紫云英與氮肥配施對早稻干物質(zhì)生產(chǎn)及氮素吸收利用的影響*

錢晨晨, 王淑彬, 楊濱娟, 黃國勤**

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紫云英與氮肥配施對早稻干物質(zhì)生產(chǎn)及氮素吸收利用的影響*

錢晨晨1,2, 王淑彬1,2, 楊濱娟1,2, 黃國勤1,2**

(1. 江西農(nóng)業(yè)大學生態(tài)科學研究中心 南昌 330045; 2. 江西省高校生態(tài)學學科聯(lián)盟 南昌 330045)

為綜合評價紫云英與氮肥配施對早稻干物質(zhì)生產(chǎn)及氮素吸收利用的影響, 篩選紫云英等量翻壓條件下, 較適宜的施氮水平, 以冬閑常規(guī)施氮[150 kg(N)?hm-2]處理為對照, 在翻壓紫云英22 500 kg?hm-2條件下, 設置90 kg(N)?hm-2、120 kg(N)?hm-2、150 kg(N)?hm-2和180 kg(N)?hm-24個施氮水平, 研究紫云英和施氮量對早稻干物質(zhì)生產(chǎn)及氮素吸收利用的影響。結(jié)果表明: 紫云英與氮肥配施各處理的干物質(zhì)積累量均高于對照, 其中紫云英配施氮肥90 kg(N)?hm-2和120 kg(N)?hm-2的干物質(zhì)積累量最多, 分別達9.65 t?hm-2和9.97 t?hm-2, 比對照分別增加11.18%和14.86%。各處理在水稻播種—分蘗期及抽穗—灌漿期干物質(zhì)積累量較大, 占成熟期干物質(zhì)量的19.26%~24.77%和45.23%~52.75%, 這兩個生育階段是干物質(zhì)主要積累時期。紫云英與氮肥配施各處理的氮素積累量均高于對照, 增幅為6.95%~18.68%。氮素干物質(zhì)生產(chǎn)效率和氮收獲指數(shù)均以紫云英配施90 kg(N)?hm-2處理最高, 比其他處理分別增加3.94%~14.08%和6.65%~14.90%。紫云英配施氮肥有利于提高早稻的干物質(zhì)積累量和氮素利用率, 其中以紫云英配施氮肥90 kg(N)?hm-2和120 kg(N)?hm-2效果較優(yōu), 可實現(xiàn)減氮增效目的, 是較理想的施肥模式。

