Zero Tilled-Paddy Straw Mulched Potato (Solanum tuberosum) Cultivation in the Coastal Saline Soils Reduce Soil Salinity, Increase Yield and Profitability

Abstract

Rice is the predominant crop during wet season (July–December) and majority of land remain fallow during dry season (January–June) in the coastal saline region of West Bengal, India. Sustainable cropping system intensification in this salt affected region needs improved package of practices which conserve soil moisture, facilitate early crop establishment, ensures profitability and has positive effect on soil health. To achieve these objectives in a rice-based cropping system, we evaluated seven treatments for potato crop during the dry season viz. T1: ridge sowing (control), T2: Zero tillage (ZT) sowing with 9 t ha−1 paddy straw mulching (PSM), T3: T2 + foliar spray of nutrients, T4: ZT sowing with 12 t ha−1 PSM, T5: T4 + foliar spray of nutrients, T6: ZT sowing with 15 t ha−1 PSM, T7: T6 + foliar spray of nutrients in randomized block design with five replications. This study was conducted during 2016-2019 in the Gosaba island of the Indian Sundarbans. Cost of cultivation of potato reduced by about 27% due to ZT sowing (₹ 81,287 ha−1) compared to ridge sowing (₹ 1,11,260 ha−1). Tuber yield, net return and irrigation water productivity was significantly increased in T5, T6 and T7 over other treatments. There was reduction in soil salinity (ECe reduced from 5 to 3 dS m−1), bulk density (from 1.49 to 1.44 Mg m−3), irrigation water use (less 20 cm), conservation of soil moisture (4–8%), and increase in organic carbon (0.39 to 0.44%) due to ZT sowing with PSM. Rice-ZT potato-green gram cropping system was the most profitable one with highest net return (₹ 1,71,752 ha−1), however, the benefit-cost ratio was highest (2.33) with Rice-ZT potato cropping system.

Potato Zero-Tillage and Mulching Is Promising in Achieving Agronomic Gain in Asia

“…Thus, Bhagat et al [63] reported an increase of 33% compared to non-mulched soils (Table 2). Similarly, Sarangi et al [39] observed a 12.8% increment in soil organic carbon (SOC) by combining rice-straw mulching and zero-tillage (Figure 4). Thus, PZTM could enhance soil quality and carbon sequestration by preventing soil erosion, leaching, and runoff of nutrients (enhancing nutrient use-efficiency, Figure 4), boosting soil microbial diversity and associated enzymatic activity and restricting weed infestation [73][74][75].…”

“…It has been reported that mulching has a significantly positive effect on potato crops improving seedling emergence, plant height, numbers of stems, and tuber yield [36]. In addition, zero-tillage practices promote early seeding because seed tubers are planted immediately after rice harvest [37][38][39]. According to those authors, conventional tillage used many resources (e.g., time, energy, money, and labour) and required a significant investment of labor in rice systems.…”

“…Numerous studies have applied different evenly spread mulch quantities (5-9 t ha −1 , [36,38,53,54,56,58,59]). Sarangi et al [39] reported a 20-cm layer of rice straw mulching (12 t ha −1 ) and foliar application of fertilizers as the optimum treatment to guarantee the appropriate quantity and quality of the tuber yield. These authors emphasized that an optimum thickness of paddy straw mulch should be maintained to avoid the tubers greening.…”

“…Finally, to promote significant efficiency in crop production, Ref. [60] recommended using crop residue mulch and minimum tillage, which would significantly increase the fiber content of the tubers [39]. The most common potato variety cultivated in India (mainly in Karnataka and West Bengal [21]) was "Kufri Jyoti," followed by "Kufri Chandarmukhi" and "Kufri Pukharj".…”

“…Li et al [41] also stated that straw mulching significantly increased potato WP by 8.3% in areas with low water input, but had no significant effect in areas with high water input. When combining zero-tillage and rice-straw mulching, about 200 mm of irrigation (compared with conventional tillage) water can be saved, thereby reducing the water footprint [39].…”