Objective High temperature and heat damage frequently occur in the summer maize production areas of the Huang-Huai-Hai area, which severely inhibits the growth and development and impairs functions such as water and nutrient uptake and storage of maize roots. Elucidating the effects of the ethephon-glycine betaine-salicylic acid (EGS) mixture on root system architecture and yield formation under heat stress could provide the technical support and theoretical basis for establishing chemical regulation strategies for heat resistance and yield increase in summer maize cultivation in the Huang-Huai-Hai area. Method Field experiments were conducted at the Xinxiang Experimental Station of the Chinese Academy of Agricultural Sciences in 2022 and 2023. Using Yudan 9953 (YD9953) and Zhengdan 958 (ZD958) as test materials, chemical regulation treatment and heat str ess treatment were established. For the chemical regulation treatment, the EGS mixture was sprayed on the leaves at the 6 th-leaf stage (V6), while an equal amount of water was applied to the control group. Heat stress treatments were implemented for 4 days at the 9 th-leaf stage (V9) and tasseling stage (VT), respectively, with field heating treatment (H) and normal temperature control (CK). The study aimed to investigate the effects of EGS treatment on root system architecture, physiological functions, and yield of maize under heat stress during different growth stages. Result Under heat stress treatment in V9 and VT stages, compared with normal temperature control, in terms of root system architecture, the root dry weight, root-shoot ratio, the number of roots, root length, root surface area and root volume of YD9953 and ZD958 were significantly decreased; in terms of root physiological functions, root activity and activities of root antioxidant enzymes (SOD, POD, and CAT) were decreased significantly, while malondialdehyde (MDA) content increased significantly. Consequently, yield components and final output were severely compromised, with significant reductions in kernel number per ear, 100-kernel weight, and grain yield. Compared with heat stress treatment, EGS-H treatment improved root system architecture, alleviated the inhibition effect of heat stress on the number of roots, especially the number of aerial roots, significantly increased the root dry weight, root length, root surface area and root volume, and root volume was significantly positively correlated with yield. EGS-H treatment enhanced root physiological functions, significantly increased root activity and root antioxidant enzymes (SOD, POD, and CAT), while membrane peroxidation degree was significantly decreased. EGS-H treatment significantly increased the kernel number per ear and yield. After heat stress was applied at the V9 and VT stages, compared with heat stress treatment, EGS-H treatment increased the yield of YD9953 by an average of 19.42% and 19.56% in 2022, respectively, and by 14.40% and 17.95% in 2023, respectively. For ZD958, the yield increased by 9.81% and 13.02% in 2022, respectively, and by 7.68% and 7.78% in 2023, respectively. Conclusion The EGS mixture could regulate the root system architecture of summer maize under heat stress, promote root growth and development, and increase maize yield under heat stress.

Intensified kernel position effect is a common phenomenon in maize production under higher plant density, which limits the crop productivity. Subsoiling is considered as an effective agronomic practice to improve crop productivity. In order to clarify the effect of subsoiling before winter wheat on kernel position effect of densely grown summer maize and its regulatory mechanism, field experiments were conducted during 2020-2021 and 2021-2022 growing seasons by using a split-plot design. Main plot include two tillage practices: conventional tillage practice (CT) and subsoiling before winter wheat (SS); subplot consist three plant densities (D1-D3, 6.0×104, 7.5×104, and D3, 9.0×104 plants ha-1). Compared with CT, SS alleviated the kernel position effect by increasing the weight ratio of inferior to superior kernel (WR) of D2 and D3 treated plants. The higher WR of SS treated plants attribute largely to the improved filling of inferior kernel. Under the same plant density, SS significantly improved the root dry matter accumulation (DMA) and antioxidant enzyme activities (SOD and POD), and reduced malondialdehyde (MDA) concentration, especially for the plants grown under higher plant densities. These result indicated that SS delayed the root senescence, which is associated with the reduced soil bulk density. In addition, by comparison with CT, SS increased the leaf chlorophyll content from 20 days after silking to physiological maturity and post-silking leaf area duration, and decreased post-silking leaf chlorophyll reduction rate and leaf area reduction rate, reflecting the post-silking leaf senescence is alleviated. Under the same plant density, the post-silking DMA of SS was obviously higher than that of CT, which is probably related to the improved leaf area duration and photosynthetic enzyme activity (PEPC and Rubisco). The correlation analysis revealed that the main mechanism of SS in alleviating kernel position effect of densely grown summer maize is: SS delayed the post-silking root-shoot senescence by regulating soil physical properties, and further improved the post-silking DMA and filling of inferior kernel, ultimately alleviated the kernel position effect and improved grain yield. The present result will provide a new theoretical support for the promotion of summer maize yield by subsoiling before winter wheat.

