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1.
冬小麦氮素吸收及产量对喷灌施肥均匀性的响应   总被引:9,自引:1,他引:9  
 为了为喷灌均匀系数设计标准的制订提供更充分的依据,分别于2002~2003和2003~2004年度在北京进行了喷灌施肥均匀系数和施肥量对冬小麦氮素吸收量和产量影响的田间试验。试验中生育期平均喷灌均匀系数变化范围为72%~84%。除了基肥外,其它肥料利用喷灌系统施入,生育期平均喷灌施肥均匀系数变化范围为71%~85%,喷灌施肥量的变化范围为0~180kgN/hm2。试验结果指出,在所研究的均匀系数范围内,均匀系数对氮素吸收量和产量的影响不明显。施肥量对冬小麦产量的影响不明显,但秸秆全氮含量和氮素吸收量均随施肥量的增加呈现出增加趋势。本研究结果表明,对华北平原的冬小麦喷灌来说,目前我国采用的喷灌均匀系数不小于75%的设计标准不会对氮素吸收量和产量造成负面影响。  相似文献   

2.
为明确水肥一体化灌溉模式中施肥量与基追肥比例对大蒜产量与品质的影响,以山东嘉祥紫皮蒜为试验品种,在减施化肥20%条件下,设置不同的灌溉方式和基追肥比例。结果表明,大蒜水肥一体化灌溉较常规大水漫灌,每667 m2平均节水40.85 m3,节水率平均达52.50%;在不同的基肥追肥比例及灌溉方式中,水肥一体化喷灌并施用基肥60%和追肥40%处理增产效果最明显,蒜薹和蒜头产量分别提高了14.48%和10.89%,且可溶性蛋白、可溶性糖含量相比于常规大水漫灌处理分别提高了9.01%、15.75%。研究表明,通过水肥一体化模式,在合适的基追肥比例下,能够实现大蒜种植的节水、减肥和增产。  相似文献   

3.
为了寻找马铃薯适宜的水肥管理模式,通过大田试验,以大水漫灌+肥料条施为对照(CK),研究了喷灌+肥料条施、滴灌+肥料条施和滴灌水肥一体化对马铃薯土壤酶活性及产量的影响。结果表明,与CK相比,滴灌水肥一体化、滴灌+肥料条施、喷灌+肥料条施处理均不同程度地提高了马铃薯土壤酶活性,其影响程度为滴灌水肥一体化滴灌+肥料条施喷灌+肥料条施,滴灌水肥一体化能够显著提高马铃薯生育后期的土壤酶活性。滴灌水肥一体化处理下马铃薯的产量和商品薯率最高,显著高于其他处理,其中,产量较CK及喷灌+肥料条施、滴灌+肥料条施处理分别提高49.07%及27.94%、14.91%,商品薯率较CK及喷灌+肥料条施、滴灌+肥料条施处理分别提高19.41个百分点及10.36、4.72个百分点。  相似文献   

4.
滴灌系统运行方式施肥频率对番茄产量与根系生长的影响   总被引:8,自引:0,他引:8  
利用田间试验,在日光温室内研究了滴灌施肥灌溉系统运行方式和施肥频率对番茄产量、品质及根系生长的影响。系统运行方式包括不同灌水和施肥次序组成的3种方案;施肥频率取每周一次,两周一次和四周一次三个水平。在生育期内对番茄的光合速率等参数进行观测,收获后测定番茄的根密度,并统计产量。研究结果表明,施肥频率对番茄的产量影响显著,施肥频率从四周一次增加到每周一次时产量显著增加(P=0.012)。随着施肥次序向后推移,番茄的产量有下降的趋势,但差异未达到显著水平。施肥频率和运行方式对番茄各项品质的影响都不显著。施肥频率对根密度的影响主要是引起各土层根密度大小的变化,运行方式则对根密度在各土层的分配产生影响。在分析了运行方式和施肥频率对光合速率影响的基础上,计算整个生育期内的光合累积量,用来分析光合作用的变化对产量的影响。结果表明,光合累积量和产量有显著的相关性(P=0.043);从提高产量和品质的角度看,施肥频率取每周一次较为适宜,滴灌施肥灌溉过程中的施肥次序应尽量前移。  相似文献   

