Effect of Poultry Compost Applications On Ginger Growth and Phosphorous Phytoremediation

Ginger is an important spice horticultural crop with variety of nutritional and medicinal uses where its optimum growth requires large amount of nutrients application.   Excessive poultry compost applications on the Delaware, Maryland and Virginia Peninsula may be potential inexpensive nutrient sources for growing ginger.  In this study the propagation of ginger from rhizomes was investigated in the greenhouse where poultry compost and Promix were mixed at ratios ranging from 0% to 15%.  Ginger seedlings were also transplanted in the field where poultry compost was applied at rates ranging from 0 to 27 tons ha^-1.  Plants did not receive any chemical fertilizers.  Plants were harvested and number, weight and type of rhizomes were determined.  The ability of ginger plants to hyperaccumulate nutrients, such as nitrogen (N), phosphorous (P), ferrous (Fe), copper (Cu), zinc (Zn) from soil amended with various concentrations of poultry compost was also examined.  Results showed that ginger plants grown in the greenhouse at the rate of 5.0 and 7.5% poultry compost were significantly taller, healthier and had higher numbers of primary, secondary and tertiary rhizomes than those grown in Promix amended with any other ratios.  However, growth of ginger and number of rhizomes were significantly decreased with increasing compost/Promix ratios to 10 and 15%.  Results of the field experiments indicate that ginger growth was also enhanced with the addition of poultry compost at rates up to 10 tons ha^-1, then significantly decreased with increasing the poultry compost rates.  The soil and plant chemical analyses show that the concentrations of N, P, Cu and Zn increased significantly by increasing the rates of poultry compost applications.  On the contrary, the concentrations of Fe and Al were not significantly affected by increasing the rate of poultry compost applications.  In the greenhouse study when the rates of poultry compost application increased from 0 to 15%, the ability of the plants to hyperaccumulate N, P, Zn and Cu increased by 124, 202, 198 and 190%, respectively.  Similar trend was also observed in the field studies.  In these studies, the ability of ginger to uptake P, Zn and Cu increased by 40, 88 and 115%, respectively.  It is concluded from this study that ginger can be grown not only as a medicinal and horticultural crop, but also as a crop with high ability to phytoremediate P, N and Cu from the Delmarva soil which is known for its high contents of these elements.