【作者】 王在敏；

【导师】 靳孟贵；

【作者基本信息】 中国地质大学 ， 水文学及水资源， 2013， 博士

【摘要】 干旱缺水是一个世界性的问题,在中国西北干旱地区尤为明显,水资源供需矛盾成为干旱地区农业生产和经济发展的主要限制因素之一。针对水资源紧缺问题,西北干旱区广泛分布的微咸水越来越多地被应用于灌溉棉花等作物。微咸水中盐分(包括微量元素)作为营养物质一定程度可促进棉花生长并增产,但微咸水灌溉不当,可能导致土壤盐碱化。探明微咸水膜下滴灌土壤水盐热的分布和迁移规律,制定适宜的棉花微咸水灌溉制度和合理施用肥料对于西北干旱区农业发展具有重要的理论和实际意义。本文通过三年田间试验和一年盆栽试验,探寻棉花与水盐和营养元素的相互关系。通过优化作物布局、灌溉制度和田间管理建立干旱区微咸水膜下滴灌棉花-水-溶质优化系统。2008-2010年,在新疆巴音郭楞蒙古自治州水利管理处水利部重点灌溉试验站开展田间试验。采用一膜双管四行种植方式种植棉花,设计2个对照、4个轮灌和4个调亏灌溉,共10个处理,每个处理3个重复。耕种前取田间原状土样测定土壤干容重及岩性,并获取不同深度土壤水分特征曲线；利用围框法测定试验田田间持水率；试验开始利用负压计监测土壤剖面基质势；利用土壤水分中子仪监测各处理不同位置不同时间土壤剖面含水率；利用Stevens Hydra Probe土壤传感器监测对照处理不同深度不同时间土壤剖面含水率、电导率和温度；利用地温计监测对照处理不同位置不同深度不同时间土壤剖面温度；适时取土壤样测定土壤电导率EG1:5棉花种植开始,适时监测其生长情况及产量。2012年3月到10月,在中国科学院武汉植物园开展盆栽试验,采用无土栽培方式,设计30个正交处理。每个处理3个重复,包括6个NaCl浓度和5个Mn浓度。试验开始适时监测棉花生长情况。发芽之后130天收获棉花,测定棉花各组织干重；消解之后利用ICP-OES (ICAP6300, Thermo Scientific, England)测定棉花各组织的14种元素含量,主要包括了B、Ca、Cu、Fe、K, Mg、Mn、Na和Zn等元素。采用多种数学方法分析和SPSS、Matlab和Surfer等数学工具处理以上试验数据,并结合数值模拟分析了微咸水膜下滴灌棉田土壤水分、盐分及热的分布和迁移规律,以及棉花各生育期对灌溉水质及土壤水盐状态的响应；建立了考虑棉花生育期的水盐生产函数；探讨了适宜的微咸水膜下滴灌灌溉制度及其长期效应；分析了微量营养元素Mn对棉花盐害的协同与拮抗机理；探寻微咸水膜下滴灌棉花-水-溶质优化系统。得到主要结论如下：(1)微咸水膜下滴灌条件下,滴头灌水量越大,土壤湿润锋扩展距离越大。灌水定额越大,土壤剖面含水率越快呈周期变化。相同灌水定额,随着灌水次数增加,土壤剖面含水率最终呈周期变化。土壤初始含水率影响土壤剖面水分运移。初始含水率越小,剖面含水率增加越迟缓。不同初始含水率条件,一次灌水结束,随时间同一深度含水率趋于相同。随灌水定额增加,初始含水率对剖面含水率变化的影响减小。随深度增加,初始含水率的影响增大。0-60cm土壤含水率受蒸发蒸腾的显著影响；土壤剖面含水率随灌水波动。对照处理和轮灌处理棉花根区土壤剖面含水率随时间变化差异不大。调亏各处理土壤剖面含水率受灌水量影响明显,根层土壤含水率有差异。所有处理土壤剖面含水率满足棉花根系吸水需求。(2)膜下滴灌条件下,微咸水灌溉会给根层土壤带入盐分,使根层土壤电导率EC15增加。微咸水膜下滴灌湿润锋边缘及膜间地表土壤容易积累盐分。棉花花铃期灌水量增大,淋洗分数增加,根层土壤盐分有所减小,电导率EC1：5减小。土壤剖面初始含盐量显著影响盐分迁移,初始含盐量较高时,试验条件的微咸水淋洗土壤盐分。试验各处理之间土壤盐分变化差异较大。微咸水膜下滴灌土壤剖面盐分迁移转化受初始含盐量、灌水量和灌水水质的显著影响,不同的初始条件需要配置不同的灌水量和水质,确定是否需要淋洗根层土壤盐分,保证棉花不受盐分胁迫。(3)微咸水膜下滴灌条件下,0-40cm土壤温度随气温周期波动。40cm以下土壤温度周期变化不明显,受气温影响减小。一个变化周期,即一天内,覆膜和未覆膜地温0：00时到12：00时差异不大；12：00时开始到第二天0：00时,0-15cl’n深度覆膜处地温明显高于未覆膜处地温；深度大于15cm,土壤地温受覆膜影响减小。覆膜处棉花覆盖位置(窄行)与无棉花覆盖位置(宽行)地温0：00时到12：00时差异不大；12：00时开始到第二天0：00时,0-15cm深度宽行地温明显高于窄行地温;深度大于15cm,土壤地温受棉花覆盖影响减小。土壤温度影响土壤水分迁移,影响棉花根系吸水。土壤温度受气温、地表覆盖等影响,利用覆膜技术提高地温促进棉花发芽有效且可行。(4)微咸水膜下滴灌条件下,当灌溉微咸水电导率EC为3.35-4.86dS/m时,微咸水中的盐分作为营养成分,可使棉花增产；在棉花耐盐性较差的生育前期灌淡水其他生育期灌微咸水的轮灌处理棉花产量最高。花铃期灌淡水其他生育期灌微咸水的轮灌处理2008-2010三年里产量波动最小。棉花各生育期对水分胁迫的敏感性排序是：花铃前期>苗期>蕾期>花铃后期；对盐分胁迫的敏感性排序是：花铃后期>蕾期>苗期>花铃前期。当灌溉水NaCl浓度大于35mmol/L,电导率EC大于6.11dS/m时,灌溉水中盐分抑制棉花营养生长(株高,根和茎干重),促进棉花生殖生长。微咸水膜下滴灌棉花蕾期对土壤水盐的敏感系数九1为-0.249,花铃期敏感系数k为0.887。(5)棉花播前利用淡水洗盐,生育期内应用微咸水膜下滴灌。通过计算,一个耕种年,播前灌水283m3/亩,蕾期灌水39m3/亩,花铃期424m3/亩；计算灌水量根据理想条件,不利于节水。调整计算量后的灌溉制度为：播种前灌水量为102m3/亩(15cm)；苗期不灌水；蕾期灌水量为27m3/亩(滴头额定流量2.2L/h,灌水时长4h),灌水间隔15天,灌水1次;花铃期总灌水量为297m3/亩,次灌水量为29.7m3/亩(滴头额定流量2.2L/h,灌水时长4.6h)。利用识别验证成功的数值模型评价调整后的灌溉制度,不改变种植结构,模拟10年土壤水盐热迁移。结果显示,调整后的灌溉制度满足棉花各生育期根系吸水需求；各生育期土壤溶液浓度低于棉花耐盐限值；10年后棉花根层土壤没有出现积盐。通过计算并调整后的灌溉制度为适宜的灌溉制度,该灌溉制度满足棉花需水和耐盐。(6)当灌溉水中NaCl浓度为15-25mmol/L时,棉花营养生长情况最好。灌溉水中NaCl与Mn对棉花生长和产量不存在交互作用,表现相互拮抗的作用关系。营养元素Ca、Mg、Na、 B、Mn和Zn在棉花叶中含量高于其他组织；K元素在铃中含量高于其他组织;而元素Cu和Fe不易迁移,富集在棉花根部。微咸水膜下滴灌,灌溉水中NaCl含量明显影响棉花营养元素吸收和分布。(7)推荐试验区棉花灌溉制度及施肥配置为：播种前漫灌淡水,灌水量为102m3/亩(15cm),施底肥(尿素：30kg/亩,磷酸二铵：10kg/亩,45%硫酸钾：50kg/亩,农家肥：1m3/亩,微量元素肥：0.5kg/亩),苗期不灌水,蕾期灌水量为27m3/亩(滴头额定流量2.2L/h,灌水时长4h),灌水间隔15d,灌水一次,灌水过程中追肥(尿素：10kg/亩,磷酸二铵：2kg/亩,45%硫酸钾：15kg/亩,微量元素肥：0.1kg/亩,花铃期总灌水量为297m3/亩,次灌水量为29.7m3/亩(滴头额定流量2.2L/h,灌水时长4.6h),花铃期第3、6、9次灌水追肥(追肥配置为：尿素：12kg/,磷酸二铵：3kg/亩,45%硫酸钾：10kg/亩,微量元素肥：0.2kg/亩)。更多还原

