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  • Author or Editor: J. C. Stark x
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Abstract

Field studies were conducted in 1985 and 1986 to compare the effects of banded ammonium polyphosphate (APP) and acid urea phosphate (AUP) on P nutrition and yield of potatoes (Solanum tuberosum L. cv. Russet Burbank). The studies were conducted on a Declo silt loam containing 9% CaCO3 equivalent. Soil NaHCO3-P values were 6.9 and 12.1 mg·kg-1 in 1985 and 1986, respectively. Ammonium polyphosphate and AUP were applied at planting in bands above the seedpiece at 0, 60, and 120 kg P/ha in 1985 and 0, 40, and 80 kg P/ha in 1986. Nitrogen fertilizer was applied at a uniform rate of 240 kg N/ha. In both years, petiole P concentrations for the APP treatments were higher than those for the AUP treatments during most of the tuber growth period and tuber yields were 9% to 15% higher with APP than with AUP.

Open Access
Authors: and

Abstract

Significant interactions between irrigation and N management for total yield and for incidence of brown center or hollow heart in potatoes (Solanum tuberosum L. cv Russet Burbank) were found in field studies conducted in southeastern Idaho during 1987 and 1988. When soil water content was maintained at 80% to 90% available, 30 kg N/ha applied weekly for 3 weeks, beginning shortly after tuber initiation, resulted in a higher incidence of brown center or hollow heart than when the same total amount of N was applied pre-plant or in smaller increments over a longer period of time.

Open Access

Abstract

Celery (Apium graveolens cv. Tall Utah 52-70R) was grown with only preplant N (100 kg/ha) or preplant plus 100, 200, or 300 kg/ha of additional N split into equal sidedress applications. Marketable yield and total N uptake significantly increased by the addition of sidedressed N, but there were no significant differences among sidedress treatments. However, increasing increments of N consistently increased early season crop and leaf growth rates and hastened maturity. With only preplant N, growth response was delayed but growth rates continued to increase after those of the side-dressed plants had begun to decrease.

Open Access