|Brown, B - UNIVERSITY OF IDAHO|
|Johnson-Maynard, J - UNIVERSITY OF IDAHO|
Submitted to: Proceedings of the Idaho Nutrient Management Conference
Publication Type: Abstract Only
Publication Acceptance Date: March 7, 2006
Publication Date: April 1, 2006
Citation: Brown, B., Johnson-Maynard, J., Leytem, A.B., Lentz, R.D., Lehrsch, G.A. 2006. Dairy manure/compost n release for sugarbeets and subsequent wheat. Proceedings of the Idaho Nutrient Management Conference. III:13-18. Technical Abstract: Given their limited land resources, there is a strong incentive for Idaho dairy and feedlot operations to export their excess manure to nearby farm fields. But the slower N release from organic N sources could be problematic for sugarbeets if the timing of N release interferes with late season sugarbeet growth and sugar content. We compared fall applied dairy manure and composted manure N sources with conventional fertilization. The study measured treatment effects on N mineralization and sugarbeet production in year one, and N-mineralization and winter-wheat grain production in the following year. Compost had more readily available N than manure for early season sugarbeet growth but N mineralized after sugarbeet plantings was greater from manure, particularly during June through early August, and through the following season. Fall applied compost and manure N release for sugarbeets was less than from the spring split applied conventional urea treatment despite applying 5.0 and 2.5 times as much total N. Though manure and compost provided less available N, they increased sugarbeet brei conductivity. The N release for subsequent wheat yield was unaffected by organic N source and wheat yield did not consistently differ for organic and conventional fertilization. However, mineralization beyond wheat maturity and through the remainder of the growing season was greater for manure than compost. The rates of organic N source application in this study are several fold greater than are commercially used, assuming commercial rates are only 4.5 to 6.7 Mg/Ha. Therefore the available N contributed from commonly used rates would not be sufficient to appreciably affect sugarbeet growth or quality unless rates were applied annually over extended periods.