Journal: Nature Communications
Article Title: Identifying and characterizing pesticide use on 9,000 fields of organic agriculture
doi: 10.1038/s41467-021-25502-w
Figure Lengend Snippet: Lognormal hurdle models estimating the change in the probability of pesticide use ( a ) and the percent change in pesticide use for fields with positive use ( b ) for organic relative to conventional fields. The x -axis indicates different measures of pesticide use outcomes: kg ha −1 active ingredients (AI), kg ha − 1 products (Prd), kg ha −1 of products targeting insect pests only (Insect), kg ha −1 of products with a propensity to drift (Drift), kg ha −1 products of potential hazard to fish and bees (Fish, Bee), as well as products of higher (EPA signal word 1–2) and lower (EPA signal word 3–4) acute human toxicity (High, Low). Across all outcomes, organic fields have a significantly lower probability of using pesticides ( a ), though there is little difference between organic and conventional fields for those that do spray, with the exception of higher and lower toxicity chemicals ( b ). Symbols indicate point estimates (mean) and error bars represent the 95% CI. All models include cluster robust standard errors clustered at the farm-by-crop family level. For the second hurdle ( b ) in Figs. 2– , percent change is calculated from the log-level model as \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$100(e^{\beta }-1)$$\end{document} 100 ( e β − 1 ) and standard errors are derived using the delta-method implemented with the nlcom function in Stata. All models include covariates for field size, farm size, and soil quality as well farm-by-crop family random effects. N = 91,926 for all specifications in the first hurdle ( a ) and N = 68,704 (AI), N = 68,816 (Prd), N = 52,606 (Insect.), N = 67,988 (Drift), N = 60,653 (Fish), N = 48,254 (Bee), N = 61,883 (High), and N = 65,593 (Low) in the second hurdle ( b ), where abbreviations are as described above. Coefficient estimates for all covariates are provided in Supplementary Table .
Article Snippet: For the second hurdle ( b ), percent change is calculated from the log-level model as \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$100(e^{\beta }-1)$$\end{document} 100 ( e β − 1 ) and standard errors are derived using the delta-method implemented with the nlcom function in Stata.
Techniques: Pesticides, Derivative Assay