膜下滴灌条件下不同土壤盐度和施氮量对棉花生长的影响

通过盆栽试验研究了膜下滴灌条件下不同土壤盐度水平和施氮量对棉花生长的影响。研究结果表明低盐度处理,随着施氮量的增加棉花株高显著增加;而在土壤盐度较高的条件下棉花株高则随着施氮量的增加显著降低。棉花籽棉和总干物质重随土壤盐度的增加显著降低,合理的施用氮肥可显著提高籽棉重和总干物质积累量。棉花的氮素吸收量受盐分、施氮量和盐氮交互作用影响显著。随着土壤盐度的增加,棉花氮素吸收量显著降低。在低盐度条件下,增加氮肥施用量可显著提高棉花的氮素吸收量;中量盐度下,适量的氮肥施用可显著提高棉花的氮素吸收量,但施用量过大并不能增加棉花的氮素吸收量;高盐度条件下,盐分是限制棉花生长和氮素吸收的主要因素,施用氮肥对棉花的氮素吸收量无显著影响。     

磁化水滴灌对土壤盐分及玉米产量品质的影响

以玉米为对象,研究不同强度磁化水灌溉对玉米产量、品质及生长状况的影响,并结合土壤盐分和养分的变化情况,探寻磁化水玉米增产提质的最佳磁化强度。结果表明:磁化水灌溉能够有效提高土壤盐分淋洗效率,加速对盐分的淋洗作用,磁化水灌溉可有效促进玉米产量的增加及品质的提升,以1 200~2 400 Gs效果最佳。磁化水灌溉使玉米产量增加了4%~16.2%。磁化处理的可溶性糖、蛋白质及淀粉含量分别较CK提升了1.4%~38.2%、11.7%~39.6%、9.6%~12.8%。这些结果不仅表明磁化水有效地促进玉米植株的生长及产量、品质的提升,也可以作为一种技术方法大面积推广。     

滴灌树状管网水力计算的有限元法

大型滴灌系统的水力计算必须借助计算机用管网分析技术来解决,若使用普通微机,占用的内存的数目可能成为主要的障碍。本文提出一种节省内存,计算方法简便的有限元法,使3000～6500高阶矩阵问题能在普通个人计算机上求解。作者对有限元法中的单元离散、非线性问题的线性化、总体方程构造、元素储存以及求解等一系列问题都提出了新的见解。     

Poinsettia growth,tissue nutrient concentration,and nutrient uptake as influenced by nitrogen form and stage of growth

Growth, development, and uptake of essential nutrients as influenced by nitrogen (N) form and growth stage was evaluated for ‘Freedom’ poinsettias (Euphorbia pulcherrima Willd. Ex Klotz.). Treatments consisted of five nitrate (NH₄ ⁺):ammonium (NO₃ ^‐) ratios (% NH₄ ⁺:% NO₃ ^‐) of 100:0, 75:25, 50:50, 25:75, and 0:100 with a total N concentration of 150 mg L^‐1. Plants were grown in solution culture for ten weeks under greenhouse conditions. Nutrient uptake data was combined into three physiological growth stages. Growth stage I (GSI) included early vegetative growth (long days). Growth stage II (GSII) began at floral induction and leaf and bract expansion (short days). Growth stage III (GSIII) was from visible bud through anthesis and harvest. Dry weights for all plant parts and height increased as the ratio of NO₃ ^‐ increased. Leaf area and bract area were maximized with 25:75 and 50:50 N treatments, respectively. Nitrogen treatments significantly affected foliar nutrient concentrations with calcium (Ca⁺⁺) and magnesium (Mg⁺⁺) being highest when NO₃ ^‐ was the predominant N form. Uptake of each macronutrient was averaged across all treatments and divided into physiological growth stages (GS) to identify peak demand periods during the growth cycle. The greatest uptake of NH₄ ⁺ and NO₃ ^‐ was from the early vegetative stage to floral induction (GSI). Phosphorus (P), potassium (K⁺), and Mg⁺⁺ uptake were greatest from floral induction to visible bud (GSII) and Ca⁺⁺ uptake remained relatively unchanged through GSI and GSII. Uptake was lowest for all nutrients from visible bud to anthesis (GSIII). Results from this study clearly indicate that peak demand periods for macronutrient uptake existed during the growth cycle of poinsettia.     

