The Effects Of Soil Water Tension And Irrigation Frequency On Growth And Nutrient Absorption Of Potato Under Drip Irrigation

Through researching the effects of different soil tensions and irrigation frequencies on potato growth characteristics, tuber yield, water use efficiency, tuber quality, under drip irrigation, the results showed that:The plant heights were heightened with increasing irrigation frequency. At the tuber form stage, potato dry matter (stems and leaves), tuber fresh weight were high under the irrigation frequency between ltime/6d~ltime/8d,at the tuber enlargement stage and starch deposit stage, while the irrigation frequency was ltime/d,the dry matter, tuber fresh weight were all tiptop ,and the increments of dry and tuber fresh weight were fastest in whole procreant stage under the irrigation frequency of Itime/d.Potato heights did not reduce as the soil water tension increasing, when soil water tension of irrigation start point over or down to 25KPa, the heights would be reduced. At the tuber form stage, when soil water tension was 55KPa, dry matter was highest, at the tuber enlargement stage and starch deposit stage, dry matter were highest under 25KPa disposal; tuber fresh weight were relatively high in whole procreant stage when soil water tension between 15KPa and 25KPa; the dry matter and tuber fresh weight were high in whole procreant stage under soil water tension was 25KPa.Tuber yield and water use efficiency of potato were enhanced by increased irrigation frequency, when irrigation frequency was 1time/d,the tuber yield of potato was highest, amounting to 3163kg/mu,potato tuber yield declined 10%~29.2% with irrigation frequency down from Itime/d to ltime/8d. tuber yield of potato was highest(2985.8kg/mu) when soil water tension-was 25KPa, it had increased tuber yield 4.2%~29.8%compared to other soil water tension' tuber yield; water use efficiency of potato was not increasing with increasing soil water tension, under highest soil water tension (55KPa), water use efficiency was also highest(47.7kgmm-1mu-1), when soil water tension was 25KPa, compared to highest water use efficiency , it's water use efficiency was lower, but higher other soil water tensions, water use efficiency was lowest with lowest soil water tension(20.5kgmm-1mu-1).At tuber form stage, tuber enlargement stage and starch deposit stage, contents of chlorophyll a, b in leaves were highest when soil water tension was 55KPa, contents ofchlorophyll a, b in leaves were declining with increasing soil water tension at the harvest stage. Albumen content of potato tuber was highest (14.44%) when soil water tension was 25KPa, and starch content of potato tuber was highest (66. 35%) when soil water tension was 55KPa.At tuber form stage and starch deposit stage, when irrigation frequency was 1time/d or 1 time/2d, contents of chlorophyll a> b in leaves were higher. Albumen content of potato tuber were highest (13. 71%) when irrigation frequency was 1time/6d, while irrigation frequency was ltime/2d, starch content of tuber was highest (64. 62%).When irrigation frequency was ltime/2d, Nitrogen content of leaves was always highest during the whole growth stage; at the tuber form stage and starch deposit stage, while irrigation frequency was ltime/4d, Phosphorus content of leaves was highest, but the highest was Itime/d in harvest stage; Potassium content of leaves were tiptop when irrigation frequency was ltime/6d at the tuber form stage and tuber enlargement stage, in starch deposit stage the highest was Itime/d, but in harvest stage the highest was ltime/2d.Nitrogen content of leaves was declined by increased soil water tension in the whole growth stage; at the tuber form stage, Phosphorus content of leaves was highest when soil water tension was 25KPa, at tuber enlargement stage and starch deposit stage, Phosphorus content of leaves was highest when soil water tension was 55KPa, but the highest was 35KPa in harvest stage; Potassium content of leaves were relatively high when soil water tension was varied between 35KPa and 45KPa.