Responses of Wheat Production, Quality, and Soil Profile Properties to Biochar Applied at Different Seasons in a Rice-Wheat Rotation

In the rice-wheat rotation system,biochar(BC)can be applied at the initiation of the rice or wheat season.Here,we compared the effects of BC that were applied at two different crop seasons on wheat production,quality,and soil profile properties in a rice-wheat rotation system with nitrogen(N)fertilizer applied at 280 kg/ha rate.Results showed that both wheat grain production and N recovery use efficiency were influenced by BC applied at two crop seasons.Biochar application did not affect the total non-essential amino-acid,but when applied during wheat season,BC significantly(p<0.05)increased total essential amino acid in grain by 12.3%,particularly for the valine(+48.2%),methionine(+43.8%),and isoleucine(+10.3%).We found that BC significantly(p<0.05)decreased the pH of soil at 0–6 cm and 20–30 cm by 0.14–0.18 and 0.05–0.08 units,respectively.The NH4+-N content of the whole observed soil profile were reduced by BC application,however,the effect of BC on NO3–-N content varied with the application season and profile depth.Interestingly,BC applied at wheat and rice season significantly(p<0.05)improved topsoil N contents by 48.4%and 19.7%,respectively.In addition,data suggested that BC applied during wheat season performed better in enhancing soil available phosphorus,potassium,and organic matter contents.In conclusion,we suggest that the optimum application time of BC for enhancing crop production and quality(take amino-acid content for example)and improving soil fertility is at the initiation of the wheat season.

Carbon Dioxide, Methane, and Nitrous Oxide Emissions from a Rice-Wheat Rotation as Affected by Crop Residue Incorporation and Temperature

Field measurements were made from June 2001 to May 2002 to evaluate the effect of crop residue application and temperature on CO2, CH4, and N2O emissions within an entire rice-wheat rotation season. Rapeseed cake and wheat straw were incorporated into the soil at a rate of 2.25 t hm(-2) when the rice crop was transplanted in June 2001. Compared with the control, the incorporation of rapeseed cake enhanced the emissions of CO2, CH4, and N2O in the rice-growing season by 12.3%, 252.3%, and 17.5%, respectively, while no further effect was held on the emissions of CO2 and N2O in the following wheat-growing season. The incorporation of wheat straw enhanced the emissions of CO2 and CH4 by 7.1% and 249.6%, respectively, but reduced the N2O emission by 18.8% in the rice-growing season. Significant reductions of 17.8% for the CO2 and of 12.9% for the N2O emission were observed in the following wheat-growing season. A positive correlation existed between the emissions of N2O and CO2 (R-2 = 0.445, n = 73,p < 0.001) from the rice-growing season when N2O was emitted. A trade-off relationship between the emissions of CH4 and N2O was found in the rice-growing season. The CH4 emission was significantly correlated with the CO2 emission for the period from rice transplantation to field drainage, but not for the entire rice-growing season. In addition, air temperature was found to regulate the CO2 emissions from the non-waterlogged period over the entire rice-wheat rotation season and the N2O emissions from the nonwaterlogged period of the rice-growing season, which can be quantitatively described by an exponential function. The temperature coefficient (Q(10)) was then evaluated to be 2.3+/-0.2 for the CO2 emission and 3.9+/-0.4 for the N2O emission, respectively.

A Field Study on Effects of Nitrogen Fertilization Modes on Nutrient Uptake,Crop Yield and Soil Biological Properties in Rice-Wheat Rotation System

