[Amelioration effect of humic acid on saline-alkali soil].

A field experiment was conducted to investigate the effects of three types of humic acid, i.e. oxidized humic acid (OHA), aminated humic acid (AHA) and microbial-humic acid (MHA), on physico-chemical properties of saline-alkali soil and maize growth.

Effects of yam/leguminous crops intercropping on soil chemical and biological properties of yam field.

We investigated the effects of yam/leguminous crops intercropping on soil chemical and biological properties as well as soil comprehensive fertility in a field experiment. Results showed that compared with the monoculture, both yam/alfalfa and yam/clover intercropping increased the concentrations of nitrate nitrogen (N), available phosphorus (P) and available potassium (K) in the 0-20 cm and 20-40 cm soil layers, while reduced soil pH and electrical conductivity (EC) in early growth period and rhizome rapid expansion period of yam. Intercropping with leguminous crops enhanced the activities of urease, alkaline phosphatase and catalase, and also enhanced soil basal respiration in the 0-20 cm and 20-40 cm soil layers during the whole growth period of yam.