控释氮肥与普通尿素配施比例和方法对冬小麦灌浆特性的影响

Effects of blending ratio and application method of controlled-release nitrogen fertilizer and common urea on grain-filling properties of winter wheat

【目的】控释氮肥施用模式影响小麦的灌浆和产量构成因素,利用Richards模型模拟陕西关中地区冬小麦灌浆进程并分析产量构成参数,探究控释氮肥掺混尿素的施肥方式和配施比例对冬小麦增产机理及灌浆特性的影响。【方法】以小麦品种‘小偃22’为供试作物,供试控释尿素的释放期为180天,于2017、2018年在陕西农林科技大学旱区灌溉站进行控释氮肥与尿素配合施用田间试验。共设置3个控释氮肥和普通尿素氮配施比例,依次为8∶2(N2)、7∶3(N3)和6∶4(N4);2种施肥方式,即掺混肥料一次性基施(B,简称基施)和基施控释氮肥+拔节期追施普通尿素(T,简称追施);同时设不施氮肥(CK0)、单施普通尿素(基追比4∶6,CK1)和单施控释氮肥(一次性基施,CK2)3个对照。在分蘖期和返青期统计分蘖数;在成熟期统计穗数,测量穗长、穗粒数、千粒重。从冬小麦开花结束第5天开始,每隔5天取1次样,共取9次,计算千粒重。以花后时间t为自变量,以该时间测得的千粒重(W)为因变量,采用方程W=A/(1+Be^-Kt)^1/E,计算灌浆参数和生长势。【结果】施氮能显著提高籽粒千粒重和产量,追施氮可保证灌浆物质来源更加充分,追施氮比例增加,起始生长势增大。适量追氮能延长灌浆持续时间,最大延长11.83天,促使最大灌浆速率出现日提前,最早提前3.791天;各处理在快增期均获得最大生长比率(Pw2),与基施处理相比,追施增加了快增期(Pw2)和缓增期(Pw3)的持续时间和生长比率,持续时间分别延长1.28~2.27天(T2)、4.46~7.49天(T3),生长比率分别增加4.69%~7.80%(PW2)和20.12%~37.25%(PW3)。基施处理的单位面积分蘖数和有效穗数均高于追施处理,与追施处理相比平均分别增加204.1~264.0个/m2、29.0~97.1穗/m2。施肥方式和配施比例的交互作用对产量和单位面积有效穗率具有极显著影响,TN2和BN3产量最高,与CK1相比产量分别提高14.54%和13.09%,与CK2相比产量分别提高11.46%和10.85%;其中,TN2处理千粒重较高,为41.32 g,BN3处理单位面积有效穗数较高,为546.5穗/m2。【结论】控释氮肥配施普通尿素的比例和施用方法能有效调控灌浆动态和产量构成。本试验条件下,以控释尿素和普通尿素7∶3混合后全部基施(BN3)和比例为8∶2时追施普通尿素(TN2)的效果最为理想。BN3主要通过增加最大灌浆速率和推迟最大灌浆速率出现日期提高籽粒物质量,并通过单位面积分蘖数保证较高的单位面积有效穗数以提高产量。TN2主要通过保证较高的有效穗率,在灌浆期通过延长灌浆持续时间和提高缓增期的生长比率提高籽粒物质量累积,并获得较高的千粒重以提高产量。在冬小麦生产过程中,优先推荐BN3处理的施氮模式,可在获得高产的同时节约劳动力和成本,但从千粒重角度考虑,TN2处理为较优施氮模式。

【Objectives】The application pattern of controlled-release urea affects the grain-filling and yield components of wheat.This study used Richards model to simulate the filling process of winter wheat under different fertilization patterns,and proposed the appropriate fertilization modes and blending ratios.【Methods】Field experiments were conducted in Guanzhong area of Shaanxi,using winter wheat‘Xiaoyan 22’as tested crop and a controlled-release urea with 180-days releasing period as tested fertilizer.The three blending ratios of controlledrelease urea to common urea were 8∶2(N2),7∶3(N3)and 6∶4(N4).The two fertilization patterns were once basal applying of all blended fertilizers(referred to basal application,B),and basal applying controlled-release urea and topdressing common urea at jointing stage of wheat(referred to topdressing,T).No N fertilization(CK0),pure common urea applied in ratio of basal and topdressing of 4∶6(CK1),and pure controlled-release urea once basal applied(CK2)were the three controls.The tiller number was investigated at tillering and reviving stage,the yield components were investigated at harvest.The first grain sample collection was conducted on the 5th day after the end of flowering,then repeated in 5 days intervals and 9 collection in all,and the 1000-grain weight was calculated.Taking sampling days after flowering as independent variable(t)and the corresponding 1000-grain weight as dependent variable(W),the grain-filling parametersand growth potential were calculated using formula W=A/(1+Be^-Kt)^1/E.【Results】N fertilizer significantly increased the 1000-gain weight and yield of the wheat.Topdressing of N fertilizer increased photosynthetic products,the higher the proportion of topdressed N,the greater the initial growth potential was.Appropriate topdressing ratio prolonged the duration of the filling period,with the longest extension of 11.83 days,and reached the maximum filling rate earlier,with the earliest of 3.791 days.All the treatments reached the maximum growth potential in the fast increase period(Pw2),topdressing treatments increased both the duration and growth rate of the fast increase(Pw2)and slow increase periods(Pw3),compared with the basal treatments.The duration was extended by 1.28–2.27 days in T2 and 4.46–7.49 days in T3,respectively,and the growth potentials increased by 4.69%–7.80%(Pw 2)and 20.12%–37.25%(Pw3).Basal treatments significantly increased the number of tillers and effective panicles than topdressing did,with averaged increases of 204.1–264.0 and 29.0–97.1 No./m2,respectively.Fertilization methods and blending ratios showed significant interaction on effective ear rate and yield,among all the treatments,TN2 and BN3 achieved the highest yields.TN2 also produced the largest 1000-grain weight(41.32 g),and BN3 had the most effective panicle number(546.5 panicles/m2).【Conclusions】Fertilization patterns and blending ratio of controlled release urea with common urea effectively regulate the filling process and yield formation.Using the controlled-release urea with 180 days releasing period,mixing controlled-release urea with common urea in 7∶3 and applied once as basal(BN3),or in ratio of 8∶2 and topdressed urea(TN2)all perform well.BN3 is effective in producing higher tiller number and effective ear number,increasing the maximum filling rate and delaying the appearance of the maximum growth rate.TN2 does well mainly by keeping longer and higher filling rate and growth potential.Considering the labor cost in topdressing,BN3 is preferred to TN2,while for higher 1000-grain weight,TN2 is preferred in the tested area.