5.
While fertigation can increase fertilizer use efficiency, there is an uncertainly as to whether the fertilizer should be introduced at the beginning of the irrigation or at the end, or introduced during irrigation. Our objective was to determine the effect of different fertigation schemes on nitrogen (N) uptake and N use efficiency (NUE) in cotton plants. A pot experiment was conducted under greenhouse conditions in year 2004 and 2005. According to the application timing of nitrogen (N) fertilizer solution and water (W) involved in an irrigation cycle, four nitrogen fertigation schemes [nitrogen applied at the beginning of the irrigation cycle (N-W), nitrogen applied at the end of the irrigation cycle (W-N), nitrogen applied in the middle of the irrigation cycle (W-N-W) and nitrogen applied throughout the irrigation cycle (N&W)] were employed in a completely randomized design with four replications. Cotton was grown in plastic containers with a volume of 84 l, which were filled with a clay loam soil and fertilized with 6.4 g of N per pot as unlabeled and 15N-labeled urea for 2004 and 2005, respectively. Plant total dry matter (DM) and N content in N-W was significantly higher than in N&W in both seasons, but these were not consistent for W-N and W-N-W treatments. In year 2005, a significantly higher nitrogen derived from fertilizer (NDFF) for the whole plant was found in W-N and N-W than that in W-N-W and N&W. Fertigation scheme had a consistent effect on total NUE: N-W had the highest NUE for the whole plant, but this was not significantly different from W-N. Treatments W-N and W-N-W had similar total NUE, and N&W had the lowest total NUE. After harvesting, the total residual fertilizer N in the soil was highest in W-N, lowest in N-W, but this was not significantly different from N&W and W-N-W treatments. Total residual NO3-N in the soil in N&W and W-N treatments was 20.7 and 21.2% higher than that in N W, respectively. The total 15 N recovery was not statistically significant between the four fertigation schemes. In this study, the fertigation scheme N-W (nitrogen applied at the beginning of an irrigation cycle) increased DM accumulation, N uptake and NUE of cotton. This study indicates that Nitrogen application at the beginning of an irrigation cycle has an advantage on N uptake and NUE of cotton. Therefore, NUE could be enhanced by optimizing fertilization schemes with drip irrigation.  相似文献   

6.
Site-specific delivery of fertilizer is a useful tool to address differences in crop need. Modern systems with wirelessly networked sensors and valves allow multiple hydrozones to be created more easily than traditional wired systems. This allows irrigation and fertigation rates to be varied across small portions of a field. However, fertigation to multiple hydrozones with different fertilizer requirements may be complex if each zone cannot be fertigated in an independent set. Instead, it might be necessary to operate several fertigation zones simultaneously. This raises a concern over the ability to deliver fertilizer uniformly within each zone. Four fertigation strategies were tested. The conventional method was to fertigate multiple hydrozones at different times. Three site-specific strategies were considered, involving overlapping fertigation phases in multiple hydrozones. Fertilizer distribution uniformity tests were conducted with a 64-emitter drip line to determine which strategy gave the most uniform distribution of fertilizer within a hydrozone. All fertigation techniques performed well, with fertilizer distribution uniformities between 0.88 and 0.96. Selection of the optimum site-specific fertigation strategy will depend on crop needs, scheduling limitations, and system design parameters such as emitter type, fluid travel time, and slope. Similar to conventional fertigation, the main factor in fertilizer distribution uniformity for this study was drip emitter variability. In the presence of sloped terrain, the site-specific control strategy that involved a delay between fertilizer injection and flushing had the least uniform fertilizer application.  相似文献   

7.
滴灌春麦水肥一体化肥效试验研究   总被引:3,自引:1,他引:2  
[目的]研究春麦在滴灌条件下的水肥利用情况,为滴灌春麦科学施肥提供技术支撑.[方法]通过大田试验,采用“3414”试验方案研究随水施肥对肥料利用率及小麦经济、生物产量的影响.[结果]滴灌春麦至开花期对氮、磷、钾肥吸收量已达全生育期的78.1;、82.14;和84.9;;施用等量氮、磷、钾肥(N240P52.5K375),滴灌施肥较常规施肥氮、钾利用率分别提高了4.7;和3.2;,但磷素差异不大.单一肥料氮肥的作用最大,其次是磷肥;随施氮量的增加,小麦产量得到提高,但过多施入氮肥产量反而下降;氮肥农学效率和偏生产力则随氮肥增加呈递减趋势.[结论]春麦采用水肥滴灌模式可提高肥料利用率并增加小麦产量.  相似文献   

