Drip fertigation and plant hedgerows significantly reduce nitrogen and phosphorus losses and maintain high fruit yields in intensive orchards

A field experiment was carried out to evaluate the effects of drip fertigation combined with plant hedgerows on nitrogen and phosphorus runoff losses in intensive pear orchards in the Tai Lake Basin.Nitrogen and phosphorus runoff over a whole year were measured by using successional runoff water collection devices.The four experimental treatments were conventional fertilization(CK),drip fertigation(DF),conventional fertilization combined with plant hedgerows(C+H),and drip fertigation combined with plant hedgerows(D+H).The results from one year of continuous monitoring showed a significant positive correlation between precipitation and surface runoff discharge.Surface runoff discharge under the treatments without plant hedgerows totaled 15.86%of precipitation,while surface runoff discharge under the treatments with plant hedgerows totaled 12.82%of precipitation.Plant hedgerows reduced the number of runoff events and the amount of surface runoff.Precipitation is the main driving force for the loss of nitrogen and phosphorus in surface runoff,and fertilization is an important factor affecting the losses of nitrogen and phosphorus.In CK,approximately 7.36%of nitrogen and 2.63%of phosphorus from fertilization entered the surface water through runoff.Drip fertigation reduced the accumulation of nitrogen and phosphorus in the surface soil and lowered the runoff loss concentrations of total nitrogen(TN)and total phosphorus(TP).Drip fertigation combined with plant hedgerows significantly reduced the overall TN and TP losses by 45.38 and 36.81%,respectively,in comparison to the CK totals.Drip fertigation increased the vertical migration depth of nitrogen and phosphorus nutrients and reduced the accumulation of nitrogen and phosphorus in the surface soil,which increased the pear yield.The promotion of drip fertigation combined with plant hedgerows will greatly reduce the losses of nitrogen and phosphorus to runoff and maintain the high fruit yields in the intensive orchards of the Tai Lake Basin.

Growth and nitrogen productivity of drip-irrigated winter wheat under different nitrogen fertigation strategies in the North China Plain

Excessive application of nitrogen (N) fertilizer is the main cause of N loss and poor use efficiency in winter wheat (Triticum aestivum L.) production in the North China Plain (NCP).Drip fertigation is considered to be an effective method for improving N use efficiency and reducing losses,while the performance of drip fertigation in winter wheat is limited by poor N scheduling.A two-year field experiment was conducted to evaluate the growth,development and yield of drip-fertigated winter wheat under different split urea (46%N,240 kg ha^(-1)) applications.The six treatments consisted of five fertigation N application scheduling programs and one slow-release fertilizer (SRF) application.The five N scheduling treatments were N0–100 (0%at sowing and 100%at jointing/booting),N25–75 (25%at sowing and 75%at jointing and booting),N50–50(50%at sowing and 50%at jointing/booting),N75–25 (75%at sowing and 25 at jointing/booting),and N100–0 (100%at sowing and 0%at jointing/booting).The SRF (43%N,240 kg ha^(-1)) was only used as fertilizer at sowing.Split N application significantly (P<0.05) affected wheat grain yield,yield components,aboveground biomass (ABM),water use efficiency(WUE) and nitrogen partial factor productivity (NPFP).The N50–50 and SRF treatments respectively had the highest yield(8.84 and 8.85 t ha^(-1)),ABM (20.67 and 20.83 t ha^(-1)),WUE (2.28 and 2.17 kg m^(-3)) and NPFP (36.82 and 36.88 kg kg^(-1)).This work provided substantial evidence that urea-N applied in equal splits between basal and topdressing doses compete economically with the highly expensive SRF for fertilization of winter wheat crops.Although the single-dose SRF could reduce labor costs involved with the traditional method of manual spreading,the drip fertigation system used in this study with the N50–50 treatment provides an option for farmers to maintain wheat production in the NCP.

