Glacier area change and its impact on runoff in the Manas River Basin,Northwest China from 2000 to 2020

Understanding the distribution and dynamics of glaciers is of great significance to the management and allocation of regional water resources and socio-economic development in arid regions of Northwest China.In this study,based on 36 Landsat images,we extracted the glacier boundaries in the Manas River Basin,Northwest China from 2000 to 2020 using eCognition combined with band operation,GIS(geographic information system)spatial overlay techniques,and manual visual interpretation.We further analyzed the distribution and variation characteristics of glacier area,and simulated glacial runoff using a distributed degree-day model to explore the regulation of runoff recharge.The results showed that glacier area in the Manas River Basin as a whole showed a downward trend over the past 21 a,with a decrease of 10.86%and an average change rate of–0.54%/a.With the increase in glacier scale,the number of smaller glaciers decreased exponentially,and the number and area of larger glaciers were relatively stable.Glacier area showed a normal distribution trend of increasing first and then decreasing with elevation.About 97.92%of glaciers were distributed at 3700–4800 m,and 48.11%of glaciers were observed on the northern and northeastern slopes.The retreat rate of glaciers was the fastest(68.82%)at elevations below 3800 m.There was a clear rise in elevation at the end of glaciers.Glaciers at different slope directions showed a rapid melting trend from the western slope to the southern slope then to the northern slope.Glacial runoff in the basin showed a fluctuating upward trend in the past 21 a,with an increase rate of 0.03×10^(8) m^(3)/a.The average annual glacial runoff was 4.80×10^(8) m^(3),of which 33.31%was distributed in the ablation season(June–September).The average annual contribution rate of glacial meltwater to river runoff was 35.40%,and glacial runoff accounted for 45.37%of the total runoff during the ablation season.In addition,precipitation and glacial runoff had complementary regulation patterns for river runoff.The findings can provide a scientific basis for water resource management in the Manas River Basin and other similar arid inland river basins.

春灌定额对棉田水温盐分布及棉花苗期生长发育的影响

【目的】研究新疆南疆小海子灌区不同春灌定额对棉田水温盐和棉花苗期生长的影响,为小海子灌区棉花苗期的春灌定额提供科学依据。【方法】设置3个春灌水分处理(W_(1):1350 m^(3)/hm^(2)、W_(2):1800 m^(3)/hm^(2)、W_(3):2250 m^(3)/hm^(2)),分析不同春灌定额对棉田水温盐与棉花苗期生长发育的影响。【结果】0~60 cm土层平均土壤含水率W_(3)处理高于W_(1)和W_(2)处理,在其上部耕作层保水能力更好。W_(3)处理较W_(1)、W_(2)处理不同土壤深度地温低,膜下地温均高于2膜间裸行地温。W_(1)处理表层含盐量低于W_(2)和W_(3)处理,0~50 cm的盐分淋洗率分别为6.77%、22.22%和30.03%,春灌水量越大淋洗盐分的效果越好,50~100 cm土壤平均积盐率分别为-39.89%、-58.95%和-68.91%,随着灌水量的增加,盐分被水分带入深层增多。W_(1)处理棉花幼苗的株高、茎粗与叶面积最大,一定的水分亏缺有利于棉花幼苗的生长。【结论】不同春灌定额均有一定程度的洗盐增墒作用,表现为W_(3)>W_(2)>W_(1)处理。

滴灌带布置模式对北疆机采棉生长及土壤水热盐分布特征的影响

随着新疆机采棉膜下滴灌技术的发展,滴灌带的布置模式不断发生改变。为研究新疆地区膜下滴灌带的布置模式对土壤水热盐分布特性及棉花生长的影响,探索新疆机采棉种植最适宜的滴灌带布置模式,该研究采用2 a田间小区试验,设置2种膜下滴灌机采棉种植模式(T1:一膜两管六行模式;T2:一膜三管六行模式),另设置传统种植模式(T3:一膜两管四行模式)作为对照处理。结果得出T1和T2模式下土壤的保温隔热效果均优于常规模式T3,地膜覆盖下土壤温度增温快、降温慢,表现出较好的保温效果,有利于棉花早期的出苗发育;棉花生长中后期,T2模式下0~60 cm土层土壤平均含水率显著高于T1和T3模式(P<0.05),其耕层中上部保水能力更优;在棉花生长中期,T2模式下棉花主根系层形成一个脱盐区;整体而言,棉花生长后期0~60 cm土层土壤平均盐分T2<T3<T1,T2模式对控制土壤盐分积累效果最好,该滴灌带布置方式下棉花根区含盐量较利于棉花生长;T2处理棉花农艺性状及品质相对优于T1和T3;相比T1和T3,2017和2018年T2模式下棉花产量分别增加了6.15%、11.0%和8.1%、12.3%,WUE分别增加17.4%、22.7%和20.9%、22.8%,对新疆干旱地区而言,考虑节水和提高棉花产量推荐采用T2滴灌带布置模式进行机采棉种植。该研究对促进棉花生长、产量、品质及提高劳动效率,确保中国新疆区域棉花生产健康可持续发展具有重要意义。

水肥耦合对滴灌骏枣产量及果品等级的影响研究

【目的】探索南疆滴灌骏枣的产量及骏枣等级比例对水肥耦合的响应规律,为当地骏枣生产提供节水节肥优质的水肥配比模式。【方法】研究对象为南疆典型自压灌区昆玉市224团10 a成龄骏枣,参考当地生产实践,以灌水量770 mm、施肥量1125 kg/hm^(2)为对照,采用水(W1:540 mm,W2:630 mm,W3:720 mm)、肥(F1:562.5 kg/hm^(2),F2:810 kg/hm^(2),F3:1080 kg/hm^(2))双因素三水平试验,运用二元回归方程及归一化处理方法。【结果】灌水量对灌溉水分利用效率(IWUE)和骏枣单果质量、纵横径、等级比例影响均达到显著性水平(P<0.05),对产量影响达到极显著水平(P<0.01)。施肥量对骏枣等级比例影响达到显著性水平(P<0.05),对肥料偏生产力(PFP)、单果质量、纵横径影响达到极显著水平(P<0.01)。水肥交互作用对骏枣产量、IWUE、PFP、骏枣等级比例(除四级果率外)影响均达到极显著水平(P<0.01)。骏枣产量、IWUE均为W2F3处理最高,与CK具有显著性差异(P<0.05)。骏枣单果质量、纵横径为W2F2处理最优。骏枣特级、一级、三级与四级果率均为W2F2处理最优,W2F2处理除了在一级果率中与W2F3处理差异不显著,其余等级果率均具有显著性差异(P>0.05)。【结论】适宜水肥配比量是提高骏枣产量、外观品质、果品等级比例的关键因素。通过分析不同水肥配比与产量、骏枣等级比例数学模型,综合考虑骏枣提质增效目标,提出适宜水肥配比区间为灌水量(639.21~642.85mm),施肥量(N 374.38~384.02 kg/hm^(2)、P2O5187.19~192.01 kg/hm^(2)、K2O 280.79~288.02 kg/hm^(2))。