坡耕地退耕后，土壤和下游河流通常会发生什么变化？
What usually changes in the soil and the downstream river after slope farmland is retired?
上游泥沙减少、河水更清，下游河道淤积放缓、洪峰被植被"削平"；但短期内坡面产流可能改变，需要配套管护避免新的滑坡。
Upstream sediment drops and water clears, downstream aggradation slows and floods are "flattened" by vegetation—though short-term runoff shifts need management to avoid new slides.
难度 进阶 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Odum & Barrett,《Fundamentals of Ecology》第5版,Brooks/Cole,2004
E. P. Odum and G. W. Barrett, Fundamentals of Ecology, 5th ed., Brooks/Cole, 2004
独立核验依据 · Independent verification: 核验依据 2 OPENLIBRARY 标识 /works/OL3334843W：Fundamentals of ecology
#退耕 #泥沙 #下游
退耕还林还草，为什么能减少水土流失？
Why does converting farmland back to forest and grassland reduce soil erosion?
坡地上庄稼收割后地表裸露，雨一冲土就跑；恢复林木草被后，根系抓土、落叶护表、减缓径流，土壤就被"留"住了。
On slopes, harvested crops leave bare soil that rain washes away; restored trees and grass use roots to hold soil, litter to shield the surface and slower runoff to keep soil in place.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Odum & Barrett,《Fundamentals of Ecology》第5版,Brooks/Cole,2004
E. P. Odum and G. W. Barrett, Fundamentals of Ecology, 5th ed., Brooks/Cole, 2004
独立核验依据 · Independent verification: 核验依据 2 OPENLIBRARY 标识 /works/OL3334843W：Fundamentals of ecology
#退耕还林 #水土流失 #根系
为什么退下来的坡地种树，反而比种粮更"护水"？
Why does planting trees on retired slopes protect water better than crops?
林木常年有叶有根，蒸腾与截留有节律，枯落物像海绵一样蓄水保土；而粮田翻耕频繁、裸露期长，更容易跑水跑土。
Trees keep leaves and roots year-round, transpiring and intercepting water while litter sponges up soil moisture; cropland is often tilled and bare, losing both water and soil.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Odum & Barrett,《Fundamentals of Ecology》第5版,Brooks/Cole,2004
E. P. Odum and G. W. Barrett, Fundamentals of Ecology, 5th ed., Brooks/Cole, 2004
独立核验依据 · Independent verification: 核验依据 2 OPENLIBRARY 标识 /works/OL3334843W：Fundamentals of ecology
#坡地 #蓄水 #植被