Deficit saline water irrigation under reduced tillage and residue mulch improves soil health in sorghum-wheat cropping system in semi-arid region

Abstract

Judicious application of saline water except for critical growth stages, could be the only practical solution to meet the crop water demand in arid and semi-arid regions, due to limited access to freshwater, especially during dry winter months. A field experiment was conducted to study the effect of tillage [conventional (CT), reduced (RT), and zero (ZT)], rice straw mulch and deficit saline-water irrigation in wheat (100, 80 and 60% of wheat water requirement, CWR) followed by rainfed sorghum on soil properties and the yields of the cropping system. Yields of both the crops were comparable between RT and CT, but the wheat yield was reduced in ZT. The RT, mulching and deficit saline irrigation in wheat season (60% CWR) increased the sorghum fodder yield. Olsen’s P (8.7–20.6%) and NH4OAc-K (2.5–7.5%) increased in RT and ZT, respectively, over CT under both the crops. Deficit irrigation reduced soil salinity (ECe) by 0.73–1.19 dS m−1 after each crop cycle, while soil microbial biomass C (MBC) and N (MBN), dehydrogenase, urease and alkaline phosphatase reduced with an increase in ECe. The α-glucosidase, MBC, ECe, KMnO4oxidizable N, and urease were identified as major contributors in developing the soil health index. Deficit irrigation (60% CWR) and rice straw mulching under ZT and RT showed higher values of soil health index. Overall, deficit saline-water irrigation under reduced tillage and straw mulching had the greatest potential in maintaining soil health, saving fresh irrigation water without affecting the productivity of the sorghum-wheat system in the semi-arid regions of India. Results also demonstrated that salt affected areas of arid and semiarid countries can replicate the protocol for indexing and screening of soil health indicators to assess the sustainability of a cropping system. This integrated management based on the nature of the available resources also provided a practical approach to achieve the target of land degradation neutrality and land restoration.

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“…Soil biodiversity and soil health can be greatly improved by the management of fungal and bacterial communities [7], disruption of pathogenic organisms [8], adding more organic matter to the soil [9], reducing tillage frequency and intensity [10], crop rotation, and adopting sustainable farming practices [11]. Results of various scientific studies have shown that conventional and organic farming systems greatly affect soil biodiversity and all production parameters.…”

Soil quality and productivity improvement: Indian story

“…Sub-tropical northern Indo-Gangetic Plains (Masto et al 2007) Maize-wheat KMnO 4 oxidizable N, SOC, MBC, alkaline phosphatase activity, bulk density and DTPA Zn Sub-tropical lower Indo-Gangetic Plains (Chaudhury et al 2005) Jute-rice-wheat Olsen's P and NH 4 OAc extractable K, MBC, mean weight diameter and SOC Brahmaputra Valley (Mandal et al 2005) Rice-rice NH 4 OAc extractable K, DTPA Zn, SOC, per cent base saturation and dehydrogenase activity East and south-eastern coastal plain (Majhi et al 2019) Rice-rice Cation exchange capacity, reserve K, total N and DTPA Zn Sub-tropical northern Indo-Gangetic Plains (Purakayastha et al 2019) Rice-wheat Wheat-vegetables SOC, DTPA Zn, and Mn, NH 4 OAc extractable K, aggregate stability, MBC and mineralizable N Sub-tropical northern saline soil of Indo-Gangetic Plains (Soni et al 2021) Sorghum-wheat α-glucosidase activity, MBC, electrical conductivity (EC e ), KMnO 4 oxidizable N, MBC:MBN after sorghum and MBC:MBN, EC e , MBC, urease activity, KMnO 4 oxidizable N after wheat to soil living system (Lohan et al 2018). Rehabilitating and reverting from degradation or regaining its productive state needs time and expensive corrective measures (Mandal et al 2016;Basak et al 2014).…”

“…Minimizing the disturbances through adoption of reduced (no) tillage practices, logically facilitate the hoarding of C into soil and accordingly the problem of global climate change can be reduced and soil quality be improved. The reduced tillage practice is beneficial upon conventional tillage with known benefit of SOC hoarding in the surface soil due to congenial soil temperature and moisture regime and protection of top soil erosion (Soni et al 2021). The positive effect of reduced tillage is likely to be greater in tropical and subtropical than the temperate regions.…”

Perspectives for cultivation of diversified crops in a rice (Oryza sativa L.)-based crop rotation in the Kyzylorda region, Kazakhstan

“…On the 6 th field of the 1 st and 3 rd crop rotation schemes, melilot is used as a cover crop, and on the 6 th field of the 2 nd scheme, DCs are sown. Because sorghum is a moderately salt-tolerant crop (Soni et al 2021), after harvesting the DCs, it is possible successfully cultivate sorghum or millet as a second crop and green fodder. We suggest that this approach can contribute to a rational and effective use of lands because less irrigation will reduce secondary salinization at the same time saving water, while inclusion of DCs will facilitate maintaining soil health (Soni et al 2021).…”