Response of CH_4 emission of paddy fields to land management practices at a microcosmic cultivation scale in China

The terrestrial ecosystem may be either a source or a sink of CH_4 in rice paddies, depending, to a great extent, on the change of ecosystem types and land use patterns. CH_4 emission fluxes from paddy fields under 4 cultivation patterns (conventional plain culture of rice(T1), no-tillage and ridge culture of rice(T2), no-tillage and ridge culture of rice and wheat (T3), and rice-wheat rotation(T4)) were measured with the closed chamber technique in 1996 and 1998 in Chongqing, China. The results showed that differences existed in CH_4 emission from paddy fields under these land management practices. In 1996 and 1998, CH_4 emission was 71 48% and 78 82%(T2), 65 93% and 57 18%(T3), and 61 53% and 34 22%(T4) of that in T1 during the rice growing season. During the non-rice growing season, CH_4 emission from rice fields was 76 23% in T2 and 38 69% in T1 The accumulated annual CH_4 emission in T2, T3 and T4 in 1996 decreased by 33 53%, 63 30% and 65 73%, respectively, as compared with that in T1 In 1998, the accumulated annual CH_4 emission in T1, T2, T3 and T4 was 116 96 g/m^2, 68 44 g/m^2, 19 70 g/m^2 and 11 80 g/m^2, respectively. Changes in soil physical and chemical properties, in thermal and moisture conditions in the soil and in rice plant growth induced by different land use patterns were the dominant causes for the difference in CH_4 emission observed. The relative contribution of various influencing factors to CH_4 emission from paddy fields differed significantly under different land use patterns. However, the general trend was that chlorophyll content in rice leaves, air temperature and temperature at the 5 cm soil layer play a major role in CH_4 emission from paddy fields and the effects of illumination, relative humidity and water layer depth in the paddy field and CH_4 concentration in the crop canopy were relatively non-significant. Such conservative land use patterns as no-tillage and ridge culture of rice with or without rotation with wheat are thought to be beneficial to reducing CH_4 emission from paddy fields and are, therefore, recommended as a significant solution to the problems of global(climatic) change.

Changes in Soil Properties of Paddy Fields Across a Cultivation Chronosequence in Subtropical China

Rice production plays a crucial role ia the food supply of China and a better understanding of the changes in paddy soil fertility and the management effects is of practical importance for increasing rice productivity. In this study, field sampling in a typical red soil region of subtropical China, Jiangxi Province, was used to observe changes in the soil physical, chemical,and biological properties in a cultivation chronosequence of paddy fields. After cultivation, clay (＜ 0.002 mm) content in the soil, which was 39% in the original uncultivated wasteland, decreased to 17% in the 80-year paddy field, while silt(0.02-0.002 mm) content increased. Additionally, macroporosity increased and pore shapes became more homogeneous.Soil pH generally increased. Soil organic C and total N contents of the 0-10 cm layer increased from 4.58 and 0.39 g kg-1to 19.6 and 1.62 g kg-1, respectively, in the paddy fields after 30-year cultivation and then remained stable. Soil total P content increased from 0.5 to 1.3 g kg-1 after 3 years of rice cultivation, indicating that application of phosphate fertilizer could accelerate phosphorous accumulation in the soil. Total K content in the 0-10 cm soil layer for the 80-year paddy field decreased by 28% compared to that of the uncultivated wasteland land. Total Fe and free Fe contents declined with years of cultivation. The bacterial population increased and urease activity noticeably intensified after years of cultivation.In this chronosequence it appeared that it took 30 years to increase soil fertility to a relatively constant value that was seen after 80 years of cultivation.

