Adjusting Water Management Based On Canopy Temperature to Maintain Optimal Source of Cotton

Cotton is an indeterminate crop. Prior to fruiting, vegetative growth will only be source limited in unusual conditions of disease or water stress. Just prior to first flower, vegetative growth receives the vast majority of assimilates produced. However, if fruit retention is high, reproductive growth rapidly increases in assimilate demand and has higher priority for assimilates. This reduces assimilate allocation to vegetative growth and can be observed by the rate of decline in NAWF. With vegetative and reproductive growth both competing for assimilates produced (source), environments that reduce the source during this period result in reduced yield. Optimum crop canopy temperature has been demonstrated to be near 28 C. Smartfield has developed tools to continuously monitor crop canopy temperature, and can quantify the observed daily environment into a stress accumulation index. Daily stress can be correlated to final yield. Examples will be given where various levels of stress were monitored throughout the fruiting period with the associated effects on yield. Smartfield algorithms can show the effects of various levels of stress at different stages of growth on ultimate yield. Canopy temperature monitoring in combination with Smartfield analytics can provide clients real time data on the effects of canopy temperature (water status) on yield accumulation. Clients can then make adjustments to water management to maintain a desired level of stress, or the elimination of yield reducing water stress.