紫云英; 氮肥; 早稻; 干物質(zhì); 氮素吸收

紫云英(L.)是我國南方稻區(qū)傳統(tǒng)的冬綠肥, 翻壓后能夠增加土壤養(yǎng)分、改善土壤理化性狀、提高植株氮磷鉀含量、減少化肥用量[1-3]。近幾十年來, 隨著我國農(nóng)業(yè)集約化程度的加深, 化肥因具有便捷、增效快等優(yōu)點成為糧食增產(chǎn)的主要依賴對象, 這使我國普遍存在忽視綠肥施用、過度依賴化肥的現(xiàn)象, 化肥特別是氮肥用量過大, 目前我國水稻平均氮肥施用量為180 kg?hm-2, 較世界平均水平增加75%, 有些地區(qū)甚至超過300 kg?hm-2[4-5]。而過量施用氮肥會降低氮素利用效率[6], 造成作物貪青晚熟, 并引發(fā)一系列環(huán)境問題[7]。因此, 利用冬季空閑茬口種植紫云英, 并進行合理的養(yǎng)分管理, 在維持水稻產(chǎn)量高產(chǎn)的同時提高氮肥利用率, 對于實現(xiàn)水稻優(yōu)質(zhì)、高產(chǎn)、高效, 減少肥料損失具有十分重要的意義。國內(nèi)外關于綠肥與化肥配施對水稻增產(chǎn)效果的研究已有不少報道, 多數(shù)研究表明, 利用紫云英根瘤菌固氮, 并配施適量化肥, 改善了土壤肥力, 其增產(chǎn)效果較好[8-9]。謝志堅等[10]通過研究翻壓等量紫云英配施不同量化肥的土壤養(yǎng)分有效性表明, 紫云英配施60%~80%常規(guī)施肥量的化肥(常規(guī)施肥為: N 150 kg?hm-2、P2O575 kg?hm-2、K2O 120 kg?hm-2), 土壤中的堿解氮和速效鉀能夠增加10%~59%。王建紅等[11]研究了紫云英還田配施化肥對單季晚稻養(yǎng)分利用和產(chǎn)量的影響, 結(jié)果表明紫云英鮮草翻壓配施化肥處理的稻谷產(chǎn)量比不施肥處理提高8.5%~ 17.4%。侯紅乾等[12]連續(xù)25年在江西省雙季稻區(qū)進行田間定位試驗, 研究表明, 有機無機肥配施條件下早晚稻平均產(chǎn)量比單施化肥增產(chǎn)3.9%~7.8%。徐昌旭等[13]研究結(jié)果表明, 早稻減少化肥用量20%(常規(guī)施肥為: N 150 kg?hm-2、P2O575 kg?hm-2、K2O 120 kg?hm-2)能有效促進水稻植株對氮、磷、鉀養(yǎng)分的吸收與積累。國內(nèi)外學者關于作物合理施肥研究很多, 但對于通過綠肥種植翻壓減少化肥施用的水稻環(huán)境友好型栽培條件下水稻氮肥適宜用量的研究報道較少。而很多綠肥還田的研究多以紫云英還田與化肥配施(或有機無機肥配施)為重點, 對紫云英配施氮肥的研究不夠系統(tǒng)充分。本研究利用冬季空閑茬口種植紫云英, 通過比較紫云英還田配施不同氮肥施用量下水稻干物質(zhì)生產(chǎn)特性及氮素吸收利用的情況, 對冬種紫云英條件下稻田的合理施氮量進行探究, 從而為水稻可持續(xù)生產(chǎn)和水稻保護性耕作提供理論依據(jù)。

1 材料與方法

1.1 試驗區(qū)概況

試驗于2014年10月至2015年7月在江西農(nóng)業(yè)大學科技園水稻實驗田(28°46′N, 115°55′E)進行。試驗區(qū)為亞熱帶季風性濕潤氣候, 年均太陽總輻射量4.79×1013J?hm-2, 年均日照時數(shù)1 852 h, 年日均溫≥0 ℃積溫達6 450 ℃, 年平均氣溫17.1~17.8 ℃, 年降水量1 624 mm。供試土壤為發(fā)育于第四紀的紅黏土, 為亞熱帶典型紅壤分布區(qū)。紫云英種植前試驗耕層土壤pH 5.59, 有機質(zhì)29.48 g?kg-1, 全氮2.17 g?kg-1, 堿解氮38.69 mg?kg-1, 有效磷12.22 mg?kg-1, 速效鉀30.31 mg?kg-1。

1.2 試驗設計

采取單因素隨機區(qū)組設計, 以冬閑常規(guī)施氮處理[150 kg(N)?hm-2]為對照(處理A), 在等量翻壓紫云英鮮草22 500 kg?hm-2(干草養(yǎng)分含量: 全氮26.7 g?kg-1, 全磷2.1 g?kg-1, 全鉀20.1 g?kg-1)條件下, 施氮量設90 kg(N)?hm-2(處理B)、120 kg(N)?hm-2(處理C)、150 kg(N)?hm-2(處理D)和180 kg(N)?hm-2(處理E)4個水平, 共5個處理, 所有處理3次重復, 15個小區(qū), 小區(qū)面積為16.5 m2(5.5 m×3 m), 小區(qū)之間用水泥埂隔開, 以防止水肥串流。供試紫云英品種為‘余江大葉籽’, 2014年10月4日播種, 2015年4月3日盛花期翻壓。早稻品種為‘金優(yōu)458’, 于2015年3月27日播種, 4月29日移栽, 7月28日收割。每兜3苗, 每小區(qū)325兜。各處理氮肥用尿素(含N 46%), 磷肥用鈣鎂磷肥(含P2O512%), 鉀肥用氯化鉀(含K2O 60%)。磷肥、鉀肥各小區(qū)施用量相同, 磷肥(P2O5)50 kg?hm-2, 鉀肥(K2O)120 kg?hm-2, 全部作基肥; 氮肥按基肥︰分蘗肥︰穗肥=5︰3︰2施用。分蘗肥在水稻移栽后5~7 d時施用, 穗肥在主莖幼穗長1~2 cm時施用。田間管理措施同一般大田栽培。

