基于磷肥施用深度的夏玉米根层调控提高土壤氮素吸收利用

陈晓影 刘 鹏 程 乙 董树亭 张吉旺 赵 斌 任佰朝 韩 坤

基于磷肥施用深度的夏玉米根层调控提高土壤氮素吸收利用

陈晓影 刘 鹏*程 乙 董树亭 张吉旺 赵 斌 任佰朝 韩 坤

作物生物学国家重点实验室 / 山东农业大学农学院, 山东泰安 271018

良好的根系构型能够促进作物高效获取土壤养分。基于磷肥施用深度的根层调控技术可以优化夏玉米根系的时空分布并促进其与土壤水分、养分供应的空间匹配性, 为通过玉米根系挖潜实现节肥增效提供理论与技术支撑。本试验以不施磷肥处理为对照(CK), 设置距离地表−5 cm (P5)、−10 cm (P10)、−15 cm (P15)和−20 cm (P20)深度施用磷肥处理, 分析各处理对夏玉米根系分布、植株生长及产量形成、氮素吸收、积累与转运的影响。结果表明, 磷肥适当深施显著促进夏玉米根系生长, 根干重、根长密度、根系表面积和根体积均显著增加, 整体表现为P15>P10>P20>P5>CK。随着磷肥施用深度的增加, 深层玉米根系显著增加。P15和P20处理根干重所占比重, 在20~40 cm土层分别为12.3%和12.1%; 在40~60 cm土层分别为6.7%和6.9%。根系分布深度的增加促进了对土壤氮素的吸收, 深施磷肥处理各土层中尤其是20 cm以下土层土壤氮素含量显著降低。根系分布的优化同时促进了植株氮素积累与转运, P15处理较P5处理氮素吸收效率、氮积累量、转运量及氮肥偏生产力2年平均分别提高14.5 kg kg–1、19.2%、48.9%和6.4 kg kg–1, 籽粒产量2年平均增产16.4%。在本试验条件下, 磷肥集中施用在−15 cm处理, 能显著促进夏玉米深层土壤根系的生长, 扩大根系养分利用空间, 增加根系对深层土壤氮素的吸收, 促进植株氮素积累及转运, 提高其生产力, 最终提高产量。

夏玉米; 施磷深度; 根系; 产量; 氮素吸收利用

作物生产既要满足全球不断增长的人口对粮食生产日益增长的需求, 还要尽量高效利用资源、避免环境污染。优化肥料施用方式是实现作物高产高效的有效途径之一[1-2]。肥料用量及施用方式对根系具有较强的调控作用[3-4]。根层调控技术是挖掘根系生物学潜力、提高肥料的利用效率的有效途径[5-6]。根系对作物水分、养分获取有重要作用, 在发育过程中具有高度的可塑性[7-9]。良好的根系构型能够促进作物高效获取土壤养分。磷在土壤中的扩散能力较差, 其扩散系数仅为10–12~10–15m2s–1[10], 土壤有效磷主要分布在土壤表层[11], 因此作物高效获取土壤“磷”资源的理想根系构型为“表层觅食型”[12-13]。而土壤中的硝态氮在作物生长季节随降水淋洗或水位下降而移动到深土层, 氮高效的理想根系构型为“Steep, cheap, deep型”[14-15], 该理想根构型通过增加深层土壤中的根系、提高硝态氮的吸收, 从而降低氮的淋洗并提高氮利用效率[16-17]。

土壤中氮、磷空间分布的异质性, 使高效利用二者的根系构型存在一定的矛盾, 如何协调这种矛盾, 实现土壤氮磷养分协调吸收成为促进作物增产增效的重要问题[18]。磷肥用量及施用方式对根系分布有重要调控作用, 可以促进合理根系构型的建成, 改变土壤中根系的时空分布[19-21], 可将根际养分供应强度与根系生长分布的平衡调整到最佳状态, 在时间和空间上充分发挥根系生物学潜力, 提高肥料的利用效率[22-23]。前人已就肥料施用方式对作物生产能力、养分利用效率和损失进行了广泛研究[24-26]。但基于磷肥施用深度的夏玉米根层调控对挖掘作物根系生物学潜力, 提高深层土壤氮素利用效率的机理研究相对较少。该研究对夏玉米根系时空分布及其与氮素供应空间匹配性的优化效应, 为建立有效的作物高产根系调控技术、实现以根系挖潜节肥增效为核心的玉米高产高效栽培提供理论与技术支撑。

