Abstract:Water regulation has important influence on intransplanted cotton following wheat harvest. To investigate a suitable irrigation schedule of intransplanted cotton following wheat harvest, an experiment was conducted to study the effects of different water treatments on the water consumption, seed yield, water use efficiency and quality of intransplanted cotton following wheat harvest. Three irrigation level 45%~50%, 60%~65% and 75%~80% FC were set as lower limit of soil moisture for plot experiment under a rainproof canopy at squaring stage and blooming-boll forming stage, respectively. 80%~100% FC (T7), 60%~80% FC (T8), 50%~90% FC (T9) and 40%~60% FC (T10) were set for pipe experiment from seeding stage to boll opening stage, respectively. Five irrigation quota treatments, 1.6 (T11), 1.3 (T12), 1.0 (T13), 0.7 (T14) and 0.4 (T15) times of ETp(ETp was the accumulated of 20 cm pan evaporation during twice of the irrigation interval), were set for pot experiment and the irrigation time of each treatment was consistent with a cycle of 4~10 d, 3~7 d, 2~5 d and 4~10 d at seeding stage, squaring stage, blooming-boll forming stage and boll opening stage, respectively. The results were shown as follows, for plot experiment, seed yield, number of bolls per plant and single boll weight were maximum under T2, and the difference of seed yield was insignificant compared to T4, while WUE and IWUE decreased by 23.93% and 34.01%, respectively. For pipe experiment, the numbers of bolls per plant and seed yield were maximal under T7, where the seed yield decreased by 3.98% for T8 compared to CK while WUE and IWUE increased by 9.7% and 20.2%, respectively. For pot experiment, the numbers of bolls per plant and seed yield were maximal under T11, and seed yield increased by 9.7% and 30% compared to T12 and T13, respectively. This showed that moderate water stress was propitious to improve seed yield and WUE of intransplanted cotton following wheat harvest (lower limit 60%~65% FC, upper limit 80%~85% FC).