1.3 測定指標及計算方法

1.3.1 干物質(zhì)測定

于早稻分蘗期(2015年6月1日)、孕穗期(6月14日)、抽穗期(6月25日)、灌漿期(7月6日)和成熟期(7月25日)按每小區(qū)莖蘗數(shù)的平均數(shù)取代表性植株5穴(小區(qū)邊行不取), 分成葉片、莖鞘和穗(抽穗后)等部分裝袋, 105 ℃下殺青30 min, 80 ℃下烘干至恒重后稱重。干物質(zhì)轉(zhuǎn)運相關指標計算方法[14]分別為:

莖葉干物質(zhì)輸出量=抽穗期莖葉干物重-成熟期莖葉干物重 (1)

莖葉干物質(zhì)輸出率=莖葉干物質(zhì)輸出量/抽穗期莖葉干物重×100% (2)

表觀轉(zhuǎn)變率=莖葉干物質(zhì)輸出量/抽穗至成熟期穗部干物質(zhì)積累量×100% (3)

1.3.2 植株氮素測定

每時期植株干物質(zhì)積累測定完成后粉碎混勻, 采用H2SO4-H2O2消化, 以半微量開氏定氮法測定植株各器官全氮含量。相關指標計算方法[15]分別為:

氮素積累量=該時期地上部干物重×含氮量 (4)

氮素干物質(zhì)生產(chǎn)效率(NDMPE)=單位面積植株干物質(zhì)積累量/植株氮積累量 (5)

氮收獲指數(shù)(NHI)=籽粒氮素積累量/植株氮素積累量 (6)

1.4 數(shù)據(jù)處理

本研究所有數(shù)據(jù)的基本統(tǒng)計采用Microsoft Excel 2010, 采用SPSS 17.0軟件進行統(tǒng)計分析。

2 結(jié)果與分析

2.1 紫云英與氮肥配施對早稻干物質(zhì)積累的影響

2.1.1 主要生育期群體干物重

由表1可知, 不同施肥條件下早稻主要生育期地上部群體干物重因生育期不同而有所差異。分蘗期各處理間差異不顯著(>0.05)。從孕穗期開始, 各處理的差異逐漸顯現(xiàn)。除分蘗期以外, 其余生育期處理C的干物質(zhì)積累量均達最大, 且在孕穗期與其他處理間差異顯著(<0.05)。在抽穗期, 處理B、C、D的干物質(zhì)積累量顯著高于A、E處理(<0.05)。在灌漿期, 處理B、C干物質(zhì)累積量顯著高于處理A(<0.05), 增幅分別為16.77%和17.02%。在成熟期, 處理B、C、D干物質(zhì)累積量顯著高于處理A(<0.05), 且處理C與處理A、E差異顯著(<0.05)。

表1 各處理對早稻主要生育期群體干物重的影響

A: 冬閑+150 kg(N)?hm-2; B: 紫云英+90 kg(N)?hm-2; C: 紫云英+120 kg(N)?hm-2; D: 紫云英+150 kg(N)?hm-2; E: 紫云英+180 kg(N)?hm-2。數(shù)據(jù)為3個重復的平均值±標準誤; 同列不同小寫字母分別表示各處理間差異顯著(<0.05)。A: winter fallow with 150 kg(N)?hm-2application in early rice; B: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice; C: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice; D: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice; E: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice. Values in the table are mean ± SE of 3 replicates. Different lowercase letters in the same column mean significant differences at 0.05 level.

