grey humic acid

例句：

1. 1. Thissoil amendment is crucial for the growth ofmany plants.
   这种土壤改良剂对许多植物的生长至关重要。
2. 2. The humic acid in thesoil helps to improve water retention and nutrient absorption.
   土壤中的腐殖酸有助于提高水分保持和养分吸收。
3. 3. The useof humic acid can help reduce theamount of chemical fertilizers neededin agricultural production.
   使用腐殖酸可以帮助减少农业生产中所需的化学肥料量。