Plant growth regulators can enhance row crop productivity and nutrient use efficiency. We conducted 2 year field experiments (2020-2021) in the North Central China Plain (NCP) to evaluate a foliar ethephon-chlormequat chloride (ECC) and nitrogen (N) fertilizer rates (0, 60, 120, and 240 kg N ha(-1)) on sorghum (Sorghum Bicolor (L.) Moench) yield and nitrogen use efficiencies (NUEs). The control treatment (CK) received a foliar water spray. ECC increased sorghum yield by an average of 4.5%, 5.9%, and 4.7% under 60, 120, and 240 kg ha(-1), respectively, relative to CK across 2 experimental years. Moreover, ECC significantly (p < 0.05) increased sorghum root biomass, root to shoot ratio, leaf nitrate reductase activity, chlorophyll content, and nitrogen uptake, thereby improving both nitrogen uptake efficiency and agronomic efficiency. Sorghum yield increased significantly with nitrogen application up to 120 kg ha(-1), with no additional yield gain beyond this rate. Nitrogen uptake increased with higher nitrogen rates up to 240 kg ha(-1), whereas nitrogen agronomic efficiency declined when nitrogen fertilization exceeding 60 kg ha(-1) in both experimental years. Overall, foliar spraying ECC at five-leaf stage, combined with 120 kg N ha(-1), achieved high sorghum yield and improved NUE in the NCP.

Field studies were conducted in the North China Plain (NCP) during the 2023–2024 season to investigate the vertical microclimate, yield, and yield-related characteristics of winter wheat during the grain-filling stage under no-till direct seeding and conventional tillage. The aim was to compare the differences in microclimate between the two tillage methods in wheat fields and the impact of microclimate on yield. The results indicated that, compared to conventional tillage, no-till direct seeding reduced the air temperature and increased the relative humidity of the air at 20 cm and 100 cm above the ground during the wheat grain-filling period. The soil moisture content at 20 cm below the ground under no-till direct seeding was higher than under conventional tillage during the early grain-filling stage. Seven days before the wheat harvest, the dry weight per plant and the dry weight per spike were significantly greater under no-till direct seeding than under conventional tillage. Consequently, the thousand-grain weight of no-till direct seeding was significantly higher than that of conventional tillage, with an increase of 7.9%. The number of wheat sterile spikelets under no-till direct seeding was significantly lower than that under conventional tillage. Furthermore, the number of grains per spike was higher than that of conventional tillage. Although the number of harvested spikes under no-till direct seeding was 10.8% lower than under conventional tillage, the increase in thousand-grain weight and the number of grains per spike compensated for the reduced number of harvested spikes. As a result, the grain yield of winter wheat under no-till direct seeding was higher than that of conventional tillage, increasing by 2.7%. Therefore, adopting no-till direct seeding in the NCP is conducive to increasing winter wheat production and efficiency, as well as supporting sustainable agricultural development.

Innovative measures of nitrogen (N) fertilization to increase season-long N availability is essential for gaining the optimal foxtail millet (Setaria italica L. Beauv.) productivity and N use efficiency. A split plot field experiment was conducted using the foxtail millet variety Huayougu 9 in 2020 and 2021 in Northeast China to clarify the physiological mechanism of a novel polyaspartic acid–chitosan (PAC)-coated urea on N assimilation and utilization from foxtail millet. Conventional N fertilizer (CN) and the urea-coated -PAC treatments were tested under six nitrogen fertilizer application levels of 0, 75, 112.5, 150, 225, and 337.5 kg N ha−1. The results showed that compared to CN, PN increased the foxtail millet yield by 5.53–15.75% and 10.43–16.17% in 2020 and 2021, respectively. PN increased the leaf area index and dry matter accumulation by 7.81–18.15% and 12.91–41.92%, respectively. PN also enhanced the activities of nitrate reductase, glutamine synthetase, glutamic oxaloacetic transaminase, and glutamic–pyruvic transaminase, thereby increasing the soluble protein in the leaf, plant, and grain N content at harvest compared to CN. Consequently, partial factor productivity from applied N, the agronomic efficiency of applied N, recovery efficiency of applied N, and physiological efficiency of applied N of foxtail millet under PN treatments compared to CN were increased. The improvement effect of the items above was more noticeable under the low–middle N application levels (75, 112.5, and 150 kg N ha−1). In conclusion, the PAC could achieve the goal of high yield and high N use efficiency in foxtail millet under the background of a one-time basic fertilizer application.

