| The effects of irrigation schedule on growing trends, physiological index and yield effect of Indigowoad Root were studied in Yimin Irrigation District of Gansu Province during March to October in 2006. Six kinds of irrigation schedule treatments were designed for Indigowoad Root in the field. Experiment shows:1. Evapotranspiration of Indigowoad Root in the whole growing period shows that the earlier period is slightly, the intermediate stage is big, and the later period is small. In the 160d period of duration, the water consumption of the irrigates most treatment T5, does not irrigate treatment T6 and the output highest treatment T3, in three irrigation quota, are 522.96mm, 4.26mm, 244.86mm.From sowing to seedling emergence stage is the period that water consumption is the smallest stage, accounts for 2% of consumptive use in the entire period for Indigowoad Root. The seedling to the vegetative growth stage, its water consumption intensity gradually increases the stage water consumption accounts for 14% in the entire growth period. The vegetative growth stage is the water consumption peak, with the increase of irrigation times and irrigation quota, the water consumption were increased and accounts for 55% of the entire period. After the vegetative growth stage enters the taproot growth period, water consumption of each treatment gradually reduces, accounts for 29% of the entire period.2. The different irrigation scheduling of Indigowoad Root have a little influence on soil temperature in the entire period, but it to ground temperature influence existence effectiveness for a period of time. The observation results indicate that 8 to 14 days after irrigating the influence of soil temperature is extremely small, therefore, looking from the existing experiment data, could the influence of irrigation to the ground temperature lasted estimate be 7 days. Regarded the weather condition, this influence lasted possibly changed between 510 days. After irrigating, the soil temperature to be lower than the treatment without irrigation in all times, but the influence of the irrigation quota on soil temperature is not obvious; certainly change of the soil temperature descent does not along with the irrigation quota increase. The results show that soil temperatures at 5 cm depth from soil surface have the obvious daily variation, temperatures of the surface soil from 8:00 to 16:00 are rise stage, but other times are at the temperature decrease stage. With the deepens of soil depth the tendency of daily average soil temperature both irrigating and non-irrigating treatment are reducing, but irrigating treatment soil temperature below 5 cm depth from soil surface decrease quickly than non-irrigating treatment.3. In the seedling stage to six leaves stage the average growth speed is 0.33cm/d, this related with soil initial condition (mainly for soil moisture); Six leaves to the vegetative growth period, this stage are the leaves and stem growing quickest time, the increment of plant height is 2.9 times higher than it in six leaves stage. Irrigation is accelerating to the plant height increasing. In the taproot growth stage the aerial parts growth slows down, even appears stagnates, therefore we discovered the plant height change with the water quota to have the direct ratio.The growth of Indigowoad Root have intimate relation with soil moisture, the influences of irrigation quota to main root length are prominent, with the increasing of irrigation quota the main root length decrease. But along with the increasing of irrigation quota the main root is thick and the weight of fresh root is big. Compared with the fresh weight of Indigowoad Root of all treatments, the influences of irrigation quota to main root length are remarkable. The fresh weight of Indigowoad Root of T3 is the highest and the difference among T3 and T1,T2,T6 is extremely remarkable, but the difference among T3 and T4,T5 is not remarkable.4. The change of irrigation quota has remarkable influences on water consumption and the output. The high soil moisture is excessively in favor of the aerial parts growth, but is disadvantage to root dry matter accumulation. In entire period of Indigowoad Root water use efficiency of irrigation quota reduces along with the irrigation quota increase. The IWUE of T1,T2,T3,T4 and T5 are 6.43, 5.44, 3.99, 2.83 and 2.24kg/m3 respectively. The IWUE of T3 compared to T1 reduced 2.44kg/m3, to decrease rate is 38%; The IWUE of T3 compared to T5 increased 1.75kg/m3, to increase rate is 78%. The range of all treatments input is 25502792 yuan/hm2, the range of net income is 40516490 yuan/hm2.The optimal irrigation treatment 3 (T3) is both to save water and to reduce irrigation cost effectively. This irrigation scheduling is favorable to popularize and use in Yimin irrigation district.5. Water demand of different growth stage has difference for Indigowoad Root. In the seedling stage, Indigowoad Root request is strict to the soil moisture content, although it aerial parts certainly do not carry on the massive transpiration, but it radical needs the sufficient moisture content to germinate and root, therefore in seedling stage if meet the drought it should promptly irrigate. The irrigation method should use sub irrigation or sprinkler irrigation, prohibited flooding irrigation, the time of first irrigation should be as late as possible. In seedling stage, the soil water content of 0 to 60cm soil depth should not be lower than 16.92%; especially the 0 to 20cm soil depth water content should not be lower than 16.5%. In socia stage, the 0 to 60cm soil layer water content should be higher than 12.93%, if it is lower than 12.93% to need to irrigating 395m3/hm2, but does not surpass 527m3/hm2. After Indigowoad Root enters the vegetative growth stage, the dry matter and the effective component accumulates quickly, the soil moisture should not excessively high, but 0 to 80cm soil water content should not be lower than 12.93%, when it is lower than 12.93% to irrgating, irrigation quota is 667m3/hm2 and does not surpass 922m3/hm2. In the Indigowoad Root growth later period it enters root growth to expand stage, this stage soil moisture content should not too high, also should not too low, otherwise it can decrease Indigowoad Root yield. If the soil moisture content is lower than 11.75% to irrigating the soil moisture content reaches 14.1% to 16.45%. June, July and August are the peak of water consumption so in these periods to avoid having drought of the Indigowoad Root. When weather temperature is too high should pay attention to the irrigation opportunity, if water and air have large difference in temperature it is harm to adult plant growth, so we should carry through irrigation in morning or afternoon.
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