Changes in Soil C and N Contents and Mineralization Across a Cultivation Chronosequence of Paddy Fields in Subtropical China

Dynamics of soil organic matter in a cultivation chronosequence of paddy fields were studied in subtropical China.Mineralization of soil organic matter was determined by measuring CO2 evolution from soil during 20 days of laboratoryincubation. In the first 30 years of cultivation, soil organic C and N contents increased rapidly. After 30 years, 0-10 cmsoil contained 19.6 g kg-1 organic C and 1.62 g kg-1 total N, with the corresponding values of 18.1 g kg-1 and 1.50g kg-1 for 10-20 cm, and then remained stable even after 80 years of rice cultivation. During 20 days incubation themineralization rates of organic C and N in surface soil (0-10 cm) ranged from 2.2% to 3.3% and from 2.8% to 6.7%,respectively, of organic C and total N contents. Biologically active C size generally increased with increasing soil organicC and N contents. Soil dissolved organic C decreased after cultivation of wasteland to 10 years paddy field and thenincreased. Soil microbial biomass C increased with number of years under cultivation, while soil microbial biomass Nincreased during the first 30 years of cultivation and then stabilized. After 30 years of cultivation surface soil (0-10 cm)contained 332.8 mg kg-1 of microbial biomass C and 23.85 mg kg-1 of microbial biomass N, which were 111% and 47%higher than those in soil cultivated for 3 years. It was suggested that surface soil with 30 years of rice cultivation insubtropical China would have attained a steady state of organic C content, being about 19 g kg-1.

Comparative Experiment of Ground Cucumber Varieties for Open Field Cultivation

Seven ground cucumber varieties were cultivated in open field for the comparative experiment. The results showed that Texuan cucumber and Yantai ground cucumber had good commodity characters,good taste and high yield,and their output value exceeded 16 000 yuan/666. 7 m2,so they are more suitable for open cultivation in Yantai region. The next ones are Meiyu Diguawang and Aweishi ground cucumber.

Methane and Nitrous Oxide Emissions from Three Paddy Rice Based Cultivation Systems in Southwest China

To understand methane （CH4） and nitrous oxide （N2O） emissions from permanently flooded rice paddy fields and to develop mitigation options, a field experiment was conducted in situ for two years （from late 2002 to early 2005） in three rice-based cultivation systems, which are a permanently flooded rice field cultivated with a single time and followed by a non-rice season （PF）, a rice-wheat rotation system （RW） and a rice-rapeseed rotation system （RR） in a hilly area in Southwest China. The results showed that the total CH4 emissions from PF were 646.3±52.1 and 215.0±45.4 kg CH4 hm^-2 during the rice-growing period and non-rice period, respectively. Both values were much lower than many previous reports from similar regions in Southwest China. The CH4 emissions in the rice-growing season were more intensive in PF, as compared to RW and RR. Only 33% of the total annual CH4 emission in PF occurred in the non-rice season, though the duration of this season is two times longer than the rice season. The annual mean N2O flux in PF was 4.5±0.6 kg N2O hm^-2 yr^-1. The N2O emission in the rice-growing season was also more intensive than in the non-rice season, with only 16% of the total annual emission occurring in the non-rice season. The amounts of N2O emission in PF were ignorable compared to the CH4 emission in terms of the global warming potential （GWP）. Changing PF to RW or RR not only eliminated CH4 emissions in the non-rice season, but also substantially reduced the CH4 emission during the following rice-growing period （ca. 58%, P〈0.05）. However, this change in cultivation system substantially increased N2O emissions, especially in the non-rice season, by a factor of 3.7 to 4.5. On the 100-year horizon, the integrated GWP of total annual CH4 and N2O emissions satisfies PF〉〉RR≈RW. The GWP of PF is higher than that of RW and RR by a factor of 2.6 and 2.7, respectively. Of the total GWP of CH4 and N2O emissions, CH4 emission contributed to 93%, 65% and 59% in PF, RW and RR, respectively. These results suggest that changing PF to RW and RR can substantially reduce not only CH4 emission but also the total GWP of the CH4 and N2O emissions.

