Table 3 Determined coefficients for the empirical yield model (Eq. 2) and their interpretations. All yield-related coefficients are in units of tons per mu.
Parameter | Optimized Value | Interpretation |
|---|---|---|
\(p_1\) (Intercept) | 0.9110 | Base yield (ton/mu) under reference conditions. |
\(p_2\) (SQI) | 31.430 | Yield change per unit of Soil Quality Index. |
\(p_3\) (GDD) | 0.0019 | Marginal yield increase (ton/mu) per unit of GDD. |
\(p_4\) (Water) | 0.0014 | Marginal yield increase (ton/mu) per mm of water. |
\(p_5\) (Slope) | 42.868 | Quantifies yield reduction per unit of slope factor. |
\(p_6\) (Altitude) | 0.4604 | Yield change per unit of altitude suitability factor. |
\(p_7\) (Nutrient) | 0.0408 | Marginal yield increase (ton/mu) per unit of nutrient score. |
