Dry Matter, Nitrogen, Phosphorus, and Potassium Accumulation by Four Cotton Varieties
Since the mid-l940s, varieties and cultural practices have changed for cotton (Gossypium hirsutum L.) grown in the southeastern USA. We believed a more current investigation of dry matter production rates and nutrient uptake patterns was needed for representative cotton cultivars. Field studies were conducted to determine if dry matter production and distribution, and nutrient uptake and distribution are affected by the cultivar of cotton grown under nonirrigated conditions. Four cotton cultivars were compared Deltapine 90, Stoneville 825, Coker 315, and Paymaster 145. The experiment was conducted on a nonirrigated Decatur silt loam (clayey, thermic, kaolinitic Rhodic Paleudults) and a Norfolk silt loam (fine loamy, thermic siliceous Typic Paleudults). Soil fertility was uniform within a given site. Intact cotton plants were harvested at 14-d intervals throughout the growing season starting at 15 d after emergence, and separated into leaves, stems, burs, seed, and lint. Total dry matter production averaged 7923 kg ha−1 in 1986 and 7695 kg ha−1 in 1987 on the Decatur soil, and 6726 kg ha−1 on the Norfolk soil in 1986. The four cultivars produced and partitioned dry matter similarly within a location. Differences between locations (soils) were not related to a difference in cumulative heat units. Total N, P and K uptake averaged 128, 17.3 and 106 kg ha−1, respectively. Cotton plants from the study removed an average of 19.9 kg N, 2.5 kg P and 15.3 kg K for every 100 kg lint. Nutrient concentrations and nutrient uptake by a plant part, and total nutrient uptake were not affected by the cotton variety.
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