水氮耦合对固定道垄作栽培春小麦根长密度和产量的影响

引用本文

马忠明, 陈娟, 刘婷婷, 吕晓东. 水氮耦合对固定道垄作栽培春小麦根长密度和产量的影响.作物学报, 2017, 43(11):1705-1714
MA Zhong-Ming, CHEN Juan, LIU Ting-Ting, LYU Xiao-Dong. Effects of Water and Nitrogen Coupling on Root Length Density and Yield of Spring Wheat in Permanent Raised-bed Cropping System. Acta Agronomica Sinica, 2017, 43(11):1705-1714 复制到剪切板

Doi:10.3724/SP.J.1006.2017.01705
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作物学报编辑部

水氮耦合对固定道垄作栽培春小麦根长密度和产量的影响

马忠明^1,^*, 陈娟², 刘婷婷¹, 吕晓东¹

¹甘肃省农业科学院, 甘肃兰州730070

²甘肃省农业科学院经济作物与啤酒原料研究所, 甘肃兰州 730070

^* 通讯作者(Corresponding author):马忠明, E-mail:mazhming@163.com

收稿日期:2017-07-23

基金:本研究由国家公益性行业(农业)科研专项(201503125-02)资助

摘要

固定道垄作(PRB)是在农田中设固定的机械行走道的一种垄作和沟灌栽培模式, 是河西灌区春小麦取代传统平作和大水漫灌种植方式的一种新技术。为了明确PRB种植模式下合理的施氮水平和灌水量, 2014—2015年连续2年采用二因素裂区设计, 以3种灌溉定额(1200、2400和3600 m³ hm^-2)为主区, 以4种施氮水平(0、90、180和270 kg hm^-2)为副区, 研究水氮耦合对小麦不同生育期的根长密度及最终产量的影响。随灌水量和施氮量的增加, 根长密度呈现先增后降的变化趋势, 且灌水量的效应大于施氮水平的效应; 开花、灌浆和成熟期的根长密度与籽粒产量呈正相关。回归分析显示, 根长密度最大值的水氮耦合条件是灌水量约2850 m³ hm^-2、施氮量196~207 kg hm^-2。中等灌水量(2400 m³ hm^-2)条件下, 小麦主要生育期根长密度显著增加, 提高了根长密度在40~80 cm土层的分配比例, 增加了水分利用效率和氮肥农学利用效率。综合评价小麦籽粒产量、水分利用率和氮肥农学利用效率, 中等灌水量与中氮水平(180 kg hm^-2)是所有处理中的最佳水氮耦合模式, 可用于河西灌区春小麦PRB栽培模式。当加大灌水至3600 m³ hm^-2时, 产量没有显著增加, 水分利用效率和氮肥农学利用效率显著下降, 其原因可能是高灌水量使小麦主要生育期的根长密度降低, 且根长密度在0~40 cm土层的比例升高, 在40~80 cm土层的比例下降。

关键词: 水氮耦合; 固定道; 根长密度; 产量; 春小麦

Effects of Water and Nitrogen Coupling on Root Length Density and Yield of Spring Wheat in Permanent Raised-bed Cropping System

MA Zhong-Ming^1,^*, CHEN Juan², LIU Ting-Ting¹, LYU Xiao-Dong¹

¹ Gansu Academy of Agricultural Sciences, Lanzhou 730070, China

² Institute of Economic Crops and Malting Barley Material, Gansu Academy of Agricultural Sciences, Lanzhou 730070, China

Fund:This study was supported by the China Special Fund for Agro-scientific Research in the Public Interest (201503125-02)

Abstract

Permanent raised-bed (PRB) with fixed traffic lane and furrow irrigation is a new cropping pattern of spring wheat in Hexi Corridor of China, which may substitute the traditional flat-planting and flood irrigation technique in this area. To guild water and N application in spring wheat cultivation under PRB condition, we carried out a two-year (2014-2015) field experiment in a split-plot design, with irrigation as the main plot and nitrogen (N) application as the sub-plot. The irrigation amounts were 1200 (W1200), 2400 (W2400), and 3600 m³ ha^-1 (W3600), and the N application rates were 0 (N), 90 (N90), 180 (N180), and 270 kg ha^-1 (N270). The effects on wheat root length density (RLD) at different growth stages and final yield were assessed. With increasing the level of irrigation or N application, wheat RLD showed a up-down changing trend, and the irrigation effect was larger than the nitrogen effect. Grain yield was positively correlated with RLD at anthesis, filling and maturity stages. Regression analysis revealed that the highest RLD could be obtained under the combination of 2850 m³ ha^-1 irrigation and 196-207 kg ha^-1 N. In the moderate irrigation treatment (2400 m³ ha^-1), the RLD significantly increased at major wheat growth stages. Meanwhile, the RLD proportion in 40-80 cm soil depth raised, leading to increased water use efficient (WUE) and N agronomic efficiency (NUE_a) of wheat. The comprehensive consideration of wheat yield, NUE_a and WUE indicates that moderate irrigation (2400 m³ ha^-1) and N application rate (180 kg ha^-1) is the best management in PRB cropping wheat in Hexi Corridor. More irrigation to 3600 m³ ha^-1 had no significant effect to increase yield but resulted in significant decreases of WUE and NUE_a because wheat RLD at major growth stages was decreased under luxurious irrigation condition and the RLD proportion in 40-80 cm soil depth was low resulting from the increased RLD proportion in 0-40 cm soil depth.

Keyword: Water and nitrogen coupling; Permanent raised bed; Root length density; Grain yield; Spring wheat

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甘肃河西灌区小麦生产仍以传统翻耕加大水漫灌为主, 当地农民力求高产, 盲目高施氮肥加大灌溉量, 春小麦生育期施氮、灌水量在270 kg hm^-2、3600 m³ hm^-2以上, 不合理的耕作方式、灌溉及施肥导致土壤质量下降、水氮利用效率低下、水资源供求矛盾加剧, 水氮渗漏及环境污染一系列问题, 因此, 发展节水性保护性耕作并规范其水氮管理势在必行^{[1, 2]}。固定道垄作(permanent raised bed, PRB)是在农田中设固定的机械行走道, 以固定垄作和沟灌代替传统平作、大水漫灌, 垄上种植作物, 垄沟既是灌水沟, 又是机械行走道, 作物收获以后, 高留茬秸秆覆盖免耕。PRB具有高度机械化种植, 改善土壤结构、提高水肥利用效率、减少生产投入(水肥和劳动力)、增加作物产量等优点^{[3, 4, 5, 6]}。

根系是植物重要的水分和养分吸收器官, 根系大小与分布受水分与养分的制约, 其分布又会影响土壤水分与养分的含量、运移^[7]。适量灌水利于优化根系特征参数, 促进根系深扎, 增加深土层的根系分布比例, 提高水分利用率及小麦产量^[8]。根系发育状况及水分供应量显著影响硝态氮的迁移及分布, 最终影响氮肥利用效率及环境污染程度^[9]。研究表明, 灌水过量造成土壤水分含量高, 氧气亏缺, 抑制小麦根系生长, 导致小麦早衰、低产^{[10, 11]}; “ 控制性交替灌溉+氮肥优化运筹” 较“ 淹水灌溉+氮肥优化运筹” 及“ 旱种+氮肥优化运筹” 能促进水稻拔节至成熟期氮素累积, 提高功能叶谷氨酰胺合成酶活性、光合速率及根系活力, 进而提高稻谷产量及氮肥利用率。施氮方式显著影响作物根系生长、产量及氮素利用, 均匀施氮较交替施氮及固定施氮利于改善根系分布, 提高作物产量^[13]。马存金等^[14]试验表明, 适度降低玉米氮素高效品种花前施氮量、增加花后施氮量, 而适度提高氮低效品种花前施氮量、降低花后施氮量可促进根系发育, 提高氮素利用效率, 改善作物产量。控水减氮能提高作物产量, 充分利用土壤氮素, 节能增效, 改善水氮利用^[15]; 轻度水分亏缺, 适量增施氮肥可增加根系活力, 促进根系快速生长, 过度干旱抑制根系生长^[16]。干旱条件下适量减少氮肥可增加小麦产量和氮肥利用率^[17]; 氮肥过量会抑制下层春小麦根系分布, 减小小麦对土壤硝态氮的利用^[18]; 中等水、氮供应可增加20~40 cm和40~60 cm土层小麦根干重密度, 增加小麦产量^[19]。

由于PRB种植模式可以显著降低灌水量, 2004年被引进河西地区。但是, 关于PRB栽培模式不同水、氮条件下春小麦根系生长的变化特征还鲜有报道, 最佳水氮耦合也需进一步研究。本试验利用PRB研究了不同水氮耦合下小麦籽粒产量、根系分布及其相关性, 以期为探明PRB栽培下增加春小麦产量和提高其水氮高效利用提供理论依据。

1 材料与方法

1.1 试验设计

试验地位于甘肃省农业科学院张掖节水试验站(38° 56′ N, 100° 26′ E, 海拔1504 m), 该地年平均蒸发量2029 mm, 年平均气温为7.38° C。大于0° C和10° C的有效积温分别为3646° C和3149° C, 无霜期170~180 d, 年太阳辐射总量5988 MJ m^-2。降水量由张掖气象站提供, 2014、2015年小麦生育期降水分别为65.4 mm和77.7 mm (图1), 其中2015年播种至开花前期降雨较 2014年多19.5 mm。

