3.2.1. Lint Yields

Soil, landscape, and weather factors associated with lint yields in the estimated logit model were silt soil texture (Pr ≤ 0.01), loam soil texture (Pr ≤ 0.01), water-holding capacity (Pr ≤ 0.10), organic matter (Pr ≤ 0.05), soil depth (Pr ≤ 0.05), and growing degree days (Pr ≤ 0.01) (Table 5). Silt- or loam-textured soils or soils on fields with warmer growing conditions are positively attributed with the probability of lower VRN yields than FP (Table 6). Soils with greater water-holding capacity, higher organic matter content, or deeper profiles are negatively associated with the probability of lower VRN yields than FP. All else equal, higher organic matter in soils could potentially lower the probability of yield loss enough to warrant VRN adoption for some farmers through lower fertilizer N rates.


**Table 5.** Estimated logit regression coe fficients of landscape, soil, and weather e ffects on lint yield, fertilizer nitrogen (N) rate, N e fficiency (lint yield/fertilizer N rate), and net return.

Note: Standard errors are in parentheses. \* Significant at the 0.10 probability level. \*\* Significant at the 0.05 probability level. \*\*\* Significant at the 0.01 probability level. a Variable names defined in Table 3. b Intercept contains soil texture sand. c Soil texture coefficients scaled by 10%. d WHC coefficients scaled by 100. e SOM coefficients scaled by 100%.

**Table 6.** Odds ratios and percent changes in log odds probabilities for landscape, soil, and weather effects on lint yield, fertilizer nitrogen (N) rate, N e fficiency (lint yield/fertilizer N rate), and net return calculated from logit regression estimated coe fficients a.


\*,\*\*,\*\*\* 10, 5, and 1 percent significance for the estimated coefficient in the logit model, respectively. NS, not significant for the estimated coefficient in the logit model. a Odds ratios and the changes in the log odds probabilities were calculated using the estimated coefficients β of the logistic regressions reported in Table 5. b Variable names are defined in Table 3. c Intercept contains soil texture category sand. d Texture scaled by 10%. e WHC scaled by 100. f SOM scaled by 100%.

For the silt soil texture, the lint yield odds ratio indicated that VRN treatment yields were 5.73 (*e*1.7455) times as likely to be lower than FP yields under these conditions. The percent change in the log odds of VRN yields lower than FP yields was 47.29%. A field with a silt soil texture had a high probability of lower yields with VRN and could potentially benefit from a keeping the current FP N rate instead of going with VRN management. Estimating the odds ratio for the loam soil texture indicated that VRN treatments on loam textured soils were 3.65 (*e*1.2943) times likely to have lower yields than the FP. There was a 26.49% change in the log odds that VRN yields were lower than FP yields on loam textured soils. Loamy fields with the same mean landscape, soil, and weather characteristics would also likely benefit from keeping the FP instead of adopting VRN in terms of yields.