2.1.2 主要生育階段干物質(zhì)積累量和比例

從早稻主要生育階段干物質(zhì)積累量和比例來看(表2), 水稻播種—分蘗期及抽穗—灌漿期是干物質(zhì)主要積累時期, 水稻在這兩個生育階段干物質(zhì)積累量較大, 各處理在這兩個生育階段干物質(zhì)積累量占成熟期干物重的19.26%~24.77%和45.23%~52.75%, 但均未達顯著性差異(>0.05)。在分蘗—孕穗期處理C的干物質(zhì)積累量最大, 且顯著高于處理A、D、E (<0.05); 在孕穗—抽穗期, 處理D的干物質(zhì)積累量最大, 顯著高于處理C、E(<0.05), 增幅均為38.89%; 而灌漿—成熟期各處理間干物質(zhì)積累量差異不顯著(>0.05)。

表2 各處理早稻主要生育階段干物質(zhì)積累量和比例

A: 冬閑+150 kg(N)?hm-2; B: 紫云英+90 kg(N)?hm-2; C: 紫云英+120 kg(N)?hm-2; D: 紫云英+150 kg(N)?hm-2; E: 紫云英+180 kg(N)?hm-2。DMA: 生育階段干物質(zhì)積累量; RTDM: 該生育階段干物質(zhì)積累量占總積累量的比重。數(shù)據(jù)為3個重復的平均值±標準誤; 同列不同小寫字母分別表示各處理間差異顯著(<0.05)。A: winter fallow with 150 kg(N)?hm-2application in early rice; B: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice; C: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice; D: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice; E: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice. DMA: amount of dry matter accumulation at the growth stage; RTDM: ratio of dry matter accumulation to total accumulation in the growth stage. Values in the table are mean ± SE of 3 replicates. Different lowercase letters in the same column mean significant differences at 0.05 level.

2.1.3 干物質(zhì)在莖鞘、葉片和穗的分配情況

通過分析莖鞘、葉片和穗分配情況(表3)可知, 早稻干物質(zhì)莖鞘比例在抽穗期達最大, 并隨著生育進程的推進有不斷降低的趨勢。抽穗期處理C的莖鞘比例最大, 達46.50%, 與處理A、E差異顯著(<0.05), 分別增加7.83個百分點和4.75個百分點。葉片比例的變化趨勢與莖鞘比例一致, 在抽穗期達最大, 各處理間差異顯著(<0.05), 其中處理A葉片比例最大, 為41.33%; 成熟期處理D的葉片比例最大, 為14.00%, 與處理A、B、E差異顯著(< 0.05)。穗比例隨著生育進程的推進呈現(xiàn)出不斷上升的趨勢, 各處理均在成熟期達最大, 從抽穗期的18.50%~ 23.50%增加到成熟期的64.50%~68.67%。抽穗期處理D的穗比例最大, 并與處理C差異顯著(<0.05); 成熟期處理B與處理A、C、D差異顯著(<0.05)。

表3 各處理早稻中、后期干物質(zhì)在莖鞘、葉片和穗的分配情況

A: 冬閑+150 kg(N)?hm-2; B: 紫云英+90 kg(N)?hm-2; C: 紫云英+120 kg(N)?hm-2; D: 紫云英+150 kg(N)?hm-2; E: 紫云英+180 kg(N)?hm-2。數(shù)據(jù)為3個重復的平均值±標準誤; 同列不同小寫字母分別表示各處理間差異顯著(<0.05)。A: winter fallow with 150 kg(N)?hm-2application in early rice; B: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice; C: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice; D: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice; E: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice. Values in the table are mean ± SE of 3 replicates. Different lowercase letters in the same column mean significant differences at 0.05 level.