试验田土壤为石灰性灌漠土, 表土(0~20 cm)质地为轻壤土, 土壤容重为1.37 g cm^-3, pH 8.4, 含有机质14.79 g kg^-1、全氮0.95 g kg^-1、速效氮119. 8 mg kg^-1、速效磷12.18 mg kg^-1、速效钾211.16 mg kg^-1。

试验始于2011年, 固定道垄作栽培垄宽70 cm, 垄沟宽30 cm, 垄高20 cm, 垄床采用免耕、高留茬20 cm、秸秆覆盖, 秸秆覆盖量为2250 kg hm^-2。垄床种植5行春小麦, 采用条播, 行距为15 cm。每年播前只对垄床做少许修整, 固定机械行走道, 垄面无机械压实。

采用二因素裂区设计, 以灌溉定额为主区, 设3个水平, 即1200 (W1200)、2400 (W2400)和3600 m³ hm^-2 (W3600), 以施氮量为副区, 设4个水平, 即0 (N0)、90 (N90)、180 (N180)和270 kg hm^-2 (N270)。小麦全生育期从苗期开始控水, 于三叶期、挑旗期及灌浆期各灌水一次, 用水表控制水量, 灌水量分别占总量的30%、40%和30%。小区面积为3.6 m × 6.0 m = 21.6 m², 为消除小区之间水分与氮素侧向移动, 小区间打埂并覆膜。40%氮肥和P₂O₅ 180 kg hm^-2作为基肥播前施入, 剩余氮肥于三叶期(30%)和挑旗期(30%)随灌水施入。供试春小麦品种为宁春29, 2014年3月26日播种, 7月28日收获, 2015年3月28日播种, 7月26日收获, 两年播种量均为375 kg hm^-2。三叶期使用2, 4-D丁酯除草, 其他田间管理与当地生产相同。

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	图1 春小麦生育期2014年和2015年月降水量及1957-2015年平均月降水量Fig. 1 Monthly precipitation in 2014 and 2015 and average monthly precipitation from 1957 to 2015 in the spring wheat growing period

小麦成熟后, 从每小区随机取3个1 m²小麦(非边行小区且离小区边0.5 m以上)测产, 并取20株小麦测定千粒重, 晾晒至籽粒含水量为14%测定籽粒产量。

1.2 根长密度测定方法

于拔节、开花、灌浆及成熟期用根钻采集小麦根系, 土钻内径7 cm, 高度10.0 cm。作物根系分布存在空间异质性, 因此在小麦种植带连续采集5个点, 其中3点在种植行上, 2点在行间(图2), 采集深度为80 cm, 每10 cm为一个土层, 按不同土层清洗根系, 去杂后装袋, -20° C保存。

应用EPSON PERFECTION V750 PRO (Epson Inc., Beijing, China)进行根系扫描, 采用Win-RHIZO (Ré gent Instrument Inc., Qué bec, Canada)软件进行根系分析, 获得每钻的总根长。根长密度(cm cm^-3) = 根长(cm)/根钻体积(cm³)^[20]。

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	图2 固定道栽培方式与根系采样方式田间示意图Fig. 2 Sketch map of root sampling sites, permanent raised bed traffic lanes and spring wheat rows on the bed

1.3 水分和氮素利用效率测定方法

水分利用效率(kg hm^-2 mm^-1) = 春小麦产量(kg hm^-2)/农田耗水量(mm)

采用水分平衡法, 按公式ET = I+P+U-R-F± Δ W^[21]计算农田耗水量(ET), 式中I为小麦生育期灌水量(mm), P为小麦生育期有效降水量(mm), U为地下水通过毛管作用上移补给小麦水量(mm), R为地表径流量(mm), F为补给地下水量(mm), Δ S为小麦生育期土壤贮水消耗量。试验地平坦、地下水埋深4 m以下、降水入渗深度不超过2 m, 可视地表径流、地下水补给量、深层渗漏为0, 故R、U、F值可忽略不计^[21]。

氮肥农学利用效率(kg kg^-1) = [施氮处理小麦产量(kg hm^-2) - 不施氮处理小麦产量(kg hm^-2)]/施氮量(kg hm^-2)^[22]。

1.4 水氮耦合条件下的根长密度回归方程及分析

灌水量(x_1,m³ hm^-2)、施氮量(x₂, kg hm^-2)与根长密度(L, cm cm^-3)的关系可用二元二次方程描述, 两年度的回归方程分别是L₂₀₁₄ = 5.22 × 10^-4x₁ + 1.86 × 10^-3x₂ - 1.00 × 10^-7x₁² - 4.87 × 10^-6x₂² + 1.69 × 10^-8x₁x₂ + 0.233和L₂₀₁₅ = 4.85 × 10^-4x₁ + 1.16 × 10^-3x₂ - 1.03 × 10^-7x₁² - 6.23 × 10^-6x₂² + 4.97 × 10^-7x₁x₂ + 0.377。

对回归方程求偏导, 当时, 求x₁和x₂, 并带入回归方程解得L值, 即为根长密度的最大值。

采用指数方程Y=A× e^-^Bx^[23]拟合2014、2015年水氮耦合条件下的RLD随土层变化的规律, 得到不同水氮条件下的小麦根系在不同土层的分布模型, 其中Y为RLD (cm cm^-3), x为土壤深度(cm), A、B为拟合系数。设C = e^-^B (0< B< 1), 得到指数方程Y= (A × C)^x。C值随B值的增大而减小, 且0< C< 1。对Y= (A× C)^x求一阶导数得到, RLD随土壤深度变化的拟合模型为Δ Y/Δ X = (A× C)^x × lnC, 当A> 1且0< C< 1时, C值越大Δ Y/Δ X越小, B值越小, 即RLD随土层深度的增加, 下降速率放缓, 因此, 参数C表示RLD随土层深度的变化速率。

应用SPSS21.0软件进行随机区组的方差分析及显著性检验, 对小麦根系干重与产量进行回归分析, 采用SURFER v.11.0 (Golden Software Inc., Golden, CO 80401 UNITED STATES)与Origin 9.1作图。

2 结果与分析

2.1 水氮耦合对春小麦各生育期根长密度的影响

相同施氮条件下, 随灌水量的增加, RLD先增后减(W2400> W3600> W1200), W2400处理下RLD最大, 表明轻度干旱可促进春小麦根系生长, 过量灌溉或者过于干旱不利于春小麦根系生长(表1)。相同灌水条件下, RLD对氮肥的响应主要取决于灌水水平, W1200、W2400条件下, RLD随施氮量的增加先增后减, N180处理下, RLD最大, 说明适当提高施氮量有利于根系生长, 过量施氮会抑制根系生长; W3600条件下, RLD随施氮量的增加而增加, N270处理下, RLD最大, 表明增加灌水量可缓解高氮对根系生长的抑制作用, 表现为“ 以水促肥” , 各生育期RLD对水氮供应量响应一致。

F检验结果表明, 两年度二元二次方程的多重判定系数分别为0.962 (R²=0.979, F=56.29, F_{0.01(5, 6)}= 8.75)和0.914 (R²=0.953, F=24.43, F_{0.01(5, 6)}=8.75), 均达极显著水平, 说明模型总体拟合度好。对回归方程求偏导和解方程, 求根长密度最大值, 结果2014年当灌溉定额和施肥量分别为2851.55 m³ hm^-2和195.91 kg hm^-2, 最大根长密度为1.09 cm cm^-3, 2015年当灌溉定额和施肥量分别为2853.59 m³ hm^-2和206.92 kg hm^-2, 最大根长密度为1.19 cm cm^-3 (图3)。根长密度随灌水量与施氮量的增加而增加, 但灌水量与施氮量超过一定值时则呈减少趋势。

对2014年公式中各偏回归系数进行t检验, 灌溉定额一次项(t₁= 11.24, t_{0.01, 3}= 5.841)与二次项(t₂= 10.65, t_{0.01, 3}= 5.841)、施氮量一次项(t₁= 6.87, t_{0.01, 4}= 4.604)与二次项(t₂= 6.17, t_{0.01, 4}= 4.604)均达到极显著水平, 灌溉定额t值大于施氮量t值, 表明灌水水平对根长密度的影响大于施氮水平。对2015年公式偏回归系数的分析也得同样结果。

表1 不同水氮条件下的各生育期0~80 cm小麦根长密度 Table 1 Root length density (0-80 cm) of spring wheat under different water and nitrogen levels

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	图3 水氮耦合与根长密度的关系Fig. 3 Relationship between water-nitrogen interaction and root length density

2.2 水氮耦合对小麦开花期根长密度垂直分布的影响

2015年各水氮处理下春小麦开花期根系垂直分布如图4所示, 2014年开花期RLD分布趋势与2015年一致。各处理RLD均表现为边行> 次边行> 中间行, 呈作物特有的根系带状分布边行优势。在垂直分布上, RLD随土层深度的增加而减小, 0~40 cm土层W1200、W2400和W3600处理RLD分别为1.56、1.90和1.93 cm cm^-3, 40~60 cm土层分别为0.30、0.43和0.35 cm cm^-3, 而60~80 cm土层仅为0.15、0.20和0.18 cm cm^-3。比较相同施氮条件下不同灌水处理的RLD, 0~40 cm土层为W3600> W2400> W1200, 40~80 cm土层为W2400> W3600> W1200。比较相同灌水条件下不同施氮处理的RLD, 0~40 cm土层表现为N270> N180> N90> N0, 40~80 cm土层为N180> N90> N0> N270。可见, 0~40 cm土层RLD随灌水量、施氮量的增加而增加, 40~80 cm土层RLD 随灌水量、施氮量的增加呈先增后减趋势, 说明一定程度的水分和氮素胁迫导致小麦根系向土壤深处延伸, 吸取土壤下层水分和养分来满足自身生长的需求, 而高水高氮条件会使小麦浅根化分布。

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	图4 2015年不同水氮条件下小麦根长密度的垂直分布 (1)、(2)和(3)表示小区的边行、次边行及中间行。Fig. 4 Effects of irrigation and nitrogen application regimes on root distribution in 2015 (1), (2), and (3) indicate the edge, second, and central lines of a plot.