1 材料与方法

1.1 试验时间地点

2017—2018年在泰安市岱岳区马庄镇(35°58′N, 116°58′E)进行试验, 试验点地处温带大陆性季风气候区, 作物种植体系为冬小麦/夏玉米一年两熟。试验田为壤土, 试验前0~20 cm、20~40 cm、40~60 cm土壤样品理化性质见表1。试验田夏玉米全生育期平均温度与日降水量见图1。

表1 试验田养分含量

图1 试验田夏玉米生育期平均温度与降水量

1.2 试验设计

供试夏玉米品种为登海605 (DH605)。试验以不施磷肥处理为对照(CK), 磷肥用量为P2O5105 kg hm–2, 共设置4个施肥深度, 分别为距离地表−5 cm (P5)、−10 cm (P10)、−15 cm (P15)和−20 cm (P20)深度处施肥。于小麦收获后表层撒施纯氮315 kg hm–2和K2O 270 kg hm–2, 然后结合小麦灭茬旋耕5 cm。利用经改造后的深松条带式施肥机深松20 cm, 同时将磷肥施用在设计深度。试验采用随机区组设计, 3次重复, 种植密度为67,500株 hm–2, 行距60 cm, 株距25 cm。小区面积180 m2(长30 m、宽6 m)。试验所用肥料为缓控尿素(含纯N 42%)、过磷酸钙(含P2O511%)、硫酸钾(含K2O 50%), 均一次性施入。玉米生育期给予良好的管理并保证水分供应。

1.3 测定项目与方法

1.3.1 植株干物质 于抽雄期(VT)、灌浆期(R2)、完熟期(R6), 从每小区选取有代表性的植株5株。将其分成叶片、茎(茎秆、叶鞘、雄穗)、苞叶、穗轴和籽粒, 105℃杀青30 min后80℃烘至恒重, 测定干物质积累量。

1.3.2 根系取样与测定 于抽雄期(VT)对根系取样, 选择连续且生长均匀一致的植株5株, 以植株为中心, 行距方向半径取30 cm, 株距方向半径取10 cm, 每10 cm为一土层, 取样深度为60 cm。将每一土层挖出的根土混合物装入40目网袋, 在低水压下冲洗干净并挑出全部根系, 放入密封袋中1℃下保存。将根系样品用Epson Perfection V700 Photo扫描仪扫描, 然后使用WinRhizo 2016根系分析软件测定根系相关指标, 计算根长密度。将扫描完成的根系放在烘箱中烘至恒重并称干重。

1.3.3 产量及产量构成因素 于完熟期(R6)选取每小区18 m2(10.0 m×1.8 m)有代表性的玉米带, 将其全部果穗收获后晒干, 测定产量及产量构成因素。

1.3.4 植株与土壤全氮含量 将玉米植株与土壤样品研磨过筛后用H2SO4-H2O2联合消煮, 用BRAN＋LUEBBE III型(德国)连续流动分析仪测定氮素含量。

1.4 数据处理与分析

植株氮素积累量(kg hm–2)=单株重×单株含氮量×公顷株数;

营养器官氮素转运量(kg hm–2)=灌浆期营养器官氮素积累量−完熟期营养器官氮素积累量;

氮素转运效率(%)=营养器官氮素转运量/灌浆期营养器官氮素积累量×100;

氮素吸收效率(NAE, kg kg–1)=植株氮素积累量/施氮量;

氮素偏生产力(NPFP, kg kg–1)=籽粒产量/施氮量;

采用Microsoft Excel 2017和DPS 15.10统计软件LSD法进行方差分析, 用SigmaPlot l0.0作图。

2 结果与分析

2.1 磷肥深施对土壤根系分布的影响

磷肥适当深施显著促进夏玉米根系生长, 根干重(RDW)、根长密度(RLD)、根系表面积(RSA)以及根体积(RV)均显著增加, 整体表现为P15>P10>P20> P5>CK (图2)。与CK处理相比, P5、P10、P15和P20处理2年的平均RDW分别提高31.6%、41.6%、44.2%和36.7%, RLD分别提高42.9%、62.3%、72.9%和52.1%, RSA分别提高27.5%、46.6%、48.8%和33.5%, 而RV提高33.7%、44.8%、48.9%和42.3%。2年试验趋势一致, 年度间差异较大的原因是年际间降水量的差异。

