基于PLUS的耕地驱动因素分析与未来预测——以图们江流域为例

[目的] 探究图们江流域耕地时空演化特征及其驱动因素并预测与《吉林省国土空间规划(2021—2035年)》(以下简称《规划》)相关的耕地变化状况,为图们江流域耕地资源合理规划与利用提供依据和决策支持。[方法] 通过土地利用转移矩阵与重心转移分析其时空演化特征,耦合马尔可夫模型和PLUS模型,预测不同情景下耕地数量和空间变化。[结果] ①1990年以来研究区耕地面积呈持续减少趋势但整体处于可控状态,到2020年总量共减少了440.42 km²,减少的耕地主要转化为林地和建设用地。②耕地的空间分布具有明显的差异性,主要集中在中下游区域,并且耕地重心以每年43.1 m的速度逐渐向西南偏移。③社会经济因素中的GDP值、道路交通和人口等与自然因素中的坡度和降水是影响过去耕地变化的主要驱动因素。④预测结果表明,两种情景下耕地总量均呈现逐年减少的趋势,目标导向情景下2035年耕地总量比2020年将减少128.57 km²,减少的耕地主要集中在规划的开发区与保护区。[结论] 过去30 a随着社会经济的快速发展,研究区内耕地承载的压力越来越大,而且当前的状况不利于《规划》目标的实现。为了实现耕地数量、质量与生态三位一体保护与耕地资源的可持续发展,可以适当开发研究区上游与西部地区的耕地资源,推动原有农业实现规模化、科技化。此外,目标导向情景更有利于图们江流域耕地资源的可持续发展,应当继续实施《规划》目标。     

不同微细水核直径的掺水乳化柴油制备方法和影响因素

随着燃油车和重型农用机械数量的增加,石油资源消耗急剧上升,掺水乳化柴油作为一种新型可替代燃料受到了广泛关注.水核直径对掺水乳化柴油的微爆特性影响较大,但目前缺乏组分不变下的目标水核直径掺水乳化柴油的制备方法和适宜的水核直径表征方法.该研究基于CV模型,开发了适合水核微观结构的图像识别程序;创新性地提出采用对数正态分布函...     

Studies on Composition and Diversity of Species Based on Different Habitats along the Delingha-Hala Lake北大核心CSCD

To explore the diversity and spatial distribution pattern of community species in the Qaidam Basin, we calculated the species composition and diversity index of plant communities in five different habitats, and analyzed the relationship between species diversity and altitude in different habitats. The results showed that 79 species of plants were recorded in the area along Delingha-Hala Lake, and the main dominant families included Compositae, Gramineae, Leguminosae, and Cruciferae. The species diversity of different habitat types had similarities, but also differences. According to the results of the community similarity in species composition, the species composition similarity between the alpine cushion vegetation and the alpine Potentilla fruticosa shrub meadow was the highest, while that of the alpine Kobresia myosuroides and the weedy meadow was the lowest. The species richness and diversity of the community showed a trend of first decreasing and then increasing with the altitude increasing, but the uniformity remained stable. In addition, the community species diversity in the middle-altitude area was the highest, and the community species diversity in the low-altitude area was slightly higher than that in the high-altitude area. The main reasons for the difference in species composition and diversity in different habitats were the hydrothermal conditions and species competitiveness. © 2019 Authors. All rights reserved.     

基于大数据的西藏荒漠化治理植物优选与验证

植物种植作为荒漠化治理的重要方式之一,关系到荒漠化区域的高效可持续发展。为提高植物选择的科学性与合理性,在项目前期已建成荒漠生态治理大数据平台并实现中国主要荒漠化区域生态信息全方位采集的基础上,进行基于大数据的植物优选研究与试验验证。研究运用相关性分析、聚类分析等大数据分析方法对荒漠植物种质资源库中植物进行类别划分,初步筛选适应该地区气象条件的植物;进一步运用层次分析法、专家打分法等决策方法从土壤、地形、生态效益、经济效益和其他等5个方面进行综合分析与评价,以优化初选结果。将该方法应用于西藏地区荒漠化治理植物的选择,经大数据挖掘分析,初步筛选出了核桃、黑果枸杞、盐生草和花花柴等适宜植物;进一步优化分析得出,核桃具有经济效益高、耐储运、前期投入相对较少等优势,是该区域荒漠化治理中生态适应性与综合效益俱佳的植物。优选结果在西藏山南市扎囊县桑耶镇的荒漠化治理中得到了验证,目前核桃长势良好,预期生态与经济效益显著。基于大数据进行荒漠治理植物的优选可为荒漠化区域科学规划及高效治理提供坚实的理论与数据支撑。     