不同水氮处理下的根系分布模型C值各异, C值越大, 表明RLD随土层深度加深减缓速率越慢, 深层根系所占的比例增加(表2)。相同施氮条件下, C值随灌水量的增加先增后减, W2400处理下, C值最大, 说明适度水分胁迫能迫使根系深扎, 这是根系弹性生长对水分胁迫的抗逆性表现; W1200处理下, C值最小, 说明重度水分胁迫抑制小麦根系生长及下扎。W3600处理下, C值较小, 表明土壤含水量较高时, 根系向水性促使根系不再深扎, 根系分布较浅; 相同灌水条件下, 随施氮量的增加C值逐渐减小, N270处理下C值最小, 表明土壤氮素较高抑制根系深扎, 说明Y = A× e^-^Bx指数函数模型能模拟不同水氮处理下春小麦根系在土层中的分布情况。

表2 不同水氮耦合处理下小麦根系分布模型 Table 2 Effects of water and nitrogen coupling on root distribution model of spring wheat

2.3 水氮耦合对春小麦产量及水氮利用率的影响

相同施氮条件下, 春小麦株高、生物产量随灌水量的增加而增加, W3600处理的株高、生物产量显著大于W2400、W1200处理, 但W3600处理的千粒重、籽粒产量及氮肥农学利用效率(NUE_a)则与W2400处理无显著差异, 而水分利用效率(WUE)则表现为W2400处理最高, W3600处理最低(表3)。说明当灌水量达到2400 m³ hm^-2时再增加灌水量不能显著增加春小麦千粒重、籽粒产量及NUE_a。

相同灌水处理下, 生物产量随施氮量的增加而增加(N270> N180> N90> N0), 而千粒重、籽粒产量及WUE在N270和N180之间无显著差异(表4), 说明在180 kg hm^-2基础上再增加施氮量不能显著增加春小麦千粒重、籽粒产量及WUE, 同时NUE_a随施氮量的增加而减小(N270> N180> N90)。

表3 不同水氮耦合处理对小麦产量、水分利用效率及氮肥农学利用效率的影响 Table 3 Effects of water and nitrogen coupling between grain yield, water use efficiency and nitrogen agronomic efficiency

处理 Treatment	2014					2015
处理 Treatment	千粒重 TGW (g)	生物产量 Biomass (kg hm^-2)	籽粒产量 GY (kg hm^-2)	水分利用效率 WUE (kg hm^-2mm^-1)	氮肥农学利用效率 NUE_a(kg kg^-1)	千粒重 TGW (g)	生物产量 Biomass (kg hm^-2)	籽粒产量 GY (kg hm^-2)	水分利用效率 WUE (kg hm^-2mm^-1)	氮肥农学利用效率 NUE_a(kg· kg^-1)
W1200N0	42.18 a	5600.00 c	2836.77 c	8.02 c	—	44.40 a	5602.55 c	2720.66 c	6.89 d	—
W1200N90	42.10 a	6877.78 b	3508.02 bc	9.33 b	7.46 b	44.53 a	6703.35 b	3227.92 bc	8.01 c	5.91 ab
W1200N180	43.44 a	7988.89 a	4374.99 a	11.54 a	8.55 a	44.93 a	7603.55 a	3910.50 ab	9.65 b	6.61 a
W1200N270	43.57 a	8111.11 a	4316.16 ab	11.59 a	5.48 c	46.30 a	8070.70 a	4164.39 a	10.82 a	5.35 b
W2400N0	43.29 b	5822.22 d	3290.48 b	8.26 c	—	43.47 a	6636.40 c	3344.98 c	8.11 c	—
W2400N90	43.62 ab	8033.33 c	4514.91 b	11.08 b	13.6 a	44.47 a	9871.35 b	5139.87 b	12.08 b	19.94 a
W2400N180	44.11 ab	9077.78 b	5022.30 a	12.37 a	9.62 b	44.84 a	11071.70 a	6124.90 a	13.71 a	15.44 b
W2400N270	46.32 a	9977.78 a	5305.47 a	12.31 a	7.46 c	45.11 a	11405.45 a	6154.38 a	13.05 ab	10.41 c
W3600N0	42.26 a	6955.56 c	3659.90 b	7.26 c	—	42.81 a	7703.60 c	3891.25 c	7.46 b	—
W3600N90	42.30 a	9844.44 b	4977.07 a	9.61 a	14.64 a	42.61 a	11971.90 b	5686.15 b	10.54 a	19.94 a
W3600N180	41.83 a	10744.44 a	5110.73 a	9.71 a	8.06 b	43.61 a	12272.30 b	6076.34 a	10.78 a	12.14 b
W3600N270	41.40 a	11300.00 a	4808.53 a	8.70 b	4.25 c	42.81 a	13172.25 a	6131.16 a	10.31 a	8.39 c
平均 Average
W1200	42.82 b	7144.45 c	3758.99 c	10.11 ab	7.16 b	45.04 a	6995.04 c	3505.87 b	8.88 b	5.86 c
W2400	44.34 a	9029.63 b	4947.56 a	11.04 a	10.23 a	44.47 a	9746.23 b	5191.03 a	11.74 a	15.26 a
W3600	41.95 b	9711.11 a	4639.06 b	8.80 c	8.98 b	42.96 b	11280.01 a	5446.23 a	9.77 b	13.46 b

The numbers after letter W and N in the treatment code indicate the irrigation and N application amount of each treatment. Different letters after data indicate significant difference among irrigation treatments or N application treatments under the same irrigation amount (P< 0.05). TGW:thousand-grain weight; GY:grain yield; WUE:water use efficiency; NUE_a:nitrogen agronomic efficiency

处理符号中W和N及其后面的数字分别表示各处理的灌水量和施氮量。数据后不同字母表示不同灌水量处理或相同灌水量条件下不同施氮处理间差异显著(P< 0.05)。

2.4 水氮耦合春小麦产量与春小麦各生育时期根长密度的相关性

2014年和2015年春小麦4个生育时期RLD与产量具有显著的相关性(表4), 其中开花期产量与RLD相关性最高, RLD更能反映春小麦产量的变化, 此期适宜的水氮供应是高产的重要条件。

表4 春小麦产量与各生育期根长密度的相关系数 Table 4 Correlation coefficients between grain yield and root length density at different stages

3 讨论

3.1 水氮耦合对春小麦根系生长的影响

根系是作物吸收水、氮的重要器官, 合理的灌水与施氮可改善根系生长与分布, 促进根系对土壤中水、氮的吸收与利用, 进而提高作物产量, 节水节肥, 减少环境污染^{[13, 14]}。Wang等^[19]研究表明灌水量与施氮量在一定范围内与小麦根系生长呈正相关关系, 水氮过多或过少都改变根系的大小、分布, 从而影响地上部生长及产量。刘世全等^[23]研究证明适宜的灌水与施氮量也可促进小南瓜的根系生长及产量的提高。

本研究表明, 2014、2015年根长密度(RLD)随灌水量的增加先增后减, 与刘世全等^[23]和Wang等^[19]研究结果一致, 究其原因可能是在W2400处理下, 土壤通透性得以改善, 根系氧浓度增加, 进而促进根系向下层土壤生长, 改善根系吸收及同化养分的能力。而根系生长对氮肥的响应取决于土壤含水量, 在1200 m³hm^-2和2400 m³hm^-2条件下, 增施氮肥, RLD随施氮的增加先增后降, 说明在土壤水分有限条件下增施氮肥会使作物水分胁迫加重, 抑制“ 以肥调水” 的作用, 这与Cabangon等^[24]研究结果一致。在3600 m³hm^-2处理下, RLD随施氮的增加而增大, 表明根系的可塑性生长可以根据环境的变化而变化, 同时说明增施氮肥可以减少土壤水分过多对小麦根系生长的抑制作用, 是“ 以水定肥” 的具体体现。本研究证明对RLD的作用为灌溉定额> 施氮量, 可能是甘肃河西灌区, 夏季气温高干旱少雨, 蒸发量大, 土壤水分亏乏, 且水分不足限制氮肥在作物生长中的有效性, 以致灌水量对作用RLD大于施氮量。

