构建VED-SegNet分割模型提取鱼类表型比例

为提高鱼类表型分割精度和准确度,实现鱼类表型智能监测,该研究基于深度学习算法构建了VED-SegNet模型用于鱼类表型分割和测量。该模型将cross stage partial network和GSConv结合作为编码器（VoV-GSCSP）,保持足够精度的同时降低网络结构复杂性。另一方面,该模型采用EMA(efficient multi-scale attention module with cross-spatial learning)建立强化结构,加强编码器和解码器之间的信息传递,提高模型精度,并实现了8个表型类别的输出。采用自建的鱼类表型分割数据集对VED-SegNet模型进行了测试,测量结果中鱼类各表型比例与实际测量值相接近,表型最大平均绝对和平均相对误差为0.39%、11.28%,能实现无接触式提取水产养殖中鱼类表型比例。对比其他常见语义分割模型,平均交并比mean intersection over union,mIoU和平均像素准确率mean pixel accuracy,m PA最高,分别到达了87.92%、92.83%。VED-SegNet模型在环境复杂、多鱼重叠的...     

油菜籽预处理工艺对粕残油率的影响

通过扫描电镜研究了油菜籽原料、高低粕残油率挤压膨化试样及传统螺旋压榨试样的显微组织结构.结果表明:粕残油率低的试样经挤压膨化后细胞壁破坏充分,物料膨化效果好,有利于溶剂油与油脂的迅速充分接触,从而提高油脂浸出速度、降低粕残油率(＜1%);相反,粕残油率高的试样细胞壁没有被充分破坏,传统压榨工艺试样组织结构坚实细密不利于油脂浸出,粕残油率相对较高(＞9%).     

黄麻土工布覆盖对花岗岩红壤表土坡面侵蚀特性的影响

[目的]探究黄麻土工布覆盖条件下花岗岩红壤表土坡面侵蚀特性,为花岗岩红壤区坡面土壤侵蚀防治提供科学依据。[方法]通过室内模拟降雨试验,在2个坡度(5°和15°坡度)、3种密度(无覆盖,6 cm×6 cm及3 cm×3 cm网格)的黄麻土工布覆盖条件下,研究极端降雨条件下(90 mm/h)花岗岩红壤表土的坡面侵蚀特性,并观测径流系数、土壤侵蚀速率、泥沙颗粒变化规律及富集率等指标。[结果]坡面径流随降雨历时增加而增加,土壤侵蚀速率则相反,表明侵蚀过程是一个分离受限的过程。和对照组相比,黄麻土工布覆盖在不同试验条件下都具有明显的减流减沙作用。另外,由侵蚀泥沙的粒径分选规律可知,坡面土壤中的黏粒和粉粒大小的颗粒倾向于被优先选择性搬运,其结果致使坡面石英粗颗粒富集,在缓坡(5°)与高密度黄麻土工布覆盖条件下(3 cm×3 cm网格)尤为突出。坡面石英粗颗粒随降雨历时增加不断富集进一步增加了原位坡面的侵蚀抗性,产生了土壤侵蚀速率随降雨历时不断降低的现象。[结论]高密度黄麻土工布的覆盖能够有效地减流减沙,增加原位坡面抗蚀性,是一种有效的水土保持措施,在今后的土壤侵蚀防治和劣地恢复工作中应该被重视。     

Mineralization of Organic Nitrogen in Soils with Contrasting Fertility Was Regulated Differently by Addition of Biochar and Animal Manures

ABSTRACT

How to restore the soil fertility and productivity in a damaged and then reclaimed area with extremely low fertility is a big concern worldwide. To explore the method of soil restoration in the coal mining subsidence area, the effects of biochar application coupled with organic fertilizer (animal manures) on the process of organic nitrogen (N) mineralization were studied in a 149 days leaching experiment. Biochar were applied (wt/wt) at the rates of 0%, 1%, and 3%. Two organic fertilizers with different C/N ratio (chicken and sheep manures) were applied at the rate of 200 mg N·kg^?1 soil. A vegetable soil with high-fertility was used as the comparison. The results showed that when treated with chicken manure, the reclaimed soil had 11.13% lower mineralization potential and 20.00% lower inorganic nitrogen production from mineralization than the vegetable soil. Compared with the non-biochar treatment, biochar at both application rates decreased N leaching in chicken manure-treated reclaimed soil, i.e., by 21.49% (1% biochar) and 28.31% (3% biochar), respectively, whereas only high rate of biochar application decreased N leaching in chicken manure-treated vegetable soil by 8.10%. However, N leaching in sheep manure-treated reclaimed soil was unaffected by the biochar application. Thus, the effect of the biochar on the organic nitrogen mineralization was affected by both soil and organic fertilizer type.     