图2 磷肥施用深度对夏玉米植株根系性状的影响

标以不同字母的柱值间差异达0.05显著水平。CK: 不施磷肥; P5: 距离地表−5 cm处施磷; P10: 距离地表−10 cm处施磷; P15: 距离地表−15 cm处施磷; P20: 距离地表−20 cm处施磷。

Bars superscripted by different letters are significantly different among treatments at the 0.05 probability level. CK: no P applied; P5: phosphorus application depth was −5 cm; P10: phosphorus application depth was −10 cm; P15: phosphorus application depth was −15 cm; P20: phosphorus application depth was −20 cm. RDW: root dry weight; RLD: root length density; RSA: root surface area; RV: root volume.

磷肥施用位置可以调控夏玉米根系在土层中的分布, 随着磷肥施用深度的增加, 深层玉米根系生长显著增加, 其所占整体根系的比例也增大(图3和图4)。以2018年为例, 在0~10 cm土层, 以P5处理的RDW所占比例最大。10~20 cm土层, P10处理所占比例最大, 为20.1%; 20~40 cm土层, P15和P20处理RDW所占比重分别为12.3%和12.1%; 40~60 cm土层, P15和P20处理RDW所占比重分别为6.7%和6.9%。与P5处理相比, P10、P15和P20处理在20~40 cm土层内, RLD分别增加20.2%、27.7%和14.0%, RSA分别增加24.4%、28.3%和10.2%, 而RV则增加27.8%、41.2%和33.0%; 在40~60 cm土层, RLD增加12.4%、26.6%和17.7%, RSA增加21.8%、24.9%和30.5%, 而RV则增加28.0%、53.2%和55.3%。

图3 不同深度土层中根系干重占整体根干重的比例

P5: 距离地表−5 cm处施磷; P10: 距离地表−10 cm处施磷; P15: 距离地表−15 cm处施磷; P20: 距离地表−20 cm处施磷。

P5: phosphorus application depth was −5 cm; P10: phosphorus application depth was −10 cm; P15: phosphorus application depth was −15 cm; P20: phosphorus application depth was −20 cm.

图4 不同深度土层中的根系分布(2018)

CK: 不施磷肥; P5: 距离地表−5 cm处施磷; P10: 距离地表−10 cm处施磷; P15: 距离地表−15 cm处施磷; P20: 距离地表−20 cm处施磷。

CK: no P applied; P5: phosphorus application depth was −5 cm; P10: Phosphorus application depth was −10 cm; P15: phosphorus application depth was −15 cm; P20: phosphorus application depth was −20 cm. RDW: root dry weight; RLD: root length density; RSA: root surface area; RV: root volume.

2.2 磷肥深施对植株干物质积累及籽粒产量的影响

与传统施磷相比, 深施磷肥处理显著增加了植株干物质积累, 趋势为P15>P10>P20>P5>CK (图5)。VT期单株干物质积累量P10、P15和P20处理较P5处理2年平均增加9.1%、13.6%和7.3%; R6期2年平均提高6.6%、14.5%和8.2%。磷肥适当深施增加了夏玉米籽粒产量, 各处理产量表现为P15>P10>P20>P5>CK, P10、P15、P20较P5两年平均增产8.2%、16.4%、9.0%。

植株生物量、籽粒重与根干重、根长密度均呈现显著线性正相关(<0.001), 且相关系数较大, 说明玉米根系增殖有利于植株的干物质积累及产量形成(图6)。

2.3 磷肥深施对植株氮素吸收、积累及利用的影响

与传统施磷处理相比, 深施磷肥处理在各土层中尤其是20 cm以下土层中氮素含量显著降低(图7)。磷肥适当深施促进了土壤中根系的增殖, 增大了根系与土壤的接触面积, 提高了根系对氮素的吸收, 阻止氮素向深层土壤中运移。同时, 深层土壤根系的增加增大了根系对水分和养分的吸收利用空间, 促进了对深层土壤中氮素的吸收。