水氮调控根系分布, 进而提高水氮利用率^{[15, 26]}。PRB为免耕、高留茬秸秆覆盖, 春小麦根系分布较传统耕作方式浅^[27], 如何增加犁底层根系分布是本研究的一个重点。根系在土壤中的分布与土壤性质变化存在着动态适应机制, 根系具有根据土壤水肥变化的调整能力, 即根系的趋水向肥再分配机制^[28]。本研究表明, PRB栽培模式下, 85%以上的根系分布于0~40 cm土层, RLD随土层深度的增加呈指数递减, 这与王淑芬等^[25]的研究结论一致。本研究表明, 灌溉定额2400 m³hm^-2和施氮量180 kg hm^-2可以促进小麦根系在40~80 cm土层分布, 实现春小麦群体对水分氮肥的高效利用, 减少水氮深层漏渗, 其原因是当土壤水分、氮素相对较少的情况下, 根系会向下生长, 以吸收更多的水分养分。朱德峰等^[28]研究发现谷类作物根长密度、根干重密度垂直分布符合以e为底的指数递减分布规律。本研究采用模型Y = A× e^-^Bx模拟春小麦根系总长在垂直方向上的分布规律, 模型决定系数R²达到0.9以上, 该指数函数也证明灌水量2400 m³hm^-2与施氮量180 kg hm^-2的耦合条件有利于小麦根系深扎, 但灌水和施氮量过高时, 根系分布较浅。由此可见“ 以肥调水” 功能的发挥与土壤含水量、土壤养分密切相关。

3.2 水氮耦合对春小麦籽粒产量及水氮利用效率的影响

在保证作物不减产和增加水氮利用率的同时, 减少环境污染是当前节水节肥高效的主要目标^[29]。本研究表明, 灌溉定额和施氮量分别为2400 m³ hm^-2和180 kg hm^-2可显著增加春小麦产量及水氮利用效率, 而灌溉定额和施氮量增至3600 m³ hm^-2和270 kg hm^-2并未显著增加春小麦产量, 水氮利用效率不增反降, 表明合理水氮管理利于春小麦根系生长发育, 进而提高籽粒产量和水氮利用率; 当灌溉定额和施氮量为3600 m³ hm^-2和270 kg hm^-2时, 春小麦生物产量显著增加, 主要是由于过量灌溉及施氮使小麦营养生长大于生殖生长, 贪青晚熟, 叶片蒸腾旺盛, 大量奢侈消耗水分和氮素, 且不利于小麦根系生长, 造成水氮漏渗, 水分利用效率和氮肥农学利用效率降低^{[30, 31, 32]}。因此应综合考虑RLD、籽粒产量、水分利用效率及氮肥农学利用效率等多个指标来确定作物生长的最佳灌水施氮组合方案, 优化根系特征及分布, 协调地上与地下部的生长, 来提高春小麦产量。

4 结论

春小麦85%以上的根系集中分布在0~40 cm土层, 随土层深度的增加遵循指数递减分布规律。灌溉定额、施氮量与根长密度呈极显著的二元二次非线性关系, 且灌溉定额的作用大于施氮量。灌水2400 m³ hm^-2、施氮180 kg hm^-2处理可显著促进小麦根系生长, 增加40~80 cm土层根系分布, 提高籽粒产量, 改善水氮利用效率, 是本试验生态条件下, 春小麦固定道栽培方式的最佳水氮组合。

The authors have declared that no competing interests exist.

作者已声明无竞争性利益关系。

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[26]	吉艳芝, 刘辰琛, 巨晓棠, 张丽娟, 冯万忠, 刘树庆. 根层调控对填闲作物消减设施蔬菜土壤累积硝态氮的影响. 中国农业科学, 2010, 43:5063-5072 Ji Y Z, Liu C C, Ju X T, Zhang L J, Feng W Z, Liu S Q. Effects of root layer regulation on reducing soil nitrate accumulation by catch crops in greenhouse vegetable production system. Sci Agric Sin, 2010, 43:5063-5072 (in Chinese with English abstract) [本文引用:1]
[27]	Wulfsohn D, Gu Y, Wulfsohn A, Mojlaj E. Statistical analysis of wheat root growth patterns under conventional and no-till systems. Soil Tillage Res, 1996, 38:1-16 [本文引用:1]
[28]	李话, 张大勇. 半干旱地区春小麦根系形态特征与生长冗余的初步研究. 应用生态学报, 1999, 10:26-30 Li H, Zhang D Y. Morphological characteristics and growth redundancy of spring wheat root system in semi-arid regions. Chin J Appl Ecol, 1999, 10:26-30 (in Chinese with English abstract) [本文引用:2]
[29]	朱德峰, 林贤青, 曹卫星. 超高产水稻品种的根系分布特点. 南京农业大学学报, 2000, 23(4):5-8 Zhu D F, Lin X Q, Cao W X. Characteristics of root distribution of super high-yielding rice varieties. J Nanjing Agric Univ, 2000, 23(4):5-8 (in Chinese with English abstract) [本文引用:1]
[30]	Wang Q, Li F R, Zhao L, Zhang E H, Shi S L, Zhao W Z, Song W X, Vance M. Effects of irrigation and nitrogen application rates on nitrate nitrogen distribution and fertilizer nitrogen loss, wheat yield and nitrogen uptake on a recently reclaimed sand y farmland . Plant Soil, 2010, 337:325-339 [本文引用:1]
[31]	Zhou X L, Wang H, Chen Q G, Ren J. Coupling effects of depth of film-bottomed tillage and amount of irrigation and nitrogen fertilizer on spring wheat yield. Soil Tillage Res, 2007, 94:251-261 [本文引用:1]
[32]	Karam F, Kabalan R, Breidi J, Oweis T. Yield and water-production functions of two durum wheat cultivars grown under different irrigation and nitrogen regimes. Agric Water Manag, 2009, 96:603-615 [本文引用:1]

2011

0.0

魏胜文, 马忠, 牛俊义. 基于地区投入产出模型的干旱区水资源效益评价——以黑河流域甘肃张掖市为例. 中国沙漠, 2011, 31:799-803

Wei S

, Ma

, Niu J

Evaluation of water benefit in arid area based on regional input-output model:a case of Zhangye city in Gansu province, China.

J Desert Res, 2011, 31:799-803 (in Chinese with English abstract)

Agriculture especially plantindustry of Zhangye City in Gansu Province of China consumes directly and indirectly a big amount of water, and the export and import of regional agricultural products have also significant effect on the export and import of water in Zhangye. The excessive dependence on plantindustry of economy leads to excessive dependence on water resources in Zhangye, and it causes a great pressure on water supply. Based on the input-output model, a multiplier analysis of water resource benefit at regional level is conducted in this paper. The results show that it is important for the solving of water crisis in inland arid area to adjust industrial structure, upgrade the industries, develop a high efficiency water-saving agriculture, reduce proportion of agriculture, especially planting at the level of regional economy.

1.Agricultural College of Gansu Agricultural University, Lanzhou 730070, China; 2.Gansu Academy of Social Sciences, Lanzhou 730070, China; 3.Geography and Environment Science College, Northwest Normal University, Lanzhou 730070, China

张掖市农业特别是种植业,对水的直接以及间接消耗无论是数量还是比重都非常高,并且农产品的调出调入对张掖市水资源的调出调入量相应影响也比较大。张掖市过度依赖种植业的产业结构特征造成其对水资源的过度依赖,进而又对水资源的供给产生了巨大压力。论文通过对地区层面水资源的投入产出模型乘数分析,认为调整产业结构,实现产业升级,大力发展高效节水现代农业,降低农业尤其是种植业在张掖国民经济中所占比重,从而彻底改变区域对水资源的过度依赖和高消耗现状,是解决内陆河流域干旱区水资源危机的根本途径。

... 甘肃河西灌区小麦生产仍以传统翻耕加大水漫灌为主, 当地农民力求高产, 盲目高施氮肥加大灌溉量, 春小麦生育期施氮、灌水量在270 kg hm^-2、3600 m³ hm^-2以上, 不合理的耕作方式、灌溉及施肥导致土壤质量下降、水氮利用效率低下、水资源供求矛盾加剧, 水氮渗漏及环境污染一系列问题, 因此, 发展节水性保护性耕作并规范其水氮管理势在必行^[1,2] ...

2013

0.0

杨林章, 冯彦房, 施卫明, 薛利红, 王慎强, 宋祥甫, 常志州. 我国农业面源污染治理技术研究进展. 中国生态农业学报, 2013, 21:96-101

Yang L

, Feng Y

, Shi W

, Xue L

, Wang S

, Song X

, Chang Z

Review of the advances and development trends in agricultural non-point source pollution control in China.

