| Field plot experiments were conducted to analyze and investigate the effect of technique of wide plastic-
film mulching on soil water and soil temperature for seed 7melon on dryland covered with sand. The results showed that the technique of wide film mulching could collect and keep soil water and increase soil water content for seed-melon sig-nificantly. Compared with no film mulching (CK)， full film mulching，wide film mulching and half film mulching in-creased water content of 0~20 cm soil layer by 0~3.5%，0~3.4% and 0~2.6% respectively，and increased water storageof 1m soil layer by 0~34.3 mm, 0~33.0 mm and 0~20.3 mm espectively before seedmnelon anthesis. The technique increased field rainfall use rate and seed: melon water use efficiency remarkably. The rainfall use rates of field with full film mulching, wide film mulching and half film mulehing reached 78.5%，78.2% and 74.1% respectively, while the seed melon water use eficencies of them reached 10.15 kg/(mm·hm2)，10.05 kg/(mm·hm2) and 8.22 kg/(mm·hm2) respectively . The technique enhanced soil efective accumulated temperature significantly in seedmelon growing period and made the average temperature reach the best for seed melon growing. Compared with no film mulching, full film mulching, wide film mulching and half film mulching increased the average temperatureof 0~20 cm soil layer by 0~4.6℃, 0~4.4℃ and 0~2.4℃ respectively before melon expanding, increased total accumulated
temperature by 484.7℃，465.5℃ and 242.7℃ respectively， and increased average accumulated temperature by
3.8℃, 3.6℃ and 1.9℃ respectively. Compared with the technique of full film mulching, half film mulching and no film mulching, the technique of wide film mulching had remarkable economic effects. So it was the best mulching mode for dryland covered with sand at persent. |