图5 磷肥施用深度对夏玉米植株生物量与籽粒理论产量的影响

标以不同字母的柱值间差异达0.05显著水平。CK: 不施磷肥; P5: 距离地表−5 cm处施磷; P10: 距离地表−10 cm处施磷; P15: 距离地表−15 cm处施磷; P20: 距离地表−20 cm处施磷。

Bars superscripted by different letters are significantly different among treatments at the 0.05 probability level. CK: no P applied; P5: phosphorus application depth was −5 cm; P10: phosphorus application depth was −10 cm; P15: phosphorus application depth was −15 cm; P20: phosphorus application depth was −20 cm.

图6 单株生物量、籽粒重与根干重、根长密度的关系

RDW: root dry weight; RLD: root length density;***< 0.001.

图7 不同土层氮素的分布

CK: 不施磷肥; P5: 距离地表−5 cm处施磷; P10: 距离地表−10 cm处施磷; P15: 距离地表−15 cm处施磷; P20: 距离地表−20 cm处施磷。

CK: no P applied; P5: phosphorus application depth was −5 cm; P10: phosphorus application depth was −10 cm; P15: phosphorus application depth was −15 cm; P20: phosphorus application depth was −20 cm; VT: tasseling; R6: physiological maturity.

适当深施磷肥有利于玉米植株氮素积累。2017年R6期P10、P15、P20处理与P5处理相比整株氮积累量分别提高了12.5%、25.8%、14.4%, 2018年相应提高了1.7%、12.7%、5.9% (表2)。

磷肥适当深施也促进营养器官中氮素向籽粒的转运, 2017年各处理的转运量为34.7~64.2 kg hm–2, 2018年为46.9~67.4kg hm–2, 其中P15处理转运量及转运率显著高于其他处理(表2)。适当深施磷肥提高了夏玉米的氮素吸收效率及偏生产力。与P5处理相比, P10、P15、P20处理2年平均氮素吸收效率提高4.1、14.5 和8.9 kg kg–1; 氮肥偏生产力分别增加3.4、6.4和2.8 kg kg–1(表2)。籽粒氮积累量、氮素吸收效率、氮肥偏生产力与根干重、根长密度均呈现显著线性正相关(<0.001), 且相关系数较大, 说明玉米根系的增殖有利于氮素吸收、积累与利用(图8)。

表2 磷肥施用深度对植株中氮积累量、转运及吸收利用的影响

(续表2)

同列标以不同字母的值在处理间差异达0.05显著水平。CK: 不施磷肥; P5: 距离地表–5 cm处施磷; P10: 距离地表–10 cm处施磷; P15: 距离地表–15 cm处施磷; P20: 距离地表–20 cm处施磷。

Values followed by different letters within a column are significantly different among treatments at the 0.05 probability level. CK: no P applied; P5: phosphorus application depth was –5 cm; P10: phosphorus application depth was –10 cm; P15: phosphorus application depth was –15 cm; P20: phosphorus application depth was –20 cm. NAE: nitrogen fertilizer absorption efficiency; NPFP: nitrogen partial factor productivity; R2: grain filling; R6: physiological maturity.

图8 籽粒氮积累量(GNAA)、氮素吸收效率(NAE)、氮肥偏生产力(NPFP)与根干重(RDW)、根长密度(RLD)的关系

3 讨论

农田耕作方式、施肥及灌溉等田间管理措施的差异造成土壤中养分、水分分布的高度异质性。根系对土壤中养分资源的异质性在生理和形态上存在的一系列可塑性反应[22,27], 对养分斑块的响应一般包括根系的伸长, 总根长及侧根分支密度增大等一系列变化[12,28]。通过改变养分供应位置及强度, 可以有效刺激根系生长或增殖, 显著提高对土壤养分的吸收面积[19,29]。张福锁等[6]研究表明通过根层养分调控可以优化植物-土壤系统中的根区养分输入, 调节根系生长发育, 最大限度地提高根系养分获取效率, 以实现作物高产高效可持续生产。在本研究中, 通过调整磷肥施用深度对夏玉米进行根层调控, 改变磷素在土壤中的分布斑块, 对夏玉米根系生长与分布有显著的诱导效应。磷肥适当深施显著促进了土壤中根系的增殖, 增加了夏玉米根干重、根长密度和根系表面积(图2), 促进深层土壤根系的生长, 根系与土壤的接触面积显著增大。