Sensitivities of Stress Indicators for Available Soil Water and Its Salinity and for Sorghum Leaf Water Potential under Drip Irrigation

Abstract

The impact of two input amounts, two frequencies, and three salinity levels on the temporal sensitivity of the stress indicators, available soil water (K _W ), its salinity (K _S ), and leaf water potential of sorghum [Sorghum bicolor (L.)] grown in dune sand in a plastic greenhouse were investigated. The K _W for the irrigation input amount equivalent to one‐half of an open pan on a daily basis (EP0.50‐1) ranged from 0.32 to 0.51 compared with 0.51 to 0.98 for the 100% of open‐pan irrigation input on daily basis. The corresponding K _S ranges were 0.50 to 0.98 (EP1.00‐1) and 80 to 0.98 for K _s . The K _W for the three increasing salinity levels (S‐1, S‐2, and S‐3) ranged from 0.68 to 0.96 for S‐1, 0.58 to 0.90 for S‐2, and 0.43 to 0.89 for S‐3, respectively, and from 0.85 to 1.00 for the control. The corresponding K _S ranges were 0.89 to 0.98, 0.70 to 0.96, 0.49 to 0.70, and 1.00 to 1.00, respectively. The LWP ranges for the three salinity levels were ?1.70 to ?0.70 for S‐1, ?2.50 to ?1.20 for S‐2, ?2.90 to ?1.60 for S‐3, and ?0.70 to ?0.20 MPa for the control. The time series statistical parameters mean, median, coefficient of variation (CV), and the 20th percentile values (PC20), assessed to discriminate the temporal sensitivity of the stress indicators indicated that CV and PC20 are equally better than median, which in turn is better than mean. Sorghum grain yield depended on irrigation input amount and schedules, leaf water potential (LWP), and the interaction involving K _W and K _S (R² _adj 0.71 to 0.85). The temporal sensitivity of the stress indicators K _W , K _S , and LWP indicated that EP1.00‐1 provided the least‐risk irrigation option with regard to water and salinity stress in relation to sorghum grain yield.     

膜下滴灌条件下滴头流量和水质对水分运移及蒸散规律影响研究

通过土柱模拟试验,从不同滴头流量、滴水定额和滴灌水质三个方面,研究了不同滴头流量条件下水分运移规律以及不同滴头流量、水质对棉花蒸散特性的影响。研究表明,相同滴水定额条件下,大滴头流量有利于水分的水平运移,湿润锋曲线呈椭圆型,小滴头流量利于水分的垂直下渗,湿润锋更接近于圆形;苗期(6月份)和吐絮期(10月份)0.3 L h-1滴头流量处理蒸散量小于0.8 L h-1,只为后者的78.3%,而在7～9月份,小滴头流量滴灌蒸散量则明显大于大滴头流量。微咸水滴灌条件下,2.47 g L-1微咸水灌溉对蒸散量没有影响,3.50 g L-1咸水灌溉则有明显的抑制作用,整个生育期内咸水灌溉棉花蒸散总额比淡水和微咸水灌溉减少8.0%。     

