Optimum Nitrogen Application for Cotton on a Red River Alluvial Soil

S.H. Moore, G.A. Breitenbeck, and C.A. Robertson, III


 
ABSTRACT

Cotton (Gossypium spp.) was planted on 4 May, 1990 in the first year of a multi-year study to determine the boll characteristics when produced on a Red rover alluvial soil (Norwood silt loan, pH near 8.0) in central Louisiana. Seven rates of N ranging from 0 to 150 lbs/A, in 25lb increments, were applied prior to planting in a randomized complete block design. Dry mater yield (DMY) was not affected by N rate at 25 days after planting (DAP) but increased with N rate up to 75 lbs/A at 75 DAP and maturity. There was no apparent excessive vegetative growth beyond the 75 lb/A of N. Seed cotton yield increased with N up to a maximum of 3923 lb/A at the estimated optimum N rate of 111 lbs/A and then decreased. There was a 298 lb/A, or 8%, increase in seed cotton yield between the 60 and 111 lb/A rates of N. Total bolls per plant increased with N rate. The percentage of open bolls was inversely related to yield. The percentage of missing or aborted bolls increased in proportion to yield. The percentages of both immature and rotten bolls were not significantly affected by N rate. These results indicated that higher rates of N may be needed for cotton produced on Red River alluvial soils in central Louisiana as compared to other silt loam soils in the State.



Reprinted from 1992 Proceedings Beltwide Cotton Conferences pp. 1093 - 1094
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998