8.
滴灌施肥水肥耦合对温室番茄产量、品质和水氮利用的影响   总被引:40,自引:3,他引:40  
【目的】水肥是限制作物增产的两大因子,不合理的灌溉与施氮不仅难于增加产量,还会增加土壤剖面硝态氮累积、降低作物品质及水氮利用效率。针对西北半干旱地区温室蔬菜灌水和施肥存在的问题,通过滴灌施肥水肥耦合对温室番茄产量品质和水氮利用的影响,研究滴灌施肥条件下温室番茄高产优质高效的灌水施肥制度。【方法】通过温室番茄小区试验,设常规沟灌施肥(100%ET0,N240-P2O5120-K2O150 kg·hm-2)以及3个滴灌水量(高水W1:100%ET0、中水W2:75%ET0、低水W3:50%ET0)和3个施肥水平(高肥F1:N240-P2O5120-K2O150 kg·hm-2、中肥F2:N180-P2O590-K2O112.5 kg·hm-2、低肥F3:N120-P2O560-K2O75 kg·hm-2),共10个处理,分析番茄生长产量、品质、土壤硝态氮分布以及水氮吸收利用对不同灌水量和施肥量的响应规律。【结果】与常规沟灌施肥相比,滴灌施肥增加番茄产量31.04 t·hm-2、干物质量3 208 kg·hm-2和总氮吸收量73.13 kg·hm-2,增幅分别为46.9%、54.0%和82.4%,同时增加果实中维生素C(Vc)含量61.8%;降低土壤中硝态氮含量;水分利用效率(WUE)和氮肥利用率(NUE)分别增加46.4%和76.5%。滴灌施肥条件下,W1F2处理总干物质量最大(9 248 kg·hm-2),产量和植株氮素吸收量均与灌水量和施肥量正相关,增加施肥量带来的增产效应大于灌水,且W1F2处理产量和氮素吸收量增加幅度最大。增加灌水量,降低施肥量,WUE逐渐下降,NUE逐渐上升,W3F1处理WUE最大(47.7 kg·m-3),W1F3处理NUE最大(65.6%),且W3F2处理的WUE和W1F2处理的NUE增加幅度明显大于其他处理。土壤中硝态氮含量受灌水、施肥以及水肥交互效应影响显著,随灌水量的增加呈先增大后降低的趋势,随施肥量的增加逐渐增大,在滴头正下方没有明显累积,在湿润土体的横向边缘产生累积,W1F2处理土壤中硝态氮含量较小,分布更均匀。增大灌水量显著降低番茄Vc、番茄红素和可溶性糖含量以及营养累积量;增大施肥量,品质含量以及营养累积量呈先增大后降低的趋势;W3F2处理获得最大的Vc和番茄红素含量及营养累积量,最大的可溶性糖含量及较大的营养累积量。【结论】温室番茄滴灌施肥技术能够达到高产优质和高效的目的,当追求产量和氮肥利用率时,高水中肥(W1F2:100%ET0,N180-P2O590-K2O112.5 kg·hm-2)处理能获得较高的产量和NUE以及较低的土壤硝态氮含量;当追求品质和水分利用效率时,低水中肥(W3F2:50%ET0,N180-P2O590-K2O112.5 kg·hm-2)处理获得最大的维生素C、可溶性糖和番茄红素含量以及较高的水分利用效率。  相似文献   

9.
在海南香蕉生产上应用微喷灌系统进行加肥灌溉对比传统施肥试验。结果表明:应用加肥灌溉技术,平均单株产量最高可达30.4kg,比应用传统施肥技术增产15.6%,且可降低成本,达到增产增收的良好效益。  相似文献   

