ABSTRACT

The ability of poultry litter to support plant growth by supplying essential plant nutrients in the absence of other sources of the nutrients has not been studied thoroughly. The objective of this research was to determine the ability of broiler litter, as the sole nutrient source, in meeting the mineral nutrient needs of cotton and supporting plant growth. Under greenhouse conditions in an inert growing mix, broiler litter apparently supplied sufficient mineral nutrients and supported normal growth of cotton in the absence of other sources of nutrients. Tissue nutrient analysis during early boll development stage showed that the concentration of N, P, K, Mg, Fe, Cu, and Mn in the upper mainstem leaves was within published sufficiency ranges for cotton growth. The concentration of only Ca and Zn in the upper mainstem leaves fell below published sufficiency ranges. While a greater fraction of most mineral nutrients were partitioned to leaves, Fe and Cu were partitioned to in greater proportion to roots than to leaves, stems, or reproductive parts. Cotton extracted Mg and K with the greatest efficiency (up to 58%) and Cu and Zn with the least efficiency (as low as 1.7%) when litter was the only source of these nutrients. The extraction efficiency of N ranged between 21% at 120 g pot^-1 litter and 27% at 30 g pot^-1 litter. P was the most poorly extracted macronutrient with only 16% of the total applied P being extracted when 30 g pot^-1 litter was applied and only 6% with the higher litter rates. The results of this research show that broiler litter can supply apparently all essential mineral nutrients to support normal cotton growth in the absence of any significant other nutrient sources. However, the extremely poor extraction efficiency of the micronutrients and that of P indicates that repeated application of broiler litter can lead to undesirable buildup of these nutrients in the soil.