不同氮用量对四川春玉米光合特性、氮利用效率及产量的影响

doi:10.3864/j.issn.0578-1752.2022.09.004

摘要/Abstract

摘要：

【目的】明确不同施氮量下春玉米产量形成的光合机制,分析不同施氮量对氮肥利用率、土壤氮素盈余量等的影响,为当地合理施用氮肥,促进春玉米高产高效提供理论参考。【方法】以玉米品种仲玉3号为试验材料,分别于2019、2020年在四川农业大学雅安试验农场的肥效长期定位试验地进行田间试验,设置5个供氮水平,分别为0（不施氮）、90 kg·hm^-2（低氮）、180 kg·hm^-2（适量氮）、270 kg·hm^-2（农民习惯施氮）、360 kg·hm^-2（高氮）,记为N0、N1、N2、N3、N4。于拔节期、吐丝期和灌浆期测定叶面积,分别计算叶面积指数、光合势;于灌浆期测定穗位叶净光合速率等光合参数以及吐丝期、灌浆期测定叶绿素含量;吐丝期、灌浆期、收获期测定地上部群体干物质积累量,收获时测定产量,分析各部位氮含量,计算土壤氮素盈余量、春玉米氮素利用效率和施氮经济效益。【结果】（1）春玉米产量随施氮量增加先升后持平,2019、2020两年都是N2处理的产量最高,平均为9 746 kg·hm^-2,相较于N0、N1处理分别增产179%、28.7%（P<0.05）,而N2与N3、N4处理间产量无显著差异。两年产量经线性+平台拟合,平台施氮量为134.8 kg·hm^-2,平台产量为9 604 kg·hm^-2,此时产投比也最高（12.6）。（2）适量施氮（N2）相比不施氮均显著提高穗位叶叶绿素含量、净光合速率、气孔导度、蒸腾速率以及叶面积指数和光合势等,继续增施氮肥上述指标无显著差异甚至显著降低。（3）结合光合特性与收获期产量的相关性分析及偏最小二乘法分析表明,春玉米光合势、净光合速率、气孔导度、蒸腾速率、叶面积指数、叶绿素a+b与产量均呈极显著正相关关系（P<0.01）,且影响春玉米产量的主导因素是叶绿素a+b。（4）收获期籽粒氮素积累量和地上部氮总积累量两年都是随施氮量增加先显著上升,在N2处理后（超过180 kg·hm^-2）微弱上升或基本持平;经拟合表明土壤氮素盈余量为0时施氮量为139 kg·hm^-2;春玉米氮肥表观利用率两年都是N2处理最高,平均达73.7%,较N1处理提高10.8%（P<0.05）,继续增施氮肥,氮肥表观利用率则显著下降,N3、N4处理氮肥表观利用率相较于N2处理分别降低32.9%和48.1%（P<0.05）。【结论】适量施氮能明显提高春玉米叶片光合性能,延缓穗位叶总叶绿素的降解,延长光合作用持续期,优化总叶绿素、叶面积指数和光合势在春玉米产量形成中的作用。同时,适量施氮能显著增加地上部群体干物质积累量和籽粒产量,促进玉米对氮素的吸收与积累,降低土壤氮素残留,提高氮肥表观利用率。综合产量、施肥经济效益、氮肥表观利用率和氮素盈余量等因素,试验区（四川雅安）氮素投入量为139—180 kg·hm^-2能维持春玉米的高产高效目标。

关键词: 春玉米, 氮用量, 光合特性, 产量, 氮肥表观利用率, 氮素盈余量

Abstract:

