Cotton Yield Response to Nitrogen Rates in Long-Term Conventional- and Conservation-Tillage Plots in Georgia

A straight-forward nitrogen rate study was conducted in long-term (approx. 20 years) conservation and conventional tillage research plots in 2017-2019 (three years of data). Six N rates, ranging from 0 to 150 lb N/a (corresponding to 750 – 2000 lb lint/a yield goal fertilizer recommendations) were applied in each tillage system. The conservation tillage system includes a heavy rye winter cover crop that is rolled down prior to planting.  The sites are also rotated behind corn. Yield response was different in all three years and reasons will be discussed.