肥料运筹对土壤中肥力及养分分布影响显著[24,30-31]。肥料施用位置可以改变根系在土壤中的分布, 影响肥料养分在土壤中的运移、转化以及在作物体内的积累和分配[4,32-33], 提高作物产量和肥料利用效率。适度下移磷肥施用深度能够诱导玉米根系向下生长,有利于提高磷素吸收效率、磷肥利用效率和籽粒产量; 随着磷肥施用深度的增加, 玉米收获期氮素吸收量呈现显著增加趋势[21,34]。在本试验中, 随着磷肥施用深度的增加, 玉米根系呈现向深层分布的趋势, 深层土壤中玉米根系比例显著增加, 提高了根系对土壤氮素的吸收, 阻止氮素向深层土壤迁移, 同时扩大根系的养分利用空间, 促进根系对深层土壤氮素的吸收(图7)。磷肥适当深施有利于生育后期氮素从营养器官向籽粒的转运, 增大氮素的转运率, 其中以P15处理转运量最大。磷肥深施促进植株氮素吸收的原因主要是促进根系的生长发育, 增强了根层土壤氮素与根系时空分布的匹配性, 尤其增加下层土壤中根系的比重, 扩大根系对氮素的吸收利用空间, 增强氮素吸收能力。

合理根系构型能够提高植株对水分与养分等资源的获取及利用效率[8-9], 促进植株生长及产量形成。Jing等[35-36]的研究表明局部施磷和铵态氮的养分调控能够促进根系的大量增生并强化根际过程, 促进玉米生育前期的生长及养分吸收。氮肥适量深施为根系向深层扩展提供了良好条件, 促使根系下移, 保证超高产春玉米较高的有效穗数、千粒重和穗粒数, 从而提高产量[29]。本试验结果表明, 磷肥适当深施同样促进了夏玉米植株的生长, 其生物量与籽粒产量显著增加(图5)。磷肥适当深施, 在增大根系与土壤磷肥接触面积的同时, 诱导根系下扎, 增加了根系对土壤氮素吸收利用的空间, 协调了氮磷高效利用根系构型之间的矛盾, 实现了根系对土壤氮磷养分的协调吸收利用, 最终促进植株生长及籽粒产量形成。

综上所述, 磷肥深施的根层调控技术可以有效挖掘作物根系生物学潜力, 在调节根系分布, 保证根系与磷肥较大接触面积的同时, 诱导夏玉米根系分布加深, 增加水分和氮素的吸收利用空间, 促进氮素的高效吸收与转运, 提高了对土壤氮素的利用效率和籽粒产量。

4 结论

磷肥适度深施能够显著促进夏玉米根系的生长, 改变根系在土壤中的分布。磷肥集中施用在−15 cm增加了20~60 cm土层中的根系干重比重及根长密度, 促进了根系对深层土壤氮素的吸收, 显著增加了植株氮素的积累及转运, 提高其物质生产能力, 最终籽粒产量比传统的磷肥撒施显著增产16.4%。

[1] Tilman D, Cassman K G, Matson P A, Naylor R, Polasky S.Agricultural sustainability and intensive production practices.(London), 2002, 418: 671–677.

[2] Cassman K G, Dobermann A R, Walters D T, Yang H S. Meeting cereal demand while protecting natural resources and improving environmental quality., 2003, 28: 315–358.

[3] 谢佳贵,韩晓日, 王立春, 侯云鹏. 不同施氮模式对春玉米产量、养分吸收及氮肥利用率的影响. 玉米科学, 2016, 21(2): 135–138. Xie J G, Han X R, Wang L C, Hou Y P. Effect of different nitrogen application modes on maize yield, nutrition uptake and utilization efficiency., 2016, 21(2): 135–138 (in Chinese with English abstract).

