Effects of Slow-release Nitrogen on Dry Matter Accumulation,Translocation and Yield of Summer Maize

[Objectives]This study was conducted to investigate the effects of slow-release nitrogen fertilizer on dry matter accumulation and translocation of summer maize.[Methods]With Zhoudan 9 as the test variety,six different treatment were set up:blank control(CK1),slow-release urea 75 kg/hm^(2)(C1),slow-release urea 150 kg/hm^(2)(C2),slow-release urea 225 kg/hm^(2)(C3),slow-release urea 300 kg/hm^(2)(C4)and ordinary urea 300 kg/hm^(2)(CK2),to study the change law of dry matter accumulation and translocation in summer maize.[Results]Treatment slow-release urea 225 kg/hm^(2)(C4)showed summer maize yield,dry matter translocation between organs,grain contribution rate and proportion of grain dry matter in the full ripe stage higher than other treatments.Considering the weight loss and cost factors,slow-release urea 225 kg/hm^(2)(C3)could be recommended as the fertilizing amount for summer maize.[Conclusions]This study provides theoretical reference for rational selection of fertilizers for reducing fertilizer application and increasing fertilizer efficiency,and for production of summer maize in Shajiang black soil region.

Effects of Slow-release Nitrogen Fertilizer on Yield and Nitrogen Accumulation of Summer Maize in Shajiang Black Soil Area

[Objectives] This study was conducted to verify the field application effect of slow-release nitrogen fertilizer on summer maize in Shajiang black soil area by simultaneous sowing and fertilization, and explore the application scope and nitrogen metabolism mechanism, so as to lay a foundation for fertilizer reduction and efficiency improvement. [Methods] With maize variety Beiqing 340 and sulfur-coated urea as experimental materials, five nitrogen application levels were set, namely, control (C0), slow-release nitrogen 70 kg/hm^(2) (C70), slow-release nitrogen 140 kg/hm^(2) (C140), slow-release nitrogen 210 kg/hm^(2) (C210) and slow-release nitrogen 280 kg/hm^(2) (C280). The phosphorus and potassium fertilizers were all in accordance with the unified standard. [Results] With the application rate of slow-release nitrogen increasing, the nitrogen accumulation in organs increased first and then decreased after tasseling stage of maize. In order to reduce the fertilizing amount and increase efficiency, 210 kg/hm^(2) of slow-release nitrogen fertilizer was the best fertilizing amount for summer maize in Shajiang black soil area. [Conclusions] This study provides reference for fertilizer reduction, efficiency improvement and sustainable development of summer maize in Shajiang black soil area.

Multi-decadal Changes of the Impact of El Niño Events on Tibetan Plateau Summer Precipitation

Precipitation on the Tibetan Plateau(TP)has an important effect on the water supply and demand of the downstream population.Involving recent climate change,the multi-decadal variations of the impact of El Niño-Southern Oscillation(ENSO)events on regional climate were observed.In this work,the authors investigated the changes in summer precipitation over TP during 1950-2019.At the multi-decadal scale,the authors found that the inhabiting impact of El Niño events on the TP summer precipitation has strengthened since the late 1970s.The main factor contributing to this phenomenon is the significant amplification in the decadal amplitude of El Niño during 1978-2019 accompanied by a discernible escalation in the frequency of El Niño events.This phenomenon induces anomalous perturbations in sea surface temperatures(SST)within the tropical Indo-Pacific region,consequently weakening the atmospheric vapor transport from the western Pacific to the TP.Additionally,conspicuous anomalies in subsidence motion are observed longitudinally and latitudinally across the TP which significantly contributes to a curtailed supply of atmospheric moisture.These results bear profound implications for the multi-decadal prediction of the TP climate.

