Critical Limits of Zinc in Soil and Plant for Increased Productivity of Ginger (Zingiber officinale Rose.)

Field experiments were conducted at the Indian Institute of Spices Research during 2002–03 and 2003–04 to find out the critical limit of zinc (Zn) deficiency in soil (Ustic Humitropept) and leaf for increased productivity of ginger (Zingiber officinaie Rosc.). Ginger yield response was expressed in both absolute and relative terms and related to soil and plant tested values of Zn by using various statistical models (Cate-Nelson split, exponential type Mitscherlich equation and quadratic plateau). The highest rhizome yield was recorded with 5 kg Zn ha⁻¹ application during both the years. Amongst the statistical models tested, the Cate and Nelson model identified critical concentration of 2.1 mg kg⁻¹ for soil DTPA-Zn and 27 mg kg⁻¹ for leaf Zn, while the other models gave much higher values than these limits. The use of various sufficiency levels of yield resulted in a wide range of critical limits. From the results of the present study an appropriate critical limit of deficiency range of 2.1–3.74 mg Zn kg⁻¹ for soil and 27.0–53.8 mg Zn kg⁻¹ for leaf can be fixed for getting maximum ginger yield in an Ustic Humitropept.