No-Till Farming and Conservation Agriculture in South Asia – Issues, Challenges, Prospects and Benefits

Abstract

Of late, intensive farming for higher food production is often associated with many negative implications for soil systems, such as decline of soil organic matter (SOM), increase in risks of soil erosion by wind and/or water, decline in soil biological diversity, increase in degradation of soil physical quality, lower nutrient-use efficiency, high risks of groundwater pollution, falling water tables, increasing salinization and waterlogging, in-field burning of crop residues, pollution of air and emission of greenhouse gases (GHG), leading to global warming, and decline in factor productivity. These negative implications necessitate an objective review of strategies to develop sustainable management practices, which could not only sustain soil health and ensure food security, but also enhance carbon sequestration, decrease GHG emissions, and offer clean and better ecosystem services. Conservation agriculture (CA), that includes reduced or no-till practices along with crop residue retention and mixed crop rotations, offers multiple benefits. Adoption of a system-based CA conserves water, improves and creates more efficient use of natural resources through the integrated management of available soil nutrients, water, and biological resources, and enhances use efficiency of external inputs. Due to apparent benefits of CA, it is increasingly being adopted and now covers about 180 million hectares (Mha) worldwide. However, in South Asia its spread is low (<5 Mha), mostly concentrated in the Indo-Gangetic Plains (IGP). In this region, one of the serious issues is "residue burning" with severe environmental impacts. A huge amount of crop residue left over after the combine harvest of rice has forced farmers to practice widespread residue burning ($140 M tonnes) to cope with excessive stubble and also for timely planting/sowing of succeeding crops. In rice-wheat cropping systems, which cover more than 10 Mha in the IGP, CA practices are relatively more accepted by farmers. In these systems, any delay in sowing leads to yield penalty of 1-1.5% per day after the optimum sowing date of wheat. The strong adoption of CA practices in IGP is mainly to overcome delayed sowing due to the field preparation and control of weeds, timely planting, and also escape from terminal heat during the grain-filling stage. Major challenges to CA adoption in South Asia are small land holdings (<1 ha), low technological reach to farmers, nonavailability of suitable farm implements for small farm holders, and the staunch conventional farming mind-set. South Asia region consists of many countries of diverse agro-ecologies with contrasting farming systems and management. This region, recently known for rapid economic growth and increasing population, necessitates higher food production and also hot-spots for adoption of CA technologies. Therefore, in this review critically explores the possibility, extent of area, prospects, challenges, and benefits of CA in South Asia. HIGHLIGHTS Conservation agriculture (CA), consisting of reduced or no-tillage a...

Conservation Tillage, Residue Management, and Crop Rotation Effects on Soil Major and Micro-nutrients in Semi-arid Vertisols of India

“…Therefore, an optimum level of residue retention (quantity of residue) and tillage operations (reduced intensity and number of tillage operations) greatly influences the soil health, crop productivity, and conservation of energy and labour cost in the semi-arid region. One of the possible strategies to increase the adoption of CA technologies in the rainfed region is by providing incentives to farmers, based on carbon footprint/storage and other ecosystem services through residue retention (Lal 2013;Somasundaram et al 2020).…”

“…Besides, the conventional system implies the use of farm machinery in multiple tillage operations, which increases the input cost of the farmers. Therefore, it has drawn worldwide attention to revert the land degradation processes through sustainable land management practices (Lal 2007;Somasundaram et al 2020). The practice of CA has paramount importance in a climatic situation where high temperature stimulates the rapid oxidation of SOC.…”

An impact of agronomic practices of sustainable rice-wheat crop intensification on food security, economic adaptability, and environmental mitigation across eastern Indo-Gangetic Plains

“…During these two years, the lowest rice yield was recorded under ZTDSR-ZTW-ZTG production system. The initial reduction (14.15 %) in yield in zero-tillage practices compared to conventional practices (PTR, MTR) was due to the transition time in which soil takes time to stabilize attributing to increase soil stability, aggregate stability and increase soil carbon ( Somasundaram et al, 2020 ). During the third year (2017), rice yield under SRI-SWI-ZTG was at par with CTDSR-ZTW-ZTG and ZTDSR-ZTW-ZTG production system ( Table 4 ), while yield under transplanted rice (PTR and MTR) reduced by 21 %.…”

Carbon Sequestration to Avoid Soil Degradation: A Review on the Role of Conservation Tillage

“…In another study, Prasad [94] reported that conservation agriculture also reduces soil degradation problems under rainfed agriculture. Conservation agriculture comprises no-till farming (with minimal soil disturbance) and the use of crop mulches along with appropriate crop rotations [95]. According to FAO, it is also defined as a sustainable approach to enhance resource-saving and agricultural crop production while improving the environment [46].…”