Effect of timing of first and last irrigation on the yield and water use efficiency in cotton

With increasing concern about declining water resources, there is increasing thrust in improving water management in farming systems to improve water use efficiency. The present investigation was undertaken to determine the optimum timing for the first and last irrigation of cotton on the basis of meteorological approach for scheduling irrigations. The experiment was conducted in a split plot design with three timings of first irrigation as main-plots and three timing of last irrigation as sub-plots. Delay of first irrigation from 28 days after sowing (DAS) to 42 DAS, irrespective of last irrigation, resulted in an increase of 8, 14 and 17% in seed cotton yield during first, second and third year, respectively. The corresponding increases due to delay in the last irrigation from 130 to 170 DAS were 14, 32 and 8%, respectively. On the basis of 3 years average, application of first and last irrigation at optimum time (after 42 and 170 days after sowing) resulted in an increase of 36% in seed cotton yield without involving any additional cost. Water expense efficiency (WEE) increased by 54%.     

黄土高原中部冬小麦生长对气候变暖和春季晚霜冻变化的响应

利用位于黄土高原中部的甘肃西峰试验田资料和当地平行气象观测资料,分析了春季气温、终霜冻和冬小麦生长发育对气候变暖的响应特征。结果表明：1981年以来,春季平均气温和平均最低气温分别以1.2℃/10a和1.1℃/10a的速率升高,5月的极端最低气温以1.2℃/10a的速率升高;1997年以来4月极端最低气温波动幅度增大,在气候变暖大背景下2001年和2006年出现了最小值,属于反常年份,冻害严重;终霜日期提前的气候趋势比较明显,速率为3.2d/10a,终霜日地面最低温度表现为波动变化,个别年份出现反常的重霜冻灾害;终霜冻过程的持续日数表现出阶段性增加规律,地面最低温度负积温在反常年份2005-2006年有增强变化;1981年以来冬小麦拔节期以4.5d/10a的速率极显著提前（P〈0.01）,1997年以来提前趋势更加明显,1997-2008年平均拔节期比1981-1996年提前9d。气候持续变暖,冬小麦拔节期提前的速率大于终霜日提前的速率,表明冬小麦春季拔节-孕穗期遭受终霜冻危害的气候风险在增大。     

农业信息化的现状及发展对策

本文介绍了农业信息化的概念及发达国家农业信息化的现状、未来发展趋势。结合我国农业信息化的实际情况,从农业信息网络基础、资源建设、精准农业、人才培养、“最后一公里”障碍及其它制约因素等六个方面对我国农业信息化提出了建议。     

末次间冰期-冰期旋回黄土环境敏感粒度组分的提取及意义

采用粒级-标准偏差方法对黄土高原西部、河西走廊及河南西部等6个剖面末次间冰期-冰期旋回的黄土-古土壤粒度进行了系统分析，提取了对环境变化敏感的粒度组分。各剖面的环境敏感粒度组分主要分为粗细两个组分，并显示出一定的区域性差异和不同的沉积学意义。敏感组分主要受物源和沉积后成壤作用的影响：冰沟和罗家湾剖面可能受源区的影响更大而使敏感组分偏粗，暖和湾和扣马剖面可能由于后期风化的影响较大而使敏感组分偏细。对扣马剖面末次冰期旋回堆积的L1和S1的粒级一标准偏差分析表明，L1的敏感组分与全剖面相似；而S1的敏感组分与全剖面存在较大差异，可能与成壤作用有关。     

基于格点资料的1961−2018年中国霜冻灾害时空变化规律

以1961−2018年长时间序列的格点化气象数据替代以往研究中站点数据,通过趋势分析和聚类分析等方法,研究中国区域内适合格点数据的霜冻辨识阈值、霜冻发生时间及霜冻强度的时空变化规律,以在气候变化背景下合理利用气候资源,降低霜冻灾害给农业生产造成的损失。结果表明：（1）日最低气温0℃相比日最低气温2℃作为阈值辨识初/终霜冻和无霜期的空间分布更加合理。（2）1961−2018年中国大部分地区初霜冻日期推后（1～3d·10a−1）,终霜冻日期提前,无霜期增加（1～3d·10a−1）。（3）不同强度的霜冻年累计发生次数在中国北方有微弱增加态势,在南方呈现明显的减少趋势。其中,晚霜冻不同霜冻强度年发生频次高于早霜冻。（4）以霜冻日期和霜冻发生频数为标准进行中国霜冻灾害区划,全国可分为亚热带、暖温带、中温带、寒温带和青藏高原5个分区。其中,以青藏高原不同霜冻日期变化最为剧烈。整体上,中国区域的气候变暖对于霜冻灾害的发生在时间、空间和强度上有明显的减弱效果。     

Analysis of Wood Anatomy Characteristics by Fast Fourier Transfer Image Analysis

ApplicationofFFTCOlllpLlteril11ageprocessi11gisal1ex`tecI1noIog}'wI1ichmerges0ptics.electro11ics-cOI11l,uteral1dpatter11recog-[lition.ltI1asbeenappIiedt`ideI}intI1cresearcl1of`voodsciencebecauSeitl1asthepropertiesofI1igI1nleasIIri11gspeed.I1igl1precisio11…     