Chin J Eco-Agric, 2013, 21:96-101 (in Chinese with English abstract)

With further economic development in China, non-point source pollution has become a major side effect of agricultural production. There have been wide-spread reports of environment pollution, especially the water environments in China. With this, relevant control measures of agricultural non-point source pollution have gained the attention of the government and scientists in the country. This paper reviewed the current state and discussed the contributing factors and characteristics of agricultural non-point source pollution in China. It also summarized researches on pollution control technologies, including rural sewage/garbage treatment, nutrient retention in farmland runoff and reduction/reasonable use of chemical fertilizers/pesticides. Future development trends in controlling agricultural non-point source pollution in China, and especially the systematic control of rural pollution, were discussed too. Suggestions such as combination uses of systematic control and regional treatment, new techniques development and demonstration, pollution control and management, and establishment of national evaluation and early-warning systems were put forward.

随着我国经济社会的进一步发展, 农业面源污染已经成为造成我国环境污染尤其是水环境污染的主要因素, 农业面源污染治理技术的研究也越来越得到政府和科技工作者的重视。本文重点介绍了当前我国农业面源污染的状况、农业面源污染的成因及特征, 并从农村生活污水的治理技术、农村生活垃圾的处理处置技术、农田径流生态拦截技术以及包括化肥减量化技术和农药减量化与残留控制技术为主的农业化学品减量使用技术等方面介绍了我国农业面源污染治理研究的发展现状，提出未来我国农业面源污染治理的系统控制思想和相关技术研究的趋势, 包括系统控制与区域治理结合、技术研发与工程示范结合、面源污染控制与管理结合及建立健全国家级农业面源污染监测评价与预警体系等。

2007

0.0

... PRB具有高度机械化种植, 改善土壤结构、提高水肥利用效率、减少生产投入(水肥和劳动力)、增加作物产量等优点^[3,4,5,6] ...

2015

0.0

吕晓东, 马忠明. 不同耕作方式对春小麦田土壤水分过程的影响. 核农学报, 2015, 29:2184-2191

Lyu X

, Ma Z

Effects of different tillages on the soil water of spring wheat.

J Nucl Agric Sci, 2015, 29:2184-2191 (in Chinese with English abstract)

... PRB具有高度机械化种植, 改善土壤结构、提高水肥利用效率、减少生产投入(水肥和劳动力)、增加作物产量等优点^[3,4,5,6] ...

2016

0.0

... PRB具有高度机械化种植, 改善土壤结构、提高水肥利用效率、减少生产投入(水肥和劳动力)、增加作物产量等优点^[3,4,5,6] ...

2004

0.0

... PRB具有高度机械化种植, 改善土壤结构、提高水肥利用效率、减少生产投入(水肥和劳动力)、增加作物产量等优点^[3,4,5,6] ...

2010

0.0

... 根系是植物重要的水分和养分吸收器官, 根系大小与分布受水分与养分的制约, 其分布又会影响土壤水分与养分的含量、运移^[7] ...

2010

0.0

薛丽华, 段俊杰, 王志敏, 郭志伟, 鲁来清. 不同水分条件对冬小麦根系时空分布、土壤水利用和产量的影响. 生态学报, 2010, 30:5296-5305

Xue L

, Duan J

, Wang Z

, Guo Z

, Lu L

Effects of different irrigation regimes on spatial-temporal distribution of roots, soil water use and yield in winter wheat.

Acta Ecol Sin, 2010, 30:5296-5305 (in Chinese with English abstract)

Root systems play an important role in uptake of water and nutrients by winter wheat from soil. The spatiotemporal distribution of roots can be influenced by irrigation strategies. In this study, the influence of three irrigation treatments on spatiotemporal root distribution of late-sowing winter wheat and soil water consumption was investigated in seriously water-deficit North China Plain. The winter wheat cultivar Shimai15 was used as test material. The three irrigation treatments were no irrigation after sowing (W0), 75-mm irrigation at jointing stage (W1), three 75-mm irrigations respectively at double ridge stage, booting stage, and grain-filling stage (W3). Spatiotemporal distribution of roots, soil water consumption in 0-200cm soil depth and winter wheat yield were measured under field condition. The investigated root parameters include dry root weight density (DRWD), root length density (RLD), root volume density, and root branch numbers. The results showed that with decreasing irrigation, the dry root weight density (DRWD), root length density (RLD), root volume density, and root branch numbers decreased after flowering above 80cm soil depth, but increased significantly within 80-200cm soil depth. Soil water consumption beneath 100cm soil depth increased significantly during grain filling period. Total water consumption of W1 and W0 were respectively 70.9mm and 115.1mm less than W3, but soil water consumptions of W1 and W0 were respectively 79.1mm and 108.9mm more than W3. Grain yield of W1 and W0 were 653.3kg/hm2 and 1470 kg/hm2 less than W3 respectively. Water use efficiency (WUE) of W1 and W0 were 0.09kg/m3 and 0.06kg/m3 higher than W3 respectively. One time irrigation at jointing stage for late-sowing winter wheat could promote root penetration, increase root density and utilization of water in deep soil, and help to realize the unity of water saving and high yield.

为了明确华北严重缺水区晚播冬小麦灌水对根系时空分布和土壤水分利用规律的影响, 以冬小麦石麦15为材料，利用田间定位试验研究了不同灌水处理（春季不灌水W0；春季灌拔节水75mm,W1；春季灌起身水、孕穗水和灌浆水共225mm,W3）对根系干重密度(DRWD)、根长密度(RLD)、体积密度、分枝数等在0—200cm土层的垂直分布、动态变化及其对耗水和产量的影响，结果表明：随着春季灌水量的减少，开花后0—80cm土层的根干重密度、根长度密度、体积密度和分枝数密度均显著减少， 80cm—200m土层的根干重密度、根长度密度、体积密度和分枝数密度却显著增加，并且显著增加冬小麦在灌浆期间对100cm以下深层土层水分的利用，总耗水量W1 和W0分别比W3减少70.9mm、115.1mm，土壤耗水量分别比W3增加79.1mm、1089mm，子粒产量W1 和W0分别比W3减少653.3kg/hm2、1470 kg/hm2，水分利用效率(WUE)则分别比W3提高0.09kg/m3、006kg/m3。晚播冬小麦春季灌1水（拔节水）可以促进根系深扎，增加深土层的根系分布量，提高对深层土壤贮水的吸收利用量，有利于实现节水与高产的统一。

... 适量灌水利于优化根系特征参数, 促进根系深扎, 增加深土层的根系分布比例, 提高水分利用率及小麦产量^[8] ...

2004

0.0

宋海星, 李生秀. 水、氮供应和土壤空间所引起的根系生理特性变化. 植物营养与肥料学报, 2004, 10:6-11

Song H

, Li S

Changes of root physiological characteristics resulting from supply of water, nitrogen and root-growing space in soil.

Plant Nutr Fert Sci, 2004, 10:6-11 (in Chinese with English abstract)

... 根系发育状况及水分供应量显著影响硝态氮的迁移及分布, 最终影响氮肥利用效率及环境污染程度^[9] ...

2012

0.0

... 研究表明, 灌水过量造成土壤水分含量高, 氧气亏缺, 抑制小麦根系生长, 导致小麦早衰、低产^[10,11] ...

2009

0.0

... 研究表明, 灌水过量造成土壤水分含量高, 氧气亏缺, 抑制小麦根系生长, 导致小麦早衰、低产^[10,11] ...

2014

0.0

孙永健, 孙园园, 徐徽, 李玥, 严奉君, 蒋明金, 马均. 水氮管理模式对不同氮效率水稻氮素利用特性及产量的影响. 作物学报, 2014, 40:1639-1649

Sun Y

, Sun Y

, Xu

, Li

, Yan P

, Jiang M

, Ma

Effects of water-nitrogen management patterns on nitrogen utilization characteristics and yield in rice cultivars with different nitrogen use efficiencies.

Acta Agron Sin, 2014, 40:1639-1649 (in Chinese with English abstract)

The optimal water-nitrogen (N) managements and the selection of genotypes with high nitrogen utilization efficiency (NUE) play a vital note in rice production aiming at high yield, high NUE and water-saving irrigation. In order to elucidate effects of water-nitrogen management patterns on N utilization characteristics, grain yield and its physiological basis in rice cultivars with different NUEs. Two different NUE rice cultivars with high-yield and high N-efficiency (Dexiang 4103) as well as medium-yield and low N-efficiency (Yixiang 3724), were used with three water-nitrogen management patterns, including standing irrigation and optimized N application (W1N1), alternate irrigation and optimized N application (W2N1), and dry cultivation and optimized N application (W3N2). The relationship between yield or N utilization characteristics and glutamine synthetase (GS) activity, photosynthetic rate ( P n ) and root activity was investigated. The results showed that rice cultivars with different NUEs and water-nitrogen management patterns significantly affected N utilization characteristics, irrigation water use efficiency, physiological characteristics and grain yield. The regulation effects of water-nitrogen management patterns on NUE indexes (physiological efficiency, agronomy efficiency, and N recovery efficiency) were lower than those of rice cultivars with different NUEs, while the effects of water-nitrogen management on irrigation water use efficiency, total N accumulation, N dry matter production efficiency, and N production efficiency were significant. Compared with W1N1 and W3N2, W2N1 could promote the N uptake from elongation to maturing stages, enhance activity of GS, P n , and root activity, and then improve grain yield and NUE of two different NUE rice cultivars, being the best model in this experiment. Moreover, the regulation effects of water-nitrogen management patterns on the cultivar with medium-yield and low N-efficiency were significantly higher than these with high-yield and high N-efficiency rice cultivars. The results also showed that average total spikelet number, N accumulation from elongation to heading stages, GS activity and P n of leaves, and root activity of high N-efficiency rice cultivar were higher than those of low N-efficiency rice cultivar . Especially, during filling stage compared with medium-yielding and low N-efficiency cultivar, the high-yielding and high N-efficiency rice cultivar was more beneficial to higher metabolism and assimilation capacity of leaves and roots, which is the important reason for high-yielding and high N-efficiency rice cultivar further to increase yield and NUE. Correlation analysis indicated that there existed significantly positive correlations of GS activity and P n of leaves, and root activity in the two N-efficiency rice cultivars with indices of N uptake and utilization and yield, furthermore, the maximum correlation coefficients of GS activity of leaves and root activity with yield or NUE were observed at heading stage.

