Abstract: The effects of straw mulch and fertilizer reduction on yam growth, soil temperature and humidity were studied using field trials of rain-fed yam. The results showed that returning straw to the field could not only significantly reduce the temperature of the 0~5 cm topsoil during the high temperature period （14：00） （average decrease of 1.5~2.4 ℃）, but also significantly increase the 0~5 cm topsoil during the high temperature and drought periods. The water retention capacity of the layer （an average increase of 1.2~3.4 percentage points）, under the same amount of straw cover and return to the field, 15% reduction in fertilizer had no significant effect on the temperature and humidity of the 0~5 cm topsoil layer. The yield and biomass of yam during the maturity period were increased due to the cooling and moth-killer effect of straw mulch, increasing yields1 070~3 490 kg/hm² and 450~1 780 kg/hm², respectively, while the same amount of straw mulching returned to the fields, the 15% reduction in fertilizers was the opposite, reducing yields1 420~3 615 kg/hm² and 550~1 368 kg/hm², respectively. In terms of the effects of soil cooling and soil protection and yam yield increase, when the straw coverage can be selected as 6 000~7 500 kg/hm², the fertilizer reduction can be 15%.

Key words: straw mulch, fertilizer reduction, yam, yield, soil temperature, soil humidity