近50年宁夏酿酒葡萄晚霜冻日数及变化趋势分析

利用1961—2010年宁夏16个气象站的逐日最低气温资料,根据酿酒葡萄霜冻气候指标统计了终霜日、霜冻日数等。采用统计和气候诊断分析方法,研究了宁夏酿酒葡萄的晚霜冻日数和变化趋势。结果表明:近50 a全区酿酒葡萄晚霜冻平均日数为1.8 d/a;近50 a全区酿酒葡萄霜冻日数呈现减少趋势,引黄灌区霜冻日数的线性倾向率与全区接近;全区轻、中、重霜冻日数与50年平均相比,在20世纪70年代偏多,60和80年代基本持平,90年代及以后偏少;气候突变检验结果表明霜冻日数的突变年为1984年。     

农业信息的资源建设与“最后一公里”问题相关性研究

目前,"三农"领域的"最后一公里"问题受到社会各方面的广泛关注。吉林省是我国农业大省,对"最后一公里"问题也格外关注。根据对吉林省三农信息化服务状况进行抽样调查,同时深入到农民中进行访谈,对吉林省农业"最后一公里"问题进行了详细的分析,进而探讨了农业信息的资源建设状况与"最后一公里"问题解决的相关性。对消除"最后一公里"问题提出了合理的建议,即建立以农民为主体——政府为主导体系的信息资源、加大对信息资源的整合力度、降低农民获取信息资源的费用。     

Geographic variations in particle size distribution of the last interglacial pedocomplex S1 across the Chinese Loess Plateau: Their chronological and pedogenic implications

Due to northwestward attenuation of the summer monsoon and northwestward intensification of loess deposition during the last interglacial, the last interglacial pedocomplex S1 gradually differentiated from the northwest to the southeast. The three paleosols (S1S1, S1S2, S1S3) corresponding to the marine isotope sub-stages 5a, 5c, and 5e and the two intercalated loess units (S1L1, S1L2) corresponding to the marine isotope sub-stages 5b and 5d are completely preserved at northwestern sections. Towards southeast, both the S1L1 and S1L2 were annexed by the subsequent paleosol development (S1S1 and S1S2) and the three paleosols (S1S1, S1S2, and S1S3) were partially welded. At the southeasternmost site, the three soil-forming events (S1S1, S1S2, and S1S3) repeatedly occurred in a single paleosol profile. The three observed orders of particle-size variations are interpreted to have imprinted important chronological and pedogenic signatures. First-order variations, i.e., a remarkable difference between the interglacial pedocomplex S1 and the glacial loess units (L1 and L2), implies that the S1 parent material was considerably finer in the source areas or/and the proximity to the source areas was much farther during interglacial period than during the preceding (L2) and following (L1) glacial periods. Second-order variation, i.e., the parenthetical trends in > 63 μm and < 10 μm fraction curves, might have resulted from the delayed response of the source material supplies to the climate changes. The third-order variations in < 10 μm fraction correspond well to the variations in frequency-dependent magnetic susceptibility, suggesting that pedogenically formed finer particles (i.e., < 10 μm fraction) and the associated ultra-fine paramagnetic minerals as expressed by the frequency-dependent susceptibility occurred only as a minor component of the < 10 μm fraction. The third-order variations seem to be obscured by soil welding and annexation at southeastern sections where the paleosols within the S1 were partially or completely welded. The laboratory data-indicated < 10 μm fraction peaks of the third-order and field-observed clay coatings on ped-faces, together with carbonate leaching and accumulation, in the paleosols within the S1 indicate occurrence of within-S1 material translocation. To sum up, it is unrealistic to reconstruct high-resolution climatic records from the S1 pedocomplex because a number of factors might have undermined the validity of the particle size as a winter monsoon proxy. These factors include weathering in the source areas, in situ post-depositional weathering and fine fraction translocation, and downward penetration of soil formation into underlying previously deposited materials on stable land surfaces.     

Factors Affecting Gestation Length in Heavy Draft Mares

The purpose of this study was to examine the factors affecting gestation length in 209 foalings from 65 heavy draft horses by multiple linear regression analysis. The objective variable was gestation length, and the explanatory variables were stud farm, year foaled, month foaled, age of mare, parity of mare, last gestation length, foal gender, and some meteorological parameters (the mean values of prepartum 10 days: maximum temperature, minimum temperature, average barometric pressure, and hours of sunshine in a day). The mean gestation length for 209 foalings was 334.9 (standard deviation = 8.3) days, with a range of 313-352 days. Stepwise regression analysis showed that last gestation length and foal gender had significant (P < .01) effects on gestation length. Multiple regression analysis showed that last gestation length (standard partial regression coefficient = 0.54) was more influential on the present gestation length than foal gender (standard partial regression coefficient = 0.22). The present gestation length and the last gestation length were moderately positively correlated (r = 0.56, P < .01). Colt foal (n = 106) pregnancies were significantly (P < .01) longer than fillies (n = 103) (mean ± SEM: colt 337.1 ± 0.7 vs. filly 332.7 ± 0.9). According to our results, last gestation length (mare itself) and foal gender were the main factors affecting gestation length in heavy draft horses. Once several gestation lengths are known, predictions with acceptable accuracy can be made about the gestation length of that mare's following foaling.