Salinity management by Cut-soiler increases production of mustard-pearl millet cropping system in India

抄録

Soil salinity is a global issue threatening land productivity, and estimates predict that 50% of all arable land will be impacted by salinity by 2050. Salt affected soils are important ecological entity in the landscape in most arid and semi-arid regions. In India these soils occupy nearly 6.7 million ha and represent a serious threat to country’s ability to increase food production to meet the expanding needs. India loses annually 16.84 million ton of farm production valued ~ $3.0 billion (USD) due to salt affected soils (Mandal et al., 2010; Sharma et al., 2015). The salinity management, especially in arid regions, needs an ‘on farm technology’ solution that can be adopted at individual farm/farmer level. Cut-soiler is a machine developed in Japan that use and manage surface scattered straw material, residue or remaining stems to construct residue filled shallow subsurface channels, while running on the field. The preferential drainage from these channels reduces soil salinity. In this background, Japan International Research Center for Agricultural Sciences (JIRCAS) and Indian Council of Agricultural Research - Central soil salinity research institute (ICAR-CSSRI) collaborative research project has been started to evaluate utility of Cut-soiler on salt removal and effect on crop yields in salt affected soils with the use of saline irrigation water. Three saline irrigation water treatments (EC_iw 4, 8, 12 dS m^-1) were applied in two soil types i.e saline and heavy textured. Mustard-pearl millet a major cropping system in hot, arid and saline regions of Northwest India was evaluated.

The preferential drainage through subsurface drains constructed by Cut-soiler reduced 32% salinity under Cut-soiler drainage over without Cut-soiler across the soil types and irrigation water salinity. The saline soil filled plots had higher ECe (Electrical Conductivity of extract of saturated paste of soil) (5.07 dS m^-1) than the heavy textured non-saline soils (1.39 dS m^-1). The reduction in soil salinity in Cut soiler plots was higher in saline soil i.e. ~11% and with 8 dS m^-1 salinity of irrigation water (20.4%) in October 2018 and this increase was higher with 12 dS m^-1 EC_iw in October 2019. The study found that saline irrigation water up to 8 dS m^-1 could be used without any salt loading. The lower salinity resulted in marginal increase in mustard yield in maiden season and 22.86% increase in pearl millet yield in successive season. Therefore, the Cut-soiler based preferential sub surface drainage may be a possible solution for salt removal from saline soils and preventing salt accumulation with application of saline irrigation water for sustainable crop production in salt affected areas having saline groundwater.