[4] 赵亚丽, 杨春收, 王群, 刘天学, 李潮海. 磷肥施用深度对夏玉米产量和养分吸收的影响. 中国农业科学, 2010, 43: 4805–4813. Zhao Y L, Yang C S, Wang Q, Liu T X, Li C H. Effects of phosphorus placement depth on yield and nutrient uptake of summer maize., 2010, 43: 4805–4813 (in Chinese with English abstract).

[5] Chen X P, Cui Z L, Vitousek P M, Cassman K G, Matson P A, Bai J S, Meng Q F, Hou P, Yue S C, Römheld V, Zhang F S. Integrated soil-crop system management for food security., 2011, 108: 6399–6404.

[6] Zhang F S, Shen J B, Jing J Y, Li L, Chen X P. Rhizosphere processes and management for improving nutrient use efficiency and crop productivity.,2010, 107: 1–32.

[7] Williamson L C. Phosphate availability regulates root system architecture in., 2001, 126: 875–882.

[8] Shen J B, Li H G, Neumann G, Zhang F S. Nutrient uptake, cluster root formation and exudation of protons and citrate inas affected by localized supply of phosphorus in a split-root system., 2005, 168: 837–845.

[9] Shu L Z, Shen J B, Rengel Z, Tang C X, Zhang F S. Cluster root formation byis modified by stratified application of phosphorus in a split-root system., 2007, 30: 271–288.

[10] Schachtman D P, Reid R J, Ayling S M. Phosphorus uptake by plants: from soil to cell., 1998, 116: 447–453.

[11] Borling K, Barberis E, Otabbong E. Impact of long-term inorganic phosphorus fertilization on accumulation, sorption and release of phosphorus in five Swedish soil profiles., 2004, 69: 11–21.

[12] Lynch J P. Root phenes for enhanced soil exploration and phosphorus acquisition: tools for future crops., 2011, 156: 1041–1049.

[13] Richardson A E, Lynch J P, Ryan P R, Delhaize E, Smith F A, Smith S E, Harvey P R, Ryan M G, Veneklaas E,Lambers H, Oberson A, Culvenor R A, Simpson R. Plant and microbial strategies to improve the phosphorus efficiency of agriculture., 2011, 349: 121–156.

[14] Dunbabin V M, Diggle A J, Rengel Z. Is there an optimal root architecture for nitrate capture in leaching environments?, 2010, 26: 835–844.

[15] Lynch J P. Steep, cheap and deep: an ideotype to optimize water and N acquisition by maize root systems., 2013, 112: 347–357.

[16] Postma J A, Schurr U, Fiorani F. Dynamic root growth and architecture responses to limiting nutrient availability: linking physiological models and experimentation., 2014, 32: 53–65.

[17] Lynch J P, Wojciechowski T. Opportunities and challenges in the subsoil: pathways to deeper rooted crops., 2015, 66: 2199–2210.

[18] Lynch J P. Root phenotypes for improved nutrient capture: an underexploited opportunity for global agriculture., 2019, 223: 548–564.

[19] 范秀艳, 杨恒山, 高聚林, 张瑞富, 王志刚, 张玉芹. 超高产栽培下磷肥运筹对春玉米根系特性的影响. 植物营养与肥料学报, 2012, 18: 562–570. Fan X Y, Yang H S, Gao J L, Zhang R F, Wang Z G, Zhang Y Q. Effects of phosphorus application on root characteristics of super-high-yield spring maize., 2012, 18: 562–570 (in Chinese with English abstract).

[20] 陈梦楠, 孙敏, 高志强, 温斐斐, 郝兴宇, 杨珍平. 深施磷肥对旱地小麦土壤水分、根系分布及产量的影响. 灌溉排水学报, 2016, 35(1): 47–52. Chen M N, Sun M, Gao Z Q, Wen F F, Hao X Y, Yang Z P. Effect of deep application of phosphate fertilizer on soil moisture, root distribution and yield of dryland wheat., 2016, 35(1): 47–52 (in Chinese with English abstract).

[21] 杨云马, 孙彦铭, 贾良良, 贾树龙, 孟春香. 磷肥施用深度对夏玉米产量及根系分布的影响. 中国农业科学, 2018, 51: 1518–1526. Yang Y M, Sun Y M, Jia L L, Jia S L, Meng C X. Effects of phosphorus fertilization depth on yield and root distribution of summer maize., 2018, 51: 1518–1526 (in Chinese with English abstract).