以高产氮高效品种(德香4103)和中产氮低效品种(宜香3724)为材料，通过“淹水灌溉+氮肥优化运筹(W1N1)”、“控制性交替灌溉+氮肥优化运筹(W2N1)”、“旱种+氮肥优化运筹(W3N2)” 3种水氮管理模式处理，研究其对氮素利用及产量的影响及其生理特性，并探讨氮素利用及产量与生理响应间的关系。结果表明，氮效率品种间的差异与水氮管理模式对水稻氮素利用特征、灌溉水生产效率、生理特性及产量均存在显著影响；不同氮效率品种间在氮肥利用效率方面的差异明显高于水氮管理模式的调控效应；而水氮管理模式对灌溉水生产效率、总吸氮量、氮素干物质生产效率及稻谷生产效率的调控作用显著。W2N1相对于W1N1及W3N2水氮管理模式能促进不同氮效率水稻拔节至抽穗期、抽穗至成熟期氮素的累积，提高功能叶谷氨酰胺合成酶(GS)活性、光合速率( P n )及根系活力，进而提高稻谷产量及氮肥利用率，且对中产氮低效品种的调控效应显著高于对高产氮高效品种，为本试验最佳的水氮管理模式。高产氮高效品种的平均总颖花数、拔节至抽穗期稻株氮累积量、功能叶 GS活性、 P n 及根系活力均显著高于氮低效品种，尤其结实期高产氮高效品种更有利于维持叶片及根系的代谢同化能力，利于氮素转运、再分配到籽粒中提高稻谷生产效率及氮肥利用效率，是氮高效品种相对于氮低效品种高产、氮高效利用的重要原因。相关分析表明，水氮管理模式下不同氮效率水稻主要生育时期功能叶GS活性、 P n 及根系活力与氮素利用及稻谷产量均存在显著或极显著的正相关；尤其以水稻抽穗期剑叶GS活性及根系活力与氮素利用及稻谷产量的正相关性最高。

2014

0.0

漆栋良, 吴雪, 胡田田. 施氮方式对玉米根系生长、产量和氮素利用的影响. 中国农业科学, 2014, 47:2804-2813

Qi D

, Wu

, Hu T

Effects of nitrogen supply methods on root growth, yield and nitrogen use of maize.

Sci Agric Sin, 2014, 47:2804-2813 (in Chinese with English abstract)

【Objective】Ridge-furrow irrigation has been promoted widely in northwestern China, but short in alternative nitrogen application. This article described the effects of different nitrogen application methods on root growth, yield and nitrogen use efficiency of spring maize under field condition in conventional furrow irrigation situation, in order to reveal the pattern of root growth and distribution, yield, and nitrogen use under different nitrogen application methods and explore the reasonable nitrogen applications fitting to arid and semi-arid region in northwestern China.【Method】Spring maize variety Jinsui 4 was used as the experimental materials and was planted with ridge-furrow irrigation for two consecutive years. There were three treatments:conventional nitrogen supply (CN, nitrogen was applied evenly on both furrows), alternate nitrogen supply (AN, nitrogen was applied alternately in one of the furrows) and fixed nitrogen supply (FN, nitrogen was applied fixed in one furrow). Nitrogen was applied at 200 kg N•hm-2 in each treatment. Urea nitrogen was selected and applied at three times:50%, 25% and 25% with basal application in sowing, topdressing in spike formation and tasseling stages, respectively. Calcium superphosphate was applied as a base fertilizer, evenly spreaded at the rate of 45 kg P2O5•hm-2. The irrigation norm was 3 750 m3•hm-2 was conducted after sowing and at the stages of jointing, spike formation, tasseling and filling, respectively. Root lengths under the plant, in the right and left of the plant of maize in the soil layers of 0-100 cm were measured at the growth stages of maize tasselling, filling and maturity stages of maize, and each 20 cm as one layer. Root length density was calculated through the body of the sampling. Yield and the total nitrogen of the plant were measured after harvest and the nitrogen use efficiency was calculated. 【Result】The results showed that, maize roots were mainly gathered under the plant in the soil layer of 0-40 cm. Root length density showed a decreasing trend with the soil depth increasing. In general, the root length density of maize was the largest in CN, the second place was in AN and smallest in FN during the monitoring period. Root length density was larger in CN in the soil layer of 0-40 cm while was larger in FN in the soil layer 60-100 cm. As in FN, root length density had a significant difference between right and left sides of the plant. The root length densities were nearly the same between right and left side of the plant in CN. The average nitrogen uptake rate, yield and nitrogen use efficiency in CN in two years was 217.8 kg N•hm-2, 10 318 kg•hm-2 and 47.3 kg•kg-1N, respectively. Compared with FN and AN, the nitrogen uptake rate in CN improved averagely by 4.28% and 2.50%, respectively; the yield improved averagely by 8.45% and 4.42%, respectively; the nitrogen use efficiency improved averagely by 4.08% and 1.87%, respectively. 【Conclusion】 Obviously, CN could maintain a larger root mass and had a most uniform distribution of roots between right and left sides of the plant during the monitoring period. Roots distribution between right and left sides of the plant had a significant difference under FN. The AN was located between CN and FN in maintaining root growth. As maintaining of the root growth and yield formation in three treatments, the CN was the best, AN was the second and FN was the worst. It was suggested that in condition of conventional furrow irrigation, nitrogen fertilizer should be applied evenly on both furrows and it is a good way for nitrogen applications.

【目的】垄植沟灌技术在西北内陆地区应用广泛，但往往施氮方式单一，在大田常规沟灌条件下，研究不同施氮方式对春玉米根系生长及产量和氮素利用效率的影响，揭示不同施氮方式下根系的生长分布及产量和氮素利用规律，探求西北内陆干旱、半干旱地区沟灌条件下合理施氮方法。【方法】以金穗4号春玉米为供试材料，连续两年在大田条件下，采用垄植沟灌技术，设均匀沟氮（CN，即两侧沟同时均匀施氮）、交替施氮（AN，即两侧沟交替施氮）和固定施氮（FN，即始终给一侧沟施氮）3种处理。各处理施氮量均为200 kgN•hm-2，氮肥选用尿素，分3次开沟施入，基施50%，大喇叭口期和抽雄期各追肥25%；磷肥选用过磷酸钙，作为底肥开沟前均匀撒施，施磷量45 kgP2O5 •hm-2。灌溉定额3 750 m3•hm-2,分别在播后、拔节期、大喇叭口期、抽雄期和灌浆期灌水，灌水定额相同。分别在抽雄期、灌浆期和成熟期监测0—100 cm土层各层（每20 cm一层）植株下方、植株左侧和右侧的玉米根系长度，并根据采样土体折算根长密度。收获后测定产量及植株全氮量，折算氮素利用效率。【结果】玉米根系主要聚集在植株下0—40 cm土层，随着土层深度增加，根长密度呈递减趋势。监测期内，根长密度大小表现为：均匀沟施＞交替施氮＞固定施氮。0—40 cm土层根长密度以均匀施氮较大，60—100 cm土层中根长密度以固定施氮较大。固定施氮下，植株两侧根长密度值差异明显；均匀施氮和交替施氮下，植株两侧根长密度值相近。均匀施氮下，两年平均氮素吸收量、产量和氮素利用效率的值分别为217.8 kgN•hm-2、10 318 kg•hm-2和47.3 kg•kg-1N。较固定施氮和交替施氮，氮素吸收量平均提高了4.3%和2.5%；产量平均提高了8.5%和4.4%；氮素利用效率平均提高了4.1%和1.9%。【结论】均匀施氮在监测生育期内维持了较大根量，植株左右两侧根系分布最均匀；固定施氮下，根系在植株左右两侧分布差异明显；交替施氮表现介于均匀施氮和固定施氮之间。在维持玉米根系的生长和产量形成方面，均匀施氮表现最好，交替施氮次之，固定施氮最差。常规沟灌条件下，氮肥均匀撒施在两侧沟内为较好的施氮方式。

... 施氮方式显著影响作物根系生长、产量及氮素利用, 均匀施氮较交替施氮及固定施氮利于改善根系分布, 提高作物产量^[13] ...

