Zero Tillage for Mitigating Global Warming Consequences and Improving Livelihoods in South Asia

Zero Tillage for Mitigating Global Warming Consequences and Improving Livelihoods in South Asia

Rajan Bhatt (University Seed Farm, Punjab Agricultural University, India)
DOI: 10.4018/978-1-5225-1607-1.ch005
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Abstract

Declining land and water productivity, rising global temperature, underground water availability, energy, labour availability, increasing cost of production, burning of crop residues and changing climatic conditions are major challenges faced by both scientists and farmers in South Asia. To address these challenges, different resource conservation technologies were promoted in the South Asia. Zero tillage was generally practiced in the region, which retains the previous crop residues on the soil surface while establishing main crop viz. wheat seeds directly drilled in standing anchored rice straw. Further such tillage systems required no pre-sowing irrigation which further improves the irrigation water productivity. The current chapter reviews the consequences of zero tillage on soil physical, chemical and biological properties, land and water productivity and in mitigating global warming potential in texturally divergent soils under different agro-climatic regions. Our review revealed that positive effects of zero tillage are visible only after 4-5 years up to which farmer might have to sacrifice some yields. Thus, there is need to recommend an integrated climate smart agriculture package/approach, which effectively solves weed pressure problems, helps in improving land and water productivity, mitigates global warming consequences and uplifts livelihoods in South Asia.
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Introduction

Rice (Oryza sativa L.) – wheat (Triticum aestivum L.) cropping systems occupy 13.5 million hectares in the Indo-Gangetic Plains (IGP) of India, Bangladesh, Nepal and Pakistan (Gupta & Seth, 2007) and are vital for employment, income and livelihood for millions of people in the region. Current cultivation practices are responsible for degrading the soil and water resources, thereby threatening the sustainability of the rice-wheat cropping system in the region (Bhatt et al.,, 2016, Bhatt & Arora, 2015, Gupta et al.,, 2003, Kumar & Yadav,200; Ladha et al.,, 2003). Intensive tillage practices in conventional systems leads to gradual decline in soil organic matter through accelerated oxidation of soil carbon, with a consequent reduction in the capacity of the soil to regulate water and nutrient supplies to plants (Ghosh et al.,, 2010). Zero tillage increases macro-aggregation (> 0.25 mm) and mean weight diameter of soil aggregates, even in coarse textured soils, indicating the potential for zero tillage soils to sequester carbon (C) (Franzluebbers & Arshad, 1999). The potential of zero tillage to sequester C has since been verified (McConkey et al.,, 2003). As water demands in industrial and domestic sectors are increasing (Tyagi et al., 2012), concerns are being raised about the productivity of water used in agriculture (Kijne et al.,, 2003). “GRACE” satellite delineate an area of 440,000 km2 in North India, in which ground water declined at an alarming rate of 1 foot per year (Soni, 2012). The status of water resources in Punjab, India showed that annually additional underground water of 13 lakh ha-m worth USD $39 million is withdrawn for irrigation purposes and water levels in central parts of the state decline at an alarming rate. Consequently, the significance of the different resource conservation technologies (RCTs) increased, however these RCTs are not universally applicable and are site specific (Bhatt et al., 2013). Further them to become effective, a certain waiting period is required. In the central Punjab, India the water table is already declining at an alarming rate. Timely transplanting and short duration cultivars are real water saving technologies however these resource conservation technologies do not cut down drainage losses. Other resource conservation technologies can be adopted such as the use of tensiometers (Bhatt et al., 2016; Bhatt & Sharma, 2010; Kukal et al.,, 2005), leaf colour charts (Bhatt et al.,, 2011), soil test based fertilization (Bhatt, 2013; Bhatt & Sharma, 2014), neem coated fertilizers (Bhatt, 2012), laser levelling (Bhatt & Sharma, 2009; Kaur et al.,, 2012; Naresh et al.,, 2014), reduced and zero tillage, and dry seeding of rice. (Bhatt & Kukal, 2014). These may be considered as energy saving technologies as they reduce the energy required to pull that water out from ground. Additionally, they reduce drainage losses which are not at all desirable in regions facing declining water table as the case with the central Punjab, India. Thus, these RCTs may be termed as “Energy saving technologies” as these saved the energy required to withdraw from the deeper depths (Humphrey et al., 2010). However, these resource conservation technologies may be effective and efficient in south western Punjab, where problems of water logging prominent.

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