Within Canopy Distribution of Cotton Seed N.

Whole cotton seeds can be an important component of dairy rations. Nitrogen content of the seed is an important determinant of the feed value of the seed. Efforts to increase the seed value as feed will be enhanced with knowledge of the range and distribution of seed N within the cotton crop. This study was conducted to investigate seed N distribution within the cotton canopy. A two-year field study with two cultivars differing in relative maturity was conducted. Individual bolls within the cotton canopy were hand harvested and seed N was determined. There was a substantial difference between years for seed N. Average over both cultivars and all canopy positions, seed N was 25% higher in 2004 than in 2005, even though the same fertilizer N rate was applied both years. The two cultivars had different seed N contents, with the late maturing cultivar being approximately 10% higher in seed N than the early maturing cultivar. Bolls lower in the canopy had higher seed N than bolls at the top of the canopy.