[目的]研究不同浓度乙烯利复配试剂对新疆北疆滴灌棉花生长发育及产量形成的规律,分析最适浓度组合,为棉花化学打顶技术的应用及推广提供理论依据.[方法]以鲁棉研24为材料,设置5个不同浓度乙烯利(C1∶0 mg/L、C2∶100 mg/L、C3∶200 mg/L、C4∶ 400 mg/L、C5∶ 800 mg/L)与烯效唑复配的组合试剂,研究不同复配试剂对北疆滴灌棉花生长发育及产量形成的影响.[结果]相较于C1处理,其它处理最终新生主茎长度降低10.9％～34.67％.与CK相比,C1、C2、C3、C4处理下株高均显著提高10.55％～21.26％;各处理均显著增加棉花果枝1.9～2.7台、显著提高棉花叶龄2～3.2;C4、C5处理下节间长分别显著缩短7.21％、7.75％;C3处理下SPAD值在播种后101 d、125 d分别显著提高8.22％、8.46％;盛铃后期C3处理下叶片、茎秆、生殖器官干物质重量分别显著提高16.97％、14.57％、38.68％,在吐絮期,C3处理叶片、茎秆、生殖器官干物质重量显著提高22.56％、13.92％、36.6％;C3处理上部成铃率高达47.5％,提高36.67％,下单株铃数显著提高18.18％,C3处理下可增加籽棉880.5 kg/hm2,籽棉产量显著提高17.64％.[结论]乙烯利与烯效唑复配可在一定程度上控制棉花株高,增加果枝台数、叶龄,缩短主茎节间长,提高SPAD值,增加各器官干物质重量,促进棉株上部成铃,最终提高产量.乙烯利浓度为200 mg/L时与烯效唑复配施用效果最佳,可用于棉花化学打顶.

The development and utilization of coastal saline-alkali lands hold significant importance in mitigating the shortage of cultivated land resources in China, enhancing the agro-ecological environment in coastal saline and alkaline areas, and ensuring national food security. We set up both pot and field trials (randomized block design) at Xinxiang experimental station of Institute of Crop Science, Chinese Academy of Agricultural Sciences (ICS-CAAS) and Dongying Yellow River Delta Modern Agricultural Research Base in Shandong Province in 2021 and 2022, respectively. The experimental materials, Jiliang 1 and Jiliang 2, underwent seed dressing with GKI composites at concentrations of 2.5 and 5 mL·kg-1. These composites, which contained the main components of gibberellin, kinetin, and indole butyric acid, were denoted as GKI2.5 and GKI5.0, respectively. The control plots (CK) received water seed dressing. The aim was to assess the regulatory effects of GKI on salt tolerance and grain sorghum yield. Compared to CK, the GKI2.5 and GKI5.0 seed dressing treatments significantly enhanced the growth and development of the two grain sorghum varieties, increased antioxidant enzyme activity and soluble protein content of sorghum leaves, while reducing leaf malondialdehyde content. Moreover, the GKI treatments increased leaf net photosynthetic rate. Under field conditions, yields of Jiliang 1 and Jiliang 2 were enhanced by an average of 17.1% and 19.1%, respectively. In conclusion, GKI seed dressing treatment effectively promoted the growth and development of sorghum under salt stress. It enhanced the antioxidant and osmoregulatory capacities of leaves, reduced the level of membrane lipid peroxidation, and improved net photosynthetic rate of leaves, which together improved the salt tolerance and sorghum yield.

Soil moisture (SM) and atmospheric humidity (AH) are crucial climatic variables that significantly affect the climate system. However, the combined influencing mechanisms of SM and AH on the land surface temperature (LST) under global warming are still unclear. Here, we systematically analyzed the interrelationships among annual mean values of SM, AH, and LST using ERA5-Land reanalysis data and revealed the role of SM and AH on the spatiotemporal variations of LST through mechanism analysis and regression methods. The results showed that net radiation, SM, and AH could well model the long-term variability of LST well and explain 92% of the variability. Moreover, SM played an essential and different role under the different LST backgrounds. The AH always displayed a greenhouse effect on the LST. This study provides essential insights into the global climate change mechanism from the surface hydrothermal processes perspective.