不同灌溉方法对保护地土壤有机质及氮素影响的研究

分层采集连续7年分别用渗灌、滴灌和沟灌灌溉的保护地0～80cm土层土壤样品,测定有机质、全氮及无机态氮和有机态氮含量,研究灌溉方法对土壤氮素形态及其数量剖面分布的影响。结果表明,三种灌溉处理0～80cm剖面土壤有机质含量变化范围为8.47～36.48 g kg-1,渗灌与滴灌有机质剖面分布相似,二者与沟灌差异较大;沟灌除30～40cm层次有机质含量低于渗灌和滴灌外,其它层次有机质含量均高于渗灌和滴灌处理。土壤全氮含量变化范围为0.72～3.97 g kg-1,在0～20cm土层不同灌溉方法之间差异显著,渗灌最大,沟灌次之,滴灌最小。无机硝态氮、铵态氮含量的变化范围分别为19.16～1442.06 mg kg-1和0～15.28 mg kg-1,在0～20cm土层各处理之间差异较为明显,以渗灌最大,沟灌次之,滴灌最小。有机态氮含量的变化范围为683.79～2512.87 mg kg-1,各处理之间的差异主要表现在0～30cm土层,其中0～10cm土层以渗灌处理有机态氮含量最高、沟灌次之,滴灌最低,10～30cm沟灌处理有机态氮含量却高于渗灌和滴灌处理。     

不同灌溉方式对茄子栽培土壤微生物数量和土壤酶活性的影响

试验以"紫光"茄子为试材,设膜下滴灌和常规畦灌两个处理,研究不同灌溉方式对设施茄子栽培土壤微生物和酶以及茄子产量和品质的影响。结果表明,滴灌能显著提高土壤中细菌和放线菌的数量,较畦灌分别高45.25%和79.48%;显著增大B/F值,使土壤向病害发生轻的"细菌型"土壤转化。滴灌能显著提高蔗糖酶和碱性磷酸酶活性,较畦灌分别高47.05%和24.00%;滴灌处理0~40 cm土层土壤脲酶和过氧化氢酶活性显著比畦灌高,增幅分别为49.33%~64.38%和16.69%~30.08%。滴灌能显著提高茄子收获前期产量,改善果实品质,果实的可溶性糖和Vc含量分别较畦灌处理提高5.81%和4.75%。因此,膜下滴灌是有效改善土壤环境、提高茄子产量和品质的灌溉方式。     

内陆干旱区不同灌溉制度对盐碱地滴灌土壤盐分离子分布的影响

通过田间试验研究覆膜滴灌条件下不同灌溉制度对土壤盐分分布的影响。试验通过控制滴头正下方20 cm处的土壤基质势下限进行灌溉,共设5个水平的土壤基质势处理:-5 kPa(S1)、-10 kPa(S2)、-15 kPa(S3)、-20 kPa(S4)和-25kPa(S5),每个处理重复3次,按随机区组布置。结果表明:不同土壤基质势控制对盐渍土中盐分分布有显著影响,不同土壤盐分离子的分布各不相同。其中Na+与Cl-容易被淋洗,两个生长季后,各处理土壤中Na+与Cl-含量有显著降低,并且土壤基质势控制越高淋洗效果越好。SO42-与HCO3-的淋洗效果主要受离子浓度影响,第一年淋洗效果较第二年明显。Mg2+与Ca2+不易随水移动,各处理无明显差异。经过两个生长季的灌溉淋洗,各处理土壤SAR值与全盐含量均有显著降低,根区内SAR值与全盐含量的降低幅度均在50%以上。研究结果对内陆干旱区盐碱地水盐调控和灌溉制度的制定具有理论意义和应用价值。     

微咸水灌溉对土壤盐分和作物产量的影响研究

为探讨微咸水灌溉利用模式,在天津市静海县进行了微咸水灌溉试验,研究了微咸水灌溉对土壤盐分动态与作物产量的影响.结果表明,微咸水灌溉下,施用改良剂能提高土壤渗透性,降低土壤pH值和土壤电导率(EC),降低了土壤含盐量,同时在试验周期0 60 cm的土层内未出现积盐现象.此外,微咸水灌溉时,施用改良剂可显著增加小麦穗数和玉米穗粒数,提高作物产量.采用3.7 g/L微咸水灌溉配合施用改良剂是该地区适宜的微咸水灌溉模式.     