Interdecadal changes in the western Siberian summer mean and extreme rainfall during 1982-2021

本文研究发现,西西伯利亚夏季降水在1995年后显著增加,2012年后又有所减少,极端降水日数和强度呈现一致的变化特征.伴随这两次降水的年代际增加/减少,西西伯利亚上空出现异常气旋/反气旋和水汽幅合/幅散.极端降水发生时的区域环流特征在三个时段基本一致:西西伯利亚低空出现气旋性异常,高空为西北-东南向的异常气旋-反气旋偶极子型.1995-2011年期间,极端降水日数更多,强度更强,上述异常环流型也更强.

Enhanced Seasonal Predictability of Spring Soil Moisture over the Indo-China Peninsula for Eastern China Summer Precipitation under Non-ENSO Conditions

Seasonal prediction of summer precipitation over eastern China is closely linked to the East Asian monsoon circulation,which is largely affected by the El Niño-Southern Oscillation(ENSO).In this study,results show that spring soil moisture(SM)over the Indo-China peninsula(ICP)could be a reliable seasonal predictor for eastern China summer precipitation under non-ENSO conditions.When springtime SM anomalies are present over the ICP,they trigger a structured response in summertime precipitation over most of eastern China.The resultant south-to-north,tri-polar configuration of precipitation anomalies has a tendency to yield increased(decreased)precipitation in the Yangtze River basin and decreased(increased)in South and North China with a drier(wetter)spring soil condition in the ICP.The analyses show that ENSO exerts a powerful control on the East Asian circulation system in the ENSO-decaying summer.In the case of ENSO forcing,the seasonal predictability of the ICP spring SM for eastern China summer precipitation is suppressed.However,in the absence of the influence of ENSO sea surface temperature anomalies from the preceding winter,the SM anomalies over the ICP induce abnormal local heating and a consequent geopotential height response owing to its sustained control on local temperature,which could,in turn,lead to abnormal eastern China summer precipitation by affecting the East Asian summer monsoon circulation.The present findings provide a better understanding of the complexity of summer climate predictability over eastern China,which is of potential significance for improving the livelihood of the people.

Combined effects of high temperature and waterlogging on yield and stem development of summer maize

The purpose of this study was to identify the physiological mechanism underlying the effects of high temperature and waterlogging on summer maize.The stem development and yield of the maize hybrid Denghai 605 in response to high-temperature stress,waterlogging stress,and their combination applied for six days at the third-leaf,sixth-leaf,and tasseling stages were recorded.The combined stresses reduced lignin biosynthetic enzyme activity and lignin accumulation,leading to abnormal stem development.Reduction of the area and number of vascular bundles in stems led to reduced dry matter accumulation and allocation.Decreased grain dry weight at all three stages reduced grain yield relative to a control.In summary,high temperature,waterlogging,and their combined stress impaired stem development and grain yield of summer maize.The combined stresses were more damaging than either stress alone.

Study on the Sediment Transport Flux and Mechanism in the Bohai Strait at the Tidal and Monthly Scales in Summer

Based on the data of tidal currents and suspended sediment concentrations observed synchronously at 11 stations in the Bohai Strait lasting for 25 hours,the temporal and spatial variations of currents and suspended sediment concentrations in the Bohai Strait in summer were analyzed.The Study preliminarily discussed the transport mechanism,transport trend and transport flux of suspended sediments in summer,using flux-mechanism decomposition method and numerical simulation.The suspended sediment transport was mainly controlled by advection and next influenced by vertical net circulation,while resuspension is relatively weak in Bohai Strait.The single-width fluxes of investigation stations varied from 3.8 to 89.1 gm^(−1) s^(−1),with the maximum value in Miaodao Strait.The suspended sediment transport trends in Laotieshan channel along the vertical section are obviously distinct.The waters mainly flow out of the Bohai Sea in surface layer,while into the Bohai Sea in bottom layer.However,the transport trends of other channels in the centre and south are consistent vertically.The sediments in the Bohai Strait follows the transport pattern of moving outward from the south and inward from the north in summer,i.e.,the sediments are carried out of the Bohai Sea through the Laotieshan channel,while into the Bohai Sea through other channels.And the outflow flux exceeds the inflow flux in August with the net water flux of 1.4×10^(10)m^(3),basically same as the deliveries of the rivers into the Bohai Sea.Moreover,the suspended sediment flux is 0.33 Mt under the action of tidal residual currents in the Yellow Sea in August.