Investigation on Diseases and Pests of Grape Under Rain Shelter Cultivation in Shandong Province

In order to make clear the effects of rain shelter cultivation on the incidence of diseases and pests of grape in Shandong Province,with Summer Black as the material,the diseases and pests of grape under rain shelter cultivation and open field cultivation in Tai'an and Jining were investigated.The results showed that under the rain shelter cultivation condition,the phenological period of grape delayed 5-8 d.The types of grape diseases and pests under the rain shelter cultivation were the same as those in the open filed cultivation.The most serious pests were Apolygus lucorum,followed by Lycorma delicatula,Erythreura apicalis and Thrips tabaci.The most serious leaf disease was downy mildew,and the most serious disease of grape berries was grape sour rot.Compared with the open field cultivation,the rain shelter cultivation could effectively reduce the incidence of pests and diseases in grape leaves and fruit.At the end of May 2018 and 2019,the occurrence rate of grape pests under the rain shelter cultivation in Tai'an reduced by 57.69%and 60.47%,respectively,and those in Jining reduced by 72.22%and 62.50%,respectively.In the middle of July of 2018 and 2019,the incidence of grape fruit diseases under the rain shelter cultivation in Tai'an reduced by 62.49%and 50.07%,respectively,and that in Jining reduced by 49.96%and 100%,respectively.

油菜抗根肿病品种在云南省西南发病区的田间评价

通过明确‘华双5R’和‘华油杂62R’2个抗根肿病油菜品种的田间抗性、农艺性状和产量情况,为油菜根肿病重发区筛选出优良的抗病品种。本研究在云南省西南地区的腾冲市、梁河县和临翔县3个油菜根肿病病区进行田间试验,采用本课题组研发品种和当地主推品种作为对照。田间试验结果显示,‘华双5R’和‘华油杂62R’在3个试验点均能正常成熟安全越冬,生育期176~199d,各生育期表现整齐一致;‘华双5R’和‘华油杂62R’在腾冲和梁河点对油菜根肿病表现为高度抗病,在临翔点表现为抗病;‘华双5R’和‘华油杂62R’在3个试验点的农艺性状良好;‘华双5R’的产量在3个试验点与7个对照品种相比,比梁河点的‘云油杂12号’减产2.71%,与腾冲点的‘云油杂12号’和‘杂1256’、梁河点的‘云油杂15’和‘花油8号’、临翔点的‘云油杂12号’和‘德油1号’相比增产幅度为7.49%~56.83%;‘华油杂62R’的产量在3个试验点与7个对照品种相比,比梁河点的‘云油杂12号’减产5.76%,比临翔点的‘德油1号’减产4.61%,与腾冲点的‘云油杂12号’和‘杂1256’、梁河点的‘云油杂15’和‘花油8号’、临翔点的‘云油杂12号’相比增产幅度为4.12%~51.90%。‘华双5R’和‘华油杂62R’在3个试验点均能正常成熟,生育期176~199d,对根肿病表现出较强抗性,同时农艺性状良好、产量较高,可在云南省西南地区油菜根肿病病区推广种植。

面向栽培基质的二氧化钛电极EGFET pH传感器设计

针对农业生产中栽培基质直接在线检测pH准确性差的问题,采用化学腐蚀法,制备出具有氢离子敏感特性和超亲水特性的二氧化钛(TiO_(2))电极,并且采用退火工艺以提高电极表面硬度;将TiO_(2)电极与金属氧化物场效应晶体管(MOSFET)组合成基于延伸式栅极场效应晶体管(EGFET)的pH传感器.测试得到传感器灵敏度为0.05063 V/pH,重复性试验的变异系数最大为0.0057.测试结果表明该传感器具有良好的灵敏度、重复性和稳定性.选取4种典型栽培基质进行pH在线检测应用试验,pH检测误差的绝对值最大为0.18,经过温度补偿后误差的绝对值最大为0.11;使用后电极表面的亲水性依旧保持良好.应用试验结果表明,该传感器适用于栽培基质pH在线检测.

