秋闲期秸秆覆盖与减氮优化根系分布提高冬小麦产量及水氮利用效率

doi:10.3864/j.issn.0578-1752.2022.14.003

摘要/Abstract

摘要：

【目的】冬春干旱频发和氮的过度施用限制了西南丘陵旱地雨养农业区小麦的产量与可持续发展,探讨秋闲期秸秆覆盖与氮肥减施对旱地小麦根系分布、产量及水氮吸收利用的影响,为优化四川旱地小麦耕作制度和绿色高质高效生产提供依据。【方法】试验于2016–2018年在四川省仁寿县四川农业大学试验基地进行,采用裂区设计,在夏玉米收获后,以秋闲期秸秆粉碎覆盖（SM）和不覆盖（NM）为主区,以不施氮（N₀：0）、减氮（RN：120 kg N·hm^-2）和常规施氮（CN：180 kg N·hm^-2）为裂区,研究分析土壤含水量、根长、根系分布、小麦产量、耗水量（ET）、水分利用效率（WUE）和氮素利用情况。【结果】与不覆盖相比,秋闲期秸秆覆盖显著提高播种至孕穗期0—10 cm和10—20 cm土层含水量及播种时与拔节期0―100cm土层土壤贮水量,秸秆覆盖的保墒效应可持续至孕穗开花阶段;覆盖显著促进小麦拔节期和开花期耕层根系生长,尤其是0—10 cm土层根系直径增加、根长密度显著提高;覆盖下小麦总耗水量、WUE、氮素吸收量、播种至拔节期氮素积累速率、拔节至开花期氮素积累速率、氮素籽粒生产效率（NUEg）、氮肥农学效率（AEN）和氮肥偏生产力（NPFP）两年均值较不覆盖分别提高11.4%、71.8%、73.1%、119.0%、100.0%、3.6%、264.7%和78.2%;覆盖下氮肥回收效率（REN）较不覆盖增加44.4个百分点。覆盖后冬小麦有效穗数、穗粒数和产量两年均值较不覆盖分别提高31.8%、44.4%和92.9%。秸秆覆盖效应大于施氮量效应。与常规施氮量相比,减氮处理未显著降低0—10 cm土层根长密度、耗水量、水分利用效率与籽粒产量;覆盖结合减氮显著提高群体氮素籽粒生产效率、氮肥农学效率、氮肥偏生产力和氮肥回收效率。【结论】秋闲期秸秆覆盖提高播种至拔节期土壤水分含量和储量,促进拔节期小麦根系在表层土壤中的生长,进而促进氮素吸收利用、提高冬小麦产量与水肥利用效率;秋闲期覆盖结合120 kg·hm^-2施氮量是适宜四川旱地冬小麦的减氮增效高产栽培技术模式。

关键词: 旱地小麦, 秸秆覆盖, 减氮, 根系分布, 产量, 水氮利用

Abstract:

【Objective】Frequent drought in winter and spring as well as excessive application of nitrogen limited wheat yield and sustainable development in rainfed farming areas of dryland in southwest China. The objective of this study was to clarify the effects of straw mulching from autumn fallow and reducing nitrogen application on root distribution, wheat yield, water and nitrogen utilization of dryland winter wheat, so as to provide a basis for optimizing wheat tillage system and green, high quality and efficient production of winter wheat in dryland of Sichuan province. 【Method】 The experiment was carried out at Renshou experiment station of Sichuan Agricultural University in Sichuan province from 2016 to 2018. The spilt plot design was employed with main plot of maize straw mulching (mulching from autumn fallow to wheat harvesting: SM) and no mulching (NM), and sub-plot of different nitrogen application rates (N₀: 0; reducing nitrogen rate (RN): 120 kg N·hm^-2, and conventional nitrogen rate (CN): 180 kg N·hm^-2). Soil moisture, root length, root distribution, wheat yield, water consumption (ET), water and nitrogen use efficiencies were investigated. 【Result】Compared with NM, SM significantly increased the soil water content in 0-10 cm and 10-20 cm layers from sowing to booting stage and the soil water storage in 0-100 cm layer at sowing and jointing, and the soil water retention effect of straw mulching lasted until booting and anthesis stage. SM also promoted the wheat root growth at jointing and anthesis stage with higher root diameter and significantly higher root length density in 0-10 cm layer. The mean values of total ET, WUE (water use efficiency), nitrogen accumulation amount of wheat plant, nitrogen accumulation rate from sowing to jointing, nitrogen accumulation rate from jointing to anthesis, nitrogen use efficiency for grain production (NUEg), agronomic efficiency of nitrogen fertilizer (AEN), nitrogen fertilizer partial factor productivity (NPFP) and wheat yield under SM increased by 11.4%, 71.8%, 73.1%, 119.0%, 100.0%, 3.6%, 264.7%, 78.2% than that under NM, respectively, and the recovery efficiency of nitrogen fertilizer (REN) under SM increased by 44.4 percentage points compared with NM. The wheat yield under SM increased by 92.9% because of the significantly increased average spike number (31.8%) and grains per spike (44.4%). The effect of straw mulching was greater than that of nitrogen application. Compared with CN, RN did not significantly decrease the wheat root length density, ET, WUE and wheat yield. Combining with SM, RN significantly improved the NUEg, physiological efficiency of nitrogen (PEN), AEN, NPFP, and REN. 【Conclusion】Straw mulching from autumn fallow improved soil water content and storage and optimized root distribution in 0-10 cm layer with higher root length density and root diameter, thus to increase the nitrogen absorption and utilization, wheat yield, and the utilization of water and fertilizer. Straw mulching combined with 120 kg N·hm^-2 was a high yield cultivation mode with reducing nitrogen application and high water and nitrogen use efficiency for dryland winter wheat in Sichuan province, China.