间歇降雨对铁尾砂重构坡面侵蚀水动力学特性的影响

黄土高原夏季降雨集中且多暴雨,铁尾矿砂自身结构松散,堆存坡度大,雨季通常遭受多次暴雨侵蚀,严重限制植被恢复。为有效减少铁尾矿的水土流失,促进生态恢复,在干排铁尾矿砂中添加不同比例土壤和菌糠,形成6种重构坡面：松散铁尾矿砂（LT）,结壳铁尾矿砂（CT）,铁尾矿砂与菌糠混合物（TM）,铁尾矿砂、菌糠和土壤混合物（TSM）,铁尾矿砂和土壤混合物（TS）,纯土（S）。采用室内人工模拟降雨技术,研究重构坡面在间歇性降雨下的侵蚀特征和水动力因素。结果表明：1）随降雨场次增加,6种坡面的产流率均持续增大,而产沙率表现出明显的分异：LT、CT和TS产沙率持续增大,表现为高产沙型,TS、TSM和S产沙率整体上是先增加后减少,表现为低产沙型;2）随降雨场次增加,6种坡面侵蚀形态也出现分异,可分为2类：LT和CT和TS坡面侵蚀形态严重,细沟发展快,演化为宽深比较小的细沟;TM和TSM和S坡面侵蚀形态轻微,细沟发展缓慢,S坡面演化为宽深比较大的细沟,TM和TSM坡面细沟很少,多为均匀分布的菌糠小坑穴。据此表征坡面侵蚀微地形变化的沟壑面积和地形起伏度,随降雨场次增加持续增大;沟壑密度则随降雨场次先急剧增加,随后由于沟壑形态差异,部分坡面减少;3）6种坡面的坡面流流型均为层流,流态大多为急流;随降雨场次增加,流速、水流功率整体表现为增大的趋势,径流剪切力无明显趋势,阻力系数、曼宁粗糙系数表现出减小的趋势;除径流剪切力,不同降雨场次间水动力学特征差异显著（P<0.05）。6种坡面侵蚀产流产沙可用对数、线性或幂函数较好地模拟。纯尾矿砂坡面侵蚀最为严重,坡面覆土具有明显的减流效果,但添加菌糠的减沙效果最好,因此对于土源缺乏的铁尾矿砂复垦区,同时添加菌糠和土壤可以有效减少侵蚀,易于植被修复。     

机采棉种植模式对植保机械化学脱叶作业效果的影响

种植模式优化是实现新疆棉花高产优质的重要途经,但其对机采棉化学脱叶环节农机农艺融合的影响还不明确。该研究开展了\     

Comparison of regression and fat-free diet methods for estimating ileal and total tract endogenous losses and digestibility of fat and fatty acids in growing pigs

An experiment was conducted to 1) compare the regression and fat-free diet methods for estimating total or basal endogenous losses of fat (ELF) and fatty acids (ELFA) and true digestibility (TD) or standardized digestibility (SD) of fat and fatty acids in growing pigs and 2) compare these estimated values at the end of the ileum and over the entire intestinal tract. Ten barrows (initial body weight: 45.1 ± 2.8 kg) were surgically fitted with a T-cannula in the distal ileum and allotted to one of five experimental diets in a three-period Youden Square design. A fat-free diet was formulated using cornstarch, soy protein isolate, and sucrose. Four oil-added diets were formulated by adding four levels of soybean oil (2%, 4%, 6%, and 8%) to the fat-free basal diet at the expense of cornstarch. All diets contained 26% sugar beet pulp and 0.40% chromic oxide. Results indicated that there were no differences between true ileal digestibility (TID) of fat and true total tract digestibility (TTTD) of fat when pigs were fed soybean oil. The TID of C18:0 and total saturated fatty acids (TSFA) was greater than TTTD (P < 0.05). The total ELF at the end of the ileum were not different from that over the entire intestinal tract. In addition, total endogenous losses of C18:0 and TSFA were greater for the entire intestinal tract than at the end of the ileum, whereas total endogenous losses of C18:2 and total unsaturated fatty acids were just the opposite. Similar results were observed for basal ELF and ELFA. As the inclusion level of soybean oil increased, apparent digestibility (AD) of fat and fatty acids increased linearly (P < 0.05) except for apparent ileal digestibility of C18:0. However, SD of fat and fatty acids was not influenced by the inclusion level of soybean oil. Estimation of ELF and ELFA observed by the regression and fat-free diet methods did not differ when measured at the end of the ileal or total tract. There were no differences between the estimations of TD and SD of fat and fatty acids for soybean oil. Collectively, the estimation of TD or SD of fat can be measured over the entire intestinal tract, whereas the ileal analysis method should be used to determine the ELF, ELFA, and TD or SD of fatty acids. Correcting AD for basal ELF and ELFA can accurately estimate SD values of fat and fatty acids.     

