Estimation of Soil Evaporation During Fallow Seasons to Assess Water Balances for No‐Tillage Crop Rotations     

L. R. Salado‐Navarro  T. R. Sinclair  M. Morandini 《Journal of Agronomy and Crop Science》2013,199(1):57-65

Abstract Estimates of soil evaporation and available soil water of no‐tillage fields under farm conditions are important to assess soil water status at sowing of rainfed grain crops. The objective of this study was to predict stored soil water of no‐tillage fields during the fallow periods following soybean (Glycine max (L.) Merr.) and maize (Zea mays L.) crops by accounting for decreased soil evaporation as a result of the residues left on the soil surface. Three simple phenomenological models were used to simulate stored soil water under field conditions at seven locations in Argentina. Two models calculated decreased soil evaporation based on crop residue mass, and the third assumed a constant fractional decrease in bare soil evaporation. All models gave good estimates of soil water content during the fallow periods following a soybean crop. In cases with large quantities of maize residue, however, the models resulted in more water retention in the soil than observed as a consequence of underprediction of soil evaporation. These results indicate that full benefit of crop residue was not being achieved in these fields, probably due to a failure to finely chop and uniformly distribute the crop material on the soil surface.  相似文献   

Larger bioavailability of soil phosphorus for irrigated rice compared with rainfed rice in Madagascar: results from a soil and plant survey     

L. Rabeharisoa  O. R. Razanakoto  M.‐P. Razafimanantsoa  T. Rakotoson  F. Amery  E. Smolders 《Soil Use and Management》2012,28(4):448-456

Irrigated rice is less prone generally to phosphorus (P) deficiency than rainfed rice because redox reactions release P upon soil flooding. It is not known whether that is also true in highly weathered soils of Madagascar where the combination of high soil Fe and low P input may impede significant release of P. Soils and flag leaf samples were collected in 2010 in 38 irrigated rice and 46 rainfed rice fields belonging to private farmers. A critical flag leaf P content was derived from a P‐dosed pot trial study with three soils, and the results suggested 2.4 g P/kg as the critical value. Average flag leaf P was significantly larger in irrigated than in rainfed rice (2.2 compared with 1.7 g P/kg), and flag leaf P was below the critical value in 76% of irrigated rice fields while this fraction was 100% in rainfed rice. Nitrogen and K deficiencies were less prevalent. Flag leaf P increased with increasing soil pH and soil pH explained partially differences in leaf P between irrigated and rainfed rice. Flag leaf P was unrelated to soil organic matter, but increased with oxalate‐extractable soil P (P_o). Multiple regression analysis revealed greater leaf P at equal soil P_o and equal pH in irrigated compared with rainfed rice. Grain yield estimates (1‐m² squares) increased with flag leaf P but not with leaf N and K. In a regression model, about 42 % of the yield variance was explained with soil P_o and a rice‐growing system. The survey suggests that P is the main limiting nutrient for rice, and that soil P bioavailability is larger for irrigated than for rainfed rice in weathered soils of Madagascar.  相似文献   

不同类型猪小肠组织差异EST的鉴定及其SNPs分析     

朱银剑  陈宏权  潘中婷  陈华  焦明慧  陈公伟  谢亚男  周梅 《安徽农业大学学报》2013,(4):534-539

采用DDRT-PCR技术,对中国地方猪种和杜长大(大白×长白×杜洛克)猪的小肠组织进行差异EST分析。试验提取了地方猪和杜长大猪小肠组织的总mRNA,反转录成cDNA,利用3条锚定引物和6条随机引物组成18个引物对其进行PCR扩增,对特异性差异条带进行测序分析和鉴定其EST;针对EST序列特征,在不同产脂能力猪种中开展SNPs分析。结果表明,18个引物对共得到180多条EST序列,其中地方猪种个体间差异EST为6条,杜长大猪个体间差异EST为12条,地方猪与杜长大猪间差异EST为8条。选取具有代表性的3条种群间差异EST进行序列研究,结果显示,G24-300在种群之间的表达量存在明显的差异,是在杜长大猪群中高表达的EST;G01-360具有丰富的SNPs,并且其基因频率分布在不同类型猪群中存在明显的差异。  相似文献   

农村居民消费支出与金融发展的实证分析——基于甘肃省数据的协整检验     

海新权  程宏波 《渔业经济研究》2011,(5):56-60,77

消费支出是拉动经济增长的重要因素之一，通过分析甘肃省农村消费支出与金融之间的关系，得出农村居民的消费是以食品消费、居住消费、交通通信消费及文教娱乐消费为主，衣着消费、家庭服务消费及医疗保健消费支出比重较低，并且农村金融的发展水平不高限制了农村居民的消费支出。  相似文献   