Effect of fertigation frequency on soil nitrogen distribution and tomato yield under alternate partial root-zone drip irrigation

Alternate partial root-zone drip fertigation (ADF) is a combination of alternating irrigation and drip fertigation,with the potential to save water and increase nitrogen (N) fertilizer efficiency.A 2-year greenhouse experiment was conducted to evaluate the effect of different fertigation frequencies on the distribution of soil moisture and nutrients and tomato yield under ADF.The treatments included three ADF frequencies with intervals of 3 days (F3),6 days (F6) and 12 days (F12),and conventional drip fertigation as a control (CK),which was fertilized once every 6 days.For the ADF treatments,two drip tapes were placed 10 cm away on each side of the tomato row,and alternate drip irrigation was realized using a manual valve on the distribution tapes.For the CK treatment,a drip tape was located close to the roots of the tomato plants.The total N application rate of all treatments was 180 kg ha^(-1).The total irrigation amounts applied to the CK treatment were450.6 and 446.1 mm in 2019 and 2020,respectively;and the irrigation amounts applied to the ADF treatments were 60%of those of the CK treatment.The F3 treatment resulted in water and N being distributed mainly in the 0–40-cm soil layer with less water and N being distributed in the 40–60-cm soil layer.The F6 treatment led to 21.0 and 29.0%higher 2-year average concentration of mineral N in the 0–20 and 20–40-cm soil layer,respectively and a 23.0%lower N concentration in the 40–60-cm soil layer than in the CK treatment.The 2-year average tomato yields of the F3,F6,F12,and CK treatments were 107.5,102.6,87.2,and 98.7 t ha^(-1),respectively.The tomato yield of F3 was significantly higher (23.3%) than that in the F12 treatment,whereas there was no significant difference between the F3 and F6 treatment.The F6 treatment resulted in yield similar to the CK treatment,indicating that ADF could maintain tomato yield with a 40%saving in water use.Based on the distribution of water and N,and tomato yield,a fertigation frequency of 6 days under ADF should be considered as a water-saving strategy for greenhouse tomato production.

Simulation of water and nitrogen dynamics as affected by drip fertigation strategies

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.

Effect of Long-term Drip Fertigation on Root Growth of Lychee and Soil pH

Through field experiment,we explore the impact of long-term drip fertigation on growth and distribution of lychee root and changes of soil pH in different layers of soil in lychee garden.The results show that drip fertigation can significantly promote the growth of lychee roots,and increase the contact area of root and soil;if it experiences six years of drip fertigation successively,the dry weight of root,root length and surface area of root in soil in drip fertigation area,will be 2.29 times,2.17 times and 2.25 times that in non-drip fertigation area,respectively.The lychee root is mainly distributed in 0-40 cm layer of soil,but there is conspicuous difference between drip fertigation area and non-drip fertigation area in terms of root distribution in 0-20 cm and 20-40 cm layer of soil.Drip fertigation is more favorable for the root to go deep inside the soil.Under long-term drip fertigation,the soil acidification in lychee garden is prominent,and in comparison with non-drip fertigation area,there is the greatest decline in soil pH in 10-20 cm layer of soil in drip fertigation area,reaching 1.47 units.

Root Characters of Maize as Influenced by Drip Fertigation Levels

The efficient use of water by modern irrigation systems is becoming increasingly important in arid and semi-arid regions with limited water resources. Field experiments were conducted during 2008-2010 to study the effect of drip fertigation with water soluble fertilizer on root growth of maize under maize based intercropping system. The experiment was laid out in strip plot design with three replications. The treatment consists of nine fertigation levels in main plots and four inter crops in sub plots. Root spread and root dry mass were increased under drip fertigation practices while rooting depth was more under surface irrigation. Drip fertigation with water soluble fertilizer improved the root system by inducing new secondary roots which are succulent and actively involved in physiological responses. Drip fertigation has pronounced effect on the root architecture especially in the production of highly fibrous root system.