To deal with the problem of low efficiency of nitrogen uptake, assimilation and utilization, and high rate of loss and waste under the background of one-time basic fertilizer application in the northeast China, a split plot experiment was conducted using foxtail millet varieties of Zhangzagu 13（Z13） and Huayougu 9（H9） in Gongzhuling Experimental Station of Chinese Academy of Agricultural Sciences（43o29’55 " N, 124o48’43" E） in2020 and 2021. Polyaspartic acid-chitosan（PAC） and different nitrogen application levels were main plot and secondary plot, respectively. This experiment was to explore the regulation effects of conventional nitrogen with PAC on nitrogen utilization and the mechanism of yield increase of foxtail millet in the northeast China under the background of one-time basic fertilizer application. The results showed that PAC increased plant height, stem diameter and leaf area index, and improved panicle characteristics including panicle length, panicle diameter,panicle weight and grains weight per panicle of two foxtail millet varieties compared with conventional nitrogen treatments under the same nitrogen application level. The dry matter in anthesis and post anthesis were also higher. PAC enhanced plant nitrogen accumulation, partial factor productivity from applied nitrogen, agronomic efficiency of applied nitrogen and recovery efficiency of applied nitrogen, and finally increased the yield of two varieties. The yield of Z13 and H9 increased by 11.24%-21.55% and 5.53%-15.75%, respectively in 2020, and8.65%-14.22% and 10.43%-16.17%, respectively in 2021. The increase effects of the items above were more significant under the low-middle nitrogen application levels（75.0, 112.5 and 150.0kg/ha）. In conclusion, PAC combined with nitrogen fertilizer could be an important technique for achieving high grain yield and efficiency under the background of one-time basic fertilizer application in the northeast China.

To investigate the effect of polyaspartic acid-chitosan（PAC） on photosynthetic characteristics, nitrogen use efficiency, and yield of spring foxtail millet under the background of one-time basic fertilizer application, an experiment following split plot design was conducted using foxtail millet varieties of “Zhangzagu 13”（Z13） and “Huayougu 9”（H9） in Gongzhuling Experimental Station of Chinese Academy of Agricultural Sciences in 2020 and 2021. PAC and different nitrogen application levels were main treatment and secondary treatment, respectively. There were six nitrogen application levels(0, 75, 112.5, 150, 225, and 337.5 kg·hm -2 ). The results showed that PAC improved apparent efficiency of applied nitrogen for both foxtail millet varieties under the same nitrogen application level. The leaf area index and SPAD value of flag leaf in 0-40 days after anthesis were higher than those of the control. PAC application increased photosynthetic rate, transpiration rate, and conductance to H 2 O, but significantly decreased intercellular CO 2 concentration of flag leaf at anthesis and mid-filling stage, which could promote dry matter accumulation and yield. The yield of Z13 was increased by 11.24%-21.55% in 2020 and 8.65%-14.22% in 2021, and that of H9 was increased by 5.53%-15.75% and 10.43%-16.17% in 2020 and 2021, respectively. PAC application effectively relieved nitrogen deficiency and plant premature senescence resulted from one-time basic fertilizer application during the late growth period of foxtail millet, and reduced nitrogen loss caused by low nitrogen use efficiency. Therefore, PAC combined with nitrogen fertilizer application could be used as a green, high-yielding, and high-efficiency cultivation technique in foxtail millet production in China.