2.1.4 干物質(zhì)的轉(zhuǎn)運

從表4可知, 處理B的早稻莖葉干物質(zhì)輸出量、輸出率和表觀轉(zhuǎn)變率均達到最大, 處理C次之, 處理E達到最低, 處理D的3個指標高于處理A, 但未達到顯著性差異(>0.05)。說明在紫云英全量還田條件下, 減量施氮促進了早稻地上部分營養(yǎng)器官的干物質(zhì)向籽粒中轉(zhuǎn)移, 且相同施氮量下, 紫云英還田與否對干物質(zhì)從營養(yǎng)器官向籽粒中轉(zhuǎn)移效果并不明顯, 而高量施氮反而抑制了干物質(zhì)的轉(zhuǎn)移。

2.2 紫云英與氮肥配施對早稻氮素含量的影響

2.2.1 主要生育期氮素吸收積累量

由圖1可知, 紫云英配施氮肥條件下早稻主要生育期氮素吸收積累量因生育期不同而有所差異, 且呈逐漸升高的趨勢, 在成熟期達最大。分蘗期各處理間氮素吸收積累量差異不顯著(>0.05)。除抽穗期處理D的氮素積累量最大外, 孕穗期、灌漿期和成熟期都是處理C的氮素積累量達最大, 且均顯著高于處理A, 其中灌漿期和成熟期亦顯著高于處理B(<0.05)。

表4 各處理早稻干物質(zhì)的轉(zhuǎn)運

A: 冬閑+150 kg(N)?hm-2; B: 紫云英+90 kg(N)?hm-2; C: 紫云英+ 120 kg(N)?hm-2; D: 紫云英+150 kg(N)?hm-2; E: 紫云英+180 kg(N)?hm-2。數(shù)據(jù)為3個重復的平均值±標準誤; 同列不同小寫字母分別表示各處理間差異顯著(<0.05)。A: winter fallow with 150 kg(N)?hm-2application in early rice; B: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice; C: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice; D: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice; E: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice. Values in the table are mean ± SE of 3 replicates. Different lowercase letters in the same column mean significant differences at 0.05 level.

A: 冬閑+150 kg(N)?hm-2; B: 紫云英+90 kg(N)?hm-2; C: 紫云英+120 kg(N)?hm-2; D: 紫云英+150 kg(N)?hm-2; E: 紫云英+ 180 kg(N)?hm-2。不同小寫字母分別表示同一生育時期各處理間差異顯著(<0.05)。A: winter fallow with 150 kg(N)?hm-2application in early rice; B: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice; C: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice; D: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice; E: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice. Different lowercase letters mean significant differences at the same growth stage at 0.05 level.

2.2.2 成熟期莖、葉、穗的氮素養(yǎng)分含量及吸收量

由表5可知, 不同施肥處理成熟期早稻莖、葉、穗氮素養(yǎng)分含量存在差異, 且不同施肥處理對各養(yǎng)分器官的氮素養(yǎng)分吸收量存在較為明顯的影響。從莖全氮含量看, 處理C、D、E均顯著高于處理B(<0.05), 可能是紫云英還田條件下, 較高施氮量一定程度上促進了莖中氮素的累積, 也可能是由于處理B本身的施氮量較其他處理少; 從葉全氮含量看, 各處理間并無顯著差異; 從穗全氮含量看, 也是處理E顯著高于其他處理(<0.05)。從莖氮素吸收量看, 處理C顯著高于處理B(<0.05); 從葉片氮素吸收量看, 處理D顯著高于處理B(<0.05); 從穗氮素吸收量看, 4種紫云英配施氮肥處理均顯著高于處理A(<0.05)。

表5 各處理早稻成熟期莖、葉、穗的氮素養(yǎng)分含量及吸收量

A: 冬閑+150 kg(N)?hm-2; B: 紫云英+90 kg(N)?hm-2; C: 紫云英+120 kg(N)?hm-2; D: 紫云英+150 kg(N)?hm-2; E: 紫云英+180 kg(N)?hm-2。數(shù)據(jù)為3個重復的平均值±標準誤; 同列不同小寫字母分別表示各處理間差異顯著(<0.05)。A: winter fallow with 150 kg(N)?hm-2application in early rice; B: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice; C: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice; D: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice; E: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice. Values in the table are mean ± SE of 3 replicates. Different lowercase letters in the same column mean significant differences at 0.05 level.