Rational application of nitrogen （N） fertilizers is an important measure to raise N fertilizer recovery rate and reduce N loss.A two-year field experiment of rice-wheat rotation was employed to study the effects of N fertilization modes including a N fertilizer reduction and an organic manure replacement on crop yield,nutrient uptake,soil enzyme activity,and number of microbes as well as diversity of microbes.The result showed that 20% reduction of traditional N fertilizer dose of local farmers did not significantly change crop yield,N uptake,soil enzyme activity,and the number of microbes （bacteria,actinomycetes,and fungi）.On the basis of 20% reduction of N fertilizer,50% replacement of N fertilizer by organic manure increased the activity of sucrose,protease,urease,and phosphatase by 46-62,27-89,33-46,and 35-74%,respectively,and the number of microbes,i.e.,bacteria,actinomycetes,and fungi by 36-150,11-153,and 43-56%,respectively.Further,organic fertilizer replacement had a Shannon＇s diversity index （H） of 2.18,which was higher than that of other modes of single N fertilizer application.The results suggested that reducing N fertilizer by 20% and applying organic manure in the experimental areas could effectively lower the production costs and significantly improve soil fertility and biological properties.

On the source of the quasi-Carrington Rotation periodic magnetic variations on the Martian surface: InSight observations and modeling

In a recent paper(Luo H et al.,2022),we found that the peak amplitudes of diurnal magnetic variations,measured during martian days(sols)at the InSight landing site,exhibited quasi Carrington-Rotation(qCR)periods at higher eigenmodes of the natural orthogonal components(NOC);these results were based on~664 sols of magnetic field measurements.However,the source of these periodic variations is still unknown.In this paper we introduce the neutral-wind driven ionospheric dynamo current model(e.g.,Lillis et al.,2019)to investigate the source.Four candidates-the draped IMF,electron density/plasma density,the neutral densities,and the electron temperature in the ionosphere with artificial qCR periodicity,are applied in the modeling to find the main factor likely to be causing the observed surface magnetic field variations that exhibit the same qCR periods.Results show that the electron density/plasma density,which controls the total conductivity in the dynamo region,appears to account for the greatest part of the surface qCR variations;its contribution reaches about 67.6%.The draped IMF,the neutral densities,and the electron temperature account,respectively,for only about 12.9%,10.3%,and 9.2%of the variations.Our study implies that the qCR magnetic variations on the Martian surface are due primarily to variations of the dynamo currents caused by the electron density variations.We suggest also that the timevarying fields with the qCR period could be used to probe the Martian interior's electrical conductivity structure to a depth of at least 700 km.

Yield Gap Analysis of Wheat in Rice-wheat Rotation Regions of Anhui Province,China

The present study was planned to analyze the yield gap of wheat and its production constraints in order to explore the approaches for narrowing the yield gap of wheat in different wheat-rice rotation regions of Anhui Province. The production status and limiting factors of wheat in three rice-wheat rotation regions which are named Region Ⅰ,Region Ⅱ and Region Ⅲ were surveyed by using participatory rural appraisal method. The personnel,who were engaged in wheat production in rice-wheat rotation regions of Anhui Province,mainly ageing from 41 to 60,accounted for 79% of the total personnel in the regions. There were significant differences in yield of wheat which was planted after rice in Anhui. The yield was ranging from 8 907. 00 to 2 700. 00 kg/ha from north to south with an average of 4 978. 5 kg/ha,and the rank of overall average yields at province level was Region Ⅰ( 5 685. 60 kg/ha) > Region Ⅱ( 5 600. 10 kg/ha) > Region Ⅲ( 3 048. 60 kg/ha). The average yield gap of wheat in wheat-rice rotation regions at province level was up to 2 637. 00 kg/ha,and the extreme yield gaps per hectare in the same region were 2 778. 00 kg( Region Ⅰ),2 502. 00 kg( Region Ⅱ) and 1 575. 00 kg( Region Ⅲ) respectively. The objective constraints were Fusarium head blight and pre-harvest sprouting;the subjective constraints were variety selection and layout,poor sowing quality and low seedling quality;social constraints were high cost,low market price and poor efficiency;and ecological constraints were poor soil texture,soil infertility and poor water-and-fertilizer retention. The yield gap of wheat in rice-wheat rotation regions can be effectively reduced by improving yield potential of low-and-medium-yielding fields. Selecting appropriate wheat varieties and layout,constructing disease forecast system,improving agricultural machinery and social service organizations of plant protection,and strengthening scientific training as well as technological training of new agricultural operators and agricultural machinery technicians are the core means to narrowing the yield gap of wheat in rice-wheat rotation regions at province scale.