The purpose of this study is to explore the effects of different water and nitrogen interaction on yield and processing quality of high-quality wheat with strong gluten Shiluan 02-1,and to provide theoretical basis for how to achieve the goal of synergistically improving grain yield and processing quality through reasonable irrigation and optimal nitrogen application rate in the production of strong gluten wheat.From 2017 to 2020,the two factors split zone experiment of watering times and nitrogen application amount was set under field conditions.The main-plot factor was watering times[spring watering one time（W1,jointing water）and spring watering two times（W2,jointing water+flowering water）];and the split-plot factor was nitrogen（N）fertilizer treatment in six levels(N0:0,N1:60,N2:120,N3:180,N4:240,and N5:300 kg hm –2 ).The study showed that:When N application rate was 0–300 kg hm –2 ,the yield of spring irrigating one time and spring irrigating two times increased first and then decreased with the increase of N application rate,and the N application amount corresponding to the maximum grain yield was 240kg hm –2 in the different precipitation years.When N application rate was 120–300 kg hm –2 ,the yield of spring irrigating two times was significantly higher than that of spring irrigating one time.Water and N interaction had the greatest effect on the number of grains per unit area,followed by 1000-grain weight,which had the least effect on grain number per spike.When N application rate was 0–300 kg hm –2 ,the average value of wet gluten content,sedimentation value,water absorption rate,dough stability time,tensile energy,and maximum tensile resistance of winter wheat treated with spring irrigating two times were higher than those treated with spring irrigating one time in 2017 and 2018（wet year）.However,in 2018–2019 and 2019–2020（drought year）,it was opposite:spring irrigating one time was higher than spring irrigating two times.The wet gluten content and sedimentation value of wheat in spring irrigating one time and spring irrigating two times increased first and then decreased or gradually increased with the increase of N application rate in different precipitation years,the N application rate corresponding to the maximum of the two quality indicators was 240 kg hm –2 or 300 kg hm –2 .The stabilization time,tensile energy,and maximum tensile resistance increased first and then decreased with the increase of N application rate,and reached the maximum value when N application rate was 240 kg hm –2 .The grain yield and processing quality of high-quality wheat with strong gluten Shiluan 02-1 were the best when it was watered twice in spring and N was applied at 240 kg hm –2 in different precipitation years.

The way of one-time basic fertilizer application causes imbalance of nutrients supplies in the whole growth period of crops, which results in the deficiency of nutrients and premature senility in the late growth period. In order to investigate the mechanism of polyaspartic acid-chitosan（PAC） in soil nitrogen supply and regulation of antioxidant properties in foxtail millet leaf after flowering in the northeast China and establish an anti-aging and high-yielding technology under the background of one-time basic fertilizer application, a field experiment was conducted using foxtail millet（Setaria italica） varieties of Zhangzagu 13 and Huayougu 9 in Gongzhuling Experimental Station of Institute of Crop Sciences（Chinese Academy of Agricultural Sciences） from 2020 to 2021. Conventional fertilization（CN） and PAC with fertilization（PN） treatments were set under six nitrogen levels of 0, 75, 112.5, 150, 225, and 337.5 kg·hm –2 with all fertilizer applicated before sowing. Our results showed that, compared with CN under the same nitrogen application level, PAC increased NO 3 - -N and NH 4 + -N content in the 0–20 cm and 20–40 cm soil layers of two foxtail millet varieties at anthesis and mid-filling stage. Meanwhile, PAC increased leaf area and decreased leaf area reduction per plant significantly. The activities of superoxide dismutase, peroxidase and catalase of the flag leaf increased but the content of malondialdehyde reduced in 0–40 days after flowering. Thus, PAC ensures the supply of nitrogen in soil during the middle-late growth period, increases the antioxidant properties of leaf to delay the progress of leaf senescence and increase yield of foxtail millet effectively. In 2020 and 2021, the yield of Zhangzagu 13 increased by 11.24%–21.55% and 8.65%–14.22%, respectively, and the yield of Huayougu 9 increased by 5.53%–15.75% and 10.43%–16.17%, respectively, compared with CN under the same nitrogen application level. The effect of the items above was more significant at low-middle nitrogen application levels of 75, 112.5 and 150 kg·hm –2 . Therefore, PAC combined with nitrogen fertilizer could be an anti-aging and high-yielding cultivation technique in foxtail millet production in the northeast China spring-sowing region.