[22] Hodge A. The plastic plant: root responses to heterogeneous supplies of nutrients., 2004, 162: 9–24.

[23] 张德闪, 李洪波, 申建波. 集约化互作体系植物根系高效获取土壤养分的策略与机制. 植物营养与肥料学报, 2017, 23: 1547–1555. Zhang D S, Li H B, Shen J B. Strategies for root′s foraging and acquiring soil nutrient in high efficiency under intensive cropping systems., 2017, 23: 1547–1555 (in Chinese with English abstract).

[24] Rogerio B, Mallarino A P. Deep banding phosphorus and potassium fertilizers for corn managed with ridge tillage., 2001, 65: 376–384.

[25] Ma Q H, Zhang F S, Rengel Z, Shen J B. Localized application of NH4+-N plus P at the seedling and later growth stages enhances nutrient uptake and maize yield by inducing lateral root proliferation., 2013, 372: 65–80.

[26] Nash P R, Nelson K A, Motavalli P P. Corn yield response to timing of strip-tillage and nitrogen source applications., 2013, 105: 623–630.

[27] 王鹏, 牟溥, 李云斌. 植物根系养分捕获塑性与根竞争. 植物生态学报, 2012, 36: 1184–1196. Wang P, Mou P, Li Y B. Review of root nutrient foraging plasticity and root competition of plants., 2012, 36: 1184–1196 (in Chinese with English abstract).

[28] Li H B, Ma Q H, Li H G, Zhang F S. Root morphological responses to localized nutrient supply differ among crop species with contrasting root traits., 2014, 376: 151–163.

[29] 于晓芳, 高聚林, 叶君, 王志刚, 孙继颖, 胡树平, 苏治军. 深松及氮肥深施对超高产春玉米根系生长、产量及氮肥利用效率的影响. 玉米科学, 2013, 21(1): 114–119. Yu X F, Gao J L, Ye J, Wang Z J, Sun J Y, Hu S P, Su Z J. Effects of deep loosening with nitrogen deep placement on root growth, grain yield and nitrogen use efficiency of super high-yield spring maize., 2013, 21(1): 114–119 (in Chinese with English abstract).

[30] Schwab G J, Whitney D A, Kilgore G L, Sweeney D W. Tillage and phosphorus management effects on crop production in soils with phosphorus stratification., 2006, 98: 430–435.

[31] 马存金, 刘鹏, 赵秉强, 张善平, 冯海娟, 赵杰, 杨今胜, 董树亭, 张吉旺, 赵斌. 施氮量对不同氮效率玉米品种根系时空分布及氮素吸收的调控. 植物营养与肥料学报, 2014, 20: 845–859.Ma C J, Liu P, Zhao B Q, Zhang S P, Feng H J, Zhao J, Yang J S, Dong S T, Zhang J W, Zhao B. Regulation of nitrogen application rate on temporal and spatial distribution of roots and nitrogen uptake in different N use efficiency maize cultivars., 2014, 20: 845–859 (in Chinese with English abstract).

[32] Liu X J, Mosier A R, Halvorson A D, Zhang F S. The Impact of nitrogen placement and tillage on NO, N2O, CH4and CO2fluxes from a clay loam soil., 2006, 280: 177–188.

[33] 苏志峰, 杨文平, 杜天庆, 郝教敏, 孙敏, 高志强, 杨珍平. 施肥深度对生土地玉米根系及根际土壤肥力垂直分布的影响. 中国生态农业学报, 2016, 24(2): 142–153. Su Z F, Yang W P, Du T Q, Hao J M, Sum M, Gao Z Q, Yang Z P. Effect of fertilization depth on maize root and rhizosphere soil fertility vertical distribution in immature loess subsoil., 2016, 24(2): 142–153 (in Chinese with English abstract).