【Abstract】 The shortage of water is a worldwide problem, especially in the arid area in northwest of China. The contradiction between supply and demand of water resources becomes one of the key problems to confine the agricultural and economic development for arid area. According to water shortage problem, the brakish water distributed widely in northwest arid area of China is increasingly applied for irrigation cotton and other crops. Salinity (include trace elements) in the brackish water as nutrients can promote cotton growth and its yield. But, using brackish water without appropriate method would result in salinization of the soil. It is important for theoretical and partical significance to prove up soil water, salt and heat distribution and transfer rules on the condition of drip irrigation under membrane with brackish water, and to make proper irrigation regime and fertilization for cotton in northwest China.Three years field experiments and one year pot experiments were conducted to research the relationship of cotton, water, salts and nutrient elements for establishing the optimal system of cotton-water-solute under the mulched drip irrigation with brackish water.The experiments were carried out in cotton fields in Water Conservancy Administration Irrigation Experimental Station of Ministry of Water Resources located in Bayingolin Mongol Autonomous Prefecture of Xinjiang between2008and2010. Two irrigation lines were installed for each four rows of cotton. The experiments include2control irrigation treatments,4alternative irrigation treatments and4deficit irrigation treatments in three replicates randomly. Undisturbed soil samples were sampled to measure the soil dry density and lithology. Then, the soil moisture characteristic curves at various depth were obtained. The field soil moisture capacity was measured after the basin irrigation treatments. The soil matric potential were monitored in-situ using Depressimeter; the soil water content were monitored using; and The soil water content, EC and temperature were monitored in-situ using Soil Moisture Neutron Instrument, Stevens Hydra Probe soil sensors and Geothermometer. Soil were sampled at different time to measure soil electric conductivity EC1:5. Cotton growth were monitored timely and the yield were measured after harvest. Pot experiments were conducted in a greenhouse at Wuhan Botanical Garden. Chinese Academy of Sciences from March to October2012. The pot experiments used soilless culture and included30orthogonal tests with6NaCl levels and5Mn levels in three replicates randomly. The cotton growth were monitored timely and harvested130days after germination. Cotton dry weight were weighed. And14elements contents in cotton were measured after acid digestion, such as B, Ca, Cu, Fe, K, Mg, Mn, Na, Zn and so on.Many mthematical methods were used to analyze experimental data. Mathematical tools, such as SPSS, Matlab and Surfer were used to process experimental data. And numerical simulation was used to assist the field experiments. The specific obejectives were to prove up soil water, salt and heat distribution and transfer rules under mulched drip irrigation with brackish water in cotton field; to analyze the effects of irrigation water-salt and soil water-salt on cotton; to build cotton-water-salt production function considering growth season; to make proper mulched drip irrigation regime with brackish water and evaluation the long time effect of this regime; to research on the combined effect of salinity and Mn on cotton; to research the optimal system of cotton-water-solute in field under mulched drip irrigation with brackish water. Then, the resuts may be concluded as fllows.