Seasonal and Interannual Variations of Carbon Exchange over a Rice–Wheat Rotation System on the North China Plain

Rice-wheat （R-W） rotation systems are ubiquitous in South and East Asia, and play an important role in modulating the carbon cycle and climate. Long-term, continuous flux measurements help in better understanding the seasonal and interannual variation of the carbon budget over R-W rotation systems. In this study, measurements of CO2 fluxes and meteorological variables over an R-W rotation system on the North China Plain from 2007 to 2010 were analyzed. To analyze the abiotic factors regulating Net Ecosystem Exchange （NEE）, NEE was partitioned into gross primary production （GPP） and ecosystem respiration. Nighttime NEE or ecosystem respiration was controlled primarily by soil temperature, while daytime NEE was mainly determined by photosythetically active radiation （PAR）. The responses of nighttime NEE to soil temperature and daytime NEE to light were closely associated with crop development and photosynthetic activity, respectively. Moreover, the interannual variation in GPP and NEE mainly depended on precipitation and PAR. Overall, NEE was negative on the annual scale and the rotation system behaved as a carbon sink of 982 g C m 2 per year over the three years. The winter wheat field took up more CO2 than the rice paddy during the longer growing season, while the daily NEE for wheat and rice were -2.35 and -3.96 g C m-2, respectively. After the grain harvest was subtracted from the NEE, the winter wheat field became a moderately strong carbon sink of 251-334 g C m-2 per season, whereas the rice paddy switched to a weak carbon sink of 107-132 per season.

A Process-based Model of N_2O Emission from a Rice-Winter Wheat Rotation Agro-Ecosystem:Structure,Validation and Sensitivity

In order to numerically simulate daily nitrous oxide （N2O） emission from a rice-winter wheat rotation cropping system, a process-based site model was developed （referred to as IAP-N-GAS） to track the movement and transformation of several forms of nitrogen in the agro-eeosystem, which is affected by climate, soil, crop growth and management practices. The simulation of daily N2O fluxes, along with key daily environmental variables, was validated with three-year observations conducted in East China. The validation demonstrated that the model simulated well daily solar radiation, soil temperature and moisture, and also captured the dynamics and magnitude of accumulated rice aboveground biomass and mineral nitrogen in the soil. The simulated daily N2O emissions over all three years investigated were generally in good agreement with field observations. Particularly well simulated were the peak N2O emissions induced by fertilizations, rainfall events or mid-season drainages. The model simulation also represented closely the inter-annuM variation in N2O emission. These validations imply that the model has the capability to capture the general characteristics of N2O emission from a typical rice-wheat rotation agro-ecosystem. Sensitivity analyses revealed that the simulated N2O emission is most sensitive to the fertilizer application rate and the soil organic matter content, but it is much less sensitive to variations in soil pH and texture, temperature, precipitation and crop residue incorporation rate under local conditions.

MHD UNSTEADY FLOWS DUE TO NON—COAXIAL ROTATIONS OF A DISK AND A FLUID AT INFINITY

Exact analytical solution for flows of an electrically conducting fluid over an infinite oscillatory disk in the presence of a uniform transverse magnetic field is constructed. Both the disk and the fluid are in a state of non-coaxial rotation. Such a flow model has a great significance not only due to its own theoretical interest, but also due to applications to geophysics and engineering. The resulting initial value problem has been solved analytically by applying the Laplace transform technique and the explicit expressions for the velocity for steady and unsteady cases have been established. The analysis of the obtained results shows that the flow field is appreciably influenced by the applied magnetic field, the frequency and rotation parameters.

Period-One Rotating Solutions of Horizontally Excited Pendulum Based on Iterative Harmonic Balance

In this study, the iterative harmonic balance method was used to develop analytical solutions of period-one rotations of a pendulum driven horizontally by harmonic excitations. The performance of the method was evaluated by two criteria, one based on the system energy error and the other based on the global residual error. As a comparison, analytical solutions based on the multi-scale method were also considered. Numerical solutions obtained from the Dormand-Prince method (ODE45 in MATLAB&#169) were used as the baseline for evaluation. It was found that under lower-level excitations, the multi-scale method performed better than the iterative method. At higher-level excitations, however, the performance of the iterative method was noticeably more accurate.