宁夏中部干旱区露地甘薯栽培适应性比较研究

为丰富宁夏干旱区适宜栽种的甘薯品种,实现区域甘薯产业高质高效持续发展,以收集的国内外23个甘薯品种为材料,对植株农艺性状、甘薯产量、甘薯品质、栽培适应性等多指标进行比较分析。结果表明,徐薯25、苏薯8号、安平一号、济薯26号、徐薯55-1、安纳芋、徐薯27、岩薯5号8个品种为早熟品种,9月中旬为最佳采收期。徐薯28和烟薯25号2个品种9月中旬至10月初采收均可;其他品种为中晚熟品种,适宜10月初采收。烟薯25号、川薯产量高(单株产量分别为2518 g、2295 g),综合品质较好。济薯26号和徐薯55-2产量及可溶性糖含量(分别为3.32%和3.25%)、富硒方面均有优势,适宜开发本地区鲜食品种;徐紫8号、徐紫5号2个紫薯品种产量均不高;徐紫8号粗纤维含量低,硒含量较高;徐紫5号淀粉含量较高。烟薯25号、川薯、济薯26号和徐薯55-2可作为宁夏干旱区域甘薯推荐种植品种。

农作物秸秆资源化利用问题及发展策略研究

分析了我国现阶段农作物资源化利用存在的附加值低、农户积极性不高、筹资难、农业机械化发展不均衡、人才缺乏等问题,研究适合我国农作物秸秆资源化利用的发展策略及措施,以推动我国农作物秸秆资源化利用。

基于场域理论的校园足球立德树人落实困境和实践选择

运用文献资料等方法,基于场域理论对校园足球立德树人落实困境和实践选择进行研究。校园足球场域是指足球教育者、足球受教者和足球参与者之间以足球知识为互动媒介形成的多元关系网络。校园足球立德树人存在场域生态环境欠佳、校园足球文化资本相对匮乏、传统惯习调适滞后等落实困境。应从优化学校场域体育生态环境;营造浓厚的足球发展氛围,加快课程资源的积累,提高校园足球文化资本竞争力;完善惯习调适的制度体系等方面加强校园足球立德树人落实。

新时代师德修养:现实困境、逻辑转向及实践进路

师德养成是“外塑”和“内生”相结合的产物,师德养成既离不开教育政策规制和社会力量整体监督,还需要研究范式逻辑转向和教师群体道德自觉,如此才有利于破解现实中师德修养的复杂问题,进而更好地为实现教育现代化、建设教育强国、培养担当民族复兴大任的时代新人培育大国良师。实践中,师德修养面临着主体残缺、边界泛化和价值错位的实践样态,师德修养正呈现出由“融合场域”迈向“专业场域”、由“外驱逻辑”转向“内驱逻辑”、由“传统师德”走向“现代师德”的复杂特征,经历着场域重构、动力转换和价值变迁的逻辑转向。师德修养应突破现实困境和适应逻辑转向思维,明确师德修养目标、优化师德修养场域、转换师德修养思维,重构师德修养主体、强化专业师德培育、塑造教师美好形象,对师德修养进行全新阐释和重构,完成对师德修养主体性的逻辑转换,促进新时代教师以德立身、以德立学、以德施教、以德育德。

基于流域尺度的耕地时空格局演变与分异性研究

流域尺度下的耕地分布跨度大,为探究流域耕地时空格局演变规律,基于1990、2000、2010、2020年4期土地利用遥感监测数据,以黄河、淮河、海河和长江4大流域为研究区,利用土地利用转移矩阵、重心模型、核密度方法分析流域耕地与其他土地利用类型转移情况、耕地重心迁移和耕地聚集特征,并对4大流域水田旱地分异现象进行分析。结果表明:1990—2020年间4大流域耕地面积均减小,其中海河流域耕地减小率最大,为9.16%;除海河流域耕地重心向西南方向迁移外,其他流域耕地重心均向东北方向迁移,整体耕地重心向北方向迁移,1990—2020年迁移距离分别为1.8、5.9和5.1 km;4大流域水田、旱地除部分水旱田调整外,主要是在林地、城乡用地和草地3种土地利用之间进行,转移主要发生在2010—2020年期间。1990—2020年黄河流域水田面积减少了9.35%,旱地面积减少了4.91%;淮河流域水田面积增加了3.51%,旱地则减少了7.10%;海河流域水田和旱地分别减少了70.46%和6.71%;长江流域水田和旱地分别减少了8.15%和1.72%。黄河、淮河、海河和长江4大流域为国家水网的主网,与本研究范围一致,研究成果可为进一步研究耕地资源与水网建设匹配性提供必要的前提。

