微咸水膜下滴灌对棉花植株盐分、养分吸收及品质的影响

Effects of drip irrigation with brackish water under film mulch on salinity,nutrients and quality of cotton plants

为缓解南疆地区淡水资源紧张,充分利用微咸水资源,共设置6种不同淡咸水比例的灌溉水处理,即淡咸比1∶0(对照)、4∶1(处理1)、3∶2(处理2)、2∶3(处理3)、1∶4(处理4)、0∶1(处理5),采用田间试验,研究不同微咸水对棉花植株盐分、养分及品质的影响。结果表明:(1)随着灌溉水矿化度的增大,棉花不同器官中Na^+含量呈现增加的趋势,叶片中Na^+含量最高,处理1~5较对照分别增加8.29%、32.49%、32.87%、42.62%、48.05%;不同器官中Cl^-含量随灌溉水矿化度的增大而增加,以叶中Cl^-含量最高,其次是蕾铃和茎,根中最低;不同器官中Ca^2+含量随着灌溉水矿化度增大出现下降趋势,但各处理之间差异不显著。随着灌溉水矿化度的增大,单株棉花Na^+和Cl^-积累量出现波动性,其中Na^+积累量在0.42~0.51 g·株^-1,Cl^-积累量在1.45~2.06 g·株^-1。而单株棉花Ca^2+积累量随灌溉水矿化度的增大而下降,处理1~5较对照分别下降23.59%、21.92%、25.81%、42.94%、48.22%。(2)棉花不同器官N、K含量随灌溉水矿化度的增大呈现无规律性变化;棉花茎、叶、蕾铃中的P含量随灌溉水矿化度的增大出现先增加后减小,根中的P含量随灌溉水矿化度的增大而降低,但各处理之间差异不显著。单株棉花N、P积累量随着灌溉水矿化度的增大而下降,其中处理3~5的N单株积累量与对照、处理1、2差异达到显著,对照、处理1~5单株棉花K积累量分别为7.79、6.57、5.97、5.74、5.01、3.88 g·株^-1;单株棉花P积累量随着灌溉水矿化度的增大而显著性降低,处理1~5分别较对照减少15.83%、34.56%、35.22%、48.73%、59.22%。(3)随着灌溉水矿化度的增大,棉花的短纤维指数较对照呈现不同程度的上升,对照、处理1~5的棉花短纤维指数分别为5.70、6.30、6.40、7.60、7.45、7.65,各处理之间差异不显著。其它各品质之间均较对照呈现不同程度的下降,整体棉花品质随着灌溉水矿化度的增大而下降。因此,在淡咸水比为4∶1,即矿化度为2.36~3.39 g·L^-1时,棉花植株体内盐分累积较低,对养分的吸收及品质影响最小。

In order to alleviate the shortage of fresh water resources in southern Xinjiang and make full use of brackish water resources,an experiment with different mixing ratios of fresh and brackish water were conducted.Six ratios of fresh water and brackish water were 1∶0(control),4∶1(treatment 1),3∶2(treatment 2),2∶3(treatment 3),1∶4(treatment 4)and 0∶1(treatment 5).The field experiments were conducted to study the effects of different proportion of brackish water on salinity,nutrient,and quality of cotton plants.The results showed that:(1)With the increase of salinity of irrigation water,Na^+content in different organs of cotton showed an increasing trend;the content of Na^+in leaves was the highest in different organs,and the levels of Na^+in leaves increased by 8.29%,32.49%,32.87%,42.62%and 48.05%,respectively,when compared with the control group.The content of Cl^-in different organs increased with the increase of salinity of irrigation water.The highest content of Cl^-was found in leaves,followed by buds and bolls and stems,and the lowest in roots.The Ca^2+content in different organs decreased with the increase of salinity,but there was no significant difference among the treatments.With the increase of salinity,the Na^+and Cl^-1 accumulation of cotton per plant fluctuated,in which the Na^+accumulation ranged from 0.42 g·plant^-1 to 0.51 g·plant^-1,and the Cl^-accumulation ranged from 1.45 g·plant^-1 to 2.06 g·plant^-1.The accumulation of Ca^2+in cotton per plant decreased with the increase of salinity,and the values of treatment 1~5 decreased by 23.59%,21.92%,25.81%,42.94%,and 48.22%,compared with the control group.(2)The content of nitrogen and potassium in different organs of cotton changed irregularly with the increase of salinity;the content of phosphorus in stems,leaves,buds and bolls of cotton first increased and then decreased,while the content of phosphorus in roots decreased with the increase of salinity,but there was no significant difference among the treatments.The accumulation of nitrogen and phosphorus per plant of cotton decreased with the increase of mineralization degree.The nitrogen accumulation per plant of treatment 3~5 was significantly different from that of control,treatment 1 and 2.The total potassium accumulation of cotton in control and treatment 1~5 was 7.79,6.57,5.97,5.74 g·plant^-1 and 5.01 g·plant^-1,respectively.With the increase of irrigation water salinity,the phosphorus accumulation per plant of cotton decreased significantly,which decreased by 15.83%,34.56%,35.22%,48.73%and 59.22%respectively compared with the control.Treatment 1 had the smallest decrease compared with the control.(3)With the increase of salinity,the short fiber index of cotton increased in different degrees,the short fiber index of control and treatment 1~5 were 5.70,6.30,6.40,7.60,7.45 and 7.65,but the difference was not significant.Compared with the control,other qualities decreased to different degrees.Overall,the quality of cotton decreased with the increase of salinity.Therefore,when the brackish water ratio was 4∶1,that is,the salinity was 2.36~3.39 g·L^-1,the salt accumulation in the cotton body was low,and the effect on nutrient absorption and quality was minimal.