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1.
为了优选最佳的玉米调亏灌溉方案,以东北春玉米为研究对象,通过测筒进行玉米不同生育阶段的水分调亏灌溉试验研究,利用基于实码加速免疫遗传算法的投影寻踪模型来综合评价不同调亏灌溉方案,结果表明:RAIGA具有较好的实用性和稳定性,依据样本自身的数据特性,利用PPC模型寻求最佳投影方向能够判断各指标对综合评价目标的贡献大小,应用RAIGA算法的PPC模型评价东北春玉米在调亏灌溉情况下生育指标排序结论比较可靠,对制定玉米调亏灌溉制度具有应用价值。 相似文献
2.
以河西绿洲灌区春小麦调亏灌溉2年的平均产量、水分利用效率、供水效率和2年后的土壤养分综合指标4个单项参评因子为参数建立单因子评判矩阵,对干旱环境下春小麦调亏灌溉制度进行了综合评价。结果表明,调亏灌溉处理的综合评价指标以HFF处理最高,其次为MFM处理,而以LLL处理最低,但所有调亏灌溉处理综合评价指标均显著高于高水分处理FFF。因此,无论是从作物生产力、水资源利用效率还是水资源和土壤养分的可持续利用方面来说,HFF处理调亏灌溉模式均因其最高的作物生产力和水分利用效率、较高的供水效率(为最大值的96.3%)及较高的土壤养分综合指标(为最大值的97.7%)而具有最高的综合评价指标,成为试区推荐的春小麦全生育期最优调亏灌溉模式,即春小麦孕穗和抽穗期及灌浆—生理成熟期均高水分处理(65%~70%田持)而拔节期重度水分调亏(45%~50%田持),其灌溉定额为440 mm左右(包括晚秋季储水灌100 mm)。 相似文献
3.
通过盆栽试验,于2013年研究了寒地黑土区玉米调亏灌溉条件下不同水分处理的耗水规律,结果表明：玉米不同生育阶段的总耗水量大小顺序为：拔节期＞抽雄期＞灌浆期＞苗期,其中抽雄期的敏感指数(0.6727)最高。当水分亏缺处理低于60%田间持水量时,将会影响玉米产量,产量和总耗水量之间呈二次抛物线关系,当灌水量为46.93kg/盆时,产量最高。利用玉米在不同亏水处理条件下的各生育阶段耗水量和产量数据,用Jensen模型进行拟合,得到适合该地区玉米的水分生产函数,为玉米在调亏灌溉条件下制定合理灌溉制度提供参考依据。 相似文献
4.
调亏灌溉是一种行之有效的节水灌溉方式,对于缓解农业用水紧张,提高农业用水利用效率具有重大意义。而一种灌溉制度的好坏很难直观评价,因此以大豆盆栽试验为基础,选择净光合速率、产量、水分利用效率和耗水量这4个具有代表性的指标采用灰色关联投影模型对调亏灌溉制度进行综合评价,通过对灰色关联度投影值(Di)排序得到各指标对综合评价贡献率的大小。试验结果表明,苗期和分枝期灌水为田间持水率的70%,开花结荚期灌水为田间持水率的80%,鼓粒期灌水为田间持水率80%对寒区黑土大豆生长最有利。 相似文献
5.
采取测筒试验,对玉米单生育阶段、连续生育阶段和全生育期进行不同程度的水分亏缺处理,研究了调亏灌溉对玉米耗水量、产量和水分利用效率(WUE)的影响。结果表明:就单生育阶段调亏而言,产量和耗水量之间呈开口向下的二次抛物线关系,苗期中度水分亏缺(水分控制上限为60%)为最佳的灌水处理模式,玉米产量和水分利用效率分别提高了1.23%和11.95%;连续生育阶段和全生育期调亏均对作物的产量有不利影响;全生育期充分灌溉时的产量最高,但水分利用效率较低。 相似文献
6.
通过筒测试验,研究了玉米最佳的水分调亏阶段以及各调亏阶段亏水程度的最佳上、下限阈值。结果表明,抽穗开花期水分亏缺对产量影响最大,其次是拔节期,苗期水分亏缺对产量影响最小。苗期、拔节期和抽穗开花期水分亏缺程度分别为50%FC～60%FC、65%FC～75%FC和65%FC～75%FC的灌溉处理是最佳调亏灌溉方案,产量与水分利用效率比正常灌溉处理提高了8%、12.6%。 相似文献
7.