Main Methods Applied in Fertigation Technology

In order to better promote extension and application of fertigation technology,this paper elaborates major technical issues. It presents pipeline diameter control and increasing the uniformity in selection of methods of irrigation system types and in the process of system design. Besides,it introduces characteristics and use methods of main fertilizer application equipment,filter,and control devices. In addition,it lists amount of fertilizer application and irrigation according to target yield of crops,and describes major attentions for selection of fertilizers,irrigation,and soil moisture control.

Effects of fertigation scheme on N uptake and N use efficiency in cotton

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.

滴灌施肥频率对烤烟生长、氮肥利用及烟叶产质量的影响

为探明滴灌施肥频率对烤烟生长、氮肥利用及烟叶产质量的影响,2018-2019年通过田间试验,以不施肥空白(CK)和当地常规处理(CF,即肥料干施+滴灌)为对照,研究低频滴灌施肥(DF1,即养分管理期1次滴灌施肥)、中频滴灌施肥(DF2,即养分管理期连续2天每天1次滴灌施肥)和高频滴灌施肥(DF3,即养分管理期连续3天每天1次滴灌施肥)对烤烟农艺性状、根系发育形态、氮肥累积量和利用效率及烟叶产质量的影响。结果表明,与CF相比,各滴灌施肥处理烟叶产量无显著差异(P<0.05),氮肥利用率有不同程度提高,烟株发育状况则因滴灌施肥频率而异。与DF1和DF2相比,DF3烟株旺长期叶面积系数分别增加了7.3%~33.3%和1.6%~28.7%,根系体积分别增加了3.9%~46.6%和21.2%~40.5%,氮素利用率分别提高了39.0%~95.0%和21.5%~34.3%,烟叶烟碱含量分别增加了17.5%~28.5%和12.5%~20.0%。与中频滴灌施肥和低频滴灌施肥相比,高频滴灌施肥有利于促进烟株生长和根系形态发育,提高氮肥利用效率和烟叶品质质量,是有效协同氮肥高效利用和烟叶产质量的滴灌施肥措施。

“以肥调水”缓解干旱对无膜滴灌棉花生理特性和产量的影响

【目的】研究“以肥调水”缓解干旱对南疆无膜滴灌棉花生理生长的调控作用,提高水资源限制条件下棉花产量。【方法】以中棉619为供试材料,设置亏缺灌溉(W1:45 mm)和充分灌溉(W2:54 mm)2种灌水定额,低氮(F1:150 kg·hm^(-2))、中氮(F2:225 kg·hm^(-2))和高氮(F3:300 kg·hm^(-2))3个施氮量,分析不同灌水定额和施氮量对棉花生理生长指标和籽棉产量的影响。【结果】灌水定额的增加促进了棉花生长,提高了棉花2年平均叶面积指数(leaf area index,LAI)、叶绿素相对含量(soil and plant analyzer development,SPAD值)和净光合速率(net photosynthetic rate,Pn),降低了棉花超氧化物歧化酶(superoxide dismutase,SOD)、过氧化氢酶(catalase,CAT)、过氧化物酶(peroxidase,POD)活性和丙二醛(malondialdehyde,MDA)含量。随着施氮量的增加,棉花2年平均LAI、SPAD值、抗氧化酶活性和Pn随之增加,MDA含量减少,棉花受水分亏缺的影响减轻。W1处理下施氮量的增加提高了棉花产量,W2处理下随着施氮量的增加棉花产量呈先增后减趋势,在水氮交互作用下,W2F2处理下2年平均产量最高(6821.86 kg·hm^(-2)),其次是W1F3处理(6717.72 kg·hm^(-2))。在优劣解距离法(technique for order preference by similarity to ideal solution,TOPSIS)分析中,W1F3和W2F2处理的综合评分较为接近,分别为0.57和0.56,并且W1F3和W2F2处理下籽棉产量差异不显著。【结论】亏缺灌溉下增加施氮量可有效缓解干旱对棉花生理性状和籽棉产量的不利影响。推荐南疆无膜滴灌棉田45 mm灌水定额(生育期灌水10次)搭配300 kg·hm^(-2)施氮量作为灌溉和施肥策略,以保障在水资源限制条件下的棉花产量。