复方斑蝥胶囊联合旋转容积调强技术对头颈部放疗生存期及血清XRCC1、XRCC3mRNA水平的影响

目的探究复方斑蝥胶囊联合旋转容积调强技术对头颈部放疗患者生存期及血清X线修复交错互补基因1(X-ray Repair Cross Complementing 1,XRCC1)、X线修复交错互补基因3(X-ray Repair Cross Complementing 3,XRCC3)信使核糖核酸(Messenger RNA,mRNA)水平的影响。方法选取2019年6月—2021年7月医院收治的头颈部肿瘤患者97例作为研究对象,根据治疗方法不同进行分组,对照组(48例)采用旋转容积调强技术结合放疗治疗,联合组(49例)在对照组基础上加用复方斑蝥胶囊治疗。观察比较临床疗效、中医证候积分、血清XRCC1及XRCC3mRNA水平、生存期、不良反应。结果联合组客观缓解率高于对照组(P<0.05),但疾病控制率与对照组比较差异无统计学意义(P>0.05)。联合组自汗、恶心呕吐、神疲乏力、食欲差、失眠、头晕眼花等得分低于对照组(P<0.05)。联合组血清XRCC1、XRCC3水平及外周血XRCC1、XRCC3 mRNA表达均低于对照组(P<0.05)。联合组无进展生存期和总生存期均高于对照组(P<0.05)。联合组不良反应发生率(34.69%,17/49)低于对照组不良反应发生率(72.92%,35/48)(P<0.05)。结论复方斑蝥胶囊联合旋转容积调强技术能改善头颈部放疗患者肿瘤客观缓解率,缓解临床症状,降低血清XRCC1、XRCC3mRNA水平,减少不良反应。

基于弹丸旋转规律的弹道终点辨识和引信全弹道安全控制方法

弹丸在飞行时所处的复杂环境可能引起弹药在待发状态下意外作用。基于6自由度刚体弹道方程组,运用4阶龙格-库塔算法对运动方程组进行数值计算,得到弹丸旋转速度随时间的衰减规律。采用某型榴弹开展炮射试验并回收试验数据,对弹丸旋转周期2阶导数的过零特征点进行验证。针对发射装药量和射角两个发射条件对特征点的影响规律进行研究,提出基于旋转特征点的弹道终点时刻辨识方法,设计基于磁场传感器的弹道终点实时辨识系统,并开展靶场炮射试验进行验证。研究结果表明,弹载弹道终点辨识系统和弹道跟踪雷达获取的弹道终点时刻相对误差小于5%,验证了所提弹道终点辨识方法的正确性。在此基础上,进一步提出适用于一种旋转稳定弹药的机械-电子双模全弹道安全控制方法,在利用发射后坐过载和旋转离心力两道环境信息的基础上,采用终点辨识作为第三道环境信息,实现引信全弹道安全控制。新提出的基于弹丸旋转规律的弹道终点辨识及引信安全控制方法,为提高旋转稳定弹药全弹道安全性提供了新的思路。