Stable carbon isotope ratios of water-extractable organic carbon affected by application of rice straw and rice straw compost during a long-term rice experiment in Yamagata,Japan

ABSTRACT

Hot-water- and water-extractable organic matter were obtained from soil samples collected from a rice paddy 31 years after the start of a long-term rice experiment in Yamagata, Japan. Specifically, hot-water-extractable organic carbon and nitrogen (HWEOC and HWEON) were obtained by extraction at 80°C for 16 h, and water-extractable organic carbon and nitrogen (WEOC and WEON) were obtained by extraction at room temperature. The soil samples were collected from surface (0–15 cm) and subsurface (15–25 cm) layers of five plots that had been treated with inorganic fertilizers alone or with inorganic fertilizers plus organic matter, as follows: PK, NPK, NPK plus rice straw (RS), NPK plus rice straw compost (CM1), and NPK plus a high dose of rice straw compost (CM3). The soil/water ratio was 1:10 for both extraction temperatures. We found that the organic carbon and total nitrogen contents of the bulk soils were highly correlated with the extractable organic carbon and nitrogen contents regardless of extraction temperature, and the extractable organic carbon and nitrogen contents were higher in the plots that were treated with inorganic fertilizers plus organic matter than in the PK and NPK plots. The HWEOC and WEOC δ¹³C values ranged from ?28.2% to ?26.4% and were similar to the values for the applied rice straw and rice straw compost. There were no correlations between the HWEOC or WEOC δ¹³C values and the amounts of HWEOC or WEOC. The δ¹³C values of the bulk soils ranged from ?25.7% to ?23.2% and were lower for the RS and CM plots than for the PK and NPK plots. These results indicate that HWEOC and WEOC originated mainly from rice plants and the applied organic matter rather than from the indigenous soil organic matter. The significant positive correlations between the amounts of HWEOC and HWEON and the amount of available nitrogen (P < 0.001) imply that extractable organic matter can be used as an index for soil fertility in this long-term experiment. We concluded that the applied organic matter decomposed more rapidly than the indigenous soil organic matter and affected WEOC δ¹³C values and amounts.     

电动多旋翼植保无人机升力特性综合测评方法

升力特性是电动多旋翼植保无人机性能测试的重要参数之一。为了实现对电动多旋翼植保无人机升力特性的性能检测,针对不同型号、不同规格的电动多旋翼植保无人机在评价过程中存在无统一的评价指标问题,该文提出了一种半系留式电动多旋翼植保无人机升力特性的测试与评价方法,包括性能检测平台、升力特性测试方法及指标、升力特性的评价方法。为了验证方法的可行性,对3种不同机型(分别为四旋翼机型Ⅰ、六旋翼机型Ⅱ、八旋翼机型Ⅲ)进行了升力特性指标的性能测试试验。试验结果表明:3种机型在功率载荷、重量效率、热效比等方面有较大差异,功率载荷最好的机型Ⅲ比最差的机型Ⅰ大7.6 m N/W,重量效率最好的机型Ⅰ比最差的机型Ⅱ大0.33,热效比最好的机型Ⅲ比最差的机型Ⅱ大10.5 N/℃,反映出3种机型在设计过程中整个动力系统效率、机型整体结构和材料选择上的差异,从而在整机作业性能上表现出差异。在上述指标测试的基础上,结合无人机动力系统数学模型,提出了运用功率载荷、重量效率和热效比进行电动多旋翼植保无人机升力特性综合评价的评分方法,对上述3种机型进行综合评分的结果为:机型Ⅲ机型Ⅰ机型Ⅱ,该结果表明所提出的评价方法能有效对不同类型电动多旋翼植保无人机的升力特性进行综合评判。该文所给出的测试与评价方法,不仅能用于电动多旋翼植保无人机性能的评测,还能为机型性能的进一步改进提供参考。     

黑龙港流域参考作物蒸散量的时序变化和分形特征

利用位于黑龙港流域的武强、深泽、饶阳、晋州、献县5站1957-2009年日最高气温、日平均气温、日最低气温、日平均相对湿度、日平均风速、日照时数资料,采用Penman-Monteith算法,计算各站不同时间尺度ET0,采用线性趋势分析法分析其趋势倾向,并应用滑动R/S分析方法研究该流域不同时间尺度ET0时间序列的分形特征。线性趋势分析显示,各站历史上自1957年以来的ET0年总值的气候倾向率在-33.81-10.79mm.10a^-1,即均呈下降趋势,但变化倾向率不同;各月ET0倾向率在-11.27-2.02mm.10a^-1,大多数为负值,其中5、6月份各站的下降趋势最大;春、夏、秋、冬季ET0倾向率为-15.87-1.30mm.10a^-1,且夏季各站之间的差异较大,尤以饶阳站与其他4站间的差异最大。气候要素倾向率的对比分析表明,5站参考作物蒸散量总体下降趋势的基本特征主要是由于风速下降、日照时数减少、日最高最低气温上升造成的;5、6月份下降趋势明显则主要是由于风速下降、日照时数减少、日平均气温上升减缓、相对湿度上升明显造成的;饶阳站与其他4站差异较大的主要原因在于2、3、11、12月风速下降和日照时数减少以及日最高最低气温上升趋势减缓、相对湿度和气压下降明显,以致这些月份的ET0倾向率大于0,形成秋季和冬季ET0倾向率大于0,年尺度ET0年际变化下降趋势不明显。R/S分析结果显示,5站全年和各季ET0时间序列的Hurst指数均大于0.5,相关系数均在0.98以上,分维数均小于1.5,说明各站全年和各季节ET0时间序列变化趋势在未来一段时间内具有持续性,即ET0在未来将呈较明显的下降趋势,这种趋势在除饶阳外的其他站月均有不同程度的表现。     

