秸秆深还机具特点和作业效率分析   总被引：1，自引：0，他引：1  

杨鹏  王瑞丽  张启辉  窦森 《吉林农业大学学报》2016,(5):645-650

秸秆深埋还田(秸秆深还)作为一种新兴的秸秆还田模式,其机具有别于地表覆盖还田和铧式犁翻压还田。为了科学管理、合理运用秸秆深还机械,提高机组的作业效率,在调查测试秸秆深还作业的基础上,对机具的特点进行了分析,同时对测试机组分别进行了时间利用率和作业效率分析。结果表明:对于各个机具的作业时间利用率和总作业效率影响因素有所不同。作业速度、幅宽、故障维修和地头转向是影响机械作业效率的主要因素。根据调查和分析的结果,针对秸秆深还作业中存在的问题提出了机组的合理运行模式。  相似文献   

基于SPEI_PM指数的渭河流域气象干旱时空演变特征     

杨睿  耿广坡  周洪奎  王涛 《中国农业气象》2021,42(11):962

利用渭河流域25个气象站点1980−2018年月值气象数据集，基于Penman-Monteith蒸散模型计算多个时间尺度的标准化降水蒸散发指数（SPEI），分析渭河流域气象干旱的演变、趋势、影响范围、发生频率和持续时间等时空变化特征，以期为渭河流域防灾减灾管理提供科学依据。结果表明：（1）近39a来渭河流域有明显的干湿周期变化，但整体上呈变干的趋势，干旱时段主要集中在1995−2009年，其中以2000−2009年的干旱站次比最大，平均达到36%，且干旱持续时间最长，约3.6个月，1980−1989年干旱持续时间最短，约1.6个月；（2）渭河流域秋季总体呈湿润变化趋势，而春季和夏季干旱在不断加剧，是区域年际干旱的主要驱动力；（3）渭河流域干旱以危害性较小的轻中旱为主，但2000年前后出现严重及极端干旱的站次相对较多，其中1997年研究区内发生的干旱程度较高，影响范围较广；（4）不同时间尺度各等级干旱发生频率的变化规律表现一致，均呈现出干旱等级越高发生频率越低的态势，且极端干旱在年际尺度内发生次数较为频繁，从空间上看渭河流域东北部是干旱多发区。总之，近39a来渭河流域总体干旱较为严重的时段为2000−2009年，且研究区内干旱呈北重南轻特征，因此北部地区仍需加强防灾管理。  相似文献   

补播羊草和黄花苜蓿对退化草甸植物群落特征的影响     

孙伟  刘玉玲  王德平  赵敏  杨合龙  宋倩  肖红  王开丽  曹婧  戎郁萍 《草地学报》2021,29(8):1809-1817

呼伦贝尔草原区是我国北方重要的生态屏障,近年来不合理的利用方式导致该地区退化草地面积不断扩大,为了探究牧草补播时间及补播比例对呼伦贝尔退化草甸草原植物群落特征的影响,为该地区退化草地修复提供依据。本研究以羊草（Leymus chinensis（Trin.） Tzvel.）和黄花苜蓿（Medicago falcata L.）为试验材料,采用双因素随机区组试验设计,通过测定幼苗数、高度、生物量等群落指标,并综合评价补播效果,结果表明：夏播羊草和黄花苜蓿幼苗数量显著高于春播和秋播（P<0.05）,夏播和秋播植物群落总生物量呈增加趋势,春播则呈减少趋势;补播措施提高了退化草地植物群落Shannon-Weiner指数、Simpson指数和Pielou指数,豆科和禾本科植物重要值呈增加趋势,其他科植物呈下降趋势。呼伦贝尔地区夏季补播羊草和黄花苜蓿以1∶3补播效果较好,而春播由于恢复时间短,需进一步观察。  相似文献   