2.2.3 氮素養(yǎng)分吸收利用效率

由表6可知, 不同施肥處理下早稻的氮素養(yǎng)分吸收利用效率存在差異。從氮素干物質(zhì)生產(chǎn)效率(NDMPE)看, 氮素干物質(zhì)生產(chǎn)效率表現(xiàn)出隨施氮量的增加而下降的趨勢。處理B的氮素干物質(zhì)生產(chǎn)效率最高, 比其他處理增加3.94%~14.08%。氮收獲指數(shù)(NHI)反映了氮素在植株營養(yǎng)器官與生殖器官間的分配情況, 結(jié)果顯示不同施肥處理對早稻氮收獲指數(shù)存在一定的影響。各處理氮收獲指數(shù)為61.83%~71.04%, 其中處理B的氮收獲指數(shù)顯著高于其他處理(<0.05), 處理E次之。因此, 在各處理中, 處理B的氮素干物質(zhì)生產(chǎn)效率和氮收獲指數(shù)較高, 分別為71.44 kg?kg-1和71.04%。

表6 各處理早稻的氮素干物質(zhì)生產(chǎn)效率(NDMPE)和氮收獲指數(shù)(NHI)

A: 冬閑+150 kg(N)?hm-2; B: 紫云英+90 kg(N)?hm-2; C: 紫云英+ 120 kg(N)?hm-2; D: 紫云英+150 kg(N)?hm-2; E: 紫云英+180 kg(N)?hm-2。數(shù)據(jù)為3個重復的平均值±標準誤; 同列不同小寫字母分別表示各處理間差異顯著(<0.05)。A: winter fallow with 150 kg(N)?hm-2application in early rice; B: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice; C: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice; D: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice; E: Chinese milk vetch plantation in winter and incorporation in spring combined with 90 kg(N)?hm-2application in early rice. Values in the table are mean ± SE of 3 replicates. Different lowercase letters in the same column mean significant differences at 0.05 level.

3 討論與結(jié)論

研究表明, 有機無機肥配施有利于促進植株干物質(zhì)積累[16]。徐昌旭等[13]研究結(jié)果顯示, 翻壓22 500 kg?hm-2紫云英后, 與施用100%化肥(N 150 kg?hm-2、P2O575 kg?hm-2、K2O 120 kg?hm-2)相比, 減少化肥用量可以促進干物質(zhì)的積累; 減少化肥用量20%, 水稻干物質(zhì)積累量平均增加18.8%, 而化肥用量減少到常規(guī)用量的40%~60%時, 干物質(zhì)積累量并沒有減少。楊長明等[17]研究結(jié)果表明: 有機無機肥配施有利于水稻植株在灌漿期對干物質(zhì)的積累。姜佰文等[18]研究結(jié)果顯示, 在等量有機肥用量條件下, 配施適宜比例的無機肥能夠提高總干物質(zhì)積累量18.8%~26.9%。本研究結(jié)果同樣表明, 與對照處理相比, 紫云英與氮肥配施各處理的早稻干物質(zhì)積累量均在一定程度上有所提高, 其中以紫云英配施120 kg?hm-2氮肥處理的干物質(zhì)積累量最大。各處理在抽穗—灌漿期的干物質(zhì)積累比例均最大, 而紫云英與氮肥配施處理在這一階段的干物質(zhì)積累量較冬閑處理平均增加10.01%。聶俊等[19]研究結(jié)果表明, 有機肥與化肥配施可以提高水稻分蘗期到成熟期的干物質(zhì)積累, 而本研究結(jié)果顯示紫云英與氮肥配施對干物質(zhì)積累的優(yōu)勢僅從孕穗期開始, 在分蘗期冬閑常規(guī)施氮處理、紫云英配施150 kg?hm-2氮肥和180 kg?hm-2氮肥處理的干物質(zhì)積累量均高于紫云英配施90 kg?hm-2氮肥和120 kg?hm-2氮肥處理, 這可能是因為紫云英翻壓后由于前期氣溫低, 氮素釋放慢, 并未完全轉(zhuǎn)化成可被直接利用的形式, 氮素供應相對不足[20], 而氮肥作為速效肥料, 養(yǎng)分釋放速度較快, 因此氮肥施用量大的處理在水稻生育前期長勢較好, 而紫云英與氮肥配施處理在水稻生育中后期長勢較好。從早稻干物質(zhì)轉(zhuǎn)運情況看, 隨著施氮量的增加, 莖葉干物質(zhì)輸出量、輸出率及表觀轉(zhuǎn)變率呈下降趨勢, 這與朱冰[21]、趙田徑等[22]的研究結(jié)果一致。

