| The experiment about mulched drip irrigation under water deficit regulation of pepper with growing in the feild was conducted at Yimin Irrigation Experimental Station during April to Agust in 2016.The‘Jinjiao 6' was selected as the pepper cultivar(Capsicum annuum)and the whole growth period of pepper was divided into the four periods: seedling,blossom and fruit pe riod,full fruit period and later fruit period.The experiment was composed of three water regulated deficit(WRD)leves,mild WRD(soil moisture was maintained between 65% and 75% of Field Capacity),mederate WRD(soil moisture was maintained between 55% and 65% of field capacity)and severe WRD(soil moisture was maintained between 45% and 55% of field capacity)at both seedling and blossom and fruit period,respectively,or mild WRD and mederate WRD at both full fruit period and later fruit period,respe ctively.In the meanwhile,CK represented the control group with sufficient water supply(soil moisture was maintained between 75% and 85% of field capacity).The main studies were about the variation of soil moisture content and temperature in root zone,water consumption characteristics,the growth,fruit yield and water use of pepper in each water treatment at different growth periods.Besides,the water product functions of pepper was established and solved by Blank model and Jensen model.The main results were as follows:(1)Under the condition of mulched drip irrigation,the plant height,stem diameter and leaf area index(LAI)in control group with adequate water supply in the whole growth period of pepper remained the highest level during the differe nt growth periods.The different degrees of WRD at seedling,blossom and fruit period and full fruit period all caused pepper plant height,stem diameter and leaf area index significantly(P>0.05)less than control,and the greater were the extents of WRD,the smaller were plant height,stem diameter and LAI.But the WRD during later fruit period had no significant(P>0.05)effects on the plant height,stem diameter of pepper.(2)The WRD at both seed ling and Blossom and fruit period made the pepper biomass of ground parts and root decreased,and the drop of biomass both ground parts and root were greater with the extent of WRD increasing.Besides,the WRD could significantly(P>0.05)affect the root-shoot ratio and harvest index of pepper in which the moderate WRD at seedling would significantly increase root-shoot ratio and harvest index of pepper which was up to 0.68 and the maximum among all the water treatments.(3)The ground temperature fluctuation decreased with the increase of soil depth.The increase of soil water can decrease extreme value of t he average ground temperature in 25 cm soil layer under film during the day,especially at seedling of low temperature period,the ground temperature of the treatment with sufficient water supply was higher than the reatment with severe WRD by 2.2 ?.(4)The water consumption at different pepper growth periods in each water treatment were decreasingly ordered as: full fruit period,later fruit period,blossom and fruit period and seedling,and the water consumption moduls were above 31.47%,22.34 %,20.56 % and14.76 %,respectively.The WRD at different pepper growth periods could signicantly(P<0.05)reduce the water consumption druring water-deficit period of pepper and the water consumption caused by water deficit inceased with level of WRD.Besides,the amounts of saving water at the same level of WRD incresed with the water consumption of pepper growth period.(5)The effect of mulched drip irrigation under water deficit regulation on the change of soil moisture content from 0 to 40 centimeter was greater than on the change at 40 to 60 centimeter below plastic film.The water consumption of pepper was mainly from the soil layer within 0 to 30 centimeter under the condition of sufficient water supply and the water consumption in soil from 30 to 60 centimeter below film was improved with increase in the extent of water regulated deficit.(6)The water sensitive index at different pepper periods in both Blank and Jensen water product functions were descendingly ordered as: blossom and fruit period,full fruit period,seedling and later fruit period.Consequently,blossom and fruit period was the critical water requirement period of pepper,sufficient water supply should be made in order to get high yield.(7)The maximum yield was found in the fully irrigated pepper(CK)with fruit yield of 36203.90 kg·hm-2,while the minimum yield was in the severe WDR treatment with fruit yield of 26951.42 kg·hm-2 during Blossom and fruit period.Comprehensively considering fruit yield(Y),WUE and IWUE of pepper,the integrated evaluation index(IEI)for RDI regimes of water treatment(SRD-2)with moderate WRD at seedling was the maximum.Consequently,SRD-2 was the optimal irrigation treatment of pepper in this study. |
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