【Objective】 In order to clarify the photosynthetic mechanism affecting the yield formation of spring maize under different nitrogen application levels, the effects of different nitrogen application levels on nitrogen use efficiency and soil nitrogen surplus were analyzed, so as to provide the theoretical reference for rational application of nitrogen fertilizer and promoting high yield and high efficiency of spring maize.【Method】Using the maize of variety Zhongyu 3 as experimental material, the field experiments were carried out in 2019 and 2020 at the long-term fertilizer effect experimental site of Ya’an Experimental Farm of Sichuan Agricultural University. Nitrogen supply included five levels, such as 0 (no nitrogen application), 90 (low nitrogen), 180 (appropriate amount of nitrogen), 270 (farmers’ habitual nitrogen application), and 360 kg·hm^-2 (high nitrogen), which were marked as N0, N1, N2, N3, and N4, respectively. The leaf area was measured at jointing period, silking period and grain-filling period, and the leaf area index and leaf area duration were calculated, respectively. The photosynthetic parameters, such as net photosynthetic rate of ear leaves were measured at grain-filling period, and chlorophyll content was measured at silking period and grain-filling period. The dry matter accumulation of aboveground population was measured at silking period, grain-filling period, and harvest period, the yield was measured at harvest, the nitrogen content of each part was analyzed, and the soil nitrogen surplus, nitrogen use efficiency of spring maize and economic benefit of nitrogen application were calculated.【Result】(1) The spring maize yield increased first and then remained flat with the increase of nitrogen application levels. In 2019 and 2020, the yield under N2 treatment was the highest, with an average of 9 746 kg·hm^-2, which was 179% and 28.7% higher than that of N0 and N1 treatments (P<0.05), respectively, but there was no significant difference among N2, N3, and N4 treatments. 2-year yield was fitted by linear + platform fitting, the platform nitrogen application level was 134.8 kg·hm^-2, the platform yield was 9 604 kg·hm^-2, and the output-input ratio of platform nitrogen fertilizer (134.8 kg·hm^-2) was the highest (12.6). (2) Compared with no nitrogen application, the appropriate amount of nitrogen application (N2) significantly increased chlorophyll content, net photosynthetic rate, stomatal conductance, transpiration rate of ear leaves, leaf area index and leaf area duration. However, with the increase of nitrogen fertilizer application, there was no significant difference or even decreased significantly in the above indexes. (3) Combined with the correlation analysis and partial least square analysis of photosynthetic characteristics and harvest yield, the yield was significant positively correlated with leaf area duration, net photosynthetic rate, stomatal conductance, transpiration rate, leaf area index, chlorophyll a+b of spring maize (P<0.01), and the main factor affecting spring maize yield was chlorophyll a+b. (4) During the harvest period, the grain nitrogen accumulation and total aboveground nitrogen accumulation increased significantly with the increase of nitrogen application level, and increased slightly or basically flat after N2 treatment (more than 180 kg·hm^-2) in the two years. The fitting results showed that the nitrogen application level was 139 kg·hm^-2 when the soil nitrogen surplus was 0 kg·hm^-2; The nitrogen apparent recovery efficiency of spring maize under N2 treatment was the highest in the two years, with an average of 73.7%, which was 10.8% higher than that under N1 treatment (P<0.05), the nitrogen apparent recovery efficiency decreased significantly with the continuous application of nitrogen fertilizer. Compared with N2 treatment, the nitrogen apparent recovery efficiency of N3 and N4 treatments decreased by 32.9% and 48.1%, respectively (P<0.05).【Conclusion】The proper amount of nitrogen application could obviously improve the photosynthetic performance of spring maize leaves, delay the degradation of total chlorophyll in ear leaves, prolong the duration of photosynthesis, and optimize the role among total chlorophyll, leaf area index and leaf area duration in the yield formation of spring maize. At the same time, the proper amount of nitrogen application could significantly increase the dry matter accumulation of aboveground population and grain yield, promote the absorption and accumulation of nitrogen to maize, reduce nitrogen residue in soil, and improve the nitrogen apparent recovery efficiency. Considering the factors such as yield, economic benefit of fertilization, apparent nitrogen use efficiency and nitrogen surplus, the nitrogen input of 139-180 kg·hm^-2 could maintain the goal of high yield and high efficiency of spring maize in the experimental area (Ya’an, Sichuan).

Key words: spring maize, amount of nitrogen, photosynthetic characteristics, yield, nitrogen apparent recovery efficiency, nitrogen surplus

熊伟仡, 徐开未, 刘明鹏, 肖华, 裴丽珍, 彭丹丹, 陈远学. 不同氮用量对四川春玉米光合特性、氮利用效率及产量的影响[J]. 中国农业科学, 2022, 55(9): 1735-1748.

XIONG WeiYi, XU KaiWei, LIU MingPeng, XIAO Hua, PEI LiZhen, PENG DanDan, CHEN YuanXue. Effects of Different Nitrogen Application Levels on Photosynthetic Characteristics, Nitrogen Use Efficiency and Yield of Spring Maize in Sichuan Province[J]. Scientia Agricultura Sinica, 2022, 55(9): 1735-1748.

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https://www.chinaagrisci.com/CN/Y2022/V55/I9/1735

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处理 Treatment	pH	有机质 Organic matter (g·kg^-1)	碱解氮 Available N (mg·kg^-1)	有效磷 Available P (mg·kg^-1)	速效钾 Available K (mg·kg^-1)
N0	6.35	27.7	118	67.8	76.1
N1	6.38	28.4	139	55.3	72.6
N2	6.08	31.9	169	49.0	71.7
N3	6.05	32.8	175	53.1	74.2
N4	5.66	33.1	179	51.2	72.8