以玉米为研究对象,进行测坑微区试验,研究了地面滴灌条件下调亏灌溉对玉米植株与土壤水分分布、根长、根长密度、根数、产量以及作物水分利用效率的影响。试验于2016年分别设苗期轻度、苗期中度、拔节期轻度、拔节期中度、苗期中度拔节期轻度5个水分亏缺处理,另设全生育期适宜灌水作为对照。结果表明,各调亏处理的玉米冠部最终湿基含水率比对照处理增加-6.03%~4.61%、根部最终湿基含水率比对照处理增加1.30%~8.15%;苗期轻度调亏处理,产量比对照处理降低了7.89%、较对照处理节水8.26%、水分利用效率较对照处理提高0.33%;苗期中度调亏处理,产量比对照处理增加了5.20%、较对照处理节水16.71%、水分利用效率较对照处理提高26.25%;拔节期轻度调亏处理,产量较对照处理增加了1.49%、较对照处理节水14.07%、水分利用效率较对照处理提高18.27%;拔节期中度调亏处理,产量比对照处理降低了23.47%、较对照处理节水28.35%、水分利用效率较对照处理提高6.64%;苗期中度拔节期轻度调亏处理,产量比对照处理降低了28.13%、较对照处理节水38.54%、水分利用效率较对照处理提高16.94%。苗期中度处理与拔节期轻度处理是促进滴灌玉米节水增产的适宜水分亏缺处理,其结果对指导黑龙江西部玉米制定合理的灌溉制度具有实质性意义。 相似文献
8.
在河西走廊张掖市甘州区党寨镇田家闸灌溉试验站开展了马铃薯不同生育期调亏灌溉的试验研究。在保持其他生育期土壤水分为正常灌溉（土壤含水率65%～75%）的情况下,在马铃薯的幼苗期、块茎形成期、块茎膨大期和淀粉积累期分别进行轻度（土壤含水率55%～65%）的调亏处理,以全生育期的正常灌溉作为对照,进行马铃薯生长指标、产量和水分利用的测定。试验结果表明,不同生育期水分调亏均引起马铃薯株高、茎粗和单株总生物量降低,其中块茎膨大期水分亏缺降低程度最为显著。调亏处理中,苗期轻度水分调亏处理马铃薯产量33 027.22 kg/hm2,与对照无显著差异,水分利用效率和灌溉水利用效率最高,分别达到6.91和9.38 kg/m3,而且能够显著提升马铃薯综合品质。而块茎形成期马铃薯产量和水分利用效率最低,仅分别为24 047.32 kg/hm2和5.85 kg/m3,且造成马铃薯品质下降。膜下滴灌调亏可促进水分利用效率和灌溉水利用效率提高,且苗期轻度水分调亏对马铃薯稳定提质和改善当地水分利用现状有积极意义。 相似文献
9.
为提高苜蓿饲草产量和水分利用效率,研究了地下滴灌条件下调亏灌溉对紫花苜蓿株高、叶绿素、茎叶比和产量的影响。试验设置3个灌溉下限处理,田间持水量的70%为对照处理,设置田间持水量的50%和60%2个调亏灌溉处理。研究结果表明:随灌溉调亏程度加重苜蓿前2茬株高和草产量呈递减趋势,对第3茬影响不显著;调亏灌溉对苜蓿叶绿素SPAD值和茎叶比无显著影响;轻度调亏灌溉(田间持水量的60%)下苜蓿干草产量无显著降低。综合分析表明,地下滴灌轻度调亏灌溉(田间持水量的60%)下可实现紫花苜蓿丰产节水生产。 相似文献
10.
【目的】提高寒区春玉米产量和水分利用效率。【方法】设置保水剂(S)、秸秆(G)、地膜(M)保墒处理和无保墒(K)处理及W1、W2、W3、W4调亏处理和W5充分水分处理,进行测筒试验,研究了不同保墒措施和调亏灌溉条件下玉米生长生理及产量和水分利用效率对水分亏缺程度的响应。【结果】试验处理中,M-W4处理的玉米产量和水分利用效率均最大,分别为17 555.02 kg/hm2和3.77 kg/m3。与对照(K-W5处理)相比,S-调亏处理耗水量减少了12.86%~26.17%,产量亦减少了3.55%~19.42%,而水分利用效率提高了2.71%~18.24%;G-调亏处理耗水量减少了13.54%~20.98%,而产量和水分利用效率或有增减,G-W1、G-W2处理产量和水分利用效率分别减少了18.40%和0.22%、14.38%和0.84%,G-W3、G-W4处理产量和水分利用效率分别增加了2.33%和25.74%、2.31%和29.65%;M-调亏处理耗水量减少了17.45%~27.82%,M-W1、M-W2、M-W3产量分别减少了0.36%、9.38%、3.39%,M-W4处理产量增加了3.17%,而调亏处理水分利用效率提高19.36%~38.47%。【结论】保墒调亏优化处理确能提高产量和水分利用效率。 相似文献
11.
