半干旱区坡耕地抗旱保水技术集成对大豆水分利用效率的影响

黑龙江省西部半干旱区属典型的东北黑土区,为我国重要的商品粮生产基地。然而,由于地形地貌、气候条件的复杂多变,降水的时空分布不均,以及人类的长期干预造成的生态环境的改变,致使该区连年干旱。干旱及水土流失已成为制约该区经济发展的主要因素。根据黑龙江省西部半干旱区的自然特点,选取了坐水播种和苗期补灌2种抗旱节水技术和垄向区田保水技术,在甘南县国家863试验基地研究了该3项技术的集成对WUE的影响。结果表明,该项技术可以显著的提高大豆的WUE值。     

保水缓释肥料保水性能及养分释放特性

为了明确添加水溶性保水剂(羧甲基纤维素钠、聚丙烯酰胺、聚丙烯酸钠)肥料的保水缓释效果,利用圆盘造粒工艺制备了保水缓释肥料,通过土壤培养和土柱淋溶试验,研究了保水缓释肥料在土壤中的保水性能和养分缓释效果。结果表明:3种保水缓释肥料均具有一定保水性和养分缓释效果,随保水缓释肥料用量增加,土壤最大持水率逐渐增加,土壤水分蒸发率逐渐减小;其中,以添加聚丙烯酸钠的保水缓释肥料保水性能和养分缓释效果最佳,首次淋溶后氮磷钾养分释放率较普通肥料分别减少了50.38%、55.74%、48.37%,当肥料添加量为2%时,土壤最大持水率较纯土壤提高了43.28%,培养至30 d土壤水分蒸发率较纯土壤降低了22.86%。     

保水剂的吸水和保水特性研究

保水剂的吸水和保水特性的研究结果表明，保水剂在去离子水、蒸馏水、泥水中的吸水倍率分别为300倍、192倍、130倍。保水剂的吸水能力随溶液中盐浓度的升高而下降，当盐浓度超过0．5％以上时，保水剂的吸水能力不再下降；在相同的离子浓度下，保水剂在含Ca^(2 )离子溶液中的吸水能力低于含K^ 离子的溶液。溶剂的pH值为7时，保水剂的吸水倍率最大；其pH值小于或大于7都会使保水剂的吸水能力下降。土壤中掺保水剂可以有效地抑制土壤中的水分蒸发，使土壤的总蒸发量下降2．94％～9．36％，致使土壤含水率在实验末期比对照增加20．1％～69．5％。保水剂用量越大，效果越好。     

保水处理对橡胶树叶片生理特性及胶乳产量的影响初探

以橡胶树品种‘云研77-4’为试材,采用盖膜、盖草和添加保水剂的处理方式,以常规管理（不覆盖）为对照,通过田间比较试验研究3种保水处理对橡胶树全年中不同生长阶段叶片生理特性及胶乳产量的影响。方差分析结果表明：盖膜、盖草和添加保水剂在干季均显著提高了土壤含水量,并显著影响了橡胶树叶片的可溶性蛋白（SP）、脯氨酸（Pro）、可溶性糖（SS）和蔗糖（Suc）含量;3种保水处理处理均不同程度的提高了胶乳产量。主成分分析结果表明：提取3个主成分,累计贡献率为84.8%,说明前3个主成分可反映原始变量的绝大部分信息;根据综合得分,各保水处理优劣顺序依次为：添加保水剂、盖草、盖膜、对照;橡胶树全年中不同生长阶段叶片生理指标综合表现优劣顺序依次为：12月、3月、1—2月、11月、6月、7月、9—10月、8月、5月、4月。因此,从本研究结果可以推断,各保水处理均能有效缓解季节性干旱对橡胶树生长的不利影响,在生产上可以根据橡胶树全年中不同生长阶段叶片生理指标综合表现选择合理的割胶时期。     

可耕种坡地的土壤水力参数非均质性变化

The spatial variations of the soil hydraulic properties were mainly considered in vertical direction. The objectives of this study were to measure water-retention curves, θ（ψ）, and unsaturated hydraulic conductivity functions, K（ψ）, of the soils sampled at different slope positions in three directions, namely, in vertical direction, along the slope and along the contour, and to determine the effects of sampling direction and slope position of two soil catenas. At the upper slope positions, the surface soils （0-10 cm） sampled in the vertical direction had a lower soil water content, 0, at a certain soil water potential （-1 500 kPa 〈 ψ 〈 -10 kPa） and had the greatest unsaturated hydraulic conductivity, K, at ψ 〉 -10 kPa. At the lower slope positions, K at ψ〉 -10 kPa was smaller in the vertical direction than in the direction along the slope. The deep soils （100 110 cm） had similar soil hydraulic properties in all the three directions. The anisotropic variations of the hydraulic properties of the surface soils were ascribed to the effects of natural wetting and drying cycles on the structural heterogeneity. These results suggested that the anisotropy of soil hydraulic properties might be significant in influencing soil water movement along the slope and need to be considered in modeling.     

