendation and NPK alone application as inorganic fertilizer constituted the eight treatments. The nutrient application was according to the POP (KAU, 2002) recommendation @ 20 : 30 : 10 kg ha-1 along with 20 t farmyard manure in all the treatments except the treatment receiving only inorganic fertilizer.
Soil characters like porosity, water holding capacity, pH, CEC, organic C content, available nutrients (N, P, K, Ca, Mg, Mn, Zn and Cu), enzyme activities (dehydrogenase and phosphatase) were significantly enhanced with vermicompost application either alone or in combination with PSM, but bulk density, soil temperature and C : N ratio get decreased with it. S status was improved by poultry manure addition. Available soil P significantly increased with PSM application.
The growth characters including height of plant, number and weight of effective nodules, leaf area index recorded the highest values with vermicompost + PSM application (T5). Regarding yield, the treatment with POP recommendation (T1) was found to have higher pod yield and harvest index. Bhusa yield and total dry matter production got the highest values with vermicompost + PSM application. Statistically pod yield was found to be on par in (T1),(T5) and (T4) treatments.
Concerning the quality attributes vermicompost + PSM application got superior values. The highest protein content, shelf life and the lowest fibre content were with vermicompost + PSM application. Organoleptic result showed superiority of poultry manure and vermicompost application.
The nutrient content (N, P, K, Ca, Mg, Mn, Zn and Cu) in bhusa at 50 per cent flowering stage and at harvest stage was the highest with vermicompost + PSM application (T5) except Mn and Cu which got slightly higher values with vermicompost application alone. P values were higher with PSM application for the three manures. S got higher values with poultry manure + PSM application. Regarding N, P, K, Ca and Mg, the treatment with POP recommendation showed a greater difference in values between the two stages of analysis.
Pod nutrient status also showed the same trend, except the fact that the highest value for pod Mn was with the treatment receiving vermicompost alone. The bhusa, pod and total uptake values for N, P, K, Ca, Mg, Mn, Zn and Cu was with vermicompost + PSM application except Zn which got higher values with vermicompost alone application. S uptake was highest with poultry manure + PSM application.
All the soil characters, plant growth characters and yield attributes were best correlated with yield. Uptake of all nutrients and quality attributes showed positive and significant correlation.
From the above points, it can be concluded that POP recommendation registered the highest pod yield, even though statistically it was on par with T5 and T4. While concerning environmental safety and quality of products, vermicompost + PSM application stands supreme.