5TYS280玉米脱粒清选试验台的设计研究   总被引：4，自引：0，他引：4  

崔中凯  邸志峰  周进  张华  卜令昕  高强 《农机化研究》2017,(5):113-117

我国夏播玉米主要集中在黄淮海地区,其生长期短、收获时籽粒含水率高,直接脱粒收获易造成籽粒破碎,脱净率与籽粒破碎率和含杂率之间的矛盾,作业质量较难保证。目前,针对高含水率玉米脱粒清选装置的系统理论与试验研究均较少,因此设计开发了一种玉米脱粒清选试验台。其主要由机架、脱粒分离装置、清选装置、输送装置、电机控制及转速数据采集系统等部件组成。以籽粒破碎率和含杂率为评价指标,通过调整滚筒转速、滚筒倾角、凹板间隙、筛网倾角、曲轴转速及风机转速等关键因素水平,进行单因素多水平试验及多因素多水平正交试验,确定高含水率玉米脱粒清选装置的最佳参数组合,为玉米籽粒收获机脱粒清选部件设计、改进及参数选择提供依据。  相似文献   

基于数字PI算法的精准施肥控制系统设计及仿真     

李宜汀  张富贵  卢剑锋  吴雪梅  樊国奇  高贵 《农机化研究》2017,(10)

为了使施肥速度与机器行进速度同步,提出了一种基于数字PI算法的闭环施肥系统,主要由传感器、PLC、脉宽调制电机驱动器(PWM驱动器)、GPRS模块及直流无刷电机组成。通过检测拖拉机的速度信号及外槽轮转速,PLC根据所输入决策经PWM驱动器对外槽轮下料速度进行闭环控制,从而实现精准施肥。仿真实验结果表明:基于数字PI算法的闭环控制系统提高了施肥精度和响应速度,机具操作简单,在田间工作性能稳定。  相似文献   

浅析宁明县农业机械化发展现状与对策   总被引：1，自引：0，他引：1  

陆华 《安徽农学通报》2010,16(20):122-124

通过对宁明县农业机械近几年来的发展现状,以及存在的问题进行分析,找出原因所在,并提出了解决问题的对策和建议。  相似文献   

云计算环境下图书馆信息服务创新的基本路径     

仵华 《计算机与农业》2010,(12):66-69

云计算正在推动图书馆信息服务变革,图书馆的云时代即将到来。通过创新发展环境、创新信息资源共建共享模式、创新图书馆业务流程、创新信息资源安全策略及创新图书馆信息服务队伍等,推动云计算环境下图书馆信息服务创新。  相似文献   

山羊c-Myc原癌基因克隆、原核表达和GST-Myc融合蛋白纯化   总被引：2，自引：0，他引：2  

赵华  杨照海  刘平  卢晟盛  卢克焕  毕方方  郑喜邦 《农业生物技术学报》2010,18(5)

本研究的目的是通过分子克隆、原核表达和蛋白纯化技术获得山羊GST-Sox2融合蛋白.用RT-PCR方法从山羊(Capra hircus)肠组织克隆了c-Myc基因,通过TA克隆,构建了pMD18-T-Myc质粒.DNA测序证明,山羊c-Myc全长cDNA约1320 bp,该序列包含一个完整的开放阅读框,编码439个氨基酸,经分析该序列与绵羊(Ovis aries)的c-Myc序列同源性为99.2%.将该cDNA片段亚克隆至pGEX-KG载体,构建了重组质粒pGEX-KG-Myc.经酶切鉴定和测序,将重组质粒导入大肠杆菌(Escherichia coli)BL21,由IPTG诱导表达,以谷胱甘肽-Sepharose 4B亲和纯化GST-Myc融合蛋白.SDS-PAGE分析表明,纯化的GST-Myc融合蛋白约75 kD,与预期值相符,且呈现清晰的单一条带.Western blot检测证实,该融合蛋白能够被GST抗体所识别.本实验克隆了山羊c-Myc基因,获得了高纯度的GST-Myc融合蛋白,为其多克隆或单克隆抗体的制备提供了基础资料,为山羊iPS细胞(induced pluripotent stem cells)检测创造了条件.  相似文献   

水果型番木瓜组织培养的研究   总被引：1，自引：0，他引：1  

谢恩倍  欧善生  姚军  石梅娟  梁盛  朱国兵  闵华  赵广存 《农业科学与技术》2010,11(7):29-32

[目的]研究水果型番木瓜的组织培养。[方法]以经预处理的种子为试材,通过MS基本培养基附加不同浓度的6-BA和IBA,对水果型番木瓜组培快繁技术进行了研究。[结果]无菌条件下用75%酒精均匀擦拭水果型番木瓜果皮表面,取出种子,用无菌水冲洗3次是较好的灭菌方法,种子污染率仅为2.52%;水果型番木瓜种子经1000mg/LGA3＋1mg/L6-BA（等体积混合）浸泡18h后接种于MS培养基中培养,种子发芽率、胚芽长度、胚根长度和苗高达到较高值,分别为68.42%、2.25、0.80和1.52cm,幼苗整体生长较好;继代增殖培养基为MS＋0.5mg/L6-BA＋0.1mg/LIBA时增殖系数最高（7.92）,幼苗长势较好;组培苗玻璃化随着光照强度的增强而呈减弱趋势,3000lx处理下玻璃化苗比率最低（3.21%）。[结论]该研究为水果型番木瓜的组培快繁研究提供了参考。  相似文献