Abstract
A new type of slow-release Zn fertilizer was tested for crop response. This fertilizer is a partially polymerized, short chain polyphosphate, which has low water solubility but is highly soluble in citrate and diethylenetriamine pentaacetic acid (DTPA). Field trials were conducted to study the efficiency of this bio-release Zn fertilizer in different agro-climatic regions in India. The results are definitely encouraging. Significant increases in yield of grain and straw were observed at very low levels of Zn application. In Nagpur (alkaline black soil; Vertisol), 1.14 kg ha-1 Zn as the bio-release fertilizer, increased yields of wheat grain by 38% and in Bangalore (acidic red-lateritic soil; Alfisol), maize yield increased by 59%; in Lembuchera (acidic hill soil; Inceptisol), 2.27 kg ha-1 Zn application resulted in an increase of 53.9% in the yield of rice. Significant increases in Zn uptake by grain and straw were also evident.