養(yǎng)分吸收是物質(zhì)生產(chǎn)的基礎。植物中的養(yǎng)分從土壤中獲得, 楊馨逸等[23]認為在相同肥力下, 土壤氮素轉(zhuǎn)化率隨著施氮量的增加呈現(xiàn)先上升后下降的趨勢, 只有施入適宜的氮量才能協(xié)調(diào)好土壤供氮和作物需氮之間的關系。因此, 氮肥施用不合理、養(yǎng)分供應不同步是氮素利用效率低的主要原因[24]。常用的氮肥是速效肥料, 冬閑處理在水稻生長前期供肥過旺、后期供肥不足, 而紫云英與化肥的養(yǎng)分釋放速率不同, 翻壓紫云英處理在水稻全生育期都有充足的養(yǎng)分供應。要文倩等[25]研究結(jié)果表明, 有機無機肥配施有利于提高水稻養(yǎng)分利用效率, 促進氮素吸收。商躍鳳[26]研究表明有機無機氮肥混施氮肥利用率比單施化肥提高7%~18%。張小莉等[27]研究結(jié)果亦表明, 有機無機復混肥處理的氮素積累量、氮素利用效率均顯著高于化肥處理。本試驗中, 紫云英與氮肥配施增加了水稻的氮素吸收量, 與不施紫云英處理相比, 紫云英與氮肥配施處理的早稻氮素吸收量增加6.95%~18.68%, 其中紫云英配施120 kg?hm-2氮肥處理的氮素吸收積累量最高。這與李賀[28]、孟琳[29]的研究結(jié)果類似。本試驗中, 氮素干物質(zhì)生產(chǎn)效率隨著施氮量增加呈先上升再下降的趨勢, 說明在一定范圍內(nèi), 施氮量增加能促進作物對氮素的吸收利用, 但當?shù)蔬^量施用時, 會造成水稻對氮素的奢侈吸收[30], 從而降低氮素利用率, 這與前人[11]的研究結(jié)果一致。

本試驗條件下, 與不施紫云英處理相比, 紫云英配施氮肥處理提高了水稻干物質(zhì)積累量、氮素吸收積累量以及氮素利用率, 其中以紫云英配施純氮90 kg?hm-2和120 kg?hm-2處理的效果較優(yōu), 明顯地實現(xiàn)了減氮增效的目的, 是較理想的施肥模式。

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Effect of combined application of Chinese milk vetch and nitrogen fertilizer on nitrogen uptake, utilization and dry matter accumulation in early rice*