... 1 水氮耦合对春小麦根系生长的影响根系是作物吸收水、氮的重要器官, 合理的灌水与施氮可改善根系生长与分布, 促进根系对土壤中水、氮的吸收与利用, 进而提高作物产量, 节水节肥, 减少环境污染^[13,14] ...

2014

0.0

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

, Liu

, Zhao B

, Zhang S

, Feng H

, Zhao

, Yang J

, Dong S

, Zhang J

, Zhao

Regulation of nitrogen application rate on temporal and spatial distribution of roots and nitrogen uptake in different N use efficiency maize cultivars.

J Plant Nutr Fert, 2014, 20:845-859 (in Chinese with English abstract)

... 马存金等^[14]试验表明, 适度降低玉米氮素高效品种花前施氮量、增加花后施氮量, 而适度提高氮低效品种花前施氮量、降低花后施氮量可促进根系发育, 提高氮素利用效率, 改善作物产量 ...

2015

0.0

彭亚静, 汪新颖, 张丽娟, 郝晓然, 乔继杰, 王玮, 吉艳芝. 根层调控对小麦-玉米种植体系氮素利用及土壤硝态氮残留的影响. 中国农业科学, 2015, 48:2187-2198

Peng Y

, Wang X

, Zhang L

, Hao X

, Qiao J

, Wang

, Ji Y

Effects of root layer regulation on nitrogen utilization and soil NO₃--N residue of wheat-maize system.

Sci Agric Sin, 2015, 48:2187-2198

【目的】针对华北平原冬小麦-夏玉米轮作区高产田水肥资源利用效率低、氮素累积严重的问题,探索不同根层调控措施对作物氮素利用及土壤NO3--N残留的影响。【方法】以华北平原高产粮田为对象,设置传统水氮、水氮调控、调控+土壤调理剂(Agh)、调控+CRU(用含量为43%的缓释尿素代替氮肥)和调控+植物生长调节剂(GGR)田间小区试验,采集测定土壤、植株及根系样品,分析不同根层调控措施对氮素利用的效果。【结果】在控水减氮前提下,调理剂和GGR处理的小麦玉米周年产量、吸氮量均高于传统水氮。小麦拔节期GGR处理80—100 cm土层根系分布较多,表明GGR能促进中下层根系的发育;玉米大喇叭口期,藁城调理剂和大名GGR处理20—50 cm土层的根长密度均明显高于传统水氮。第一个轮作季,藁城和深州GGR的0—200 cm土体各土层硝态氮残留量均显著低于传统水氮,尤其在60—100 cm土层硝态氮的残留最低;第二个轮作季,藁城调理剂和大名GGR处理各土层硝态氮的残留量显著低于传统水氮。第一个轮作季的调理剂和第二个轮作季的GGR(藁城)的氮素表观亏缺量较大,说明根层调控促进了作物对土壤累积氮素的利用。根层调控措施能够达到经济和生态的双赢,灌溉水分利用效率(WUE)和氮偏生产力(PFPN)较传统水氮平均提高了2.47 kg·m-3和18.08 kg·kg-1,平均增收258.43元/667 m2。【结论】在华北平原高产田,不同根层调控措施的小麦、玉米单季及周年的产量较传统水氮平均分别提高了8.58%、5.99%和7.13%;两季作物收获后0—100 cm土层中土壤硝态氮残留量较传统水氮平均分别降低了70.73和59.44kg·hm-2,明显降低了土壤硝态氮的残留,减缓了向土体深层的淋溶损失;促进了小麦、玉米关键生育期根系的发育。总之,通过在控水减氮的基础上添加土壤调理剂和植物生长调节剂(GGR)可以显著提高作物产量,能使其充分挖掘土壤累积氮素,实现节本增效,提高水肥利用效率。

... 控水减氮能提高作物产量, 充分利用土壤氮素, 节能增效, 改善水氮利用^[15] ...

... 水氮调控根系分布, 进而提高水氮利用率^[15,26] ...

2006

0.0

张凤翔, 周明耀, 周春林, 钱晓晴. 水肥耦合对水稻根系形态与活力的影响. 农业工程学报, 2006, 22(5):197-200

Zhang F

, Zhou M

, Zhou C

, Qian X

Effects of water and fertilizer coupling on root morphological characteristics and activities of rice.

Trans CSAE, 2006, 22(5):197-200 (in Chinese with English abstract)

Under the condition of soil culture, three moisture rates and two nitrogen application rates were designed to investigate the effects of water and nitrogen coupling on morphological characteristics and activity of root system in Shanyou 63. The results show that the dry weight, volume and depth of root system increase with higher nitrogen supplying level under less water supplying condition. The vertical distribution of root dry weight could be expressed by logarithmic function, power function, exponential function and polynomial function and each correlation coefficient was more than 0.9. However exponential function was the best. With higher nitrogen supplying level and less water supplying level, the root effective area and α-NA-oxidizing ability increased and the growth of root system accelerated. But root activities were bated with overmuch less water supplying level.

在土培条件下，设计3个水分水平和2个施氮水平，研究水肥耦合对水稻汕优63不同生育阶段根系形态与活力的影响。结果表明：在低土壤水分条件下增加氮素供应水平能够显著增加根干重、根体积和促进根系的扎深。根系干重的垂直分布可用对数模型、乘幂模型、指数函数模型、多项式函数模型来表示，相关系数均在0.9以上，且以指数函数的模拟精度最高。轻度降低土壤水分，增加施氮量能迅速提高根系活跃吸收面积和根系α-萘胺氧化活力，促进根系快速生长；过度降低土壤水分对水稻根系活力有抑制作用。

... 轻度水分亏缺, 适量增施氮肥可增加根系活力, 促进根系快速生长, 过度干旱抑制根系生长^[16] ...

2005

0.0

... 干旱条件下适量减少氮肥可增加小麦产量和氮肥利用率^[17] ...

1988

0.0

... 氮肥过量会抑制下层春小麦根系分布, 减小小麦对土壤硝态氮的利用^[18] ...

2014

0.0

... 中等水、氮供应可增加20~40 cm和40~60 cm土层小麦根干重密度, 增加小麦产量^[19] ...

... Wang等^[19]研究表明灌水量与施氮量在一定范围内与小麦根系生长呈正相关关系, 水氮过多或过少都改变根系的大小、分布, 从而影响地上部生长及产量 ...

... 本研究表明, 2014、2015年根长密度(RLD)随灌水量的增加先增后减, 与刘世全等^[23]和Wang等^[19]研究结果一致, 究其原因可能是在W2400处理下, 土壤通透性得以改善, 根系氧浓度增加, 进而促进根系向下层土壤生长, 改善根系吸收及同化养分的能力 ...

1979

0.0

... 根长密度(cm cm^-3) = 根长(cm)/根钻体积(cm³)^[20] ...

2008

0.0

... W^[21]计算农田耗水量(ET), 式中I为小麦生育期灌水量(mm), P为小麦生育期有效降水量(mm), U为地下水通过毛管作用上移补给小麦水量(mm), R为地表径流量(mm), F为补给地下水量(mm), #cod#x00394 ...

... 试验地平坦、地下水埋深4 m以下、降水入渗深度不超过2 m, 可视地表径流、地下水补给量、深层渗漏为0, 故R、U、F值可忽略不计^[21] ...

2016

0.0

陈娟, 马忠明, 吕晓东, 刘婷婷. 水氮互作对固定道垄作栽培春小麦根系生长及产量的影响. 应用生态学报, 2016, 27:1511-1520

Chen

, Ma Z

, Lyu X

, Liu T

Influence of different levels of irrigation and nitrogen application on the root growth and yield of spring wheat under permanent raised bed.

Chin J Appl Ecol, 2016, 27:1511-1520

To establish an optimum combination of water and nitrogen for spring under permanent raised bed (PRB) tillage, a field investigation was carried out to assess effects of irrigation and N application on root growth, yield, irrigation water productivity and N efficiency. The experiment followed a completely randomized splitplot design, taking furrow irrigation 1200 m 3 ·hm -2 (W 1 ), 2400 m 3 ·hm -2 (W 2 ), 3600 m 3 ·hm -2 (W 3 ) as main plot treatments, and N rates (0, 90, 180, 270 kg·hm -2 ) the subplot treatments. Our results showed that the root mass density (RWD) was significantly affected by irrigation and N application, the RWD of spring wheat reached a maximum at the filling stage, followed by a slow decline until maturity, while the effect of N on RWD depended on soil water conditions. The application of N2 produced the maximum RWD under W 2  irrigation, the application of N 1 produced the maximum RWD under W 1 irrigation, and the application of N 3 produced the maximum RWD under W 3  irrigation. The order of irrigation regime effect on RWD of spring wheat was W 2 >W 3 >W 1 . The order of irrigation regime and N rate effect on RWD of spring wheat was irrigation>N>irrigation and N interaction. W 2 N 2 treatment produced the highest RWD value. The roottoshoot ratio (R/S) descended with the rising of irrigation water and nitrogen amount, and the combined treatment (W 1 N 0 ) produced the maximum R/S. The root system was mainly distributed in the 0-40 cm soil layer, in which the RWD accounted for 85% of the total RWD in 0-80 cm soil depth. There was a significantly positive relationship between RWD in the 0-40 cm and the yield of spring wheat, RWD in the 40-60 cm had higher linear dependence on the yield of spring wheat. W 2  increased the proportion of RWD in the deep soil layer (40-60 cm). The irrigation and N rate had a significant impact on biomass and grain yield of spring wheat, the biomass increased as the N rate and water amount increased, W 2 N 2  treatment produced the highest grain yield, irrigation water productivity descended with increasing the irrigation amount, and the nitrogen agronomic efficiency descended with increasing N rate. It was concluded that the irrigation level W 2 (2400 m 3 ·hm -2 ) and nitrogen level N 2 (180 kg·hm -2 ) could be recommended as the best combination of water and N, which promoted the root growth, improved grain yield, water and nitrogen use efficiencies of spring wheat production under PRB tillage in the experimental area.

