The use of urea fertilizers in grasslands is likely to increase in areas with concentrated animal feeding operations as restrictions on manure applications are implemented. Concerns have been raised about the economic and environmental impacts of NH3 loss from these urea fertilizers. This study evaluated NH3 losses from Nitamin (a urea polymer), urea–NH4NO3 (UAN), and granular urea applied to tall fescue (Festuca arundinacea Schreb.) plots at 50 kg N ha−1 in fall and spring for 2 yr. Fertilizers were applied to circular plots (30‐m diameter) and NH3 loss was measured by the modified passive flux method for 69 to 120 d after application. In a separate laboratory study, Nitamin, UAN, and urea were surfaced applied to fescue thatch at 100 kg N ha−1 and treatments were incubated at 24°C and 90% relative humidity for 31 d. In fall applications, urea lost more NH3 (19% in 2004, 46% in 2005) than UAN or Nitamin, which were not different from each other (6% in 2004, 34% in 2005). In contrast, there were no differences among fertilizers in spring applications, with average losses of 13% in 2005 and 17% in 2006. In the laboratory study, urea lost significantly more NH3 (24%) than UAN or Nitamin, which were not different from each other (average 9% loss). These results indicate that Nitamin and UAN undergo similar NH3 losses, and that both fertilizers may lose less NH3 than urea under conditions favorable to volatilization.

A study of predictive factors for locoregional recurrences after curative surgery for breast cancer was undertaken. Specifically, the authors wished to determine whether such recurrences correlated with either hormonal receptor status or a delay between the initial biopsy and the definitive surgery. A retrospective chart review was done on all women with breast cancer who had surgery for cure between 1970 and 1982. Factors analyzed included, among others, size of the tumor, clinical and pathologic status of the axilla, estrogen and progesterone receptors status, and delay between biopsy and definitive surgery. There were 404 patients studied. Pathologic axillary nodal status was the most important predictor of locoregional recurrence, with failures in 36 of 188 (19%) node-positive but only 9 of 216 (4%) node-negative patients (P = 0.0001). In node-positive patients, tumor size was a predictor of local recurrence, with failure in only 4 of 51 (8%) of tumors less than 2 cm, but in 14 of 44 (32%) of tumors greater than 6 cm (P = 0.004). Progesterone receptor (PR) status correlated with locoregional recurrence, but estrogen receptor status did not. In node-positive women, there were 4 of 14 PR-negative but 0 of 15 PR-positive local failures (P = 0.017); this result has not been previously reported. The presence of palpable axillary disease was also found to be a predictor of local recurrence. Finally, no increase in locoregional recurrence could be attributed to the delay between biopsy and definitive surgery. Two new predictors for locoregional recurrence in breast cancer, not previously emphasized, are PR and clinical axillary status. Should these findings be substantiated, patients at high risk for locoregional recurrence could then be more readily identified.

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