面向扑翼飞行机器人的电子稳像算法设计

在扑翼飞行机器人的飞行过程中,由于其特有的驱动方式,机身存在周期性的俯仰和滚转运动,导致航拍视频出现抖动,影响成像效果的清晰度和稳定性.为了解决这一问题,本文提出了一种基于ORB和滑动均值滤波的电子稳像算法,用于在线消抖处理.首先,针对扑翼飞行机器人航拍图像的抖动周期与机翼扑动周期相一致的特性,设计了一种估计算法来根据图像特征估计机翼扑动周期.这一算法能够更准确地捕捉到抖动的周期性特征,为后续的稳像处理提供了重要参数.其次,提出了一种与扑动周期相关联的运动滤波算法,能够根据不同飞行工况对滤波参数自适应地进行动态调整.本文提出的算法优点在于能够根据扑翼飞行机器人实际飞行情况实时调整参数,从而更好地适应不同的飞行工况,进一步提高了稳像效果.最后,为了验证算法的可行性和稳定性,将视觉成像装置搭载在扑翼飞行机器人上进行了飞行实验.实验结果表明,相较于常用的电子稳像算法,本文所设计的算法在扑翼飞行机器人中表现出更好的稳像效果.最后,总结了本文所提出的算法优点,并对未来研究方向做出了展望.

基于广义Faustmann模型的营林管理决策方法学研究前沿及展望

可持续营林及相关联的最优轮伐期决策是缓解全球气候变化的重要途径。经典Faustmann模型关于“所有参数在不同轮伐期内保持一致”的基本假设无法得到满足,有必要以广义Faustmann模型为基础探求多因素影响下的最优轮伐期决策问题。本研究围绕广义Faustmann模型,归纳总结其理论扩展及前沿应用,梳理可持续营林决策方法学中广义Faustmann模型的最新研究进展。研究发现:1)广义Faustmann模型已在碳汇效益、异龄林管理、自然风险和税收政策4个方向得到拓展,其中土地期望值及相应的利润最大化一阶条件能够帮助林地所有者制定合理的营林管理方案;2)利用广义Faustmann模型,能够将Pressler指示率中的数量增长率、质量增长率和价格增长率具体化,允许林地所有者在不知道未来价格的情况下,结合自身风险偏好使用事前决策的方法决定当年是否采伐林分;3)林分的土地价值和木材价值在广义Faustmann模型下能够被明确区别开来,从而在转让一片未成熟林分时,实现对林分的土地和木材准确估值,并在不同税收政策下确定其各自税率。广义Faustmann模型在未来最优轮伐期决策研究中的拓展方向还包括以下几个方面:1)将碳汇效益由地上生物量碳库扩展至完整林业碳库;2)将税收政策由国外政策扩展至中国特色林业税费体系;3)将模型假设由确定环境扩展至随机环境;4)将研究尺度由林分层面扩展至森林层面;5)将生态效益由碳汇效益扩展至森林生态系统服务。

地球自转速率变化的非线性特性

为研究地球自转速率变化的非线性特性,结合自适应噪声完备经验模态分解、定量递归分析和Grassberger-Procaccia算法,从周期、混沌和分形多角度对1962年1月1日至2023年12月31日反映地球自转速率变化的日长变化(length of day,ΔLOD)观测序列的非线性特性进行全面分析,并着重对比分析扣除周期成分或混沌成分前后ΔLOD特性是否存在明显区别.主要结论如下:1)ΔLOD时间序列由趋势成分、周期成分和混沌成分构成,具有明显的多时间尺度、混沌动力学特性和分形结构;2)扣除混沌成分后的时间序列周期与原始ΔLOD时间序列的周期完全相同;3)原始ΔLOD时间序列和其扣除趋势成分和周期成分后的时间序列的混沌特性无显著性差异,但前者分形结构的复杂性相对更强.

旋转液体测量重力加速度的研究

利用FD-RLE-A型旋转液体综合实验仪,将之前的测量方法进行优化,减少了所测变量的个数,在相同的测量条件下使测量结果更加精确.给出一种简单快捷的调节激光束平行于转轴入射的方法.对用测旋转液体最低液面高度法和激光束平行转轴入射测斜率法测量重力加速度时如何选择旋转周期进行了研究.