10.
The excessive nitrogen(N) fertilizer input coupled with flood irrigation might result in higher N leaching and lower nitrogen recovery efficiency(NRE).Under an intensive rice system in the Ningxia irrigation region,China,environmental friendly N management practices are heavily needed to balance the amount of N input for optimum crop production while minimize the nitrogen loss.The objective of this study was to determine the influences of side-dressing(SD) technique in mechanical transplanting systems on the NRE,N leaching losses and rice yield in anthropogenic-alluvial soil during two rice growing seasons(2010-2011).Four fertilizer N treatments were established,including conventional urea rate(CU,300 kg ha~(-1)yr~(-1));higher SD of controlled-release N fertilizer rate(SD1,176 kg ha~(-1)yr~(-1));lower SD of controlled-release N fertilizer rate(SD2,125 kg ha~(-1)yr~(-1));and control(CK,no N fertilizer).Field lysimeters were used to quantify drainage from undisturbed soil during six rice growing stages.Meanwhile,the temporal variations of total nitrigen(TN),NO_3~--N,and NH_4~+-N concentrations in percolation water were examined.The results showed that SD1 substantially improved NRE and reduced N leaching losses while maintaining rice yields.Across two years,the averaged NRE under SD1 treatment increased by 25.5%as relative to CU,but yet the rice yield was similar between two treatments.On average,the nitrogen loss defined as TN,NH_4~+-N,and NO_3~--N underthe SD1 treatment reduced by 27.4,37.2 and 24.1%,respectively,when compared with CU during the study periods.Although the SD2 treatment could further reduce N leaching loss to some extent,this technique would sharply decline rice yield,with the magnitude of as high as 21.0%relative to CU treatment.Additionally,the average NRE under SD2 was 11.2% lower than that under SD1 treatment.Overall,the present study concluded that the SD technique is an effective strategy to reduce N leaching and increase NRE,thus potentially mitigate local environmental threat.We propose SD1 as a novel alternative fertilizer technique under an irrigated rice-based system in Ningxia irrigation region when higher yields are under consideration.  相似文献   

11.
施肥与灌溉对甘肃省苜蓿碳足迹的影响   总被引:3,自引:1,他引:2  
【目的】评估甘肃省苜蓿不同种植模式的碳足迹,探明温室气体的主要排放环节。分析施肥与灌溉对甘肃省苜蓿碳足迹的影响,评估可能的减排潜力,为甘肃省苜蓿生产的可持续发展提供理论依据。【方法】应用生命周期评价理论和IPCC(2006)田间温室气体计算方法,建立苜蓿碳足迹评估方法。通过调研甘肃省苜蓿主产区陇东、陇中和河西地区10个县区的苜蓿种植农户和农场,收集苜蓿的产量、化肥、灌溉等生产数据。根据施肥和灌溉水平及灌溉水源将甘肃省苜蓿种植模式分为4种,使用建立的苜蓿碳足迹评估方法和甘肃省苜蓿生产投入/产出数据,分析4种种植模式的碳足迹构成特点、施氮水平与灌溉对苜蓿干物质产量和碳足迹的影响特征。使用情景分析方法揭示氮肥减施、改进氮肥生产工艺、无机有机肥混施、滴灌和喷灌技术降低苜蓿种植过程温室气体排放的潜力。【结果】甘肃省苜蓿4种种植模式的碳足迹(以CO2 eq计)从小到大依次为0.02(不施肥不灌溉模式,NFNI)、0.19(施肥不灌溉模式,SFNI)、0.22(施肥+河水灌溉模式,SFRI)、0.64(施肥+井灌模式,SFWI)kg CO2 eq·kg-1苜蓿干物质(DM)。SFNI模式除与SFRI模式之间碳足迹差异不显著外,与其他种植模式之间的差异均显著。不同种植模式之间的碳足迹构成环节和各环节对碳足迹的贡献率存在差异。NFNI模式的碳足迹主要由苜蓿残茬和农机使用两部分的排放组成;SFNI模式和SFRI模式碳足迹的主要产生环节是化肥生产和氮肥田间施用的排放,其次是农机使用;SFWI模式碳足迹的最大来源是灌溉耗电,其次为化肥生产和氮肥田间施用的排放。通过氮肥减施、无机有机肥混施、降低氮肥生产过程中排放可使甘肃省SFNI、SFRI和SFWI模式的苜蓿碳足迹分别降低10.0%-18.0%、-3.0%-8.0%和1.8%-5.8%。如果不考虑节水管材生产的额外温室气体排放,节水灌溉(喷灌和滴灌)可减少SFWI模式苜蓿碳足迹的12.7%-38.5%。【结论】甘肃省4种苜蓿种植模式的产量和碳足迹均存在差异,高投入高产出的SFWI模式的苜蓿产量最高,但碳足迹也显著高于其他模式。除NFNI模式外,其他3种模式均存在过量施肥现象。减施氮肥和降低氮肥生产过程中的温室气体排放均可降低甘肃省苜蓿生产的碳足迹;无机有机肥混施可以降低SFNI和SFRI模式的碳足迹,但同等施氮水平下,无机有机肥混施短期内会降低产量。因此,在保证一定产量同时降低温室气体排放量的目标下,有机肥和化肥混施的最佳比例及实际减排潜力仍需通过田间的长期试验进一步验证;节水灌溉是SFWI模式的主要减排措施,但节水灌溉所能带来的综合减排潜力仍需针对具体区域的田间节水试验和额外耗材带来的温室气体排放进一步评估。  相似文献   

