| Objective:In this experiment,barrel planting combined with artificial rainproof and artificial drip irrigation was used to control soil moisture.Water consumption characteristics and water use efficiency of drip irrigation sugar beet at different growth stages were studied under deficit-regulated irrigation.Material accumulation,yield and quality characteristics of sugar beet in each treatment were analyzed.On this basis,water production function model of drip irrigation sugar beet was established to clarify drip irrigation sugar beet at different growth stages.The water sensitive index of vegetable provides theoretical support for water saving,high quality and high efficiency cultivation of Sugarbeet in arid area.Methods:During the period of rapid growth of Sugarbeet leaves,expansion of root tubers and accumulation of sugar,the soil water content of 0~60 cm layer was set to be full irrigation(70%field water holding capacity)and inadequate irrigation(regulated deficit irrigation).Among them,regulated deficit irrigation included 50%field water holding capacity and 30%field water holding capacity.Seven treatments(T1~T7)were tested,and each treatment was repeated five times.Before the beginning of water control during the growth period of Sugarbeet Leaf cluster,all treatments were irrigated to saturated water content.By controlling irrigation time and amount,Sugarbeet was subjected to water stress at different growth stages.The effects of water stress at different growth stages on water consumption characteristics,water use efficiency,root quality and yield of Sugarbeet were studied.Results:(1)The total water consumption was T1>T6>T2>T7>T4>T3>T5,of which the total water consumption and total evapotranspiration of T1 treatment(70%field water holding during the whole growth period was the water control limit)were the highest,while that of T5 treatment(30%field water holding during the root expansion period was the water control limit)was the lowest.The stage water consumption and stage evapotranspiration under different deficit regulation treatments at the same growth stage were 70%FC>50%FC>30%FC.Daily water consumption of regulated deficit irrigation treatment at growth stage was significantly lower than that of non-regulated deficit irrigation treatment at growth stage,with 70%FC>50%FC>30%FC among treatments.The daily water consumption and evapotranspiration of T3 treatment at rapid growth stage of leaf cluster were the smallest(3.98 mm/d and 5.59 mm/d),and that of T5 treatment at root expansion stage were the smallest(7.3 mm/d and 4.36mm/d),and that of T7 treatment at sugar accumulation stage.The daily water consumption and evapotranspiration were the smallest(3.85 mm/d and 4.93 mm/d).The daily water consumption and evapotranspiration of T1 treatment were the highest in the rapid growth period of leaf cluster and the swelling period of root tuber,reaching 13.93 mm/d,13.65 mm/d and 16.72 mm/d,14.52 mm/d,respectively,and there was no significant difference between T1 treatment and no deficit irrigation treatment.The daily water consumption of T3 treatment during sugar accumulation period was 10.22mm/d,which was significantly higher than that of other treatments.The daily evapotranspiration of T2treatment was 13.13 mm/d in sugar accumulation period,which was significantly higher than that of other treatments.The yield and water use efficiency of T2 were the highest in all treatments.The yield and water use efficiency of Sugarbeet under moderate deficit irrigation were higher than those under severe deficit irrigation at all growth stages.Water consumption,yield and water use efficiency of Sugarbeet under each treatment at the same growth stage were 50%FC>30%FC.(2)In all treatments,the growth indexes(root weight,petiole weight,leaf weight,leaf number)of Sugarbeet in T2 treatment reached the maximum,while the root weight in T5 treatment was the lowest,followed by T3 treatment,and there was no significant difference in root weight among other treatments.Beet production and Sugar production in sugar beets were significantly different under different regulated deficit irrigation treatments.Sugar content was not significantly different among different regulated deficit irrigation treatments.Sugar content of T6 treatment was the highest(16.55%)and that of T2 treatment was the highest(1.37×10~5 kg/ha).The yield(7.03×10~4 kg/ha)and Sugar production in sugar beets(9.4×10~3 kg/ha)of T5 treatment were significantly lower than those of other treatments.Sugar yield of Sugarbeet was the highest in T1 treatment.Na~+,K~+,?-N and ash content in root tubers reached their maximum values under T5,T1,T6 and T2 treatments,respectively,and the differences among treatments were as follows:?-N>K~+>ash>Na~+.(3)Jensen model was used to analyze the water sensitivity indices of three growth stages of drip irrigation sugar beet.The results showed that the water sensitivity indices were 0.411 in the rapid growth stage of leaf cluster,0.375 in the swelling stage of root tuber and 0.143 in the sugar accumulation stage.Conclusions:The stage water consumption and stage evapotranspiration under different deficit regulation treatments at the same growth stage decreased with the increase of water shortage.The water consumption,yield and water use efficiency of the treated beets in the same growth stage were:50%FC>30%FC. |
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