Water-Retention Characteristics and Available Water Capacity in Three Cropping Systems of Lower Indo-Gangetic Alluvial Plain

This study was conducted in Chinchura-Mogra and Polba-Dapur Blocks of Hugli District, West Bengal to determine the changes in cropping systems on water-retention characteristics (WRC) and available water capacity (AWC) and their relations with other soil properties. In the present study, three sites contained adjacent cropping systems of banana and mango orchard, paddy–paddy, and paddy–potato–vegetables were selected. Soil samples were collected from depths of 0–30 and 30–60 cm in three representative sites of each cropping system with three replications guided by land use and soil map of study area. Analysis of variance was performed to compare the impact of cropping systems on available water content and water-retention characteristics. The mean clay content was greater both on the surface (61.70%) and in the subsurface (55.06%) in the soils under the paddy–paddy cropping system than banana and mango orchard and paddy–potato–vegetable cropping systems. Paddy–potato–vegetables cropping system (0.55%) has lower soil organic carbon compared to the banana and mango orchard (0.63 %) and paddy–paddy cropping system (0.65%) at 0–30 cm deep, whereas no significant difference in soil organic carbon was recorded in 30–60 cm deep. The results of available water capacity indicated that paddy–paddy cropping system recorded lower available water capacity at both ranges of depth. Available water capacity is significantly positively correlated with silt and organic carbon. The results of water-retention studies indicated that 75 and 85% of available water was removed from the soil of paddy–potato–vegetable cropping system by 0.5 M Pa at 0–30 and 30–60 cm deep, respectively, whereas only 56–62% of available water was removed by 0.5 M Pa in the other two systems. The results show that the paddy–potato–vegetable cropping system is more vulnerable to moisture stress during drought periods.     

温度及矿化度对土壤持水性能的影响

采用离心机法测定了不同矿化度(1、3、5、10g/L)的NaCl和Na2SO4溶液在不同温度条件下(5、10、20、30℃)对土壤水分特征曲线及其van Genuchten方程参数的影响。结果表明,温度与θs、α均呈现显著的负相关,相关系数分别为-0.83、-0.99;θs与α呈极显著的正相关关系,与n呈极显著的负相关关系,α与n呈极显著的负相关关系。溶液的盐分类型对土壤水分特征曲线的影响在不同的吸力段影响不同,在近饱和段影响比较明显,且对参数α值也有显著影响,其中Na2SO4的影响较NaCl明显。溶液矿化度对土壤水分特征曲线参数(θs,α,n)的影响均不显著。     

Groasis Waterboxx造林技术在沙丘的造林效果

[目的]为解决干旱荒漠区沙丘造林成活率低的技术难题,从荷兰Groasis引进Waterboxx保水、节水造林器及技术,并分析其应用效果。[方法]在甘肃省民勤县流动沙丘和半固定沙丘上,用梭梭、花棒、柠条锦鸡儿、柽柳等固沙植物进行造林试验,采用直观统计观测的方法,研究Groasis Waterboxx在沙丘上造林后的风蚀、温度、保水和苗木成活率情况。[结果](1)春季用Groasis Waterboxx沙丘造林技术,流动沙丘风蚀情况比半固定沙丘严重2.0~6.0倍,造林效果差;从沙丘迎风面不同部位的风蚀情况来看,流动沙丘和半固定沙丘总体均表现为:顶部中部底部;(2)Groasis Waterboxx沙丘造林技术在高温季节能有效降低苗木根际土壤地温近50%,保护苗木免受高温灼伤,促进苗木生长;低温季节还能有效保持根际表面地温在5℃左右,防止苗木遭受低温冻害;(3)Groasis Waterboxx沙丘造林技术能使苗木周边0—40cm表土层含水量长期保持在6%~12%,保证苗木成活期的水分持续供给;(4)Groasis Waterboxx沙丘造林技术能显著提高苗木成活率30%~60%。[结论]Groasis Waterboxx沙丘造林技术在半固定沙丘造林效果优于流动沙丘,能够显著提高苗木成活率。     

抗旱保水剂对小麦生长的作用研究

研究了保水剂拌种和基施对小麦生长的影响。结果表明：两种方法均能促进小麦返青及中后期生长，株高、整齐度、叶面积等性状显著优于对照，穗粒数、千粒重比对照增加10％-15％，产量增加17％以上；保水剂基施具有明显的持效性，第二季小麦的土壤含水量比对照提高了0．8～4．6个百分点，两季小麦共增产27．8％。     

地膜覆盖对椪柑保水效应的影响

通过两年的椪柑大区试验,研究了地膜覆盖对5年生硬芦和4年生枳砧椪柑的保水效应.结果表明,不同覆盖处理的保水效果明显,且以稻草加生物降解麻地膜(SR61-1)处理保水效果最佳,土壤含水量达到84.66%,比对照提高了128.8%.另外,地膜覆盖还能显著提高椪柑树体生长,有利于枝梢生长和提高椪柑产量,但对椪柑果实品质无明显影响.