12.
针对温室大棚盐渍化土壤灌水洗盐而导致的农业面源污染问题,以常规肥水管理方式为对照,在上海崇明东滩温室大棚采用土壤次生盐渍化监测、灌水洗盐过程模拟和农作物生产试验等方法研究精确滴灌施肥技术在降低土壤次生盐渍化程度和减少农田氮磷流失中的作用.结果表明,滴灌施肥技术可有效降低农田表层土壤的盐分积累速度,以此降低洗盐频次,进而显著削减温室大棚因灌水洗盐而引起的氮磷流失负荷.当滴灌施肥区洗盐频次降低为常规区的一半时,总氮、总磷、硝氮和氨氮的年流失负荷较常规方式削减45%~53%.而作物产量基本可以保持;当洗盐频次降低为常规区的1/4时,总氮、总磷、硝氮和氨氮的年流失负荷的削减率达58%~75%,但后茬作物减产明显.  相似文献   

13.
肥水管理方式对蔬菜田N2O释放影响的模拟研究   总被引:10,自引:3,他引:7  
通过田间静态箱临测和DNDC模型模拟的方法,对比研究了崇明岛东滩蔬菜田在常规肥水管理和精确滴灌施肥方式下N2O的排放情况,从排放特征、全年通量、单位氮肥N2O损失率以及单位作物产量排放量等方面分析了不同肥水管理方式对旱田土壤N2O排放的影响.结果表明,基于土壤和作物养分平衡管理的精确滴灌施肥技术,由于减少了氮肥施用量并改进了肥水分配方式,提高了肥料的利用效率,在保持农作物产量的基础上减少了N2O的排放.与常规肥水管理方式相比,滴灌施肥区2006年和2007年的N2O排放通量分别减少6.2和6.8 kg N.hm-2·a-1,单位氮肥N2O损失率明显降低,2006年和2007年单位产量排放量分别削减53.2%和58.9%.  相似文献   

14.
 【目的】与地表滴灌相比,地下滴灌的特殊性在于系统性能不仅受水力设计参数的影响,而且还与土壤特性的空间变异密切相关。本文的目的是定量评估地下滴灌系统水力参数和土壤特性空间变异对土壤水氮空间分布和夏玉米生长的影响。【方法】试验田块的土壤为砂质壤土。试验中滴灌带埋深设置0、15和30 cm 3个水平,施肥装置选择国内外常用的压差式施肥罐和文丘里施肥器两种类型;土壤特性测试指标包括颗粒组成、容重、水分特征曲线、含水量、硝态氮和铵态氮含量。采用人工神经网络模型估算了土壤饱和导水率。夏玉米收获时测定了地上部分干物质、产量和氮素吸收量的分布。【结果】试验田块内土壤初始硝态氮含量的变异程度最大,饱和导水率次之,土壤容重的变异程度最小;土壤特性空间变异程度为弱-中等。滴灌带埋深对施肥灌溉后土壤硝态氮在垂直剖面上的分布影响明显,滴灌带附近一般硝态氮含量较高。但施肥装置类型对土壤硝态氮分布的影响不显著;滴灌带埋深和施肥装置类型对土壤铵态氮含量分布的影响均不显著。由地下滴灌系统水力设计和土壤特性空间变异引起的作物地上部分干物质、吸氮量和产量的变异系数明显小于灌溉施肥后土壤氮素的变异系数,接近或小于灌水量与施肥量的变异系数。【结论】对试验土壤来说,土壤特性的空间变异,尤其是土壤初始含水量和氮素含量的不均匀性,可能是导致施肥灌溉后土壤水氮分布不均匀的重要原因。因此在地下滴灌系统设计中应考虑土壤特性空间变异的影响。  相似文献   

