Preemergence applications of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine], chloramben (3-amino-2,5-dichlorobenzoic acid), fluometuron [1,1-dimethyl-3-(α,α,α-trifluro-m-tolyl)urea], propachlor (3-chloro-N-isopropylacetanilide), and trifluralin (α,α,α-trifluro-2,6-dinitro-N,N-dipropyl-p-toluidine) were compared in 10 North Carolina soils and the relationship of activity to soil physical and chemical properties appraised. Oats (Avena sativaL. ‘Carolee’) were used as the indicator plant in bioassays under greenhouse conditions. Fifteen soil properties were measured and correlated with herbicide I50(50% fresh weight inhibition) values. Organic matter was the soil variable most highly correlated with herbicide phytotoxicity. There was an inverse relationship between herbicide water solubility and inactivation by organic matter. Volume weight determinations and water holding capacity values (0.1 bar) provided relatively good estimates of soil organic matter contents, but were not as highly related to herbicide activity as organic matter content.

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Sypnosis Oil quality and yield of peppermint were related to the plant nutrient status. Nitrogen, P, K, and S produced in that order decreasing influences on oil and hay yield. Menthol content of oil, especially in 1953, was decreased in those plants with increased nitrogen content, whereas menthofuran was increased. Leaf N was slightly more effective than leaf P in predicting menthol content and three times as effective in predicting menthofuran content. Menthol and menthofuran accounted for 76% of the variation in optical rotation of the oils in 1953. Menthol was more important in determining optical rotation in 1953.

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