内蒙古河套灌区有效灌溉及盐碱控制的战略思考

位于中国干旱地区的河套平原,有着得天独厚的自然条件,在我国农业生产上占有重要的地位。但是这里没有灌溉就没有农业。长期过量灌溉引起了该地区土地的盐碱化。水资源短缺问题受到越来越广泛的关注,该地区引黄河水量将进一步削减,但另一方面随着社会和经济的发展,耕地面积将进一步扩大;农业节水和传统的用水洗盐方式是一对需要解决的矛盾。现代灌溉技术如喷灌、滴灌、微灌等无论是在技术上还是在经济上都很难在这里得到应用,地面灌溉方式在近期内仍将是主要的灌溉方式。合理的灌溉方式和地下水位的有效控制将是解决问题的     

Effect of Mixed-Salt Salinity on Growth and Ion Relations of a Barnyardgrass Species

ABSTRACT

Recent investigations of the plant genome have revealed a large degree of similarity among cereal crops (specifically within the family Triticeae) and other related grass species. Recognition of the close genetic relationship among the grasses indicates that more exotic species, such as weedy grasses, may be exploited by plant breeders to enhance biotic/abiotic stress tolerance in cereal crops. Echinochloa crus-galli (L.) ^{1 1} Mention of company names or products is for the benefit of the reader and does not imply endorsement, guarantee, or preferential treatment by the USDA or its agents. Beauv. (barnyardgrass), a wide-spread, persistent C₄ weed species of agricultural importance, is reported to tolerate high levels of salinity. Growth and ion relations were studied in barnyardgrass using mixed-salt salinity (with final electrical conductivities (ECi) of 3 (control), 7, 11, and 19 dS m^?1 in the irrigation water) to determine whether the mechanism(s) for its salt tolerance are similar to those previously reported for other cereal crops. Such a finding would indicate that barnyardgrass may possess valuable genetic traits. Ion accumulation and ion selectivity ratios in the various treatments were determined from oven-dried shoot tissue. Significant (P < 0.01) linear regressions were obtained between either fresh weight or plant height and ECi. The point of 50% reduction (C₅₀) in fresh weight was predicted to occur at about 13.9 dS m^?1; the C₅₀ value for plant height was at about 22.9 dS m^?1. Statistical analysis of calculated Gapon constants for potassium (K)/sodium (Na) indicated that ion selectivity was not affected until after 11 dS m^?1. Calcium (Ca)/Na selectivity was not significantly affected by salinity. We concluded that, similar to some cereal crops, barnyardgrass maintains growth under saline conditions by maintaining high K/Na ratios, possibly because of better membrane integrity due to high Ca selectivity.     

滴灌条件下液体地膜覆盖土壤保温保湿效应及棉花生长响应

为解决干旱区棉田日益严重的"白色污染"问题,从根本上杜绝农田残膜增加,采用桶栽试验研究了5种处理方式:液体地膜1 900 kg/hm~2(LFD1),液体地膜2 200 kg/hm~2(LFD2),液体地膜2 500 kg/hm~2(LFD3),塑膜滴灌(PFD),裸地对照(NFD)对土壤的保温保湿效应及棉花生长响应,探讨了滴灌条件下液体地膜代替塑料地膜的可行性。结果表明:液体地膜覆盖可提高土壤温度,降低土壤水分蒸发量,增强棉株根系吸收与合成能力,加快滴灌棉花前期生长速度,适度抑制后期旺长,增产效果显著。液体地膜覆盖滴灌棉花对土壤环境无不良影响,在干旱区滴灌棉田具有重要研究价值和应用前景。     

Evapotranspiration and Mineral Content of Sedum kamtschaticum Fischer Under Saline Irrigation