Monsoon Break over the South China Sea during Summer: Statistical Features and Associated Atmospheric Anomalies

This study identifies break events of the South China Sea(SCS)summer monsoon(SCSSM)based on 42 years of data from 1979 to 2020,and investigates their statistical characteristics and associated atmospheric anomalies.A total of 214 break events are identified by examining the convection evolution during each monsoon season.It is found that most events occur between June and September and show a roughly even distribution.Short-lived events(3–7 days)are more frequent,accounting for about two thirds of total events,with the residual one third for long-lived events(8–24 days).The SCSSM break is featured by drastic variations in various atmospheric variables.Particularly,the convection and precipitation change from anomalous enhancement in adjoining periods to a substantial suppression during the break,with the differences being more than 60 W m−2 for outgoing longwave radiation(OLR)and 10 mm d−1 for precipitation.This convection/precipitation suppression is accompanied by an anomalous anticyclone in the lower troposphere,corresponding to a remarkable westward retreat of the monsoon trough from the Philippine Sea to the Indochina Peninsula,which reduces the transportation of water vapor into the SCS.Besides,the pseudo-equivalent potential temperature()declines sharply,mainly attributable to the local specific humidity reduction caused by downward dry advection.Furthermore,it is found that the suppressed convection and anomalous anticyclone responsible for the monsoon break form near the equatorial western Pacific and then propagate northwestward to the SCS.

Skilful Forecasts of Summer Rainfall in the Yangtze River Basin from November

Variability in the East Asian summer monsoon(EASM)brings the risk of heavy flooding or drought to the Yangtze River basin,with potentially devastating impacts.Early forecasts of the likelihood of enhanced or reduced monsoon rainfall can enable better management of water and hydropower resources by decision-makers,supporting livelihoods and major economic and population centres across eastern China.This paper demonstrates that the EASM is predictable in a dynamical forecast model from the preceding November,and that this allows skilful forecasts of summer mean rainfall in the Yangtze River basin at a lead time of six months.The skill for May–June–July rainfall is of a similar magnitude to seasonal forecasts initialised in spring,although the skill in June–July–August is much weaker and not consistently significant.However,there is some evidence for enhanced skill following El Niño events.The potential for decadal-scale variability in forecast skill is also examined,although we find no evidence for significant variation.

The Effect of Boreal Summer Intraseasonal Oscillation on Mixed Layer and Upper Ocean Temperature over the South China Sea

Intraseasonal oscillation of the mixed layer and upper ocean temperature has been found to occur over the South China Sea(SCS)in the summer monsoon season based on the multiple reanalysis and observational data in this study.The method of composite analysis and an upper ocean temperature equation assisted the analysis of physical mechanisms.The results show that the mixed layer depth(MLD)in the SCS has a significant oscillation with a 30-60 d period over the SCS region,which is closely related to boreal summer intraseasonal oscillation(BSISO)activities.The MLD can increase(decrease)during the positive(negative)phase of the BSISO and usually lags behind by approximately one-eighth of the lifecycle(5 days)of the BSISO-related convection.The BSISO may cause periodic anomalies at the air-sea boundary,such as wind stress and heat flux,so it can play a dominant role in modulating the variation in MLD.There also are significant intraseasonal seawater temperature anomalies in both the surface and subsurface layers of the SCS.In addition,during the initial phase of the BSISO,the temperature anomaly signals of the thermocline are obviously opposite to the sea surface temperature(SST),especially in the southern SCS.According to the results from the analysis of the temperature equation,the vertical entrainment term caused by BSISO-related wind stress is stronger than the thermal forcing during the initial stage of convection,and it is more significant in the southern SCS.