Adoption of a new technology, such as irrigation, is a complex phenomenon. Several factors of economic and social nature contribute to the farm-level decisions affecting adoption. In this study, the role played by attitudes of potential adopters towards irrigation and its subsequent adoption on their farm unit was estimated. Two models were estimated, one incorporating only adopters' socio-economic characteristics, and the other, only their attitudes towards irrigation. Results suggest that adopters' attitude, particularly with respect to economic and environmental effects of irrigation, were significant determinants of their decision to proceed with adoption of irrigation, and have a role to play in adoption of irrigation over and above that explained by socio-economic characteristics. In particular, these results suggest that negative perceptions with respect to economics of irrigation and those related to its detrimental impacts on environmental quality, particularly through soil salinity, may be significant deterrents for adoption of irrigation. The study suggests that planning of large scale water development projects, particularly those involving irrigation, must be cognizant of attitudes of potential adopters. Furthermore, during the planning stages, more attention should be paid to the development of proper educational programs, as well as extension packages, to ensure that potential adopters formulate correct attitudes towards the new technology. 相似文献
12.
数学作为一门基础性学科，在学生的各个学习阶段都起到了不可替代的作用，在工科院校中数学教学的重要性更是升到了一个新的高度。通过数学的学习，可以培养学生的应用能力和探究思维，通过对数学知识的学习和灵活运用，学生的综合能力会得到系统性的提高。对于数学的教学工作，应当做到有针对性、有目标，在教学工作中，充分做到对症下药、有的放矢，让学生通过对数学的学习，提高自身的综合能力，更好地为社会建设贡献力量。 相似文献
13.
分析了四川简阳地区砂岩和土壤中的水分运动特性和砂岩中储存的水分对土壤水分补给量的多少。对当地的砂岩和土壤进行了水分特征曲线的测定试验、入渗试验和蒸发试验,并采用研究中常用模型对试验结果进行了拟合,通过对拟合结果的分析,得出了当地土壤和砂岩的水分特性,总结出了该地区表面土层在缺水时水分很容易被下部砂岩层补给,砂岩中的水分是作物利用的重要水资源的结论。这对于充分利用当地水资源,合理确定类似地质条件地区灌溉定额,解决无灌溉条件丘陵区作物缺水问题,实现农业节水灌溉有一定的参考价值。 相似文献
14.
Agricultural ecosystems and their associated business and government systems are diverse and varied. They range from farms, to input supply businesses, to marketing and government policy systems, among others. These systems are dynamic and responsive to fluctuations in climate. Skill in climate prediction offers considerable opportunities to managers via its potential to realise system improvements (i.e. increased food production and profit and/or reduced risks). Realising these opportunities, however, is not straightforward as the forecasting skill is imperfect and approaches to applying the existing skill to management issues have not been developed and tested extensively. While there has been much written about impacts of climate variability, there has been relatively little done in relation to applying knowledge of climate predictions to modify actions ahead of likely impacts. However, a considerable body of effort in various parts of the world is now being focused on this issue of applying climate predictions to improve agricultural systems. In this paper, we outline the basis for climate prediction, with emphasis on the El Niño-Southern Oscillation phenomenon, and catalogue experiences at field, national and global scales in applying climate predictions to agriculture. These diverse experiences are synthesised to derive general lessons about approaches to applying climate prediction in agriculture. The case studies have been selected to represent a diversity of agricultural systems and scales of operation. They also represent the on-going activities of some of the key research and development groups in this field around the world. The case studies include applications at field/farm scale to dryland cropping systems in Australia, Zimbabwe, and Argentina. This spectrum covers resource-rich and resource-poor farming with motivations ranging from profit to food security. At national and global scale we consider possible applications of climate prediction in commodity forecasting (wheat in Australia) and examine implications on global wheat trade and price associated with global consequences of climate prediction. In cataloguing these experiences we note some general lessons. Foremost is the value of an interdisciplinary systems approach in connecting disciplinary knowledge in a manner most suited to decision-makers. This approach often includes scenario analysis based on simulation with credible models as a key aspect of the learning process. Interaction among researchers, analysts and decision-makers is vital in the development of effective applications — all of the players learn. Issues associated with balance between information demand and supply as well as appreciation of awareness limitations of decision-makers, analysts, and scientists are highlighted. It is argued that understanding and communicating decision risks is one of the keys to successful applications of climate prediction. We consider that advances of the future will be made by better connecting agricultural scientists and practitioners with the science of climate prediction. Professions involved in decision making must take a proactive role in the development of climate forecasts if the design and use of climate predictions are to reach their full potential. 相似文献
15.