为探讨固定道小麦栽培方式下适宜的水氮组合，以低水1200 (W 1 )、中水2400 (W 2 )、高水3600 m 3 ·hm -2  (W 3 )为主处理，0 (N 0 )、低氮90(N 1 )、中氮180 (N 2 )、高氮270 kg·hm -2 (N 3 )为副处理，采用裂区设计，对固定道垄作栽培方式下水氮互作对春小麦根系生长及产量的影响进行了研究.结果表明：水氮互作能显著影响春小麦根干质量密度(RWD)，RWD随着小麦生育期的进程表现为先增大后减小的趋势，在灌浆期达最大；RWD对施氮量的响应取决于灌溉量，在W 1 下，RWD在N 1 处理下最大，在W 2 下，RWD随着施氮量的增加在N 2 处理下最大，在W 3 下，RWD随着施氮量的增加在N 3 处理下最大；不同灌溉处理下RWD表现为W 2 >W 3 >W 1 ；施氮与灌水显著影响RWD，表现为灌水>氮肥>水氮互作，在W 2 N 2 处理下最大.根冠比随着灌水量与施氮量的增加逐渐减小，在W 1 N 0 处理下根冠比最大；85%以上的小麦根系分布于0～40 cm土层，产量与0～40 cm土层RWD呈显著抛物线回归关系，与40～60 cm土层RWD呈显著线性正回归关系.W 2 灌溉条件可以促进小麦根系向中下层(40～60 cm)分布；灌水施氮能显著影响春小麦籽粒产量与生物产量，生物产量随着施氮量和灌水量的增加而增加，籽粒产量在W 2 N 2 最大；灌水生产力随灌水量的增加逐渐降低，氮肥农学利用率随施氮量的增加而减小.因此，在固定道垄作栽培方式下，施肥量与灌水量控制在N 2 (180 kg·hm -2 )与W 2 (2400 m 3 ·hm -2 )条件下有利于促进根系生长，进而提高春小麦籽粒产量及水氮利用效率，是河西灌区固定道小麦栽培方式下适宜的水氮组合.

... 氮肥农学利用效率(kg kg^-1) = [施氮处理小麦产量(kg hm^-2) - 不施氮处理小麦产量(kg hm^-2)]/施氮量(kg hm^-2)^[22] ...

2014

0.0

刘世全, 曹红霞, 张建青, 胡笑涛. 不同水氮供应对小南瓜根系生长、产量和水氮利用效率的影响. 中国农业科学, 2014, 47:1362-1371

Liu S

, Cao H

, Zhang J

, Hu X

Effects of different water and nitrogen supplies on root growth, yield and water and nitrogen use efficiency of small pumpkin.

Sci Agric Sin, 2014, 47:1362-1371 (in Chinese with English abstract)

... e^-^Bx^[23]拟合2014、2015年水氮耦合条件下的RLD随土层变化的规律, 得到不同水氮条件下的小麦根系在不同土层的分布模型, 其中Y为RLD (cm cm^-3), x为土壤深度(cm), A、B为拟合系数 ...

... 刘世全等^[23]研究证明适宜的灌水与施氮量也可促进小南瓜的根系生长及产量的提高 ...

2004

0.0

... 的作用, 这与Cabangon等^[24]研究结果一致 ...

2006

0.0

王淑芬, 张喜英, 裴冬. 不同供水条件对冬小麦根系分布、产量及水分利用效率的影响. 农业工程学报, 2006, 22(2):27-32

Wang S

, Zhang X

, Pei

Impacts of different water supplied conditions on root distribution, yield and water utilization efficiency of winter wheat.

Trans CSAE, 2006, 22(2):27-32 (in Chinese with English abstract)

... 本研究表明, PRB栽培模式下, 85%以上的根系分布于0~40 cm土层, RLD随土层深度的增加呈指数递减, 这与王淑芬等^[25]的研究结论一致 ...

2010

0.0

吉艳芝, 刘辰琛, 巨晓棠, 张丽娟, 冯万忠, 刘树庆. 根层调控对填闲作物消减设施蔬菜土壤累积硝态氮的影响. 中国农业科学, 2010, 43:5063-5072

Ji Y

, Liu C

, Ju X

, Zhang L

, Feng W

, Liu S

Effects of root layer regulation on reducing soil nitrate accumulation by catch crops in greenhouse vegetable production system.

Sci Agric Sin, 2010, 43:5063-5072 (in Chinese with English abstract)

... 水氮调控根系分布, 进而提高水氮利用率^[15,26] ...

1996

0.0

... PRB为免耕、高留茬秸秆覆盖, 春小麦根系分布较传统耕作方式浅^[27], 如何增加犁底层根系分布是本研究的一个重点 ...

1999

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李话, 张大勇. 半干旱地区春小麦根系形态特征与生长冗余的初步研究. 应用生态学报, 1999, 10:26-30

, Zhang D

Morphological characteristics and growth redundancy of spring wheat root system in semi-arid regions.

Chin J Appl Ecol, 1999, 10:26-30 (in Chinese with English abstract)

Six spring wheat cultivars bred at different years in semi-arid regions were selected to comparatively study the numbers and morphological characteristics of their seminal root systems, and to analyse the relationship of these indexes with crop drought-resistance and yield production. The results show that in semi-arid regions of loess plateau, the cultivars had a growth redundancy of root systems, which was unfavourable to the yield production. With the lapse of breeding years, the cultivars tended to have less root, shorter root length, larger active root absorption area, and smaller diameter of metaxylem vessel of seminal roots. These features made the cultivars bred at recent years use water more savingly at their earlier vegetative growth period, and conserve certain amount of soil water to satisfy their water needs at flowering and seed-filling stages, and hence, enhance their yield production.

以半干旱地区6个不同年代春小麦品种为材料,对各品种苗期种子根系的数量、形态特征进行了比较研究,分析了这些指标与作物抗旱高产的关系。结果表明,黄土高原半干旱地区春小麦品种在根系生长上存在着对产量不利的冗余。在以提高产量潜力为宗旨的品种更新替代过程中,不同年代春小麦品种随着年代推进逐渐呈现出根条数和根长减小、根活性吸收面积比增加、种子根中央大导管直径减小的趋势。这些特点使得现代春小麦品种在早期营养生长过程中能够节约用水而保留一定土壤水分以满足花期和灌浆期水分需求,因而提高了作物产量。

... 根系在土壤中的分布与土壤性质变化存在着动态适应机制, 根系具有根据土壤水肥变化的调整能力, 即根系的趋水向肥再分配机制^[28] ...

... 朱德峰等^[28]研究发现谷类作物根长密度、根干重密度垂直分布符合以e为底的指数递减分布规律 ...

2000

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朱德峰, 林贤青, 曹卫星. 超高产水稻品种的根系分布特点. 南京农业大学学报, 2000, 23(4):5-8

Zhu D

, Lin X

, Cao W

Characteristics of root distribution of super high-yielding rice varieties.

J Nanjing Agric Univ, 2000, 23(4):5-8 (in Chinese with English abstract)

利用不同类型水稻品种和组合,采用根箱钉板法研究了全量根系在土壤中纵向和横向的分布特征.结果表明,根系生物量的52%～63%分布在0～12 cm土层中,70%～79%分布在0～24 cm土层中.后期耐早衰的协优9308表现根系生物量大,深根系比例高.根系横向分布随土壤深度增加,趋向离开植株中心分布.根系重量密度以表层最高,并随深度增加逐渐下降.协优9308在表土层以下的根系重量密度比其他品种明显提高.

... 2 水氮耦合对春小麦籽粒产量及水氮利用效率的影响在保证作物不减产和增加水氮利用率的同时, 减少环境污染是当前节水节肥高效的主要目标^[29] ...

2010

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... 当灌溉定额和施氮量为3600 m³ hm^-2和270 kg hm^-2时, 春小麦生物产量显著增加, 主要是由于过量灌溉及施氮使小麦营养生长大于生殖生长, 贪青晚熟, 叶片蒸腾旺盛, 大量奢侈消耗水分和氮素, 且不利于小麦根系生长, 造成水氮漏渗, 水分利用效率和氮肥农学利用效率降低^[30,31,32] ...

2007

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2009

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