Recent Enhancement in Co-Variability of the Western North Pacific Summer Monsoon and the Equatorial Zonal Wind

The western North Pacific summer monsoon(WNPSM)is an important subcomponent of the Asian summer monsoon.The equatorial zonal wind(EZW)in the lower troposphere over the western Pacific may play a critical role in the evolution of the El Niño-Southern Oscillation(ENSO).The possible linkage between the EZW over the western Pacific and the offequatorial monsoonal winds associated with the WNPSM and its decadal changes have not yet been fully understood.Here,we find a non-stationary relationship between the WNPSM and the western Pacific EZW,significantly strengthening their correlation around the late 1980s/early 1990s.This observed shift in the WNPSM–EZW relationship could be explained by the changes in the related sea surface temperature(SST)configurations across the tropical oceans.The enhanced influence from the springtime tropical North Atlantic,summertime tropical central Pacific,and maritime continent SST anomalies may be working together in contributing to the recent intensified WNPSM–EZW co-variability.The observed recent strengthening of the WNPSM–EZW relationship may profoundly impact the climate system,including prompting more effective feedback from the WNPSM on subsequent ENSO evolution and bolstering a stronger biennial tendency of the WNPSM–ENSO coupled system.The results obtained herein imply that the WNPSM,EZW,ENSO,and the tropical North Atlantic SST may be closely linked within a unified climate system with a quasi-biennial rhythm occurring during recent decades,accompanied by a reinforcement of the WNPSM–ENSO interplay quite possibly triggered by enhanced tropical Pacific–Atlantic cross-basin interactions.These results highlight the importance of the tropical Atlantic cross-basin influences in shaping the spatial structure of WNPSM-related wind anomalies and the WNPSM–ENSO interaction.

Correlation Between the Arabian Sea Surface Temperature and the Onset Period of South Asian Summer Monsoon with Trend Analysis on the Intensity

The long-term trend of the Arabian Sea surface temperature(ASST)during the formation of the South Asian summer monsoon(SASM)is discussed in this manuscript.From April to June,ASST changed from a meridional gradual distribution to a spatially uniform distribution and then to a zonal gradual distribution.The South Asian summer monsoon intensity(SASMI)and South Asian summer monsoon direction(SASMD)indicate that the variation of the ASST is highly related to the formation of the SASM during the summer monsoon period and can contribute to the spread of the SASM from the Southwest Arabian Sea throughout all of South Asia.Results of the correlation between the ASST and SASMI for the same month and its adjacent months were the same,and the areas of the positive correlation between the ASST and SASMI significantly increased from May–June as compared to April–May.The maximum correlation coefficient was 0.86.The results of the ASST and SASMD for the same month and its adjacent months were substantially different.However,the ASST and SASMD for May and April also showed a high positive correlation with a maximum correlation coefficient of 0.61 in the southwestern Arabian Sea.Existence of the ASST had a spatially consistent and significant upward trend with a mean increase of 0.6℃during the summer monsoon period from 1980 to 2020(between April and September),whereas the SASMI had a strengthening trend along the western and southwestern regions of the Arabian Sea and the southeastern region of the Arabian Peninsula.Meanwhile,the rest of the study regions showed a declining trend.Overall,the entire study region showed a slight downward trend,and the average value decreased by 0.02ms^(−1).

Contrasting Regional Responses of Indian Summer Monsoon Rainfall to Exhausted Spring and Concurrently Emerging Summer El Nino Events