荷斯坦奶牛休息时间的群体特征及影响因素分析     

马龙刚  安涛  张海亮  竹磊  王磊  宁景扬  王炎  郭刚  黄锡霞  王雅春 《中国畜牧兽医》2021,48(9):3323-3331

为探究北京地区荷斯坦奶牛休息时间的群体规律及影响因素,本研究收集了北京地区某规模化牧场2018年4月至2020年4月共838头荷斯坦奶牛的休息时间及对应的奶牛生产性能测定记录及环境温湿度数据,利用SAS 9.2软件的GLM过程分析了年份、季节、场区、胎次和泌乳月等因素对荷斯坦奶牛休息时间的影响,并分析了休息时间对荷斯坦奶牛生产性能的影响。结果显示,荷斯坦奶牛平均休息时间为397.39 min/d,范围为87.74~707.03 min/d,变异系数为26%;休息时间随季节呈先降低后升高的趋势,夏季最低,冬季最高;随环境温湿度的升高而逐渐降低;产犊和发病对休息时间均有较大影响,产犊和发病当天奶牛休息时间均存在一个峰值,之后逐渐降低至正常水平;测定年份、季节、场区、胎次和泌乳月份对休息时间均有极显著影响（P<0.01）;荷斯坦奶牛产奶量随休息时间的升高而降低。本研究为利用自动化记录设备探究奶牛的行为规律及利用连续测定的休息时间数据提高牛群的精准管理水平提供了理论依据。  相似文献   

Changes in Physical Properties of Soils with Land Use Time in the Brazilian Savanna Environment     

Kleber Trabaquini  Antnio Roberto Formaggio  Lênio Soares Galvo 《Land Degradation \u0026amp; Development》2015,26(4):397-408

Soils from central Brazil have been intensively used over the last decades because of the rapid conversion of savannas ( Cerrado ) into corn/soybean fields. The objective of this work is to study modifications in the physical properties of soils in the Rio Verde watershed, as a function of the land use time for agriculture, determined from classification of Landsat satellite images between 1980 and 2010. Soil samples were collected at surface (0–20 cm) and subsurface (20–40 cm) horizons for the different classes of land use time (<10, 10–20, 20–30, and >30 years). The following physical properties were measured: bulk density (BD), air permeability (K_a), penetration resistance (PR), microporosity (MI), macroporosity (MA), and total porosity (TP). Results showed a strong expansion with time of agriculture that occupied 35·3% (1980), 37·4% (1990), 51·3% (2000), and 60·9% (2010) of the watershed area. When properties were compared with those from the reference areas (preserved soils under native vegetation), significant differences were observed for all the physical attributes of soils for a land use time higher than 20 years. Overall, BD and PR increased with land use time, and the opposite was verified for K_a, MA, and TP. Some physical properties presented values (e.g., 1·54 g cm⁻³ for BD and 0.06 cm³ cm⁻³ for MA) close to the critical ones reported to affect crop development, but they were not still impacting on local soybean yield. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

基于HHT变换的PSO-LSSVM耦合模型估算气象资料短缺地区ET_0     

曾向辉  赵礼曦  张宇 《灌溉排水学报》2015,34(2)

为准确估算气象资料短缺地区参考作物腾发量,构建了一种基于HHT变换的PSO-LSSVM耦合模型,并利用新疆和田气象站2000—2009年单日数据做训练、双日数据做验证。结果表明,该模型估算ET0方法明显优于常规的PSO-LSSVM和GRNN,预测精度较二者分别提高了15.7%~85.6%和15.8%~93.7%;该方法预测ET0的气象要素重要性为RsTmaxTminRHWn,利用该方法对气象要素组合为Tmax/Tmin/RH/Wn、Tmax/RH/Wn、Tmin/Wn、Wn条件下的ET0预测,MSE分别为0.407、0.185、0.149、0.135,说明该方法可以很好地估算资料缺失地区ET0。  相似文献   

基于无线传感器网络的水质监测系统研究     

黄亦磊  郁炜  叶国聪  周凯杰  赵金鑫 《湖南农机》2015,(3):51+53

针对国内外水质环境研究中水质样品异地监测分析存在的巨大缺陷,研究了水质自动监测系统。文章介绍了基于无线通讯传感器网络的简易水质自动监测系统,实现水质数据自动采集和实时上传,可以实现对钱塘江源头水质（衢州水质）进行更好的监测及保护。  相似文献   

Cloning and Bioinformatic Analysis of L1 Gene of BPV from Guizhou Province     

ZHANG Hai  ZHOU Bi-jun  YANG Zhong-cheng  LIAO Mei  WANG Kai-gong  WEN Ming  CHENG Zhen-tao  WANG Wei  FENG Xu-fang 《中国畜牧兽医》2016,43(11):2834-2843

