2022 年 32 巻 S 号 p. 113-116
The large extent of sodic soils i.e. ~1.67 million hectares (M ha) and the problem of sub-surface soil sodicity restricting root growth reduce crop production in Indo-Gangetic Plain of Punjab and Haryana states. These states account for approximately 41 and 58% of the total food production and of the total 84-141 MT yr-1 crop residue surplus production, respectively in India. This surplus production of cereal crops residue exhibits a typical problem of on-farm residue burning by the farmers and the rice residue management especially involves high cost, and time and energy intensive. To manage the twin problems of soil sub-surface sodicity and rice residue burning, ICAR-Central Soil Salinity Research Institute, Karnal and the Japan International Research Center for Agricultural Sciences (JIRCAS) have taken up a farmers’ field study to assess the comparative effect of gypsum and rice residue placement by Cut-soiler at different lateral intervals on amelioration of soil sub-surface sodicity and improvement in crop yield. The Cut-soiler assisted sub-surface application of gypsum, rice residue and gypsum + rice residue treatments consisted of, running the machine at 2.5, 5.0 and 10.0 m lateral spacing.
Placement of gypsum, rice straw residue and gypsum at 40 cm depth reduced subsurface sodicity (ESP) by 23.77, 14.92 and 5.95% at lateral distance of 0.30, 0.60 and 1.25 m, respectively. Decreasing lateral interval of Cut-soiler assisted subsurface placement, of gypsum, rice straw and gypsum + rice residue straw, from 10 to 5 and 2.5 m increased grain and biological yield of rice and wheat. The respective increase in rice and wheat yields were 16 and 15.5% in 2.5 m; 6% and 10.7% in 5.0 m spacing, respectively over control, but no significant increase in 10.0 m spacing. Therefore, closer spacing (2.5 m or less) seems promising for subsurface sodicity management in maiden study season.
