To determine growth and development patterns of irrigated melon (Cucumis melo L.) plants as a function of heat units accumulated after planting (HUAP), as well as to develop a general irrigated cantaloupe plant development model as a function of HUAP. Fifteen commercial melon fields managed by cooperator-growers were selected at five locations in Arizona from 2003 through 2006 to conduct phenological monitoring studies. Basic plant growth and development measurements were collected at phenological stages that corresponded to pre-bloom, early fruit set, early netting, and physiological maturity. Results indicate that in general, growth and development stages of melons occurred with a high degree of consistency as function of HUAP in all sites. Varietal differences did not appear to have large effects on phenological development. Also, a general irrigated cantaloupe plant development model as function of HUAP for all sites and varieties was obtained. The purpose of this phenological baseline or model is to assist growers in predicting and identifying critical stages of growth for crop management purposes. Early bloom occurred at 357 ± 41 HUAP; early fruit set at 619 ± 81 HUAP; early netting at 820 ± 82 HUAP; and physiological maturity (of primary fruit set or crown fruit) was identified to occur at 1297 ± 128 HUAP.

To determine growth and development patterns of irrigated green chile plants as a function of heat units accumulated after planting (HUAP), as well as to develop a general irrigated chile plant development model as a function of HUAP. Field experiments were conducted in 2004 and 20055 at Sunsites in Cochise County, AZ (about 4,000 ft. elevation) and at the Massey Farm in the Animas Valley, NM (about 4,392 ft. elevation). Basic plant growth and development measurements were collected routinely and important phenological stages that corresponded to first bloom, early bloom, peak bloom, physiological maturity, and red harvest were identified and recorded. Results indicate that among all sites, all varieties have performed similarly in relation to HU accumulation patterns and preliminary plant phenology models are under development in this program. The primary difference between sites was that at Sunsites varieties tend to reach a 50/50 (green: red chile) ratio at 2900 HUAP and for Animas valley; this same ratio was reached at 3200 HUAP. Also, a general irrigated green chile plant development model as a function of HUAP for all sites and varieties was obtained. The purpose of this phenological baseline or model is to assist growers in predicting and identifying critical stages of growth for crop management purposes. First bloom occurred at 1369 ± 72 HUAP, early bloom at 1667 ± 79 HUAP, peak bloom at 1998 ± 84 HUAP; physiological maturity at 2285 ± 159 HUAP, and red chile harvest was identified to occur at 3295 ± 216 HUAP.

Field experiments were conducted at four sites in 2005 in the Yuma Valley, AZ (approximately 150 ft. elevation) to evaluate the performance of CN9 fertilizer [a N-calcium (Ca) based fertilizer (9-0-0-11)] in comparison to a conventional N fertilizer source with irrigated melons/cantaloupes (Cucumis melo L.). Each field was divided into two equal (approximately 40 acres) sections. One section received the grower’s N fertilizer source (Conventional) while the other section received the CN9 fertilizer. Basic plant growth and development measurements, aboveground biomass, total and marketable yield, Sugar fruit content as well as total nutrient analysis were among the main variables analyzed. In general, all phenology variables responded similarly between conventional and CN9 treatments. Fresh weight yields ranging from 4,000 to 10,000 kg/ha were observed between conventional and CN9 treatments. Statistical analyses show that total yield between conventional and CN9 was statistically the same; with the exception of the Perriconi site. Similar results were observed for marketable yield. Brix values ranged from 10 to 14 percent, statistical differences for Brix values between the conventional and CN9 treatments were found on the Perriconi and Mason 80 sites where the conventional treatment had higher sugar content in the fruit. Overall, there were no differences in nutrient uptake and allocation patterns due to the addition of CN9 among experimental sites or sampling dates. Regarding the allocation of nutrients in the rind and flesh of melons, the same patterns between treatments at all sites were observed.