| Aiming at the reality of fallow farmland area enlarging in dry season of southwest dry-hot valley, this paper researches the change regulation and synergic relation of fallow farmland temperature with evaporation in 24 hours at the beginning and end of the dry season. The results showed that: The fallow farmland temperature curves and evaporation summation curves are mainly presented the change of waveform function curve. With the soil depth and farmland mulch increase, the curves backwardly evolved in proper order, the amplitudes also gradually reduced. It indicated that the farmland mulch will be played a certain function for stable soil temperature and water conservancy, can obviously reduce the soil moisture losses. The synergic function of fallow farmland temperature with evaporation was presented a positive synergic relationship and the synergic coefficient was generally rather large. But with the soil depth and land surface mulch gradual increase, the synergic relationship will be gradually decreased.Yet the drought will be useful to strengthen the synergic relation. It can illustrate that the land evaporation will be increasing when the farmland temperature going up, so the farmland temperature still is the main driving factor for the farmland evaporation. Therefore to develop and utilize the seasonal fallow farmland in the southwest dry-hot valley area, it must be doing best to save and store the soil water in dry season by adding the land surface mulches, reducing the noneffective evaporation for thr soil moisture, to establish a good water foundation for developing and utilizing the fallow farmland. |