An alternative water resource such as graywater could be used for irrigation on green roofs during hot, dry summers, although it contains salt. In this study, the response to high-salt stress of a C3–CAM (Crassulacean acid metabolism) intermediate species, Sedum kamtschaticum Fischer, was evaluated over a 2-month experiment in terms of evapotranspiration (ET) and chemical compounds in plant tissue in triplicate for both experiments. High ET (10–15 mm day^?1) was observed under non-stressed conditions. On the day following the first saline irrigation, the peak ET at noon decreased as much as one-third of the maximum. After 9 days, ET remained below 3 mm day^?1, corresponding mostly to evaporation from the wet soil surface. The balance of chemical component contents in leaves changed depending on the electrical conductivity of irrigation water electrical conductivity (EC_i). The potassium to sodium (K⁺/Na⁺) ratio, which indicates levels of sodium toxic for plant growth, decreased with higher EC_i, while it excluded sodium from roots. However, based on enhanced water use efficiency under higher EC_i regardless of reduced carbon dioxide (CO₂) assimilation under salinity stress, the plant’s method of photosynthesis shifted from C3 to CAM metabolism. These findings show that S. kamtschaticum could survive for more than 2 months under low or moderate salinity of irrigation water in hot conditions.     

离子色谱法和毛细管电泳法测定土壤中氯离子、 硫酸根及其差异性

分别采用离子色谱法(IC)、毛细管电泳法(CE)两种仪器方法对不同pH土壤中Cl~–、SO_4~(2–)含量进行测定,并对其结果进行差异性分析。结果显示:参照标准物质的参考值(滴定法),IC与CE测定值的准确度、回收率均满足实验分析要求,但精密度差异较大,IC(RSD,3.61%)的稳定性优于CE(RSD,8.97%)。据差异性(F与t检验)分析,两种仪器方法测定酸性土壤中Cl~–、SO_4~(2–)含量存在显著性差异,而碱性、中性土壤的测定结果保持一致。对比4个被测样品基本性质发现,酸性土壤的pH与离子强度均低于其他样品,从而影响了石英毛细管的电渗流,最终改变了CE分离过程,这可能是Cl~–结果偏离的主要因素。同时,对于IC,酸性土壤较中性、碱性土壤更易由于离子交换效应产生次级保留(拖尾)。此外,采用碱性分离体系分离酸性样品易形成结晶,从而导致SO_4~(2–)含量的偏离。可见,两种方法各有优缺点。但是,IC较经典,而CE是一种新兴的仪器方法。测定像土壤这样基体较复杂的样品(特别是酸性土壤)中阴离子的仪器条件还需要进行更多摸索与优化,以促进这两种方法在土壤领域的推广与应用。     

滴灌条件下排水暗管埋深及管径对土壤盐分的影响

为探索高效节水的暗管排盐技术,通过田间灌溉排水试验,研究了滴灌条件下排水暗管不同管径(50、90 mm)、和不同埋深(0.6、1.0、1.4 m)对土层含盐量分布及脱盐效果的影响。结果表明:两次灌水后各土层脱盐效果差别较大。0~60 cm土层脱盐程度较高,土壤含盐量已降至12 g kg~(-1)以下中度盐化水平,100 cm以下土层脱盐效果不明显;暗管0.6 m埋深脱盐效果优于1.0、1.4 m埋深,总体盐分减少14.34 g kg~(-1),相比未铺设暗管对照减少了13.32 g kg~(-1)。增加暗管埋深至1.4m对暗管降盐效果无显著影响;暗管管径对各土层盐分的影响相对更加显著,90 mm管径相较50 mm管径暗管脱盐效果明显,50、90 mm管径暗管不同埋深0~1.4 m土层脱盐率分别在20.69%~30.20%和34.59%~57.04%之间。暗管埋深0.6 m、管径90 mm时,两次灌水后0~60 cm土层已降至轻度盐化水平(3~6 g kg~(-1)),暗管排水排盐效率较高,为北疆盐渍土的暗管排水最优埋深与管径布设参数。     

Effects of Irrigation Water Salinity and Leaching Fraction on Yield and Evapotranspiration in Spring Wheat

