Cotton Response to Long-Term No-Tillage and Cover Cropping in the San Joaquin Valley

Despite approximately 45% of U. S. cotton being produced using no-tillage (NT) or striptillage, these seeding techniques are not yet being used commercially in California. From 2010 to 2013, we compared cotton production under NT versus standard tillage (ST) practices with a winter cover crop (CC) or without (NO) cover crops in Five Points, CA. Tractor trips across the field were reduced by 40% in the NT systems relative to the ST approaches. Residue cover was 93, 83, and 2% for the NTCC, NTNO, and the ST systems, respectively. Average lint yields combined over the four years of this study were similar between ST and NT (1481.4 vs 1484.7 kg ha(-1)), however, the average yield with NO was higher than with CC (1526.1 vs 1440.0 kg ha-1). There was a tillage X cover crop interaction in 2011 with a yield difference between CC and NO within ST, but not NT. There were no differences between the STNO and NTNO systems across the four years. As long as yields can be maintained, externalities such as shifts in irrigation systems away from surface to drip and overhead irrigation, as well as continued water shortages could warrant the learning curve effort and the retooling that will be required to scale up the conversion from traditional tillage cotton production to NT in this region.