| To ascertain the mechanisms of the pepper under different Regulated Deficit Irrigation during the whole growth period.The effects of drip irrigation on the soil temperature,water consumption characteristics and growth,root growth,fruit quality,yield and water use efficiency of pepper during different growth stages were analyzed.The experiment was conducted at the Yimin Irrigation Experimental Station of Minle County,Oasis Irrigation District,Hexi Corridor,Gansu Province from April to September 2017.According to the water-demand characteristics of different growth stages of pepper,the water deficit degree is set to three gradients,which are mild(65%~75%field capacity,Field Capacity,FC),moderate(55%~65%FC).And heavy(45%~55%FC);There are 6 water deficit treatments and 1 full irrigation control during the whole growth period:C1(mild WD at seedling),C2(moderate WD at seedling),C3(severely WD at seedling),C4(mild at seedling-mild WD at full fruit period),C5(moderate at seeding-mild WD at full fruit period)and C6(moderat at seeding-mild WD at later fruit period)and controlled(CK)with adequate irrigation(75%~85%FC).Research indicates:(1)The film insulation effect is significant,and the daily variation of soil temperature decreases with the increase of soil depth,while irrigation can reduce soil temperature within 0~25 cm and increase soil heat capacity.At full fruit period,the higher the soil moisture,the lower the average soil temperature within 25cm,and the full irrigation treatment was 2.3℃lower than the slight adjustment of the results.Therefore,drip irrigation under the membrane can effectively adjust the soil temperature change of field crops.(2)The growth dynamic indicators(plant height,stem diameter and leaf area)of fully irrigated treatment during the whole growth period are always at the highest level during the whole growth period,and the mild,moderate and severe water regulation at the seedling stage and the mild at full fruit period of the results were significantly(P<0.05)inhibited the growth of pepper dynamic index,and the greater the degree of deficit reduction,the more serious the index decreased.The results mild regulation of at later fruit period had no significant effect on the ecological index of pepper(P>0.05).The moderate water deficit in the seedling stage could significantly increase the pepper harvest index(HI),which increased by 33.3%.(3)The water deficits were significantly decreased(P<0.05).The total water consumption of peppers during the whole growth period was 9.63%~17.12%.The results indicates full fruit period and at later fruit period were the two growth periods with the largest water consumption during the whole growth period.The water consumption modulus was 34.0.%~36.6%and 25.29%~27.28%,followed by blossom and fruit period,the water consumption in seedling stage is the smallest,and the water consumption modulus is only about 14.76%.(4)The effects of different water deficits on root growth,(root length,root weight,roots number and root volume of pepper)were different.The moderate and severe water deficit treatment in seedling stage was significantly lower than the control CK(P<0.05)reducing root length 16%and 7%,reducing root weight by 32.1%and48.7%,do not conducive to the absorption of water and nutrients by pepper plants.The mild and moderate water deficit adjustment in seedling stage had no significant effect on the number of lateral roots(P>0.05),but the seedling stage severely reduced the number of lateral roots by 42.4%.The results showed that the effect of mild water deficit adjustment on root growth was not significant at the end of the period and the end of the results.(5)There was no significant difference(P>0.05)between the three harvests and the control in the three harvests of mild and moderate water-deficient pepperling fruit length,shoulder width and pulp thickness.Results The slight adjustment of the loss during the peak period did not significantly affect the length of the fruit and the shoulder width of the second and third harvests,but significantly(P<0.05)reduced the thickness of the pulp by 9.1%~21.1%.Results The mild water deficit at the end of the period was not significant,which affected the third long fruit length,but significantly(P<0.05)reduced the pulp thickness by 10.3%.Moderate and severe seedlings can significantly increase the weight of single fruit by 18.0%and 14.9%.The results showed that the slight weight loss at the peak and the end of the results significantly reduced the single fruit weight by 16.4%and 12.6%.(6)There was no significant effect on the Vc content and soluble protein of fruit in mild and moderate water regulation at the seedling stage and the slight decrease in the final stage(P>0.05).The results showed that the slight adjustment of the loss during the peak period was significant(P<0.05).The vitamin C content in the second harvested green fruit was 7.8%~9.13%,the soluble sugar content was 9.8%~10.61%,and the soluble protein content was 9.3%~10.4%.(7)The total yield of pepper was the highest mild in the seedling stage,which was up to 36107.61kg/hm~2.The water use efficiency was the highest moderat at seeding-mild WD at later fruit period,which was 140.97kg/mm·hm~2,significantly(P<0.05)increased by 12.10%;The economic benefit of pepper was the highest in the mild water-deficient treatment at the seedling stage,which was 10.23%higher than the control,and moderate at seeding-mild WD at full fruit period was significant decreased of 11.17%compared with the control. |