牡丹江地区杨树短轮伐期条材经营模式的研究

采用渤丰3号杨和177杨,并将扦插密度提高到13.3万株/hm^(2),培育杨树1年生条材,可以将单位面积生物量产出从迎春5号杨现行育苗方式的5.09 t/hm^(2),分别提高到15.43 t/hm^(2)和15.6 t/hm^(2),效益显著。试验数据初步论证了牡丹江地区采用短轮伐期经营模式培育杨树条材的可行性。

探究纽曼护理模式联合预警性预防护理模式在乳腺旋切患者围术期中的应用

目的探究纽曼护理模式联合预警性预防护理模式在乳腺旋切患者围术期中的应用。方法方便选取2020年10月—2022年10月在解放军第七十三集团军医院实施乳腺旋切手术治疗的患者89例作为本研究对象。以随机数表法将其分组,对照组(44例)接受常规围术期护理;观察组(45例)在对照组的基础上接受纽曼护理模式联合预警性预防护理模式。比较两组护理前后心理状态评估量表(Mental Status Scale in Nonpsychiatric Settings,MSSNS)评分、纽卡斯尔护理满意度量表(Newcastle Nursing Satisfaction Scale,NSNS)及术后并发症发生率。结果两组护理前MSSNS中焦虑、抑郁、愤怒、孤独评分对比,差异无统计学意义(P>0.05);观察组护理后MSSNS中焦虑、抑郁、愤怒、孤独评分低于对照组,差异有统计学意义(P均<0.05)。观察组NSNS评分为(81.75±3.86)分,高于对照组的(78.89±4.13)分,差异有统计学意义(t=3.373,P<0.05)。观察组术后并发症发生率为2.22%,低于对照组的18.18%,差异有统计学意义(P<0.05)。结论对乳腺旋切患者围术期中实施纽曼护理模式联合预警性预防护理模式可以有效调节其心理状态,减少术后并发症,并提高患者满意程度。

怀化市稻油轮作模式下优质杂交水稻品种比较试验

为筛选出适应怀化山区高产、优质、抗性好的杂交水稻品种,在采用稻油两熟制生产模式的基础上,选用湖南省主推的17个杂交水稻品种开展比较试验。结果表明:悦两优1672、悦两优8549、玮两优6246、悦两优钰占、玮两优倩丝、誉两优1267、野香优海丝、华浙优261、晶两优534、泰优农39、淳丰优6319的综合表现较好;誉两优1267、玮两优6246、淳丰优6319、华浙优261、青香优香九、野香优海丝、玮两优倩丝、悦两优钰占、晶两优534、泰优农39的丰产性、综合性状突出,表现出极强的优势,在中高海拔地区具有示范推广价值。

Experiences and Research Perspectives on Sustainable Development of Rice-Wheat Cropping Systems in the Chengdu Plain, China

The rice and wheat cropping pattern is one of the main cropping systems in the world. A large number of research results showed that successive cropping of rice and wheat resulted in a series of problems such as hindering nutrition absorption, gradual degeneration of soil fertility, decline of soil organic matter, and increased incidence of diseases and pests. In China, especially in the Chengdu plain where rice-wheat cropping system is practiced, productivity and soil fertility was enhanced and sustained. This paper reviews the relevant data and experiences on rice-wheat cropping in the Chengdu Plain from 1977 to 2006. The principal sustainable strategies used for rice-wheat cropping systems in Chengdu Plain included： 1） creating a favorable environment and viable rotations; 2） balanced fertilization for maintenance of sustainable soil productivity; 3） improvement of crop management for higher efficiency; and 4） use the newest cultivars and cultivation techniques to upgrade the production level. Future research is also discussed in the paper as： 1） the constant topic： a highly productive and efficient rice-wheat cropping system for sustainable growth; 2） the future trend： simplified cultivation techniques for the rice-wheat cropping system; 3） the foundation： basic research for continuous innovation needed for intensive cropping. It is concluded that in the rice-wheat cropping system, a scientific and reasonable tillage/cultivation method can not only avoid the degradation of soil productivity, but also maintain sustainable growth in the long run.

Stochastic Resonance on a Circle Without Periodic Excitation

We analyse the appearance of coherent motion in the dynamics of the Langevin equation in the subtle case of I<1,and show that stochastic resonance does exist even in the non-critical case I<1.Moreover,we show the monotonicity of the rotation number and discuss the relationship between the center frequency of the power spectrum peak and the rotation number.