(1) Under mulched drip irrigation with brackish water, more irrigation quantity, wetting front expanded farther; more irrigation quantity, soil water content variation became periodic change faster; soil water content eventually varied cyclically with the increasing of irrigation times at the same irrigation ration. Soil water content variation was influenced by initial water content; smaller initial water content, the soil water content increased more slowly; for different initial water content, the soil water content approached to similar at the same depth with the time; the effect of initial water content on the soil water content variation reduced with the increasing of irrigation ration; the effect of initial water content on the soil water content variation increased with the depth. Soil water content at0-60cm depth was influenced significantly by evapotranspiration; soil water content fluctuated with irrigation. The soil water content between control and alternative irrigation treatments were close; the soil water content of deficit irrigation treatments were influenced by irrigation quantity significantly and were different for different treatments in root zone. The soil moisture in root zone of all the treatments could meet the cotton root water uptake.(2) Under mulched drip irrigation, saline irrigation would take salt into soil and make the soil electric conductivity EC15increase; the drip irrigation wetting font and naked soil surface were easy to be accumulated salt. Irrigation quantity increased in cotton flowering-belling stage, so the leaching fraction increased. And soil salt in root zone decreased, then, soil EC15decreased. Initial salinity significantly influenced soil salt migration; when the initial salinity was higher than irrigation salinity, saline irrigation was leaching irrigation; the soil salt veried differently for different treatments. The soil salt transport was influenced significantly by initial salinity, irrigation quantity, irrigation water quality and so on. Therefore, taking initial condition into account, irrigation water quantity and quality’needed to be adjusted to meet the cotton salt tolerance. (3) Under mulched drip irrigation with brackish water, soil temperature at0-40cm depth fluctuated periodically with ari temperature; soil temperature under40cm veried little and were influenced unobviously by air temperature. During one variation period, namely one day, membrane mulched soil temperature was the same with naked soil temperature at0:00to12:00; mulched soil temperature at0-15cm depth were higher than that of naked soil at12:00to24:00. On the condition of mulching membrane, cotton mulching soil temperature at0-15cm depth were lower than that of no cotton mulching at12:00to24:00during a variation period but they were close at0:00to12:00. The soil temperature under15cm was influenced little by mulching membrane or cotton. Soil temperature affected soil water transport and root water uptake; and it was influenced by air temperature, coverings and so on; mulching membrane to increase soil temperature was beneficial for cotton germination.(4) Under mulched drip irrigation with brackish water, when irrigation water electric conductivity ranged from3.35to4.86dS/m, the salt in water as nutrient promoted cotton yield. Cotton yield of treatment irrigated fresh water in cotton early stages that was poor salt resistance but brackish water in late stages was the highest; the least yield fluctuation were observed in the treatment irrigated fresh water in cotton flowering-belling stage but brackish water in other stages at2008to2010. Crop sensitivities to water stress during the different growth stages ranged from early flowering-belling (most sensitive)> seedling> budding>late flowering-belling (least sensitive), while sensitivities to salt stress ranged from late flowering-belling> budding> seedling> early flowering-belling. When the irrigation water NaCl concentration was greater than35mmol/L, conductivity EC was greater than6.11dS/m, irrigation water salinity inhibited the cotton vegetative growth (height, root and stem dry weight) and promoted the cotton reproductive growth. Under mulched drip irrigation with brackish water, the sensitive coefficient (ki) of cotton budding stage to soil water-salinity was-0.249and that (k2) of flowering-belling was0.887.(5) Fresh water was used to leach salinity before sowing and mulched drip irrigation with brackish water was used during growth season. Based on calculation, for a cotton growth season, irrigation water quantity was283m3/Mu befroe sowing,39m3/Mu during budding stage, and424mJ/Mu during flowering-belling stage. Irrigation water quantity calculated on the basis of ideal conditions was not benefit for water conservation. Adjusted amount was:102m3/Mu (15cm) before sowning, no irrigation during seedling stage,27m3/Mu during budding stage (dripper discharge was2.2L/h, and rrigation duration was4hours) with15d irrigation frequency,297m3/Mu during flowering-belling stage with29.7m3/Mu for ecach irrigation (discharge rate was2.2L/h, and rrigation duration was4.6hours). Soil water-salt-heat model was verified using experimental data; the model results indicated that under the same planting structure and irrigation regime, the irrigation regime could meet the water demand of cotton growth and the soil salinity is lower than cotton salt tolerance during the growth season; salinity would not accumulate in the root zone during the next10years. The final adjusted irrigation regime was proper which cound meet water demand and salt tolerance of cotton.(6) When the NaCl concentration in the irrigation water was15-25mmol/L, cotton vegetative growth was the best. Interactive effect on cotton growth and yield between NaCl and Mn in the irrigation water was not observed but antagonistic effect was observed. Contents of nutrient elements, Ca、Mg、Na、B、Mn and Zn, in cotton leaves were higher than other organizations; contents of nutrient element K in cotton bolls were higher than other organizations; and nutrient elements, Cu and Fe were not so movable that they were easy to accumulate in roots. Under mulched drip irrigation with brackish water, NaCl concentration levels in the irrigation water affected uptakes and distributions of nutrient elements in cotton.(7) The irrigation regime and fertilization recommended was:102m3/Mu (15cm) before sowning (urea:30kg/Mu, diammonium phosphate:10kg/Mu, compound fertilizer with45%potassium sulfate:50kg/Mu, farm manure:1m3/Mu, trace element fertilizer:0.5kg/Mu), no irrigation during seedling stage,27m3/Mu during budding stage (dripper discharge was2.2L/h, and rrigation duration was4hours) with15d irrigation frequency and additional fertiliazation (urea:10kg/Mu, diammonium phosphate:2kg/Mu, compound fertilizer with45%potassium sulfate:15kg/Mu, trace element fertilizer:0.1kg/Mu),297m3/Mu during flowering-belling stage with29.7m3/Mu for ecach irrigation (discharge rate was2.2L/h, and rrigation duration was4.6hours) and additional fertilization on the third, sixth and ninth irrigation (each fertilization was as following:urea:12kg/Mu, diammonium phosphate:2kg/Mu, compound fertilizer with45%potassium sulfate:15kg/Mu, trace element fertilizer:0.1kg/Mu).更多还原