Abstract
The conventional reclamation scheme for saline-sodic soils, i.e, "gypsum application followed by heavy irrigation(s)" may be inefficient or even impossible, if there is restricted leaching of soluble sodium salts due to low profile permeability as a result of fine soil texture/excess of silt etc. These fine textured saline-sodic soils, e.g. the Satgarah soil series, are considered uneconomical (Rafiq, 1975) or technically not feasible for reclamation in Pakistan. A group of scientists from University of Agriculture, Faisalabad comprising Dr. R.H. Qureshi, Dr. Nazir Ahmad, Dr. Muhammad Aslam and Mr. Manzoor Qadir alongwith Dr. G.R. Sandhu (the, then Member, Natural Resources, Pakistan Agricultural Research Council, Islamabad) accepted the challenge to resolve the problems arising during the reclamation of dense saline-sodic soils and devised a satisfactory technology for their reclamation on the basis of field experiments conducted at the Saline Agriculture Research Substation, Sadhoke, District Sheikhupura on the Satgarah soil series for a period of two years (1988-89). The technology consisted of spreading gypsum equivalent to gypsum requirement on the soil surface followed by irrigation and mixing into the soil surface through puddling. The ponded water was then drained (flushed) out of the field. The ponded water which contained large quantities of sodium salts, if drained properly, can remove appreciable amounts of sodium resulting in a decreased sodicity hazard. In controlled experiments on the Satgarah soil series (EC. 5.1-6.1 dS mol; SAR 34.5-40.3; pHs 8.8-9.2; silty clay loam to silty clay texture to a depth of 30 em), two flushings with an interval of 12 hours before rice transplanting were given in both the years. Gypsum was applied according to the gypsum requirement (8.9 t ha! for 15 em depth) of the field at the start of the experiment. Rice-wheat-rice rotation was followed. At the end of the second rice crop, in addition to satisfactory soil reclamation, good yields of the two crops were obtained (Ahmad et 0/., 1989; Ahmad et 0/., 1990; Qureshi et 0/., 1990; Qureshi et 0/., 1992).
