Three separated experiments, plus three semi-experimental works and two demonstrative field plots with PHCA (Carboxylic acids) treatments for yield enhancement, were carried out during the summer of 1991 in the Mexicali Valley, Mexico. Nutrient uptake on all PHCA treatments were significantly above UTC means, clear responses from treated cotton plants in all experiments and demonstrative plots, were unequivocally proof of an enhancement of plant physiology, finally quantified with the central variable "Yield of seed cotton" giving significantly percentages above Control means. The treatment termed full system with soil and foliar applications, rendered better yields and in-between development triggered a very rapid early growth and cell differentiation, promoting a significative number of flowers and bolls above UTC. The above treatment for the soil phase, was a modification of the technique known as Starter Fertilizer, adding PHCA granules as a bio-activator to fertilizer, results proved to enhance even more a quick starting of root and shoot early development, even on soils with heavy salt concentration where it was observed the same pattern of yield enhancement, suggesting a very good process of diminishing the harmful effects of salts in and out the plant, probably having also some part in the antioxidant system. Finally, PHCA treatments induced on cotton plants a good harmonic combination of water and nutrient uptake, phytohormones synthesis, and a delaying of leaf senescence, consequently a prolonged status of chlorophyll activity.