Innovative approaches to enhance N fertilization to improve season-long N availability are essential to optimal sorghum (Sorghum bicolor, (L.) Moench.) productivity and N use efficiency. A two-year field experiment was conducted in the 2020 and 2021 summer seasons on the North China Plain to determine the effects of a novel urea coated with polyaspartic acid (PAA) (PN) and a control treatment (CN) on grain sorghum yield and N utilization characteristics at four N application rates (0, 60, 120, and 240 kg ha−1). The results showed that sorghum yield, agronomic traits (including leaf area duration (LAD), crop growth rate (CGR), and dry matter accumulation (DMA)), the accumulation of nitrate N and ammonium N in the 0–60 cm soil layer, stover and grain N content, and total N uptake (NUT) in 2020 and 2021 significantly increased as N application rates increased from 0 to 240 kg ha−1, whereas nitrogen agronomic efficiency (NAE), N uptake efficiency (NUpE), and N utilization efficiency (NUtE) varied inversely with increasing N application rates. Compared to CN, PN demonstrated a significant enhancement in grain sorghum yield, LAD, and CGR, from 3.3% to 7.1%, from 4.8% to 6.1%, and from 5.8% to 6.8%, respectively, at 60 and 120 kg N ha−1. PN improved the N availability (mainly nitrate-N) in the sorghum soft dough and the stover and grain N content at harvest and NUT, NUpE, and NAE accordingly compared with CN at the 60 and 120 kg ha−1 N application rates. In short, our two-year field trials demonstrated that PN with 120 kg N ha−1 is recommended in grain sorghum to optimize sorghum productivity and nitrogen use efficiency at the current yield level in the North China Plain.

为明确α-萘乙酸(NAA)和激动素(KT)浸种对新植蔗产量、根系发育及抗倒伏能力的影响,完善甘蔗优质高产抗倒伏化学调控技术理论基础,采用室内盆栽试验和田间试验相结合的方法,以栽培甘蔗品种桂糖29(GT29)、桂糖42(GT42)、桂糖49(GT49)和桂糖55(GT55)为试验材料,探讨不同浓度配比NAA/KT浸种对新植蔗茎叶鲜重、根系活力、根系形态结构和茎秆抗折断力的影响.结果表明,室内条件下,NAA/KT在20～40时,GT29和GT42根系活力、总根长和根体积相比对照显著增加.田间试验中,NAA25～50mg/L配合KT 1mg/L浸种处理对收获期甘蔗叶片鲜重、根系发育及茎秆抗折断力促进效果最优,其中2019和2020年试验中4个品种叶片鲜重和产量均比对照增加;根长、根表面积、根体积、根尖数和根干重分别比对照平均增加33.0％、39.0％、43.7％、27.4％和44.9％;茎秆抗折断力平均增加26.0％.综上所述,NAA/KT浸种处理提高了新植蔗叶片鲜重和蔗茎产量,提高了根系活力,促进根系发育;田间条件下用NAA25～50mg/L和KT 1mg/L浸种可显著增加新植蔗收获期产量、总根长、根表面积、根尖数、根干重以及茎秆抗折断力,进而提高甘蔗抗倒伏能力.

为探究聚天门冬氨酸和壳聚糖复配剂（polyaspartic acid-chitosan,PAC）对东北春谷光合生产特征及产量的调控效应, 2020—2021年在中国农业科学院作物科学研究所公主岭试验站开展大田试验,以张杂谷13号（Zhangzagu 13,Z13）和华优谷9号（Huayougu 9, H9）为材料,设置常规氮素（CN）和PAC配合氮素（PN）的不同施氮量(0、75、112.5、150、225和337.5 kg hm -2 )全基施处理。结果表明,随氮素用量增加,两品种谷子旗叶净光合速率、SPAD值、可溶性蛋白含量以及净同化速率、光合势、群体生长率等群体指标均呈先升高后降低趋势。同一氮素用量下, PN处理可提高谷子花后旗叶SPAD值及可溶性蛋白含量,提高花期及灌浆中期旗叶净光合速率,同时提高谷子净同化速率、光合势和群体生长率,促进群体光合产物积累,且上述各项指标在中、低氮水平(75、112.5及150 kg hm -2 )下提高效果更为显著。PN处理后, Z13在2020年和2021年的增产幅度分别为11.24%～21.55%和8.65%～14.22%, H9两年的增产幅度分别为5.53%～15.75%和10.43%～16.17%。相关性分析表明,谷子产量与净同化速率、光合势、群体生长率及净光合速率均呈显著或极显著正相关。综上, PAC配合氮肥全基施能提高东北春谷光合生产能力和产量,可作为我国谷子生产中重要的增产增效技术措施。

