Submitted to: Journal of Plant Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/5/2005
Publication Date: 7/1/2005
Citation: Tewolde, H., Sistani, K.R., Rowe, D.E. 2005. Broiler litter as a sole nutrient source for cotton: nitrogen, phosphorus, potassium, calcium, and magensium concentrations in plant parts. Journal of Plant Nutrition. 28(4):605-619. Interpretive Summary: The total value of litter as a fertilizer is difficult to measure mainly because of its many benefits. Crop yield increases when litter is used as a fertilizer are incorrectly attributed to the nitrogen supply that the litter provides. However, benefits of using litter must be much more than just the nutrient nitrogen because, by chemical analysis, litter is a complete plant food. This research showed poultry litter can fully support normal cotton growth in the absence of any other sources of nutrients. Poultry litter supplied not only enough nitrogen but also supplied sufficient amounts of the other four major plant nutrients (N, P, K, Ca, and Mg) for normal cotton development. This implies that poultry litter can effectively substitute for several fertilizers to meet crop nutrient needs in soils deficient in any or all of these nutrients. These findings should benefit cotton farmers in using litter as a complete cotton food and poultry producers in finding disposal outlets for the litter which is typically handled as a waste.
Technical 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 objectives of this research were to (1) determine the ability of poultry litter, as the sole nutrient source, to meet the macronutrient need of cotton and support plant growth, (2) evaluate the distribution of these nutrients within the different plant parts, and (3) estimate the efficiency by which these nutrients are extracted by cotton. Broiler litter supplied adequate amounts of the micronutrients N, P, K, Ca, and Mg and supported normal growth of cotton in an inert growth medium. Tissue nutrient analysis showed that the concentration of N, P, K, and Mg in the upper mainstem leaves was within published sufficiency ranges for cotton growth. Evaluation of the N distribution indicated that the cotton plant partitions N to reproductive parts when faced with deficiency of this nutrient and favors allocating N to new leaf growth when supplied with adequate N. The partitioning of P was similar to that of N but less distinct. Cotton extracted Mg and K with greater efficiency (up to 58%) than the other 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 nutrient with only 16% of the total applied P being extracted when 30g pot-1 litter was applied and only 6% with the higher litter rates. This suggests the same problem of P buildup that has been reported in soils under pasture may occur when poultry litter is repeatedly applied to the same soil planted to cotton. These results demonstrate that broiler litter can supply N and the other macronutrients in sufficient amounts to support normal cotton growth in soils deficient in these nutrients.