幼果期调亏对不同覆膜柑橘产量品质及水分利用效率的影响

Effects of regulating deficit at young fruit stage on yield,quality,and water use efficiency of citrus with different plastic film materials

调亏灌溉具有节水保肥、提质增效等特点,该研究尝试在调亏灌溉基础上引入地表覆膜技术,利用覆膜的保水控水作用,解决水分亏缺带来的土壤水分不足及后期减产问题。以鄂西地区树龄10 a的柑橘树(红肉脐橙,枳砧)为研究对象,探究覆膜条件下水分亏缺对柑橘品质、产量及水分利用效率(water use efficiency, WUE)的影响。试验于2019-2021年在幼果期设置轻度(L:80%~90%田间持水量)、中度(M:70%~80%田间持水量)、重度(S:60%~70%田间持水量)3个程度水分亏缺水平,另设置A(日本透湿性膜)、B(杜邦特卫强膜)、C(中国银黑双色膜)和不覆膜4个覆盖水平,以不覆膜充分灌溉为对照进行试验。结果表明:水分亏缺和覆膜均可显著改善柑橘果实品质(P<0.05),其中M-A和M-B处理是提高柑橘品质的最优处理。水分亏缺和覆膜对产量及WUE的影响也达到显著水平,两者均能有效提高WUE,L和M处理均显著增加了柑橘产量,而S处理显著减小了柑橘产量,且两者的交互作用对产量及WUE影响也显著,其中M-A和M-B处理的产量和WUE均达到最高水平,2019、2020、2021年M-A和M-B处理的产量分别为44 793.6、45 325.1、43 126.8 kg/hm^(2) 和44 870.5、44 727.7、41 783.5 kg/hm^(2),WUE分别为7.31、7.68、7.08 kg/m^(3) 和7.47、7.47、6.89 kg/m^(3)。因此,最优处理为柑橘品质、产量和WUE均达到较高水平的M-A和M-B。该研究可为鄂西地区柑橘产业的灌溉管理和提质增效提供理论依据。

Regulated deficit irrigation has been one of the most typical characteristics of saving water and fertilizer,in order to improve the quality and efficiency.In this study,an attempt was made to introduce surface mulching technology with regulated deficit irrigation.The water retention and water control effect of mulching were then utilized to treat the soil moisture shortage and later yield reduction caused by water deficit.The research object was selected as the citrus trees aged 10 years old at the Cangwubang citrus experimental base(30°75′N,110°41′E,altitude:343 m)in the western Hubei Province of China.A series of field experiments were conducted to investigate the effects of water deficit on the citrus quality,yield,and water use efficiency(WUE)under film mulching.Three levels of water deficit were set at the young fruit stage:Light(L:80%-90%of field capacity),moderate(M:70%-80%of field capacity),and severe(S:60%-70%of field capacity).Four mulching levels were set:A(Japanese permeable film),B(Dupont Tyvek film),C(Chinese silver-black double-color film),and no mulching.The field experiment was conducted with full irrigation as the control,and 13 treatments were set up from 2019 to 2021.The results showed that the water deficit and film mulching significantly improved the quality of citrus fruits.The L treatment significantly increased the single fruit weight and excellent fruit rate,whereas,there was a decrease in the S treatment.The degree of water deficit was positively correlated with the soluble solids and reduced sugar content,while negatively correlated with the juice yield.Plastic film mulching significantly increased the single fruit weight,fruit color,excellent fruit rate,VC content,soluble solids content,and reduced sugar content(P<0.05),whereas,there was a significant decrease in the peel thickness,and titratable acid content(P<0.05),among which the A and B films were the best.A comprehensive evaluation of fruit quality showed that the M-B treatments were ranked first in 2019 and 2020,and the M-A treatment ranked first in 2021.There were the best fruit shape index and single fruit weight of M-B treatment in 2019.The best was found in the excellent fruit percentage and Vc content of M-B treatment in 2020.By contrast,the best was observed in the single fruit quality and excellent fruit percentage of M-A treatment in 2021.The M-A and M-B treatment were the best to improve the citrus quality.It infers that the moderate-deficiency treatment was the best treatment for better citrus quality,whereas,the A and B materials were the most suitable film mulching materials in such treatment.A significant level was also reached in the effects of water deficit and film mulching on the yield.Both L and M treatments significantly increased the citrus yield,whereas the S treatment significantly reduced the citrus yield.The interaction between the water deficit and film mulching posed a significant effect on the yield(P<0.05).Film mulching effectively reduced the effect of severe water deficit on the citrus yield reduction.Three kinds of film materials significantly reduced the ET of citrus trees(P<0.05)under the same water deficit condition.The water-saving effect of C material was better than that of A and B materials.Both water deficit and plastic film mulching effectively improved the WUE(P<0.05).The interaction between them posed a significant effect on WUE(P<0.05).The yield and WUE of M-A and M-B treatments reached the highest level.From 2019 to 2021,the output of M-A and M-B treatments were 44793.6,45325.1,43126.8 kg/hm^(2),and 44870.5,44727.7,41783.5 kg/hm^(2),respectively,and the WUE was 7.31,7.68,7.08 kg/m^(3) and 7.47,7.47,6.89 kg/m^(3),respectively.Therefore,the optimal treatment can be the M-A and M-B treatments with higher levels of citrus quality,yield,and WUE.This finding can also provide a theoretical basis for the irrigation management and quality improvement of the citrus industry in western Hubei of China.