2022 年 32 巻 3 号 p. 84
The north-western states of Punjab and Haryana account for 69% of total food grain production representing a highly productive zone of IGP (Indo-Gangetic Plains) in India. Sodic soils extend over 0.18 and 0.15 M ha in these two states, respectively. Rice-wheat rotation is the most important dominant cropping system followed in IGP. Cereals constitute 58% of 84-141 MT yr–1 total crop residue surplus produced in India and their on farm burning poses a major environmental and soil health concern. The rice residue management especially involves high cost, and time and energy intensive. To tackle the problem of sodicity and increasing residue burning in rice-wheat cropping system especially in poorly drained soils; an ‘On farm technology’ solution, that can be adopted at individual farm/farmer level, is the need of the hour. ICAR-Central soil salinity research institute (CSSRI) Karnal in collaboration with Japan International Research Center for Agricultural Sciences (JIRCAS) have introduced Cut-soiler to develop low cost and farm scale salinity management technique. Cut-soiler is a low-cost and easy to adopt technology developed in Japan. Cut-soiler constructs residue filled shallow sub-surface drainage channels, the sodicity amelioration amendments like gypsum can also be placed at subsurface that may effectively reclaim the sub surface sodicity.
Therefore, a famers’ participatory field study was undertaken to assess the Cut-soiler based sub-surface placement of gypsum and rice residue on sub surface sodicity reclamation across space and time and consequent improvement in production of rice-wheat system. The experiment is being conducted at farmer’s field in Panjab region (India). Cut-soiler was run, at 2.5, 5.0 and 10.0 m spacing, using rice crop residue/straw lying on ground surface, gypsum and straw+gypsum.
The results indicated that rice straw residue and gypsum placed at 40 cm depth reduced subsurface sodicity (ESP) by 31, 23 and 4% at lateral distance of 0.30, 0.60 and 1.25 m, respectively. Grain yield of rice and wheat also increased with decreasing Cut-soiler spacing. The respective increase in rice and wheat yields were 17.7 and 18.3% in 2.5 m and 7.6 and 10.8% in 5.0 m spacing, respectively over control, but no significant increase was noticed in 10.0 m spacing. Therefore, closer spacing (2.5 m or less) seems promising for subsurface sodicity management.