To determine the effects of irrigation water salinity and leaching fraction on crop evapotranspiration (ETc), grain yield, straw yield, shoot sodium (Na), and chloride (Cl) concentrations of spring wheat (Triticum aestivum L.) cultivar ‘Onfarom 9,’ a pot experiment was conducted using saline soil with electrical conductivity of soil paste extract (ECe) of 13.2 dS m^?1. A factorial experiment with a completely randomized design replicated seven times was used with three levels of saline irrigation water (4, 9, and 12 dS m^?1) and four leaching levels (0, 17, 29, and 37%) included as the factors. The results showed that ETc significantly decreased as a result of an increase in irrigation water salinity (ECi) and decrease in leaching level. Crop evapotranspiration deficit and decreasing irrigation and drainage water effectively resulted in grain and straw yield reduction. Increase in ECi increased accumulation of Cl and Na in crop shoot, but application of leaching decreased this accumulation.     

盐碱胁迫对香樟幼苗离子吸收与分配的影响

以2年生香樟幼苗为材料,采用不同浓度Na HCO_3和Na_2CO_3(1︰1)混合溶液(0、50、100、200、300 mmol/L)处理,研究香樟幼苗对Fe~(2+)、Mg~(2+)、K~+、Na~+的吸收和分配。结果表明:随盐碱胁迫程度的增加,香樟幼苗根系和茎器官中的K~+含量呈下降趋势,而叶片中的K~+含量呈逐步上升趋势,其中叶片中的K~+含量最高,其次是根系,茎器官中的K~+含量最低;香樟幼苗根系、茎、叶片中的Na~+含量呈逐步上升趋势,其中根系中的Na~+含量最高,其次是叶片,茎器官中的Na~+含量最低;香樟幼苗根系、茎、叶片中的K~+/Na~+呈逐步下降趋势,其中茎器官中的K~+/Na~+最高,其次是叶片,根系中的K~+/Na~+最低。低盐碱胁迫(0~100 mmol/L)提高根、茎、叶器官中Fe~(2+)的含量,提高香樟叶片中叶绿素a、叶绿素b和总叶绿素的含量;而高盐碱胁迫(100~300 mmol/L)则降低根器官中Fe~(2+)的含量,增加茎、叶器官中Fe~(2+)的含量,明显降低叶绿素a、叶绿素b和总叶绿素的含量,根器官中Fe~(2+)的含量最高,其次是茎器官,叶器官中Fe~(2+)的含量最低。盐碱胁迫对香樟幼苗根、茎、叶器官中Mg~(2+)的含量影响差异不显著。盐碱胁迫初期,香樟幼苗通过将Na~+截留在根部,促进根器官对K~+、Fe~(2+)等营养元素的吸收和转运,提高自身对低盐碱胁迫(0~100 mmol/L)的耐受性;高盐碱胁迫(100~300 mmol/L)严重影响香樟幼苗对K~+、Fe~(2+)等营养元素的吸收和转运,影响香樟正常生长发育。     

夏玉米咸水灌溉的风险性及其对策分析

在光、温、水对作物生产力影响模型的基础上，增加了基于统计经验方法的描述性盐分模拟模块，并利用田间试验数据对模型进行了检验，计算了不同气候年型和各种灌溉方案下浅层地下水灌溉对产量的影响和次生盐渍化风险度。结果显示，在生长季只需1次灌溉的前提下利用咸水灌溉几乎没有风险，但生长季需2次以上灌溉时，就需咸、淡水轮灌，生长季结束后还需利用淡水灌溉洗盐。     

膜下滴灌棉田Dobson介电模型参数修改及水盐含量反演

新疆土壤盐渍化严重,亟需防治土壤盐渍化继续蔓延,水盐含量能直观表述盐渍化程度,所以反演土壤水盐含量对于土壤盐渍化的防治具有重要意义.以新疆典型的膜下滴灌棉田土壤为例,利用探地雷达250 MHz和1000 MHz两个频率天线,通过共中心点法获取波速后转换为视在介电常数,结合野外实测数据,修正胡庆荣盐渍土介电模型参数,以修...