Efficient Use of Canal and Sodic Waters to Minimize Sodicity Hazards to Crops and Rise in Water Table Level for Sustainable Agriculture

摘要

The water-logging accompanied by secondary salinization due to brackish underground water has become an alarming problem threatening the sustainable crop production in many parts of the vast Indo-Gangetic region in northern India. It occupies an areaof about 4 and 15% of the total cultivable area of India and Haryana state, respectively. The results of a long term experiment conducted at the Research Farm of CCSHAU Research Station, Rohtak, India have shown that through the conjunctive use of canaland sodic irrigation waters and of gypsum amendment in rice-wheat system, the dominant sodic ground water could be safely used for sustainable crop production without causing much damage to the soil health. The quality of the waters used was : Canal water, EC=0.35 to 0.65 dS/m and RSC=0.3 to 1.5 me/l; sodic water, EC= 1.00 to 1.35 dS/m and RSC=8.9 to 11.8 me/1. The water table depth varied from 0.3 to 4 m during the experimental period of four years (1992-93 to 1995-96). Although there was a fall in theproductivity of the system (1.3 to 84.5%) over a spell of four years due to the use of sodic water alone as well as in conjunction with canal water at all levels of gypsum application, but the use of gypsum had a significant beneficial effect on the productivity of the system at all levels of the water quality (0.2 to 197%). Also, the conjunctive use of canal and sodic waters alone without gypsum resulted in higher productivity than that obtained by using sodic water alone without gypsum. The adverse effect of sodic water on wheat crop was not very acute as compared to its effect on rice crop i. e. rice crop was adversely affected by the use of sodic water irrespective of its conjunctive use with canal water and gypsum ameliorant.