[34] 张瑞富, 杨恒山, 范秀艳, 张宏宇, 柳宝林, 刘晶. 施磷深度和深松对春玉米磷素吸收与利用的影响. 植物营养与肥料学报, 2018, 24: 880–887. Zhang R F, Yang H S, Fan X Y, Zhang H Y, Liu B L, Liu J. Effects of phosphorus application depths on its uptake and utilization in spring maize under subsoiling tillage., 2018, 24: 880–887 (in Chinese with English abstract).

[35] Jing J Y, Rui Y K, Zhang F S, Rengel Z. Localized application of phosphorus and ammonium improves growth of maize seedlings by stimulating root proliferation and rhizosphere acidification., 2010, 119: 355–364.

[36] Jing J Y, Zhang F S, Rengel Z, Shen J Y. Localized fertilization with P plus N elicits an ammonium-dependent enhancement of maize root growth and nutrient uptake., 2012, 133: 176–185.

The root-layer regulation based on the depth of phosphate fertilizer application of summer maize improves soil nitrogen absorption and utilization

CHEN Xiao-Ying, LIU Peng*, CHENG Yi, DONG Shu-Ting, ZHANG Ji-Wang, ZHAO Bin, REN Bai-Zhao, and HAN Kun

State Key Laboratory of Crop Biology / College of Agronomy, Shandong Agricultural University, Tai’an 271018, Shandong, China

Favorable root phenotypes can promote crops to obtain soil nutrients efficiently. The root-layer regulation technology based on the depth of phosphate fertilizer application can optimize the spatial and temporal distribution of summer maize root system and promote its spatial matching with soil water and nutrients to supply, providing a theoretical and technical support for realizing fertilizer saving and efficiency improvement by tapping potential of maize root system. In the present study, there were five treatments including CK (no P applied), P5 (phosphorus placement depth of 5 cm), P10 (phosphorus placement depth of 10 cm), P15 (phosphorus placement depth of 15 cm), and P20 (phosphorus placement depth of 20 cm). The effect of phosphorus application depth on root distribution, plant growth and yield formation, as well as nitrogen uptake, accumulation and transport in summer maize was analyzed. The suitable application depths of phosphate fertilizer promoted the growth of summer maize roots and increased root dry weight, root length density, root surface area and root volume significantly totally showing a trend of P15 > P10 > P20 > P5 > CK. With the increase of phosphate fertilizer application depth, the deep corn roots increased significantly. The proportion of root dry weight in P15 and P20 treatments was 12.3% and 12.1% in the 20–40 cm soil layer, and 6.7% and 6.9% in the 40–60 cm soil layer, respectively. The increase of root distribution depth promoted the absorption of nitrogen in the soil, and the nitrogen content in each soil layer, especially below 20 cm, was reduced significantly by the deep application of phosphate fertilizer. The optimization of root distribution promoted the accumulation and transportation of nitrogen in plants. Compared with P5 treatment, the averaged nitrogen fertilizer absorption efficiency, accumulation amount, accumulation rate, partial factor productivity and the grain yield in two years of P15 treatment increased by 14.5 kg kg–1, 19.2%, 48.9%, 6.4 kg kg–1, and 16.4% respectively, showing that under the conditions of the present study, concentrated application of phosphate fertilizer in −15 cm treatment can significantly promote the growth of deep soil roots, expand the space of nutrient utilization for root system, increase the absorption of nitrogen in deep soil, promote the accumulation and transportation of plant nitrogen, improve the productivity and ultimately yield in summer maize.

summer maize; phosphorus placement depth; root; yield; nitrogen absorption and utilization

本研究由国家重点研发计划项目(2016YFD0300106, 2018YFD0300603), 国家自然科学基金项目(31771713, 31371576)和山东省现代农业产业技术体系项目(SDAIT-02-08)资助。

This study was supported by the National Basic Research Program of China (2016YFD0300106, 2018YFD0300603), the National Natural Science Foundation of China (31771713, 31371576), and the Shandong Province Key Agricultural Project for Application Technology Innovation (SDAIT-02-08).

10.3724/SP.J.1006.2020.93029

刘鹏, E-mail: liupengsdau@126.com, Tel: 0538-8241485

E-mail: 15621567129@163.com

***< 0.001.

2019-05-01;

2019-09-26;

2019-10-09.

URL:http://kns.cnki.net/kcms/detail/11.1809.S.20191009.1500.003.html