Key words: dryland winter wheat, straw mulching, reducing nitrogen application, root distribution, grain yield, water and nitrogen utilization

高仁才, 陈松鹤, 马宏亮, 莫飘, 柳伟伟, 肖云, 张雪, 樊高琼. 秋闲期秸秆覆盖与减氮优化根系分布提高冬小麦产量及水氮利用效率[J]. 中国农业科学, 2022, 55(14): 2709-2725.

GAO RenCai, CHEN SongHe, MA HongLiang, MO Piao, LIU WeiWei, XIAO Yun, ZHANG Xue, FAN GaoQiong. Straw Mulching from Autumn Fallow and Reducing Nitrogen Application Improved Grain Yield, Water and Nitrogen Use Efficiencies of Winter Wheat by Optimizing Root Distribution[J]. Scientia Agricultura Sinica, 2022, 55(14): 2709-2725.

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年份 Year	pH	有机质 Organic matter (g·kg^-1)	全氮 Total N (g·kg^-1)	全磷 Total P (g·kg^-1)	全钾 Total K (g·kg^-1)	碱解氮 Available N (mg·kg^-1)	有效磷 Available P (mg·kg^-1)	有效钾 Available K (mg·kg^-1)
2016-2017	7.62	17.46	1.03	0.59	18.90	93.35	11.27	153.91
2017-2018	7.69	16.17	1.04	0.56	21.07	84.52	12.38	174.87

年份 Year	处理 Treatment	氮素吸收量 N accumulation amount (kg·hm^-2)			氮素积累速率 N accumulation rate (kg·hm^-2·d^-1)
年份 Year	处理 Treatment	拔节期 Jointing	开花期 Anthesis	成熟期 Maturity	播种—拔节期Sowing-jointing	拔节—开花期Jointing-anthesis	开花—成熟期Anthesis-maturity
2016- 2017	NM+N₀	21.2e	39.1e	54.3e	0.27e	0.32b	0.26c
	NM+RN	34.3d	56.7d	91.1d	0.44d	0.40b	0.59a
	NM+CN	36.3d	59.6d	97.3d	0.47d	0.42b	0.65a
	均值Mean	30.6	51.8	80.9	0.4	0.38	0.5
	SM+N₀	55.5c	79.6c	118c	0.72c	0.43b	0.66a
	SM+RN	74.6b	119.7b	144.9b	0.97b	0.81a	0.43b
	SM+CN	83.4a	132.9a	166.2a	1.08a	0.88a	0.57a
	均值Mean	71.2	107.6	143	0.92	0.71	0.56
	F值F values
	覆盖类型 M	1599.2**	497.7**	2495.7**	1626.4**	580.9**	32.2*
	施氮量 N levels	118.6**	116.2**	170.9**	117.4**	21.3**	5.9*
	覆盖类型×施氮量 M×N levels	9.5**	19.2*	4.6*	9.5**	9.0**	22.9**
2017- 2018	NM+N₀	27.2e	48.2e	76.2e	0.31e	0.40c	0.56b
	NM+RN	37.7d	64.5d	103.6d	0.42d	0.52bc	0.85a
	NM+CN	41.5d	65.7d	102.3d	0.47d	0.46c	0.80a
	均值Mean	35.5	59.5	94	0.4	0.46	0.74
	SM+N₀	57.6c	92.4c	132.3c	0.65c	0.67b	0.87a
	SM+RN	77.0b	130.6b	162.0b	0.87b	1.03a	0.68ab
	SM+CN	87.1a	151.6a	184.9a	0.98a	1.20a	0.81a
	均值Mean	73.9	124.9	159.7	0.83	0.97	0.79
	F值F values
	覆盖类型 M	3806**	5785.9**	759.8**	3579.1**	1470.1**	ns
	施氮量 N levels	45.7**	131.6**	102.2**	45.6**	12.4**	ns
	覆盖类型×施氮量 M×N levels	5.3*	35.1**	13.2**	5.3*	7.0*	11.4**