The inverse relationship between the warm phase of the El Nino Southern Oscillation(ENSO)and the Indian Summer Monsoon Rainfall(ISMR)is well established.Yet,some El Nino events that occur in the early months of the year(boreal spring)transform into a neutral phase before the start of summer,whereas others begin in the boreal summer and persist in a positive phase throughout the summer monsoon season.This study investigates the distinct influences of an exhausted spring El Nino(springtime)and emerging summer El Nino(summertime)on the regional variability of ISMR.The two ENSO categories were formulated based on the time of occurrence of positive SST anomalies over the Nino-3.4 region in the Pacific.The ISMR’s dynamical and thermodynamical responses to such events were investigated using standard metrics such as the Walker and Hadley circulations,vertically integrated moisture flux convergence(VIMFC),wind shear,and upper atmospheric circulation.The monsoon circulation features are remarkably different in response to the exhausted spring El Nino and emerging summer El Nino phases,which distinctly dictate regional rainfall variability.The dynamic and thermodynamic responses reveal that exhausted spring El Nino events favor excess monsoon rainfall over eastern peninsular India and deficit rainfall over the core monsoon regions of central India.In contrast,emerging summer El Nino events negatively impact the seasonal rainfall over the country,except for a few regions along the west coast and northeast India.

Interannual Meridional Displacement of the Upper-Tropospheric Westerly Jet over Western East Asia in Summer

The interannual meridional displacement of the upper-tropospheric westerly jet over the eastern portion of East Asia in summer has been well documented.This study,however,investigates the interannual meridional displacement of the westerly jet over the western portion of East Asia in summer,which is distinct from its eastern counterpart.The results show that the meridional displacement of the western East Asian jet shows a clear asymmetric feature;that is,there are remarkable differences between the southward and northward displacement of the jet.The southward displacement of the jet corresponds to suppressed convection in the tropical western North Pacific and Maritime Continent and enhanced convection in the equatorial Pacific,which can be explained by the warmer sea surfaces found in the northern Indian Ocean and equatorial eastern Pacific.These tropical anomalies somewhat resemble those associated with the eastern East Asian jet variability.However,the northward displacement of the western East Asian jet does not correspond to significant convection and SST anomalies in the entire tropics;instead,the northward displacement of the jet corresponds well to the positive phase of the Arctic Oscillation.Furthermore,the meridional displacement of the western jet has asymmetric impacts on rainfall and surface air temperatures in East Asia.When the western jet shifts northward,more precipitation is found over South China and Northeast China,and higher temperatures appear in northern China.By contrast,when the jet shifts southward,more precipitation appears over the East Asian rainy belt,including the Yangtze River valley,South Korea,and southern and central Japan and warmer temperatures are found South and Southeast Asia.

Influences of MJO-induced Tropical Cyclones on the Circulation-Convection Inconsistency for the 2021 South China Sea Summer Monsoon Onset

The South China Sea Summer Monsoon(SCSSM)onset is characterized by an apparent seasonal conversion of circulation and convection.Accordingly,various indices have been introduced to identify the SCSSM onset date.However,the onset dates as determined by various indices can be very inconsistent.It not only limits the determination of onset dates but also misleads the assessment of prediction skills.In 2021,the onset time as identified by the circulation criteria was 20 May,which is 12 days earlier than that deduced by also considering the convection criteria.The present study mainly ascribes such circulation-convection inconsistency to the activities of tropical cyclones(TCs)modulated by the Madden-Julian Oscillation(MJO).The convection of TC“Yaas”(2021)acted as an upper-level diabatic heat source to the north of the SCS,facilitating the circulation transition.Afterward,TC“Choi-wan”(2021)over the western Pacific aided the westerlies to persist at lower levels while simultaneously suppressing moist convection over the SCS.Accurate predictions using the ECMWF S2S forecast system were obtained only after the MJO formation.The skillful prediction of the MJO during late spring may provide an opportunity to accurately predict the establishment of the SCSSM several weeks in advance.