15.
华北地区夏玉米滴灌施肥的肥料效应   总被引:1,自引:0,他引:1  
目的 通过研究华北地区中低产土壤条件下不同氮、磷、钾肥施用量在滴灌夏玉米上的肥料效应,从而优化滴灌施肥系统,为夏玉米高效滴灌施肥提供理论依据,推进水肥一体化技术。方法 通过两年田间试验,以郑单958为供试品种,滴灌带设置为一管带两行,氮磷钾分别设4个处理,其中氮肥处理为0、144、180、216 kg·hm -2(记为N0、N1、N2、N3),磷肥处理为0、72、90、108 kg·hm -2(记为P0、P1、P2、P3),钾肥处理为0、72、90、108 kg·hm -2(记为K0、K1、K2、K3),氮磷钾肥料分4次滴施,以研究不同处理对夏玉米产量及不同生育时期干物质积累的影响,分析不同处理下肥料的利用率。结果 (1)华北地区中低产田条件下夏玉米产量随施氮磷肥的用量呈抛物线性变化,当施氮量为180 kg·hm -2,施磷量为90 kg·hm -2时,作物产量最高;当氮磷肥施用量超过最高产量施肥量时,作物产量随施氮磷用量的提高呈下降趋势,但氮肥处理的下降程度差异不显著,而磷肥施用量超过90 kg·hm -2时,作物产量随施磷量的提高显著下降(P<0.05);在本处理中,夏玉米产量随施钾量的提高,均呈增加趋势。(2)不同施肥处理对夏玉米生育前期干物质积累几乎没有影响,在灌浆期与收获期时干物质积累与施氮量、施磷量均呈抛物线性变化,变化趋势与产量基本相同。(3)不同处理的氮磷钾肥利用率不同,分别为33.39%—58.44%、14.15%—28.88%、54.70%—65.75%,当夏玉米产量最高时的氮、磷、钾肥利用率两年平均为51.21%、28.88%、65.75%;在最高产量条件下,氮、磷、钾肥的平均农学效率分别为8.08、11.41和8.83 kg·kg -1;偏生产力分别为59.88、119.75和100.65 kg·kg -1结论 在华北地区中低产土壤滴灌施肥条件下,最适宜的氮磷施用量分别为180 kg·hm -2和90 kg·hm -2,当施氮量超过180 kg·hm -2、施磷量超过90 kg·hm -2时,夏玉米产量会出现下降,但随施钾量的提高,产量有增加的趋势。滴灌施肥可获得较高的氮磷钾肥利用率,分别为51.21%和28.88%和65.75%。  相似文献   

16.
为了解滴灌施肥是否能够提高水氮利用效率、降低环境污染风险,总结山东寿光设施番茄长期定位试验9季的试验结果,系统分析传统漫灌施肥和滴灌施肥对番茄产量、水氮利用效率、土壤硝态氮残留和经济效益的影响。与传统漫灌施肥相比,滴灌施肥每季氮肥和水分投入量分别降低78%和46%,氮肥偏生产力和灌溉水利用效率则分别提高5和2倍,番茄产量和经济效益分别提高6%和22%,且产量年际变异显著降低。传统漫灌施肥0~90cm土层硝态氮残留量平均高达819kg/hm2,滴灌施肥降低50%的土壤硝态氮残留。与传统漫灌施肥相比,滴灌施肥栽培体系是一个低投入、低环境代价和高效稳定的生产体系。  相似文献   

17.
The aim of drip fertigation is synchronising the application of water and nutrients with crop requirements, and maintaining the proper concentration and distribution of nutrient and water in the soil. The wetting patterns and nutrient distributions under drip fertigation have been proved to be closely related to the fertigation strategies. In order to find out the critical factors that affect the nutrient distribution under different drip fertigaiton strategies, a computer simulation model HYDRUS2D/3D was used to simulate the water and nitrate distribution for various fertigation strategies from a surface point source. Simulation results were compared with the observed ones from our previous studies. A 15° wedge-shaped plexiglass container was used in our experiment to represent one-twenty-fourth of the complete cylinder. The height of container is 40 cm, and the radius is 41 cm. The ammonium nitrate solution was added through a no. 7 needle connected to a Mariotte tube with a flexible hose. The soil water content, nitrate and ammonium concentrations were measured. The comparison of simulated and observed data demonstrated that the model performed reliably. The numerical analysis for various fertigation strategies from a surface point source showed that:(1) The total amount of irrigation water, the concentration of the fertilizer solution and the amount of pure water used to flush the pipeline after fertilizer solution application are the three critical factors influencing the distribution of water and fertilizer nitrogen in the soil.(2) The fresh water irrigation duration prior to fertigation has no obvious effect on nitrate distribution. The longer flushing time period after fertigation resulted in nitrate accumulation closer to the wetting front. From the point of avoiding the possibility of nitrate loss from the root zone, we recommended that the flushing time period should be as shorter as possible.(3) For a given amount of fertilizer, higher concentration of the fertilizer applied solution reduces the potential of nitrate leaching in drip irrigation system. While, lower concentration of the fertilizer solution resulted in an uniform distribution of nitrate band closer to the wetted front.  相似文献   