QIAN Chenchen1,2, WANG Shubin1,2, YANG Binjuan1,2, HUANG Guoqin1,2**

(1. Research Center on Ecological Science, Jiangxi Agricultural University, Nanchang 330045, China; 2. Colleges and Universities Union of Ecology in Jiangxi Province, Nanchang 330045, China)

This study evaluated the effect of combined application of Chinese milk vetch (L.) and different levels of nitrogen (N) fertilizer on dry matter accumulation and N use efficiency of early rice in order to determinate the suitable N level under application of Chinese milk vetch. Field treatments were set with four N application levels (90 kg?hm-2, 120 kg?hm-2, 150 kg?hm-2and 180 kg?hm-2) under 22 500 kg?hm-2Chinese milk vetch using the winter fallow field with general N fertilizer level (150 kg?hm-2) as the control. In the experiment, Chinese milk vetch was planted in winter and incorporated into soil in spring before early rice transplant, while N fertilizer was applied as base fertilizer, tillering fertilizer and heading fertilizer with 5︰3︰2 rate. The rice plants were sampled at tillering, booting, heading, filling and maturity stages of the early rice. Dry matter weight and N content were assayed, and the relative indexes were calculated. The results showed that all N application treatments had higher dry matter accumulation than the control. Specifically, the treatments with Chinese milk vetch combined with 90 kg(N)?hm-2and 120 kg(N)?hm-2increased dry matter (9.65 t?hm-2and 9.97t?hm-2) respectively by 11.18% and 14.86% compared to the control. Dry matter accumulation increased with duration of growth and peaked twice, one at sowing-tillering stage (19.26%-24.77%) and the other at heading-filling stage (45.23%-52.75%). The combined application of Chinese milk vetch and N fertilizer supported N integration that was beneficial to rice growth. The amounts of N accumulation of early rice treated with Chinese milk vetch and N fertilizer were higher than the control, with increases of 6.95%-18.68%. Among the treatments, that of Chinese milk vetch combined with 90 kg(N)?hm-2had the highest production efficiency of dry matter and N harvest index, with respective increases of 3.94%–14.08% and 6.65%–14.90% over other treatments. The results indicated that combined application of Chinese milk vetch with 90 kg(N)?hm-2or 120 kg(N)?hm-2was satisfactory because they reduced N fertilizer and increased N use efficiency at the same time, which was the ideal fertilization model for the study area.

Chinese milk vetch; Nitrogen fertilizer; Early rice; Dry matter; Nitrogen uptake

10.13930/j.cnki.cjea.160857

S551+.9; S511.3+1

A

1671-3990(2017)04-0563-09

2016-09-24

2016-11-23

Sep. 24, 2016; accepted Nov. 23, 2016

* 江西省研究生創(chuàng)新專項資金項目(YC2013-B030)和國家科技支撐計劃課題(2012BAD14B14-01)資助

* The study was supported by the Graduate Innovation Fund of Jiangxi Province (YC2013-B030) and the National Key Technology Research and Development Program of China (2012BAD14B14-01).

** Corresponding author, E-mail: hgqjxnc@sina.com

**通訊作者:黃國勤, 主要研究方向為作物學、生態(tài)學、農(nóng)業(yè)發(fā)展與區(qū)域農(nóng)業(yè)、資源環(huán)境與可持續(xù)發(fā)展等。E-mail: hgqjxnc@sina.com

錢晨晨, 研究方向為農(nóng)業(yè)生態(tài)學。E-mail: 827431622@qq.com

錢晨晨, 王淑彬, 楊濱娟, 黃國勤. 紫云英與氮肥配施對早稻干物質(zhì)生產(chǎn)及氮素吸收利用的影響[J]. 中國生態(tài)農(nóng)業(yè)學報, 2017, 25(4): 563-571

Qian C C, Wang S B, Yang B J, Huang G Q. Effect of combined application of Chinese milk vetch and nitrogen fertilizer on nitrogen uptake, utilization and dry matter accumulation in early rice[J]. Chinese Journal of Eco-Agriculture, 2017, 25(4): 563-571