Wetting Patterns and Nitrate Distributions in Layered-Textural Soils Under Drip Irrigation

Laboratory experiments were conducted in different sequence and thickness of the soil layers to investigate the effects of layered-textural soils on wetting patterns and water and nitrate distributions from a surface point source under various combinations of application rate and applied volume. Three layered soils, including a sandy-over-sandy loam （SL）, a sandy loam-over-sandy （LS）, and a sandy loam-sandy-sandy loam （LSL）, and two uniform soils （a uniform sandy loam and a uniform sandy soil） were tested. In the experiments, the application rate was varied from 0.69 to 3.86 L h^-1 and the applied volume from 5.7 to 12.1 L. The experimental results demonstrated that the wetting patterns and water and nitrate distributions were greatly affected by the sequence and thickness of soil layers as well as the application rate and volume applied. An interface existing in the layered soils, whether a fine-over-coarse or a coarse-over-fine, had a common feature of limiting downward water movement and of increasing horizontal water movement. For the fine-over-coarse layered soils of LS and LSL, water and nitrate were uniformly distributed at a given depth in the top layer soil. For a coarse-over-fine layered soil of SL, however, water accumulated in the sublayer soil underneath the interface and a zone of lower nitrate concentration was observed. The effect of application rate on water distribution pattern was dependent upon soil layering. A minor influence of application rate on water distribution for the fine-over-coarse layered soils （LS and LSL） than for the uniform soils was found. To obtain a greater wetted depth through selecting the emitters having a smaller application rate, which is a common method in the system design for a uniform soil, may not be necessarily applied for the layered soils. Measurements of nitrate distribution showed that nitrate accumulated toward the boundary of the wetted volume for both the uniform and the layered soils. This suggests the importance of optimal management of drip fertigation because nitrate is susceptible to the movement out of the root zone by mismanagement of fertigation. The information obtained from this research is useful in the design, operation, and management of a drip fertigation system.

Water and nutrient management effects on water use and yield of drip irrigated citrus in vertisol under a sub-humid region

Scarcity of water and nutrients in orchards are the major causes of low productivity and decline of citrus in tropics. With a hypothesis that the optimal amount of water and nutrients application through drip irrigation （DI） could save substantial irrigation and fertilizers comparative to that under traditional basin irrigation （BI） with band placement of fertilizer （BPF）, this study was conducted in citrus in vertisol of central India. Three DI regimes： I1, I2 and I3 scheduled at 50% class-A pan evaporation rate （Ep）, 75% Ep, and 100% Ep atong with three fertilizer doses： F1, F2 and F3 at 50% recommended dose of fertilizer （RDF, N：P2Os：K20=600 g：200 g：100 g）, 75% of RDF and 100% of RDF were applied to mandai＇in plants respectively. BI with band placement of fertilizer （BPF） at 100% RDF was taken for comparison. All the drip-fertigation treatments （except I1F1） produced higher plant growth and fruit yield, with better quality fruits compared with BI＋BPF. The highest fruit yield （16.39t ha^-1）, water use efficiency （3.9 kg m^-3） and fertilizer use efficiency （87.3 kg kg^-1） were observed in I2F2. The concentrations of N, K and Fe in leaves were significantly higher in I2F2 compared to other treatments. The leaf photosynthesis, stomatal conductance （G） and transpiration were the highest in I3F3. However, leaf water use efficiency （LWUE, photosynthesis/transpiration） was the highest in I2F2. The overall results of this study demonstrated that the application of optimum quantity of water and fertilizers （I2F2） through DI could be a productive and water efficient option in citrus production in vertisol.