In order to study and analyze L1 gene of bovine papillomavirus（BPV）in Guizhou province,the L1 gene of BPV-GZ01 strain was amplified,cloned and sequenced using bioinformatic softwares and methods,and the secondary structure,tertiary structure,B-cell preponderant epitope,conserved domains analysis, transmembrane domain and signal peptide of L1 gene were predicted.The results showed that the length of L1 gene was 1 494 bp,encoding 497 amino acids.The L1 gene of BPV-GZ01 strain shared an amino acid identities of 98.6%,99.4%,98.4%,94.4% and 91.3%,and a nucleotide identities of 99.1%,99.8%,99.4%,87.6% and 82.8% with those of BPV2,BPV2-SW01,BPV2-AKS01,BPV13 and BPV1 strains,respectively.The results of phylogenetic tree analysis indicated that there was a close relationship between BPV-GZ01 and BPV2-SW01 strains.The prediction of secondary structure of L1 protein indicated that the random coil,extended strand and alphahelix took a higher percentage.The L1 protein was supposed contain 6 potential antigen epitopes.And no transmembrane domains and no signal peptide were found.The tertiary structure of L1 protein was curved spiral structure.These results provided a theoretical basis for immunologic diagnosis and further research of nucleic acid vaccine of BPV.  相似文献   

Behaviour in one fast-growing and one slower-growing broiler (Gallus gallus domesticus) hybrid fed a high- or low-protein diet during a 10-week rearing period     

A. Wallenbeck  S. Wilhelmsson  L. Jönsson  S. Gunnarsson  J. Yngvesson 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2016,66(3):168-176

This study compared behavioural time budgets, presence of comfort behaviours and social behaviours in two different broiler genotypes (the fast-growing Ross 308 (R) and the slower-growing Rowan Ranger (RR)) fed organic diets with high (17.0% crude protein (CP)) or low (14.5% CP) protein content during a 10-week rearing period. 429-day-old chicks (218 R and 211 RR, respectively) were included in the study and behaviour was recorded at 2, 6 and 9 weeks of age. The results showed no effect of diet treatments but that R broilers were less active and sat, ate and drank more frequently than RR broilers, which stood and perched more frequently. However, both hybrids showed decreasing activity and foraging behaviour with increasing age, while time spent eating and sleeping was approximately similar over the entire rearing period.  相似文献   

Accuracy of genomic prediction using imputed whole‐genome sequence data in white layers          下载免费PDF全文

M. Heidaritabar  M.P.L. Calus  H‐J. Megens  A. Vereijken  M.A.M. Groenen  J.W.M. Bastiaansen 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2016,133(3):167-179

There is an increasing interest in using whole‐genome sequence data in genomic selection breeding programmes. Prediction of breeding values is expected to be more accurate when whole‐genome sequence is used, because the causal mutations are assumed to be in the data. We performed genomic prediction for the number of eggs in white layers using imputed whole‐genome resequence data including ~4.6 million SNPs. The prediction accuracies based on sequence data were compared with the accuracies from the 60 K SNP panel. Predictions were based on genomic best linear unbiased prediction (GBLUP) as well as a Bayesian variable selection model (BayesC). Moreover, the prediction accuracy from using different types of variants (synonymous, non‐synonymous and non‐coding SNPs) was evaluated. Genomic prediction using the 60 K SNP panel resulted in a prediction accuracy of 0.74 when GBLUP was applied. With sequence data, there was a small increase (~1%) in prediction accuracy over the 60 K genotypes. With both 60 K SNP panel and sequence data, GBLUP slightly outperformed BayesC in predicting the breeding values. Selection of SNPs more likely to affect the phenotype (i.e. non‐synonymous SNPs) did not improve the accuracy of genomic prediction. The fact that sequence data were based on imputation from a small number of sequenced animals may have limited the potential to improve the prediction accuracy. A small reference population (n = 1004) and possible exclusion of many causal SNPs during quality control can be other possible reasons for limited benefit of sequence data. We expect, however, that the limited improvement is because the 60 K SNP panel was already sufficiently dense to accurately determine the relationships between animals in our data.  相似文献