应用化学调控技术改善玉米的氮素代谢过程,从而实现"减氮增效",是保障玉米绿色可持续生产的重要途径.试验以玉米单交种豫单9953为材料,设置乙矮合剂(ECK)和不同氮肥水平处理(0、96、132、168、204和240kg/hm2),喷施清水为对照处理(CK),于2019和2020年分别在河北燕郊和北京顺义进行大田试验,研究ECK对不同施氮量下夏玉米氮素代谢及产量的调控效应.结果表明,ECK处理提高了不同施氮量下夏玉米开花期叶片硝酸还原酶活性和可溶性蛋白含量,提高了施氮量204和240kg/hm2处理下叶片谷丙转氨酶和谷草转氨酶的活性以及灌浆中后期的谷氨酰胺合成酶活性.ECK处理显著提高了施氮量204kg/hm2下玉米植株氮素、籽粒氮素和总氮素积累量,较CK处理分别增加8.9％、8.3％和8.6％.ECK处理下施氮量为204kg/hm2时,夏玉米产量较CK处理显著增加7.5％.ECK处理可有效改善玉米的氮素代谢,促进氮素的吸收、同化和积累,提高产量,从而实现"减氮增效".

【Objective】Root is an important organ for maize to obtain water and nutrients,and a developed root structure is the key to maximum maize yield potential,which is currently an important issue to be solved in maize cultivation research.Ethylenechlormequat-potassium and nitrogen application can affect the development of the maize root system.The aim of this study was clarify the effects of ethylene-chlormequat-potassium on the construction of summer maize root morphology and yield under different nitrogen application rates,so as to provide the theoretical and technical basis for the improvement of high yield and efficient cultivation management and rational fertilization of maize.【Method】In 2019 and 2020,the field experiments were carried out in Daliudian village,Yanjiao town,Langfang city,Hebei province,and Shunyi Experimental Base,Chinese Academy of Agricultural Sciences,Shunyi district,Beijing,respectively,using maize single cross Yudan 9953 as experimental material.A split-zone experimental design was used,with the ethylene-chlormequat-potassium treatment （ECK） and the clear water control （CK） as the main zones,and the six nitrogen levels of 0 （N0）,96 （N96）,132 （N132）,168 （N168）,204 （N204） and 240 kg·hm -2 （N240） as the secondary zones,aiming to analyze the effects of ECK on root morphology and yield of summer maize at different nitrogen application rates.【Result】The nitrogen application significantly increased root dry weight,number of aerial roots,root length,root surface area and root volume.Compared with no nitrogen application,root dry weight,the number of aerial roots,root length,root surface area and root volume increased by 15.0%-25.2%,31.7%-71.7%,15.5%-30.8%,19.0%-40.9%and 28.8%-54.0%on average with different nitrogen application rates,respectively.Compared with CK,ECK treatment increased root dry weight,number of root layers,number of roots in 1 to 2 layers and the number of aerial roots in summer maize with different nitrogen application rates by 10.4%-17.0%,5.8%-12.6%,10.8%-33.9%and 12.5%-79.6%,respectively;On the construction of root morphology,compared with CK,ECK treatment significantly increased the total root length,root surface area and root volume of summer maize with different nitrogen application rates by 7.5%-21.0%,8.4%-29.3%and 14.3%-38.8%,respectively,and the root length with root diameter＞1.0 mm was significantly increased at medium and high nitrogen levels （N≥N204）.Compared with CK,ECK treatment had no significant effect on summer maize yield per unit area in 2019 and 2020 under N0-N168,but significantly increased summer maize yield in 2019 and 2020 under N204 and N240,which increased by an average of 6.3%with N204 and 3.2%with N240.Correlation analysis showed that kernel number,1000-kernel weight,root length,root surface area and root volume were positively correlated with summer maize yield,and the correlation coefficient between yield and root length was the highest.【Conclusion】ECK and nitrogen could synergistically promote maize root development and increase summer maize yield under high nitrogen conditions.In the current study,spraying ECK at the V6 growth stage combined with 204 kg·hm -2 N fertilizer was a suitable cultivation technique and N fertilizer management practice for high-yielding summer maize in the Beijing-Tianjin area.

