Integrated Nutrient Management Enhances Yield, Improves Soil Quality, and Conserves Energy under the Lowland Rice-Rice Cropping System

Identifying sustainable crop production systems that improve yield from existing farmland while improving resource use efficiency is critical to meet the growing demands of the increasing human population and diminishing natural resources. Considering the increasing cost associated with inorganic fertilizer, integrated nutrient management using both organic and inorganic sources is important. Therefore, optimizing nutrient management practices that increase yield, improve soil quality, build up soil organic carbon storage, and maintain energy balance can help achieve sustainability in farming systems. In this regard, different nutrient management practices under the rice-rice (Oryza sativa L.) cropping system were evaluated using five different criterions, namely, (i) crop yield response, (ii) soil quality, (iii) soil carbon stock, (iv) energy efficiency, and (v) profitability under lowland situations in the Goa state situated in the western coast of India. We tested six nutrient management treatments, namely, inorganic fertilizers, organic (farmyard manure), rice straw, and their combinations over three years from 2016 to 2019. The results revealed that integrated nutrient management improved soil carbon stock, microbial biomass carbon, and soil fertility more than the other treatments. The integrated use of farmyard manure and chemical fertilizer showed significantly higher crop yield (9.86 v/s 9.41 Mg ha(-1)), microbial biomass carbon (354 v/s 233.7 mg kg(-1) soil), soil carbon stock (36.65 v/s 25.5 Mg C ha(-1)), energy efficiency (23.8 v/s 22.3), and net return (1776 v/s 1508 USD) than those associated with chemical fertilizer alone. We conclude that the application of chemical fertilizers/organic sources alone may not be sustainable for the rice-rice cropping system in the Goa state of India; the focus should be on integrated nutrient management systems.