秦岭生物学野外综合实践的基础学科创新人才培养

为提高生命科学基础学科创新人才培养质量,开展了生物学野外综合实践。在该过程中利用秦岭丰富的动植物资源,建立研究型野外实践基地;实施“基础认知-综合创新-思政育人”三层次综合实践模式;创新实践教学方法,开展基于虚拟仿真技术的沉浸式实践教学和启发式实践教学;构建将实践过程与实践结果并重、量化指标与定性指标相结合的多元化考核评价体系。实践表明,该实践体系能够有效提升学生的创新实践能力和科研素养,增强学生的生态文明意识和社会责任感,可实现“知识传授、能力培养、价值塑造”三位一体的人才培养目标。

15个辣椒品种在云南的引种表现

以从广东省农业科学院蔬菜研究所引进的15个辣椒品种为试材,筛选、培育适于石屏县乃至云南省栽培且能在窗口期上市的辣椒品种,同时筛选5种辣椒常见病害的最佳防治方法。通过对引进品种的植物学性状、农艺性状等进行调查,同时对5种辣椒常见病害(辣椒褐斑病、辣椒病毒病、辣椒白粉病、辣椒疫病和辣椒根腐病)进行田间防效试验。15个引种品种引种成功,均可在同一时间、同一栽培密度下栽培,并得出规范化栽培模式。结合田间管理难易程度、成本投入、病害发生程度及产量等因素,15个辣椒引种品种推荐种植综合排序为YTH-12>YTH-10>YTH-9>YTH-4>YTH-6>YTH-7>YTH-15>YTH-1>YTH-3>YTH-13>YTH-2>YTH-8>YTH-11>YTH-5>YTH-14。5%亚胺唑WP 600倍液处理、2%香菇多糖水剂1500倍液+壳聚糖800倍液处理、40%氟硅唑乳油7000倍液处理、52.5%噁酮·霜脲氰水分散粒剂1250倍液处理及20%二氯异氰尿酸钠悬浮剂300倍液淋根处理分别为辣椒褐斑病、辣椒病毒病、辣椒白粉病、辣椒疫病和辣椒根腐病的最佳防治方法。试验结果为辣椒引种、规范化种植、病害防治及今后的推广提供了有力依据。

新农科建设背景下作物栽培学课程教学改革研究

在新农科建设背景下,现代农业发展对涉农专业人才提出了更高的要求,而课程教学是人才培养的重要内容。本文以作物栽培学课程为研究对象,从思政元素、教学内容、教学方法和考核体系4个方面对该课程教学现状进行研究,并提出对应的优化改进建议,具体包括挖掘思政元素,更新教学内容,改进教学方法,以及建立多元考核体系。目的在于为新农科背景下涉农高校作物栽培学课程的教学改革研究提供参考,提升新农科人才培养质量。

农户分化对开发利用冬闲田种植油菜意愿的影响机制

基于长江流域冬油菜种植农户为研究样本,开展了农户分化对开发利用冬闲田种植油菜意愿的影响机制及效应分析。研究结果表明:其一,农户分化对开发利用冬闲田种植油菜意愿有负面影响。分化程度越高,越不利于农户开发利用冬闲田种植油菜。同时,个人特征、家庭特征和生产因素显著影响农户开发利用冬闲田种植油菜意愿。其二,机制分析表明,农户分化通过农业生产性服务提升开发利用冬闲田种植油菜意愿。其三,异质性分析表明,农户分化影响开发利用冬闲田种植油菜意愿在长江流域9省(市)间存在差异,其中:云南省影响较高,湖北省影响较低。基于此,建议从区分不同省(市)继续推进开发利用冬闲田种植油菜有序开展、加强农业生产性服务体系建设、合理引导农村剩余劳动力外流等方面推动农户开发利用冬闲田种植油菜。

现代产业学院建设模式研究与探索——以德肯汽车产业学院为例

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