The innovation of N fertilizer and N management practices is essential to maximize crop yield with fewer N inputs. A long-term field fertilization experiment was established in 2015 on the North China Plain (NCP) to determine the effects of a control treatment (CN) and the eco-friendly material poly(aspartic acid)-coated urea (PN), applied as a one-time basal application method, on winter wheat yield and N use efficiency at four N application rates: 0 (N0), 63 (N63), 125 (N125), and 188 (N188) kg N ha –1 . The results indicated that compared to CN, PN resulted in a significant increase in wheat yield by 9.6% and 9.2% at N63 and N125, respectively, across the three experimental years, whereas no significant ( p < 0.05) difference was detected at N188. Leaf area duration (LAD), crop growth rate (CGR), and dry matter accumulation (DMA) increased with increasing N rates, while PN significantly increased LAD and CGR by 5.1%–16.4% and 5.4%–64.3%, respectively, during the anthesis-ripening growth stage and DMA by 13.7% and 10.1% at N63 and N125, respectively, after the anthesis stage compared to CN. During the grain-filling stage, PN significantly increased the kernel maximum grain-filling rate (Gmax) by 21.7% and the kernel weight at the maximum grain-filling rate (Wmax) by 6.7% at N125 compared to CN. Additionally, compared to CN, PN significantly improved the stover and grain N content at harvest and increased NUT, NPFP, and NAE by 5.7%–40.1%, 2.5%–23.3%, and 3.9%–42.8%, respectively, at N63–N125. Therefore, PN applied using a single basal nitrogen fertilizer application method showed promising potential in maintaining a stable wheat yield and increasing N use efficiency with a 33% urea cut (approximately 63 kg N ha –1 ) compared to CN at the current wheat yield level on the NCP.

Abstract Fertilization affects water uptake by crops, the study of water transport and water use in maize after the application of organic fertilizer can provide a theoretical basis for sustainable grain production in this area. In this study, dual stable isotopes (δD and δ18O) were used to determine seasonal variation in water uptake patterns of summer maize under different fertilization treatments in Shijiazhuang, China, during 2017. The contributions of soil water at different depths to water uptake were quantified using the MixSIAR Bayesian mixing model. The average contribution of soil water from the 0–20, 20–40, 40–70, and 70–120 cm layers was 39.6%, 23.2%, 29.8%, and 7.4%, respectively, and most water was taken up from the upper soil layers (0–70 cm) during the drought season before sowing. Water uptake was mainly sourced from the 0–20 cm depth at the mid filling stage (81.2%), the 0–40 cm depth at the seedling stage (85.0%), and the 0–70 cm depth at the jointing stage (86.2%), 12-leaf stage (91.2%), heading stage (88.8%), tasseling stage (86.7%), early filling stage (95.0%), and mature stage (94.0%). Two fertilization applications led to clear differences in the proportional contribution of soil water from 0–20 cm (average 35.3% and 43.8% for chemical and organic fertilizer, respectively), 20–40 cm (25.4% and 20.9%), and 70–120 cm (9.7% and 5.2%). The contribution from the 0–20cm layer was higher after organic fertilizer treatment than after the use of chemical fertilizer. This was because the manure fertilizer changed the physical properties of the soil, improving water-holding capacity and reducing soil evaporation. Our results have scientific implications for fertilization and irrigation management.

The shortage of groundwater resources is a considerable challenge for winter wheat production on the North China Plain. Water-saving technologies and procedures are thus urgently required. To determine the water-saving potential of using micro-sprinkling irrigation (MSI) for winter wheat production, field experiments were conducted from 2012 to 2015. Compared to traditional flooding irrigation (TFI), micro-sprinkling thrice with 90 mm water (MSI1) and micro-sprinkling four times with 120 mm water (MSI2) increased the water use efficiency by 22.5 and 16.2%, respectively, while reducing evapotranspiration by 17.6 and 10.8%. Regardless of the rainfall pattern, MSI (i.e., MSI1 or MSI2) either stabilized or significantly increased the grain yield, while reducing irrigation water volumes by 20–40%, compared to TFI. Applying the same volumes of irrigation water, MSI (i.e., MSI3, micro-sprinkling five times with 150 mm water) increased the grain yield and water use efficiency of winter wheat by 4.6 and 11.7%, respectively, compared to TFI. Because MSI could supply irrigation water more frequently in smaller amounts each time, it reduced soil layer compaction, and may have also resulted in a soil water deficit that promoted the spread of roots into the deep soil layer, which is beneficial to photosynthetic production in the critical period. In conclusion, MSI1 or MSI2 either stabilized or significantly increased grain yield while reducing irrigation water volumes by 20–40% compared to TFI, and should provide water-saving technological support in winter wheat production for smallholders on the North China Plain.