肥料种类与浓度对灌水器堵塞特征的影响及防堵策略

为降低堵塞风险,延长灌溉系统使用寿命,提高灌溉施肥均匀度,研究通过3种滴灌带(管)水肥一体化长周期堵塞试验,测试尿素、硫酸钾、氯化钾、磷酸一铵、磷酸二铵在不同浓度(0、0.4、0.8、1.0、1.2 g/L)滴灌时各灌水器堵塞性能,结合场发射扫描电镜、EDS表面能谱分析和X射线衍射仪等物质分析方法,探究肥料种类及浓度对灌水器堵塞及堵塞物质累积的影响,并揭示水肥一体化滴灌灌水器化学堵塞形成过程。结果显示:不同肥料种类、浓度对迷宫灌水器造成的影响不同。随着浓度增加,尿素灌溉下侧翼迷宫滴灌带相对流量下降速率加快,存在堵塞风险;磷酸二铵灌溉下,发生明显堵塞;片状滴灌带相对平均流量和灌溉均匀系数随灌水次数增加而降低,且降幅随肥液浓度增大而增大。堵塞物干质量都随着灌水次数的增加而增加,与灌水器的相对流量和灌溉均匀系数随着灌水次数的增加而降低的趋势吻合。随着肥液浓度的升高,水流剪切力对堵塞物质影响越小。因此,磷酸二铵的施肥浓度以不超过1.2 g/L为宜。研究可为控制滴灌系统化学堵塞、延长灌水器使用寿命提供依据。

膜下滴灌减量施肥对甘蔗农艺性状、产量和养分利用率的影响

探讨不同膜下滴灌减量施肥模式对甘蔗生长、产量和肥料利用率的影响,分析最佳减肥模式,为科学指导甘蔗膜下滴灌施肥技术应用提供理论依据。以空白对照(CK_(0))、常规施肥(CK_(1))和滴灌+常规施肥(CK_(2))为对照,设置1个膜下滴灌施肥处理T_(100)(施肥量同CK_(1))以及3个膜下滴灌减量施肥处理T_(80)、T_(70)和T_(60)(减量20%、30%和40%),对甘蔗主要农艺性状、产量、蔗糖分、产糖量、经济效益及养分利用率等生产指标进行比较分析。结果表明:相较于CK_(1),增加滴灌的CK_(2)有效茎数明显提高,而T_(100)在分蘖率、株高、有效茎数、成茎率方面均显著提升,T_(80)和T_(70)则主要对有效茎数和成茎率促进明显。在产量方面,相对CK_(1),CK_(2)及T_(100)、T_(80)、T_(70)均显著增加,2年平均产量分别提升了13.64%、32.20%、27.00%和20.18%。在各滴灌施肥处理间,相对于T_(100),T_(80)产量并无显著变化,而T_(70)和T_(60)产量显著减少。在蔗糖分和产糖量方面,各滴灌施肥处理间蔗糖分并无显著差异,而产糖量与产量变化趋势基本一致,T_(100)和T_(80)产糖量最高,且二者间无显著差异。在纯收益方面,仅有T_(100)和T_(80)较CK_(1)获得显著增加,2年平均收益分别增加4534.4元/hm~2和3953.8元/hm~2。T_(70)和T_(60)纯收益相较于T_(100)则呈现显著下降,其中T_(60)纯收益甚至比CK_(1)还低2350元/hm~2。在肥料利用率方面,所有滴灌施肥处理氮、磷、钾肥利用率均显著高于CK_(1),其中T_(80)肥料利用率最高,2年试验平均氮、磷、钾肥利用率分别达到48.36%、27.70%和68.95%,分别较CK_(1)提高了28.42、17.95和30.71个百分点。综合来看,在中等肥力砖红壤蔗区,采用T_(80)膜下滴灌减量施肥模式,可以同时获得较理想的甘蔗产量和收益。

玉米大垄双行浅埋滴灌水肥一体化栽培技术

玉米大垄双行浅埋滴灌水肥一体化栽培技术是适宜齐齐哈尔地区的玉米高产高效栽培模式,按需分次精准灌溉与施肥能显著提高水分和肥料利用率,省时省力,增产增效。本文从滴灌系统安装、精细整地、科学选择品种、适期播种、加强田间管理、病虫害绿色防控、适时收获等方面介绍了玉米大垄双行浅埋滴灌水肥一体化栽培技术。

