Long‐term conservation agriculture helps in the reclamation of sodic soils in major agri‐food systems

Abstract

Globally crop production is impaired by soil salinity and sodicity and to maintain the sustainability of the production systems under such degraded lands, conservation agriculture (CA) may be an alternative in arid and semiarid regions. An experiment was initiated with different agri-food systems with CA-based practices to understand the reclamation potential of sodic soil after continuous cultivation for 4 and 9 years. This included: (i) conventional tillage (CT)-based rice-wheat system (Sc1); (ii) partial CA with puddled rice-zero tillage (ZT) wheat and mungbean (Sc2); (iii) ZT rice-wheatmungbean (Sc3); (iv) ZT maize-wheat-mungbean (Sc4). Soil samples were collected from 0 to 15 and 15 to 30-cm depth after 4 and 9 years of wheat harvesting. Results showed an 18% decline in pH 2 with Sc2 and ~30% decline in EC 2 with Sc2 and Sc3 at upper soil depth after 9 years. Higher cation exchange capacity by 35% and 89% in Sc2 and 38% and 58% in Sc3 after 4 and 9 years was found, respectively, over initial levels. A decrease in exchangeable sodium percentage was recorded in Sc2 by 43% and 50%, after 4 and 9 years over the initial level, respectively. The oxidizable carbon and total organic carbon were increased by ~76%, 69%, and 64% in Sc4, Sc3, and Sc2, respectively, over initial values at 0-15 cm soil depth. Results showed that the CA-based rice-wheat-mungbean system had more reclamation potential than other studied systems. Therefore, long-term CA practices involving ZT with crop residue recycling and efficient crop rotations have the potential to reduce the sodicity stress and improve soil organic carbon thereby bringing the sodic lands under productive crop cultivation. K E Y W O R D S conservation agriculture, long-term experiment, sodicity, soil carbon pools, zero tillage 1 | INTRODUCTION Soil salinity and sodicity are one of the major and prevalent challenges in the current era that hampers global food security and environmental sustainability in the arid and semi-arid regions of the world and adversely affect the global agricultural production and biodiversity.Globally, more than 900 million ha of land, accounting for nearly 20% of the total agricultural land and 33% of the irrigated agricultural lands is affected by salinity (Shrivastava & Kumar, 2015). The salt stress in the soil is becoming prominent due to the ever-increasing global population pressure (projected to be 9.3 billion by 2050), anthropogenic activities (e.g., intensive cultivation, over-application of groundwater and synthetic fertilizers), and climate change over decades (Mukhopadhyay et al., 2020). About 40%-60% of the World's saltaffected lands are saline and sodic in nature (Tanji, 1990). In India, the total salt-affected area is 6.74 million ha out of which approximately

Assessment and Principles of Environmentally Sustainable Food and Agriculture Systems

“…On the other hand, as a sustainable approach, conservation agriculture supports sustainable development as a result of its contribution to the protection of biodiversity and topsoil productivity, improvement in soil health, adaptation to climate change, ecosystem services, and food, water, and soil security [112,119]. Conservation agriculture contributes to numerous economic, environmental, and ecological benefits, such as being a sustainable alternative in arid and semiarid regions, promoting the synergy between food production and ecosystem protection, and increasing resilience and productivity to extreme stress conditions by using less energy and water, improving physical and biochemical properties, and increasing soil quality by reducing the breakdown of soil aggregates [120,121].…”