No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

The study consisted of two experiments conducted over two growing seasons. Urea ammonium nitrate was used as a source of N at rates of 50, 75, 100 and 150% of levels estimated to be ideal for maximum yield of cotton (Gossvpium hirsutum L.). The nitrogen fertilizer was applied through a drip irrigation system. The yield of seed cotton, flowering pattern, boll set, plant N uptake, and dry matter production were studied in relation to four N fertilizer rates and two plant populations in the 1984 study. Yield of seed cotton, plant N uptake and dry matter production were studied in relation to four N rates, three seeding rates, and three cotton cultivars in the 1985 study. Petiole nitrate patterns were studied both seasons. The effect of N applications on seed cotton yield was dependent upon the initial soil N and the yield possibility. In this study the lower rate of N appeared to be sufficient for the yields obtained. Thinning resulted in reduction of the total number of flowers and significantly decreased yield, but percent boll set was not affected. Nitrogen additions significantly increased plant N uptake and dry matter production as well as petiole NO₃-N levels during the growing season. The N need of cotton under drip irrigation was determined throughout the growing season by using petiole analysis. The levels of petiole NO₃-N for N sufficiency and deficiency which are accepted under furrow irrigation cotton were shown to be applicable for drip irrigated cotton. Yield of DPL-775 and DPL-90 cotton cultivars was significantly higher than that for DPL-41 cotton cultivar in 1985.

This thesis is a historical geography of cotton production in Arizona from the prehistoric Hohokam cotton farms to the large-scale agribusiness operations that dominate modern Arizona agriculture. The purpose is to chart the expansion and distribution of cotton production and identify important cultural, biological, and physical factors that have influenced cotton planting decisions and so contributed to the evolution of Arizona's commercial cotton production region. In a final analysis, the businesses that are backward- and forward-linked to the growers--such as banks, agricultural implement and agricultural chemical dealers, and cotton ginners and cottonseed processors--have more responsibility in the evolution and endurance of Arizona's cotton production region than do the growers.