Pesticides degrade principally through biodegradation processes, whereas antibiotics kill microorganisms or inhibit their growth in soils and thus may affect the fate of pesticides. In this study, the impact of antibiotics on the degradation of atrazine in a sandy soil is investigated in lysimeters over a ninety-day period. Four treatments, monensin, narasin, salinomycin and non-antibiotic, were assigned in triplicate to twelve PVC lysimeters. Both soil and leachate samples were collected and analyzed at predetermined time intervals. In all treatments, atrazine was found to leach down through the soil profiles with the concentration level decreasing with depth, and only trace amounts of atrazine were found in the leachate. However, the statistical analysis of the results showed that all the three antibiotic treatments yielded a significantly slower dissipation of the atrazine level as compared to the non-antibiotic treatment; the mass balance analysis indicated an increased half-life of atrazine in the presence of antibiotics. 相似文献
16.
对饮料中的柠檬黄含量进行了测定和不确定度分析,通过对各影响因素的不确定度评定,试验重复性对饮料中合成着色剂的测量结果不确定度的影响最大,其次是样品处理回收率和标准曲线拟合引入的不确定度对试验结果也有较大的影响。结果表明:饮料中柠檬黄的含量为（103.5?3.5）mgkg,k＝2。 相似文献
17.
针对野生刺五加叶片中黄酮含量的测量方法繁琐、时间较长及需破坏叶片等问题,提出了一种基于高光谱技术对不同时段的刺五加叶片中黄酮含量的估算模型。首先,分析提取地域、年龄、长势相近的20株刺五加叶片光谱特征,通过对叶片进行烘干、磨粉及利用紫外分光光度计等化学方法测得叶片中黄酮的真实含量,并选择4种预处理互相结合、比较的方式,判断出最优预处理模型;通过SPA与PCA算法的结合,选择出较明显的特征波段,通过MatLab2018a将特征波段的反射率分别与40组预测集验证相关性后,再分别选取预测值和20组实测值与BP神经网络、支持向量机进行模型建立。实验结果表明:利用BP神经网络建立的模型的校正集决定系数Rc2分别为0.8649、0.7976、0.8485,支持向量机建立的模型的校正集决定系数Rc2分别为0.7526、0.7742、0.7243,证明SNV和1 Der结合的预处理方式与BP神经网络所构建的模型效果最好。研究为高光谱技术对刺五加叶片中黄酮的反演提供了有力的支持,也会提高工业和药用采摘的效率及刺五加的利用价值。 相似文献
18.
农村精神文明建设还存在一些亟待解决的问题:思想认识不到位,阵地建设滞后,农民参与精神文明建设的积极性不够高等.加强社会主义新农村精神文明建设的措施及对策是:努力发展经济;着力提高农民整体素质,加快阵地建设;加强环境建设;突出“乡风文明“建设;积极构建社会主流评价体系;以“村校“为基地,辐射带动农村精神文明建设. 相似文献
19.
为明确北京东南郊灌区表层土壤和农作物多氯联苯(PCBs)含量和污染水平以及人体健康风险,2015年在该灌区采集了20个土壤样品和28个作物样品,利用气相色谱-质谱联用仪分析了样品中7大类PCBs含量。研究结果表明,灌区表层土壤PCBs质量比为ND(低于检出限)到0.711 776μg/kg,均值为0.43μg/kg,总体上土壤PCBs含量随污灌历史年限增加而增加。本研究区表层土壤PCBs含量处于较低水平,土壤未受到PCBs污染且其生态风险概率均小于10%。灌区采集的冬小麦籽粒、大葱、茄子、梨、白薯、芥蓝PCBs含量均低于实验检出限,未检出;夏玉米籽粒、菜心和油菜PCBs总量分别为0.17~0.47μg/kg、1.63μg/kg和5.91μg/kg。不同污灌历史年限并未显著影响夏玉米籽粒PCBs含量。本研究区农产品PCBs含量处于较低水平,均低于美国卫生及公共服务部建议限量。采集的土壤和农产品样品仅四氯联苯含量高于实验检出限,能检测出;一氯联苯到三氯联苯和五氯联苯到七氯联苯均低于实验检出限,未检出。本研究中成人和儿童PCBs致癌风险分别为8.49×10-7和4.66×10-7,非致癌风险分别为1.41×10-1和3.88×10-1,均低于US EPA规定限值,说明PCBs未对人群产生明显的健康危害。致癌危害和非致癌危害均以口-作物(玉米和蔬菜)为主,其对人体健康所造成的风险占总个人年风险的比例分别为99.79%~99.95%和99.81%~99.94%。 相似文献
20.
沈阳市既是重工业城市,也是农业大市,发展现代农业必须依靠科技进步。在介绍沈阳市农业发展现状及农业科技条件的基础上,探讨科技进步在沈阳农业发展中的重要作用,并根据沈阳市的实际情况展望今后科技进步的发展方向,为加快沈阳市的农业发展提供理论参考。 相似文献
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