年份 Year	处理 Treatment	有效穗数 Spike numbers (spike/m²)	穗粒数 Grains per spike	千粒重 1000-grain weight (g)	产量 Grain yield (kg·hm^-2)
2016-2017	NM+N₀	224.0b	24.4d	57.1a	2553d
	NM+RN	232.7b	28.8c	56.7ab	3163c
	NM+CN	216.7b	29.2c	55.8c	3178c
	均值Mean	224.5	27.5	56.5	2965
	SM+N₀	306.6a	38.6b	56.1c	6517b
	SM+RN	313.3a	44.1a	56.6b	6712ab
	SM+CN	309.3a	44.8a	56.9ab	7063a
	均值Mean	309.7	42.5	56.5	6764
	F值F values
	覆盖类型 M	396.7**	221.5**	ns	1051.0**
	施氮量 N levels	Ns	20.4**	5.2*	9.8**
	覆盖类型×施氮量 M×N levels	Ns	ns	41.5**	ns
2017-2108	NM+N₀	263.1b	29.3c	48.9d	2800c
	NM+RN	266.6b	33.3c	50.9b	4457b
	NM+CN	262.2b	33.3c	51.9a	4609b
	均值Mean	264	32	50.6	3955
	SM+N₀	330.8a	39.4b	49.2d	6340a
	SM+RN	332.6a	44.8a	50.3c	6621a
	SM+CN	339.3a	46.1a	49.3d	6801a
	均值Mean	334.2	43.4	49.6	6587
	F值F values
	覆盖类型 M	417.1**	59.3*	201.8**	3179.3**
	施氮量 N levels	Ns	10.8**	74.6**	18.3**
	覆盖类型×施氮量 M×N levels	Ns	ns	50.3**	7.5*

年份 Year	处理 Treatment	水分利用效率 WUE (kg·hm^-2·mm^-1)	氮素籽粒生产效率 NUEg (kg·kg^-1)	氮肥生理效率PEN (kg·kg^-1)	氮肥农学效率 AEN (kg·kg^-1)	氮肥偏生产力 NPFP (kg·kg^-1)	氮肥回收率 REN (%)
2016- 2017	NM+N₀	13.4d	47.1a	—	—	—	—
	NM+RN	16.7c	34.7c	16.5b	5.1c	26.4c	30.7c
	NM+CN	17.1c	32.7c	14.4b	3.5c	17.7d	23.9c
	均值Mean	15.7	38.2	15.4	4.3	22	27.3
	SM+N₀	32.3b	33.6c	—	—	—	—
	SM+RN	33.6ab	46.5a	46.1a	34.7a	55.9a	75.5a
	SM+CN	34.2a	42.6b	40.4a	25.1b	39.2b	62.2b
	均值Mean	33.3	40.9	43.3	29.9	47.6	68.9
	F值F values
	覆盖类型 M	627.5**	42.7*	95.8*	1052.4**	987.7**	983.6**
	施氮量 N levels	10.3**	Ns	ns	53.3**	323.6**	18.6*
	覆盖类型×施氮量M×N levels	ns	56.7**	ns	27.1**	32.1**	ns
2017- 2018	NM+N₀	19.1e	37.8d	—	—	—	—
	NM+RN	28.6d	41.9bc	53.6ab	12.7c	36.1c	24.6c
	NM+CN	30.9c	44.7ab	62.9a	9.9d	25.4d	15.7d
	均值Mean	26.2	41.5	58.2	11.3	30.8	20.2
	SM+N₀	36.5b	47.5a	—	—	—	—
	SM+RN	39.9a	40.9c	43.5bc	31.8a	55.2a	73.3a
	SM+CN	39.6a	36.8d	36.2c	22.2b	37.8b	61.6b
	均值Mean	38.7	41.7	39.8	27	46.5	67.4
	F值F values
	覆盖类型 M	879.7**	ns	21.6*	1025**	1100.5**	490.7**
	施氮量 N levels	97.9**	ns	ns	183.1**	871.5**	38.7*
	覆盖类型×施氮量M×N levels	59.6**	43.7**	ns	52.6**	49.9**	ns

项目Item			GY	WUE	TN	NUEg	PEN	AEN	NPFP	REN
拔节期 Jointing	总根长TRL		0.75^*	0.87**	0.82**	0.18	0.59	0.73*	0.67*	0.61
	根长密度RLD	0-10 cm	0.77^*	0.80**	0.81**	0.18	0.65	0.87**	0.78*	0.72*
		10-20 cm	0.00	0.16	0.22	-0.20	-0.52	-0.23	-0.19	-0.02
		20-30 cm	0.41	0.72*	0.43	0.21	0.57	0.23	0.25	0.09
		30-40 cm	0.60	0.86**	0.59	0.28	0.68*	0.45	0.45	0.28
开花期Anthesis	总根长TRL		0.51	0.79*	0.54	0.21	0.60	0.25	0.27	0.10
	根长密度RLD	0-10 cm	0.53	0.80**	0.56	0.19	0.62	0.24	0.25	0.07
		10-20 cm	0.33	0.65	0.37	0.27	0.52	0.21	0.24	0.09
		20-30 cm	0.51	0.76*	0.57	0.19	0.35	0.35	0.34	0.31
		30-40 cm	0.36	0.61	0.34	0.47	0.62	0.42	0.41	0.28