Interdecadal Enhancement in the Relationship between the Western North Pacific Summer Monsoon and Sea Surface Temperature in the Tropical Central-Western Pacific after the Early 1990s

This study reveals the strengthened interdecadal relationship between the western North Pacific summer monsoon(WNPSM)and tropical central-western Pacific sea surface temperature anomaly(SSTA)in summer after the early 1990s.In the first period(1979–91,P1),the WNPSM-related precipitation anomaly and horizontal wind anomaly present themselves as an analogous Pacific-Japan(PJ)-like pattern,generally considered to be related to the Niño-3 index in the preceding winter.During the subsequent period(1994–2019,P2),the WNPSM-related precipitation anomaly presents a zonal dipole pattern,correlated significantly with the concurrent SSTA in the Niño-4 and tropical western Pacific regions.The negative(positive)SSTA in the tropical western Pacific and positive(negative)SSTA in the Niño-4 region,could work together to influence the WNPSM,noting that the two types of anomalous SSTA configurations enhance(weaken)the WNPSM by the positive(negative)phase PJ-like wave and Gill response,respectively,with an anomalous cyclone(anticyclone)located in the WNPSM,which shows obvious symmetry about the anomalous circulation.Specifically,the SSTA in Niño-4 impacts the WNPSM by an atmospheric Gill response,with a stronger(weaker)WNPSM along with a positive(negative)SSTA in the Niño-4 region.Furthermore,the SSTA in the tropical western Pacific exerts an influence on the WNPSM by a PJ-like wave,with a stronger(weaker)WNPSM along with a negative(positive)SSTA in the tropical western Pacific.In general,SSTAs in the tropical western Pacific and Niño-4 areas could work together to exert influence on the WNPSM,with the effect most likely to occur in the El Niño(La Niña)developing year in P2.However,the SSTAs in the tropical western Pacific worked alone to exert an influence on the WNPSM mainly in 2013,2014,2016,and 2017,and the SSTAs in the Niño-4 region worked alone to exert an influence on the WNPSM mainly in Central Pacific(CP)La Niña developing years.The sensitivity experiments also can reproduce the PJ-like wave/Gill response associated with SSTA in the tropical western Pacific/Niño-4 regions.Therefore,the respective and synergistic impacts from the Niño-4 region and the tropical western Pacific on the WNPSM have been revealed,which helps us to acquire a better understanding of the interdecadal variations of the WNPSM and its associated climate influences.

Ecological and hydrologic evolution history in the sensitive zone of both East Asian summer monsoon and Westerly since the Last Glacial Maximum

The Qilian Mountains,located in the northeastern Qinghai-Tibet Plateau,is a sensitive zone of both East Asian summer monsoon(EASM)and westerly winds(WW).The evolution history and driving mechanism of the ecosystem and hydrologic cycle in this region on long-term timescales have not yet been clarified.In this study,we comprehensively study the hydrologic and ecological evolution history in the sensitive zone since the Last Glacial Maximum(LGM)by integrating surface sediments,paleoclimate records,TraCE-21ka transient simulations,and PMIP3-CMIP5 multi-model simulation.Results show that hydrologic and ecological proxies from surface sediments are significantly different from west to east and mainly divided into three sections:the monsoonaffected region in the eastern Qilian Mountains,the intersection region in the central Qilian Mountains,and the westerly-affected region in the western Qilian Mountains.Meanwhile,paleo-ecological and paleohydrologic reconstructions from the surroundings uncover a synchronous climate evolution that the EASM mainly controls the eastern Qilian Mountains and penetrates the central Qilian Mountains in monsoon intensity maximum,while the WW dominates the central and western Qilian Mountains on both glacial-interglacial and millennial timescales.The simulation results further bear out the glacial humid climate in the central and western Qilian Mountains caused by the enhanced WW,and the humidity maximum in the eastern Qilian Mountains controlled by the strong mid-Holocene monsoon.In general,east-west differences in climate pattern and response for the EASM and the WW are integrally stable on both short-term and long-term timescales.