不同微灌溉施肥模式对冬小麦产量和效益的影响

研究不同微灌溉施肥模式对冬小麦产量和效益的影响,可为冬小麦高效灌溉施肥提供理论依据。采用裂区试验设计,以微灌溉施肥模式(微喷灌施肥、滴灌施肥)为主区,氮磷施用量(N_(0)P_(120)、N_(180)P_(0)、N_(120)P_(120)、N_(180)P_(120)、N_(240)P_(120)、N_(180)P_(60)和N_(180)P_(150))为副区,随机排列,重复3次,研究了不同灌溉施肥模式和氮磷肥料运筹对冬小麦产量和经济效益的影响。结果表明:相同施肥水平下,微喷灌溉施肥模式的小麦产量和经济效益均高于滴灌施肥模式,2 a指标平均值分别提高了8.24%和12.00%;相同灌溉施肥模式下,均以N_(180)P_(120)处理的产量和经济效益最高。但滴灌施肥模式较微喷灌施肥模式平均节水187.5 m3/hm^(2),节水率9.26%。微喷灌施肥模式的冬小麦增产增收效果较好,该模式下N施用量为180 kg/hm^(2)、P_(2)O_(5)施用量为120 kg/hm^(2)时产量达到最高,为9405.04 kg/hm^(2)。

水肥光耦合对小粒咖啡生长特性及水肥利用的影响

为探明小粒咖啡灌溉、施肥和遮荫高效管理模式,设置灌水(W_(L):0.8 ET_(P),W_(M):1.0 ET_(P)和W_(H):1.2 ET_(P),其中ET_(P)为水面蒸发量)、施肥(F_(L)∶N∶P_(2)O_(5)∶K_(2)O=90.8∶90.8∶90.8 kg/hm^(2),F_(M)∶N∶P_(2)O_(5)∶K_(2)O=181.6∶181.6∶181.6 kg/hm^(2)和F H∶N∶P_(2)O_(5)∶K_(2)O=272.4∶272.4∶272.4 kg/hm^(2))和遮荫(NS:自然光照和S:30%遮荫度)三因素完全组合试验,研究不同灌溉、施肥和遮荫对小粒咖啡冠层结构、光合特性、水肥利用以及干物质累积的影响,同时拟合不同水肥光条件下光合指标日变化.结果表明,提高灌溉水平和遮荫度会显著降低冠层开度,增加叶面积指数、净光合速率和蒸腾速率.与NS相比,处理S光合特性日变化拟合曲线为“单峰”,同时对干物质累积量、灌溉水分利用效率和肥料偏生产力分别提高6.24%,11.21%和11.54%.提高灌溉水平能增加干物质累积量与肥料偏生产力,但降低了灌溉水分利用效率.与F_(L)相比,F_(H)提高干物质累积量和灌溉水分利用效率分别为20.59%,6.94%,F_(M)分别提高23.00%和7.63%.由极差分析及综合评分法得出,W_(M)F_(L)S组合的小粒咖啡干物质累积量与水肥利用的综合效益最大.研究结果可为小粒咖啡高效生产提供实践参考.