18.
不同滴灌施肥方式下棉花根区的水、盐和氮素分布   总被引:6,自引:0,他引:6  
 【目的】探讨不同滴灌施肥方式下土壤水、盐、氮和棉花根系的分布,对于滴灌条件下水肥盐的合理调控具有重要意义。【方法】在温室条件下应用15N标记尿素进行了不同滴灌施肥方式对土壤水、盐和氮素分布的影响及其与棉花根系分布之间关系的盆栽试验。根据滴灌灌水(W)和施肥(N)的先后顺序,设置4种不同氮肥施用方式:①氮肥在一次灌溉过程的前期施用(N-W);②后期(W-N);③中间(W-N-W);④全程施用(NW)。同时以传统的氮肥直接施入土壤后浇灌(SN-W)为对照。【结果】土壤水盐分布明显受灌溉方式的影响,但滴灌条件下不同施肥方式对土壤水盐分布无影响。氮肥滴灌施肥24 h后15N主要分布在0~20 cm深度土层,但不同施肥方式之间差异明显。NW处理15N在土壤中的垂直分布最深,但水平分布范围较小,且收获后土壤硝态氮在下层大量积累,容易造成淋失。相比之下,N-W处理15N在0~20 cm土层分布最均匀,收获后土壤硝态氮的残留量也最小,且棉花根系的生长和分布也优于其它处理。【结论】滴灌条件下,氮肥在一次灌溉过程的前期施用有利于提高氮肥利用率,减少氮素的淋洗损失。  相似文献   

19.
蔗区降雨分布与甘蔗需水及加肥灌溉效应   总被引:5,自引:0,他引:5  
1材料与方法 1.1试验概况选择有代表性的甘蔗种植区广西壮族自治区来宾市进行田间试验,供试甘蔗品种为“台糖22”,种植密度45000芽段/hm^2。各生长阶段降雨观测在田间试验旁进行,试验地养分测定按常规方法。  相似文献   

20.
Abd  El-Razek  AM  Atta  YI  Hassan  AF 《南方农业学报》2012,42(8):916-922
【目的】2008~2009、2009~2010年分别在埃及El-Sharkia省Zankalon研究站进行不同灌溉和氮肥水平对甜菜产量、品质及水分指标的影响试验。【方法】采用裂区设计,分别设3个灌溉处理即 I1(60%田间持水量)、I2(80%田间持水量)和I3(100%田间持水量)和3个施肥处理即N1(50 kg N/fed)、N2(70 kg N/fed)和N3(90 kg N/fed)。【结果】灌水处理I1的甜菜块根和糖产量最高、根径最大,其次为处理I2,处理I3的最低。随着灌溉水平的提高,甜菜块根长和蔗糖含量明显下降。当施用90 kg N/fed氮肥,甜菜根长、根径、块根和糖产量明显提高,但糖分则有所降低。灌溉和施氮肥处理均对蔗糖纯度没有明显影响。3个灌溉处理I1、I2和I3的水分利用量分别为3579.7、3042.0和2504.0 m2/fed,季节耗水量分别为58.12、52.06和47.29 cm,而甜菜块根产量、糖产量的水分利用率分别为15.86、13.78、13.35 kg 块根/m3水和2.73、2.61 and 2.56 kg 糖/m3水。随着施氮水平的提高,获得一定甜菜根产量和糖产量,所需的实际耗水量和水分利用率也不断提高。在东尼罗河三角洲地区的甜菜平均季节作物系数为0.87。【结论】可在东尼罗河三角洲地区推荐使用Kc经验值来计算耗水量。  相似文献   

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