Because of arid and semi-arid climate, excess salt accumulation in soil profile is a major constraint to crop productivity in Pakistan. The problem is more severe in soils with inadequate vegetative cover. Inadequate canal water supply has led farmers to use groundwaters, more than 70% of which contain excess salts and high residual sodium carbonate (RSC). This has resulted in crop yield reduction as well as soil degradation. Consequently, about 3.16 Mha of the canal command area are salt-affected, out of which 2.73 Mha are under cultivation and, require corrective measures.
Technology Development, Demonstration and Recommendation
During 1995-2001, a series of field experiments by soil scientists of NARC were conducted in rice-wheat system of Punjab and Sindh for developing management strategies for salt affected lands and brackish waters. It was noticed that leaching of excess salts, after gypsum application, leads to inadequate soil micronutrient supplies to support optimum crop growth. It was also observed that gypsum application positively affects the release of soil micronutrients. Additional Ca supply through gypsum application helps wheat plants to alleviate the deleterious affects of Na+ ions on plant grown by enhancing K+ uptake and reducing Na+ uptake by plants. In 2003, an MoU was signed between PARC and Pakistan Agribusiness Ltd., Islamabad to develop viable a gypsum-based product having appropriate concentrations of micronutrients. After thorough investigations, a product, named “Micron” was developed containing 5% ZnSO4, 2% Ferrous Sulphate, 5% MgSO4 and 22% organic matter. The product is being marketed by Pakistan Agribusiness Ltd. in southern Punjab and Sindh for amelioration of salt-affected lands. So far, the firm is able to meet only 60% of the demand of their dealers’ network, having Head Office in Islamabad and Regional Offices at Lahore, Kasur, Sahiwal, Sukkur and Hyderabad.
Gypsum based Micron Fertilizer increases crop yields upto 35% and also improves soil health. Beneficial impacts of the product have been demonstrated widely by Pakistan Agribusiness technical staff to farming communities. Approximately 300,000 bags of Micron were sold in last three years and sale is on the increase.
Ali, A., S. M. Gill, Rahmatullah and M. Salim. (1999). Influence of calcium on K+/Na+ selectivity of wheat under saline conditions. International Journal of Agriculture and Biology 1(4):205-209.
Niazi, B.H., I. Haq, M. Salim and M. Ahmad. (2003). Use of gypsum to increase fertilizer use efficiency on normal soils. Asian Journal of Plant Sciences 2(9): 673-676.