不同滴灌施肥模式对切花菊生物量、品质和养分吸收的影响

【目的】切花菊生产中普遍存在施肥过量和施肥方式不当的问题,通过比较4种施肥处理对切花菊形态指标、品质和养分吸收的影响,筛选最适切花菊生产的施肥体系,为切花菊减肥增效栽培提供理论依据。【方法】以切花菊‘白扇’为试材,设置分别在智能水肥一体化机设备和施肥罐机器下,追施水溶肥7次(S1、S2)和追施4次(T1、T2)4个处理,每次追肥量相同(75 kg/hm^(2))。在定植后35、62和85天,调查切花菊农艺指标、花部性状、植株氮磷钾含量及土壤氮磷钾含量。【结果】与施肥罐机器施肥(S2、T2处理)相比,定植62天时,采用智能水肥一体化机设备施肥(S1、T1处理)提高了切花菊的株高、茎粗、地上鲜重、地上干重、地下鲜重和地下干重,T1处理的效果又好于S1处理;定植85天时,T1处理切花菊株高高于S2和T2处理,花径和出花率与S1和S2处理无显著差异。定植35天时,T1处理的植株钾含量高于其他3个处理;定植62天时,T1处理植株茎叶中磷、钾含量高于其他3个处理;定植85天时,T1处理植株根中的磷、钾含量均最高。T1处理也增加了定植62和85天后土壤有效磷和速效钾含量。【结论】采用智能水肥一体化机设备条件下,将追施肥次数由7次减至4次,施肥量由525 kg/hm^(2)降低到375 kg/hm^(2),改善了切花菊‘白扇’的农艺性状和花部性状,促进了植株对养分的吸收利用,并提高了土壤有效磷和速效钾含量,而使用施肥罐机器的减肥增效效果不明显。因此,切花菊生产中应推广利用智能水肥一体化机设备,以实现减肥增效。

不同水质滴灌与施氮措施下土壤盐分及关键离子变化研究

【目的】探明不同滴灌水质和施氮量对土壤盐分及关键离子变化的影响。【方法】基于棉花盆栽试验,设置3个施氮水平,分别为:F1(255 kg/hm^(2))、F2(315 kg/hm^(2))和F3(375 kg/hm^(2));3个滴灌水质,分别为:Q1(矿化度为1.27 g/L),Q2(矿化度为3.03 g/L)和Q3(矿化度为4.90 g/L),分析不同滴灌水质与施氮水平下的土壤盐分及关键离子的响应差异。【结果】棉花生育末期,微咸水与咸水滴灌下的土壤总盐量与Na^(+)、Ca^(2+)物质的量浓度分别相比地下水滴灌高14%~78%、42%~197%与58%~253%;土壤钠吸附比(SAR)与可交换性钠百分比(ESP)相比地下水滴灌提高了5%~109%与48%~90%;较高施氮量(315、375 kg/hm^(2))下的土壤总盐量、Na^(+)、Ca^(2+)物质的量浓度相比低施氮量(255 kg/hm^(2))降低了11%~70%、6%~42%与21%~138%,土壤SAR与ESP分别降低了5%~27%与3%~19%。【结论】土壤盐分总量随着滴灌水质矿化度的增加而增加,适宜的施氮量(315kg/hm^(2))能够降低土壤盐分总量和关键离子量,缓解土壤盐碱化。

辽西北风沙土滴灌追氮次数对玉米生长和产量的影响

【目的】合理确定风沙土地区玉米滴灌氮肥追施次数。【方法】采用田间试验的方法,将生育期的追施氮肥以水肥一体化的形式分次追施,研究不同追氮次数,1次(F1)、2次(F2)、4次(F3)、7次(F4)和11次(F5)5种追氮次数对玉米生长和产量的影响。【结果】拔节期集中追施或抽穗期前分多次追施有利于玉米株高、茎粗和叶片生长,获得较大的LAI和叶片SPAD值。分多次追肥玉米考种指标,如穗长、穗粗、行粒数、百粒质量等均优于集中施肥,从而有利于产量形成。产量不仅与追氮次数有关,还与氮肥在各生育阶段的配比有关,当抽穗期及灌浆期追肥比例相对较小时,尽管全生育期追氮次数较多,但行粒数和百粒质量等指标偏小,导致产量和肥效偏低;在满足关键期需肥时,追肥分次越多,越有利于产量形成,生育期内追肥11次获得最高产量、IWUE、WUE和氮效率分别为7.36 t/hm^(2)、3.27 kg/m^(3)、1.25 kg/m^(3)和24.52 kg/kg。【结论】少量多次的追肥方式是促进玉米植株生长和提高产量的有效途径,在辽西北风沙土地区玉米滴灌追氮次数以11次为宜。