Table 1. Effects of the Grain for Green Program on between-group heterogeneity (Qb) in relation to the soil organic carbon response ratio.
| Soil layer | Conversion type | Categorical variable | Qb | P-value | F |
|---|---|---|---|---|---|
| 0–20 cm | Total | CCF/CCG | 3.438 | 0.014 | 6.107 |
| CCF | Plantation type | 2.218 | 0.014 | 3.598 | |
| Conversion period | 5.259 | 0.00000007 | 9.126 | ||
| CCG | Restoration approach | 1.374 | 0.081 | 3.073 | |
| Conversion period | 1.311 | 0.016 | 2.91 | ||
| 20–40 cm | Total | CCF/CCG | 1.21 | 0.04 | 4.306 |
| CCF | Plantation type | 0.209 | 0.597 | 0.631 | |
| Conversion period | 0.558 | 0.11 | 1.869 | ||
| CCG | Restoration approach | 0.088 | 0.472 | 0.528 | |
| Conversion period | 0.271 | 0.047 | 3.071 | ||
| 40–60 cm | CCF | Plantation type | 0.591 | 0.132 | 1.977 |
| Conversion period | 1.403 | 0.0004 | 6.53 |
CCF: Conversion of cropland to forest; CCG: conversion of cropland to grassland.