Erosion hazard evaluation for soil conservation planning that sustains life expectancy of the A‐horizon: The black soil region of China

Soil erosion is threatening crop production in the black soil region (BSR) of China. This study aims to: (i) evaluate soil erosion hazard for all sloping croplands in BSR; (ii) identify optimum soil conservation practices and propose a schedule for soil conservation. High‐quality spatial data were collected and converted to a map with 30‐m resolution for analysis, including consideration of climate, soil, gemology, topography, and land use. The current erosion hazard was evaluated with soil life expectancy of the A‐horizon (SLEA). The lands with SLEA < 0 yr, 0–20 yr, 20–100 yr, 100–1,000 yr, and ≥1,000 yr were classified as ‘Damaged’. ‘High hazard’, ‘Moderate hazard’, ‘Low hazard’, and ‘No hazard’ in erosion hazard degree, respectively. The result indicated that the current area ratio of these degrees was 8%, 5%, 22%, 61%, and 4%, respectively. Conservation practices are urgently needed. Moreover, optimum practices were identified by comparing SLEA, feasibility, and relative crop yield in the future (2020–2120) under several soil conservation scenarios. The optimum practices were found to be: (i) no‐till (zero‐tillage) for all ‘Damaged’, ‘High hazard’ in warmer BSR, and ‘Moderate’ in warmer BSR; (ii) Combo (a combination of contour tillage, terracing, and ‘green for grain’ measures) for ‘High hazard’ in cooler BSR and ‘Moderate’ in cooler BSR; (iii) maintaining present conditions for all ‘Low hazard’ and all ‘No hazard’. Practices should be implemented to assist ‘Damaged’ and ‘High hazard’ immediately, no later than 2040 for ‘Moderate hazard’ and at any time for ‘Low hazard’ and ‘No hazard’. The strategy suggested by this study is useful for soil conservation works in other regions.