Can organic manures replace chemical fertilizers to enhance nitrogen and water use efficiencies of rice-wheat systems? A review
NC Mahajan, RK Naresh, M Sharath Chandra, Pradeep Kumar Kanaujiya, Mahendra Pratap Singh, Amit Kumar and K Lokeshwar
Applying alternative fertilization practices instead of conventional fertilizers might improve rice-wheat yield and nutrient use efficiency in rice wheat cropping systems. However, the current farming system is heavily reliant on chemical fertilizers, which negatively affect soil health, the environment, and crop productivity. Manures are significant organic source of plant nutrients. Farmer's awareness is increasing towards organic farming due to high cost of synthetic fertilizers and nutrient composition in Wheat grain all over the world. Improving crop production on a sustainable basis is a challenging issue in the present agricultural system. The replacement of chemical fertilizers with organic ones has received increasing attention in recent years. Compared with the chemical fertilizer treatments, equal amounts of substitutions with cow manure or chicken manure increased production, and a 25% nutrient substitution resulted in the best yield increase. The N accumulation and DM content both exhibited a slow-fast-slow growth trend throughout the various growth stages, and the average N uptake and DM accumulation in response to the treatments followed the order of chicken manure > cow manure > chemical fertilizer > straw return > CK. The Nmin content in the profile not only increased as the Nmin application rate increased but also showed greater increases at certain depths than at the surface, indicating that excessive N led to leaching. An appropriate proportion of organic substitution not only provides enough nutrients but also improves the soil environment and leads to increased yields. Overall, the increase in grain yield from organic manures application (press mud, vermicompost and farmyard manure), alone and in combinations, was VC > VC + FYM > FYM > PM + VC > PM > PM + VC + FYM > PM + FYM with 68, 55, and 38% increase as compared to control. The highest improvement (14.1%) in grain protein contents was recorded from vermicompost as compared to control. Moreover, manure application (Fm and Fc + m) increased WUE of winter wheat by 5–9 % compared to chemical fertilization (Fc), due to the lower ET after anthesis. However, manure application decreased WUE of summer maize by 6–10 % than chemical fertilization, which caused by the higher ET before anthesis. Therefore, using organic manures instead of chemical fertilisers to improve soil quality, nitrogen and water use efficiency, and production in rice–wheat systems is a viable approach for sustainable agriculture.
How to cite this article:
NC Mahajan, RK Naresh, M Sharath Chandra, Pradeep Kumar Kanaujiya, Mahendra Pratap Singh, Amit Kumar, K Lokeshwar. Can organic manures replace chemical fertilizers to enhance nitrogen and water use efficiencies of rice-wheat systems? A review. Pharma Innovation 2021;10(7):1133-1142.