Dynamics of Zinc Fractions in the LTFE’s Soils

Surfaces soil samples (0-15 cm) were collected to study the dynamics of Zn fractions in the selective treatments of the LTFE’s codducted on groundnut-wheat-fodder sorghum at Instructional Farm, Junagadh Agricultural University, Junagadh during the year 1979-80 (15t year), 1989-90 (10th year) and 1999-2000 (20th year) after completion of crop cycle. The selected treatments were T₁-Control, T₁-FYM @ 25t/ha at an interval of 3 years, T₃-1/2 RD of NP, T₄-1/2 RD of NP + K, T₅-RD of NP and T₆-RD of NP+K to respective crops. The water soluble Zn was present in negligible quantity. Exchangeable forms of Zn differed significantly only at 20th year and also in pooled over years. Potassium enhanced the utilization of exchangeable form of Zn. The RD of fertilizers recorded the highest value of DTP A-Zn at initial and 10th year and triggering utilization in long run thereby rendering differences non significant at 20th year. Total Zn content did not differ significantly, while residual form of Zn was found significantly highest in T₃ (38.171 ppm). The total available-Zn and Zn-per cent availability were not influenced significantly by different treatments in pooled results, but Y x T interactions were found significant and the highest values were recorded in T₁-(3.648 ppm) and T₂ (3.559 ppm), respectively after 20th year crop cycle.