Effect of different rice establishment methods on soil physical properties in drought-prone, rainfed lowlands of Bihar, India

Abstract

To enhance productivity, alleviate environmental and management constraints, and enhance farmers’ incomes in the rice–wheat cropping system of the Indo Gangetic Plains, new approaches that are labour-saving, more productive and sustainable need to be developed. Most systems of rice cultivation use puddling to prepare the seedbed and control weeds in rice fields of rainfed, stress-prone environments. This practice might be helpful to reduce weed pressure and obtain slightly higher productivity, but might have negative impacts on soil physical properties. A better understanding is needed of the comparative advantage of unpuddled rice fields for maintaining good soil physical properties. To study the effect of different rice establishment methods on soil physical properties in a rice–wheat cropping system, we analysed soil samples in 2 years (2012–13 and 2013–14) from an experiment testing puddled and unpuddled rice-establishment methods. The treatments were: (i) puddled, transplanted with best management practices; (ii) puddled, transplanted with the system of rice intensification; (iii) unpuddled, transplanted; and (iv) unpuddled, direct-seeded. Omission of puddling improved soil physical properties such as bulk density, penetration resistance, aggregation stability and cracking behaviour. The absence of soil disturbance also improved soil aggregation, average mean-weight diameter and water-stable aggregates. Thus, unpuddled conditions increased the macro-aggregate fraction by 18–33%. By contrast, the higher frequency of smaller macro-aggregates (0.053–0.25 mm diameter) in puddled conditions clearly indicated the breakdown of larger macro-aggregates (>0.25 mm) into smaller size fractions. Puddled treatments were also characterised by a hard pan and wider, longer and deeper cracks, with a crack volume more than three times higher in puddled conditions. Unpuddled treatments recorded slightly higher nutrient contents in the topsoil. The study reveals that puddling deteriorates soil health. However, a long-term study is required for a better understanding of the soil changes related to different rice establishment technologies.

Short‐term (5 years) impact of conservation agriculture on soil physical properties and organic carbon in a rice–wheat rotation in the Indo‐Gangetic plains of Bihar

“…In the 0-10-cm depth soil layer, tillage in either or in both rice and wheat resulted in lowering the BD in TA, pCA1 and pCA2, whereas the omission of tillage in fCA resulted in a higher density in the layer. Similar observations were reported by others (e.g., Alvarez & Steinbach, 2009 (meta-analysis in Argentine Pampas); Mondal et al, 2013 (sandy loam soil, pigeon pea-wheat cropping system); Mondal et al, 2016 (silty clay soil, rice-wheat cropping system); and Singh & Malhi, 2006 (loam soil, barley monoculture)). Puddling in rice and/or tillage in wheat caused the formation of a compact subsurface (10-20 cm depth) soil layer.…”

Rice (Oryza sativa L.) Establishment Techniques and Their Implications for Soil Properties, Global Warming Potential Mitigation and Crop Yields

“…Adoption of non-puddled based crop establishment practices increased aggregation index and mean weight diameter of aggregates in soils relative to those in the puddled soils in both 0-15 and 15-30 cm layers [106]. Rice transplanting with the use of non-puddling or by direct seeding conserved or increased macroaggregates in soils [106][107][108]. In addition to less disturbance of soils, retention of low quality residue can stabilize aggregates in non-puddled soils [109].…”

Evaluation of long-term conservation agriculture and crop intensification in rice-wheat rotation of Indo-Gangetic Plains of South Asia: Carbon dynamics and productivity

“…Conventionally grown rice and wheat are highly money, water and energy intensive. Conventional rice requires puddling and seed bed preparation, which needs more water and labour; and in turn breaks soil aggregates exposing the soil for oxidation of organic carbon (Mondal et al, 2016). Although puddling has its advantage in terms of better weed control, lesser percolation loss and providing anaerobic condition to rice, it leads to delayed sowing of wheat, which requires well drained soil with good tilth.…”