Identification of key bacterial populations affecting early embryonic development in cattle uterus

Superovulation is an important animal breeding biotechnology, while the quality of embryos obtained from superovulation is unstable in cattle. The relationship between the microorganisms in the cattle uterus and embryo qualities was determined to identify the key bacterial populations affecting early embryonic development. A total of 10 Xia Nan cows underwent superovulation, we collected cervical mucus and flush samples to investigated by 16S rDNA sequencing. Results showed that there were abundant microorganisms in cervical mucus, but no obvious relationship with the quality of embryos. The clustering results of flush samples were consistent with the grouping of embryo quality. Proteobacteria accounted for more than 95% of the total bacterial community in group A with the best embryo quality (qualified embryo ratio above 0.8), and as embryo quality decreased, the Proteobacteria proportion also decreased. In contrast to the proportion of Proteobacteria, the proportions of Firmicutes and Bacteroidetes significantly increased as embryo quality decreased. For group C with the worst embryo quality, the proportions of Firmicutes and Bacteroidetes increased to 4.7 times and 12.3 times of group A, respectively. These results showed that the quantities and proportions of Firmicutes and Bacteroidetes may be related to early embryonic development in cattle.     

雾化网格在果树植保喷雾中的应用与试验

针对目前一些植保机械在喷洒农药的过程中难以兼顾低飘移和高沉积的问题,该研究将雾化网格应用在果树植保喷雾作业中,使喷头喷出的大粒径雾滴在接近靶标处撞击网格二次雾化为小雾滴。为了研究雾滴撞击网格后的粒径和速度分布以及沉积特性,以网格孔径、喷头与网格的距离为变量,以二次雾化后雾滴的速度和粒径分布、喷雾角、雾滴覆盖率、沉积量和飘移量为指标进行试验研究。试验结果表明：放置孔径为461、350和227 μm网格时测量点的雾滴平均速度比没有网格时的2.35 m/s分别降低23.40%、13.90%、29.00%,最大平均粒径比没有网格情况下的192.5 μm分别降低19.5%、14%、10%;随着网格孔径的减小,二次雾化后雾滴的喷雾角有逐渐降低的趋势;放置350和227 μm 孔径网格时果树冠层各层内沉积均匀性相近,沉积量变异系数最高分别为88.08%和74.22%,远低于461 μm 孔径网格的162.98%;放置350 μm 孔径网格时雾滴穿透性较好,各层之间沉积量变异系数最高为10.08%,低于461和227 μm 孔径网格的44.09%和18.25%。在该研究试验条件下,350μm 孔径网格的沉积效果优于461和227 μm 孔径网格,喷头与网格的距离对雾滴覆盖率和沉积量没有显著影响,使用雾化网格的雾滴飘移较少,非靶标区平均雾滴飘移量为靶标区沉积量的6.64%。研究结果可为果园无人机喷雾作业优化提供参考。     

关于我国国家公园适宜面积的探讨

为了科学划定国家公园适宜面积,为国家公园建设与管理提供参考,笔者系统梳理了美国、加拿大、日本等国的国家公园面积概况及我国各类自然保护地面积情况,并基于国土面积、社会经济、生态系统3方面,建议我国国家公园适宜面积的确认指标应从生态系统完整性、生态系统典型性和社会经济可持续性3方面来综合考量;针对不同国家公园,应因地制宜地制定既能保护好生态系统完整性,又能实现社区可持续发展的国家公园适宜面积。