年份 Year	处理 Treatment	叶面积指数 Leaf area index		叶绿素a Chlorophyll a (mg·g^-1 FW)		叶绿素b Chlorophyll b (mg·g^-1 FW)		叶绿素a+b Chlorophyll a+b (mg·g^-1 FW)
年份 Year	处理 Treatment	吐丝期 Silking period	灌浆期 Grain-filling period	吐丝期 Silking period	灌浆期 Grain-filling period	吐丝期 Silking period	灌浆期 Grain-filling period	吐丝期 Silking period	灌浆期 Grain-filling period
2019	N0	1.53±0.08c	1.44±0.32c	1.59±0.02c	1.70±0.25c	0.431±0.07c	0.621±0.19c	2.02±0.07c	2.32±0.33c
	N1	2.57±0.22b	2.22±0.28b	2.38±0.09b	2.48±0.04b	0.701±0.05b	1.23±0.17b	3.08±0.15b	3.72±0.15b
	N2	3.99±0.02a	3.05±0.42a	2.73±0.06a	2.66±0.05ab	1.25±0.08a	1.87±0.13a	3.98±0.07a	4.53±0.05a
	N3	4.15±0.32a	3.01±0.12a	2.73±0.07a	2.69±0.04a	1.24±0.08a	1.86±0.11a	3.97±0.12a	4.56±0.07a
	N4	4.08±0.40a	3.12±0.52a	2.74±0.07a	2.71±0.03a	1.27±0.03a	1.82±0.07a	4.01±0.09a	4.53±0.09a
2020	N0	2.12±0.03d	1.19±0.03c	1.85±0.023c	1.38±0.02c	0.482±0.09c	0.373±0.01d	2.34±0.02c	1.75±0.03c
	N1	4.07±0.04c	2.81±0.11b	2.51±0.07b	2.53±0.04b	0.998±0.09b	1.05±0.05c	3.51±0.16b	3.57±0.11b
	N2	4.46±0.02a	3.16±0.13a	2.62±0.02a	2.61±0.04a	1.17±0.08a	1.54±0.04a	3.79±0.03a	4.15±0.01a
	N3	4.47±0.05a	3.10±0.18ab	2.62±0.03a	2.64±0.02a	1.20±0.01a	1.51±0.01ab	3.81±0.02a	4.15±0.03a
	N4	4.16±0.03b	3.04±0.30ab	2.65±0.13a	2.60±0.01a	1.22±0.13a	1.48±0.02b	3.88±0.14a	4.08±0.02a
年份 Year		**	ns	ns	**	ns	**	ns	**
施氮量 N application level		**	**	**	**	**	**	**	**
年份×施氮量 Year×N application level		**	ns	**	*	**	ns	**	ns

年份 Year	处理 Treatment	净光合速率 Net photosynthetic rate (P_n) (μmol·m^-2·s^-1)	气孔导度 Stomatal conductance (G_s) (mol·m^-2·s^-1)	胞间二氧化碳浓度 Intercellular CO₂ concentration (C_i) (μmol·mol^-1)	蒸腾速率 Transpiration rate (T_r) (mmol·m^-2·s^-1)
2019	N0	13.3±0.64b	0.07±0.02b	226±17.1a	0.714±0.09b
	N1	14.9±1.62b	0.11±0.03b	221±20.7a	0.936±0.15b
	N2	17.2±1.03a	0.16±0.04a	181±13.9b	1.35±0.24a
	N3	15.8±1.16ab	0.13±0.02ab	192±26.9ab	1.23±0.12a
	N4	17.2±0.84a	0.11±0.01b	182±10.5b	0.912±0.14b
2020	N0	10.2±2.92c	0.05±0.02d	213±6.36a	0.366±0.05c
	N1	9.65±0.30c	0.07±0.03c	198±9.10b	0.391±0.05c
	N2	19.7±0.59a	0.12±0.01a	160±4.53c	0.878±0.02a
	N3	19.4±1.22a	0.11±0.03b	153±4.16c	0.795±0.04b
	N4	15.4±1.23b	0.10±0.01b	155±3.77c	0.849±0.05ab
年份 Year		ns	**	**	**
施氮量 N application level		**	**	**	**
年份×施氮量 Year×N application level		**	ns	ns	*

光合指标 Photosynthetic indicators	皮尔森相关系数 Pearson correlation coefficient	变量投影重要性 Variable importance in projection	变量投影重要性排序 Variable importance in projection order
LAD	0.976**	1.070	2
P_n	0.809**	0.938	5
T_r	0.830**	0.942	4
C_i	-0.895**	0.963	3
G_s	0.805**	0.908	6
LAI	0.981**	1.070	2
Chl a+b	0.987**	1.090	1

施氮量 N application levels (kg·hm^-2)	产值 Output value (yuan/hm²)	肥料成本 Fertilizer input (yuan/hm²)	净收入 Profits (yuan/hm²)	产投比 Output-input ratio	产值增产率 Increase rate of the output (%)
0	7674±588c	909	6765±588d	8.44±0.65d	—
90	16657±396b	1417	15240±396c	11.8±0.28b	117
134.8	21129±0a	1671	19458±0a	12.6±0a	175
139	21129±0a	1694	19435±0a	12.5±0a	175
180	21441±462a	1926	19515±462a	11.1±0.24c	179
270	20778±985a	2435	18343±985b	8.53±0.41d	171
360	21169±681a	2944	18225±681b	7.19±0.23e	176