FACE对三系杂交籼稻汕优63根系活性影响的研究

2005、2006年利用我国惟一的农田开放式空气CO2浓度增高（FACE）研究平台,设计施N量为125kg·hm^-2（LN）、250kg·hm^-2（NN）处理,研究大气CO2浓度比对照高200umol·mol^-1的FACE处理对三系杂交籼稻汕优63根系活性的影响。结果表明：（1）FACE处理使汕优63不同生育时期单位干质量根系的总吸收面积、活跃吸收面积、α-萘胺氧化量等根系活性指标均极显著小于对照。由于FACE处理促进汕优63根系发生量的大幅度增加,因此分蘖期、拔节期其单穴根系活性与对照多无明显差异,到抽穗期FACE处理单穴根系活性显著大于对照;（2）拔节期、抽穗期汕优63每穴的不定根数、不定根总长度、根系体积、根干质量与单位干质量根系活性的关系密切,根量越大单位于质量根系活性越低;（3）不同生育时期汕优63植株含氮率与单位干质量的根系活性多呈正相关,植株碳氮比与单位干质量的根系活性多呈负相关;（4）FACE处理汕优63根系生长量大、植株含氮率低、碳氮比高等可能是造成其单位干质量根系活性低于对照的重要原因。     

Root tensile strength of three shrub species: Rosa canina, Cotoneaster dammeri and Juniperus horizontalis: Soil reinforcement estimation by laboratory tests

The presence of vegetation increases soil burden stability along slopes and therefore reduces soil erosion. The contribution of the vegetation is due to mechanical (reinforcing soil shear resistance) and hydrologic controls on stream banks and superficial landslides. This study focused on the biotechnical characteristics of the root system of three shrub species: Rosa canina (L.), Cotoneaster dammeri (C.K. Schneid) and Juniperus horizontalis (Moench). The aim of this paper is to increase our understanding on root biomechanical properties of shrubs species and their contribution to soil reinforcement. The considered shrubs grew up in wood containers, exposed to natural conditions in a village near Asti (Northern Italy) for 2 years. Laboratory tests were conducted to measure the ultimate root tensile strength and to estimate the root density distribution with depth (root area ratio), in order to quantify the soil mechanical reinforcement. Root tensile strength measurements were carried out on single root specimens and root area ratio was estimated analyzing the whole root system. The improvement of soil mechanical properties obtained by the presence of shrubs was estimated using two different models. The first model, based on a simple force equilibrium model, considers that the tensile strength of all roots crossing the shear plane is fully mobilized. This classical approach is implemented by the Fiber Bundle Model concept, to account for non-simultaneous root breaking. C. dammeri roots presented the highest tensile strength and soil reinforcement values, while R. canina and J. horizontalis were characterized by lower values. Similarly at each considered depth C. dammeri showed the highest soil reinforcement effect.     

1981-2009年江苏省气候变化趋势及其对水稻产量的影响

利用江苏省1981-2009年7个农业气象站点的气象和水稻物候、产量资料,从平均气温和降水量对水稻产量影响的基本方程入手,定义了平均气温和降水量变化趋势对水稻产量趋势的贡献率,揭示江苏省近30a气候变化趋势对水稻产量的影响.结果表明,近30a来,江苏省水稻全生育期平均气温和最低气温呈上升趋势,最高气温的变化在苏南和苏北地区差异较大,尤其在开花-成熟阶段,苏南地区呈上升趋势,而苏北地区则呈相反变化趋势.气温(包括平均气温、最低气温和最高气温)与水稻产量呈正相关,1981-2009年平均气温升高对江苏省水稻产量影响的平均值约为1.2％,对产量趋势的贡献率约为30.0％.降水量的变化趋势不明显,降水量与水稻产量的相关性亦不显著,说明在研究区内降水量的变化对水稻产量的影响较小.总体上,江苏省近30a气候变化有利于水稻生产.