Özet:

The ~22 million ha soils of Pakistan (23° 53՜ to 36° 49՜ N, 61° 15՜ to 74° 50՜ E) are predominantly calcareous and low in organic matter. Boron (B) deficiency is prevalent in 35–56% areas under field crops causing yield, produce quality and economic losses. Boron deficiency is more severe in rainfed than irrigated soils. Both hot water extraction and dilute HCl method are used for evaluating B status; and locally determined B internal B requirement varies from 53 mg kg-1 in cotton leaves to 17 mg kg-1  in young sorghum plants. Extent and severity of B deficiency in crops have been determined and spatial variability of B in soils and crops has been mapped. Boron fertilization increases crop yields appreciably (e.g., cotton and wheat, 14%; rice, 15–25%) and, thus, is highly cost-effective, more so by foliar feeding. Annually applied 0.75–1.0 kg B ha-1 corrects the deficiency; 2–3 foliar sprays of 0.1% B solution are also effective. Boron use improves produce quality; e.g., rice milling return, head rice recovery and cooking quality. Soil B fertilization leaves residual effect for 2–4 crops, and repeated annual applications of 1.0 kg B ha-1 in calcareous soils were safe. However, current B fertilizer use in Pakistan is negligible, i.e., 92 Mg B per annum compared with potential requirement of 2245 Mg B per annum. Constraints to B use include stakeholders’ ignorance about benefits of B use and inadequate availability of quality B fertilizers.

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