Moisture Sources and Their Contributions to Summer Precipitation in the East of Southwest China

Complex topography,special geographical location and sea-land-air interactions lead to high interannual variability of summer precipitation in the east of Southwest China(ESWC).However,the contributions,influencing factors and mechanisms of remote and local evaporation remain to be further investigated.Using clustering analysis and Hybrid Single-Particle Lagrangian Integrated Trajectory version 5 model,we analyze the contributions of remote moisture transport and local evaporation to summer precipitation in the ESWC and their causes.There are mainly five remote moisture channels in the ESWC,namely the Arabian Sea channel,Bay of Bengal channel,western Pacific channel,Northwest channel 1 and Northwest channel 2.Among the five channels,the western Pacific channel has the largest number of trajectories,while the Bay of Bengal channel has the largest contribution rate of specific humidity(33.33%)and moisture flux(33.14%).The amount of regional average precipitation is close to that of the precipitation caused by remote moisture transport,and both are considerably greater than the rainfall amount caused by local evaporation.However,on interannual time scales,precipitation recirculation rates are negatively correlated to regional average precipitation and precipitation caused by remote moisture transport but are consistent with that caused by local evaporation.An apparent"+-+"wave train can be found on the height anomaly field in East Asia,and the sea surface temperature anomalies are positive in the equatorial Middle-East Pacific,the South China Sea,the Bay of Bengal and the Arabian Sea.These phenomena cause southwest-northeast moisture transport with strong updrafts,thereby resulting in more precipitation in the ESWC.

Comparison of the reaction of polar mesosphere winter echoes and polar mesosphere summer echoes to high-frequency heating in terms of modulated characteristics

In this work,for the first time,we have analyzed and compared the responses of polar mesosphere winter echoes(PMWE)and their summer counterpart,polar mesosphere summer echoes(PMSE),to high-frequency(HF)heating in terms of modulated characteristics(i.e.,backscatter intensity reduction,recovery,and overshoot).Both PMWE and PMSE observations were from the same site(Tromsφ,Norway;69.6°N,19.2°E)and radar(EISCAT[European Incoherent Scatter Scientific Association]very high frequency,224 MHz).The heating patterns of both PMWE and PMSE were found to be similar;however,PMSE was more greatly affected by HF heating.Polar mesosphere summer echoes showed recovery and overshoot more frequently than did PMWE.In addition,the mean recovery and overshoot of PMSE were greater than those of PMWE.The associated electron temperature enhancement was estimated for both PMWE and PMSE and showed that,compared with PMWE,the electron temperature enhancement was more significant in PMSE.The strong heating effects on PMSE may be due to the considerable increase in electron temperature.

Identifying the critical phosphorus balance for optimizing phosphorus input and regulating soil phosphorus effectiveness in a typical winter wheat-summer maize rotation system in North China

Phosphorus(P)is a nonrenewable resource and a critical element for plant growth that plays an important role in improving crop yield.Excessive P fertilizer application is widespread in agricultural production,which not only wastes phosphate resources but also causes P accumulation and groundwater pollution.Here,we hypothesized that the apparent P balance of a crop system could be used as an indicator for identifying the critical P input in order to obtain a high yield with high phosphorus use efficiency(PUE).A 12-year field experiment with P fertilization rates of 0,45,90,135,180,and 225 kg P_(2)O_(5)ha^(-1)was conducted to determine the crop yield,PUE,and soil Olsen-P value response to P balance,and to optimize the P input.Annual yield stagnation occurred when the P fertilizer application exceeded a certain level,and high yield and PUE levels were achieved with annual P fertilizer application rates of 90-135 kg P_(2)O_(5)ha^(-1).A critical P balance range of 2.15-4.45 kg P ha^(-1)was recommended to achieve optimum yield with minimal environmental risk.The critical P input range estimated from the P balance was 95.7-101 kg P_(2)O_(5)ha^(-1),which improved relative yield(>90%)and PUE(90.0-94.9%).In addition,the P input-output balance helps in assessing future changes in Olsen-P values,which increased by 4.07 mg kg^(-1)of P for every 100 kg of P surplus.Overall,the P balance can be used as a critical indicator for P management in agriculture,providing a robust reference for limiting P excess and developing a more productive,efficient and environmentally friendly P fertilizer management strategy.