黄土坡面不同植被冠层降雨截留模型模拟效果及适用性评价

为探明植被冠层降雨截留水文生态效应,该文通过对黄土区坡面柠条林和杏树林冠层截留量的动态监测与模型模拟,分析了不同类型植被冠层降雨截留规律及其模型模拟的适用性。结果表明:2种不同类型植被冠层降雨截留的特征差异显著。柠条林冠层截留量随大气降雨量的增加而逐渐增加,稳定截留率约为15%。杏树林冠层截留率相对较低,特别是在降雨量小于5mm的量级,冠层"漏斗"效应明显。杏树林冠层截留率与降雨量之间未表现出明显的趋势关系,稳定截留率约为10%。对于柠条林冠层截留规律的模拟,以降雨量和冠层郁闭度为变量的崔启武模型的决定系数为0.74,以降雨量为变量的王彦辉模型的决定系数为0.68;但对于"漏斗"状结构的杏树林冠层,2个模型均未能得到较好的模拟结果。     

利用网格法确定县域农田整治优先度

为了科学测算农田整治难度系数,合理确定不同评价单元整治的优先次序,该文根据研究区域农田整治特点,以江苏省宝应县为例,以规则网格为评价单元,从土地利用结构、农田空间格局、可提高生产能力、土壤环境质量、人口社会因素等5个影响因素,构建农田整治优先度评价指标体系。对研究区按1′×1′的经纬度网格划分的532个网格评价单元进行农田整治优先度测算,并根据计算结果,按整治优先顺序将整个研究区划分为近期、中期和远期网格单元,分别占42%、31%和27%。远期网格单元分布在宝应县中部和南部的平原区,该区域农田的连片性、细碎度和质量等别等优于其他区域。研究结果表明,该文提出的区域农田整治优先度评价方法,有助于确定农田整治先后顺序,明确优先开展整治区域和方向。该方法为区域土地整治规划提供支撑,也为中国各县市开展高标准基本农田建设提供科学参考。     

微酸性电解水结合壳聚糖对水蜜桃护色保鲜的效果

为了防止水蜜桃(Prunus persicaL.Batsch)采后的果肉颜色变化而严重影响其商品价值。该研究以南汇水蜜桃为材料,分别利用自制羧甲基壳聚糖复合保鲜剂,以及微酸性电解水对水蜜桃进行护色保鲜处理,并对冷藏条件下(2℃)水蜜桃果肉颜色及与颜色品质变化相关的指标进行了检测,同时还利用核磁共振成像(MRI)合成T2-MAP图研究了冷藏开始和结束后水蜜桃内部变化的规律。结果表明,在贮藏结束后,对照组果肉颜色的L*值、H*值、C*值分别是羧甲基壳聚糖复合保鲜剂和微酸性电解水处理组的85%～91%、85%～93%和114%～122%(p<0.05)。显然,羧甲基壳聚糖复合保鲜剂和微酸性电解水由于可以抑制水果自身乙烯的产生,减少水果的细胞膜透性和T2-MAP图中T2弛豫常数的变化,降低了多酚氧化酶(PPO)活性的增加速度,减少了酚类物质的累积,进而延缓了果肉的变色。另外,与仅用电解水处理相比,结合羧甲基壳聚糖处理具有较好的护色保鲜效果。通过该研究,可以为提高采后南汇水蜜桃的果肉护色保鲜效果提供参考。     

Competitive enzyme-linked immunoassay for sialoglycoprotein of edible bird's nest in food and cosmetics

The proliferation of fake and inferior edible bird's nest (EBN) products has recently become an increasingly serious concern. To identify and classify EBN products, a competitive enzyme-linked immunoassay (ELISA) was developed to quantitate sialoglycoprotein in EBN used in food and cosmetic applications. The characteristic sialoglycoprotein in EBN was found, extracted, purified, and analyzed. Sialoglycoprotein, considered the main carrier of sialic acid in EBN, consisted of 106 and 128 kDa proteins. A monoclonal antibody that could recognize both proteins was prepared. The heat-treated process did not change the affinity of sialoglycoprotein with the antibody. An optimized ELISA method was established with a cross-reactivity of less than 0.1% and an IC(50) of 3.3 μg/mL. On the basis of different food and cosmetic samples, the limits of detection (LOD) were 10-18 μg/g. Recoveries of fortified samples at levels of 20 and 80 μg/g ranged from 81.5 to 96.5%, respectively. The coefficients of variation were less than 8.0%.     

Comparative proteomic analysis of mushroom cell wall proteins among the different developmental stages of Pleurotus tuber-regium

Cell wall proteins (CWPs) play a vital role in the development of the different morphological stages including mycelium, fruiting body, and sclerotium in mushrooms which are important human food sources. Using fractionation by detergents and reducing agents, mushroom cell wall fractions from the different developmental stages of Pleurotus tuber-regium (PTR) were prepared. Using one-dimensional gel electrophoresis coupled with LC-MS, there were 103, 91, and 48 noncovalently linked CWPs identified in the cell wall fractions of the PTR mycelium, fruiting body, and sclerotium, respectively. Comparing the CWPs in these cell wall fractions, 19 of them were in common, among which 17 belonged to the functional categories of translation, ribosomal structure, and biogenesis. This is the first study to provide important biochemical insights into the different developmental stages of PTR mediated by CWPs, and the identified CWPs helped to explain the morphological changes of PTR mushrooms during cultivation.     

基于生态足迹模型的西部资源型城市可持续发展评价

生态足迹是衡量区域自然资源可持续利用的重要指标。该文运用调整后的生态足迹模型,计算西部9个典型性资源型城市的生态足迹及其生态承载力,并对各城市资源利用程度和生态环境可持续发展状况进行评价与分析。结果表明:西部资源型城市普遍存在生态赤字,表现出较强的不可持续性,而造成这些问题的主要原因就是经济发展对化石能源的高度依赖,使得能源用地的需求量远远大于供给量。最后,文中提出了减少生态足迹需求和增强生态承载力供给的政策建议。     

贵州省喀斯特地区坡面产流产沙特征

土壤侵蚀和石漠化严重影响了贵州喀斯特地区的可持续发展。为了有效防治该地区的土壤侵蚀,利用径流小区观测法,通过布设经济林地(梨树)、水保林地(香樟、柏树)、坡耕地(农作物)和裸地(对照)5种径流小区,对该地区不同地类坡面产流产沙特征进行研究。结果表明:坡度为13°的坡耕地和经济林地减流减沙效果显著,产流量分别减少了47.5%和25.8%,产沙量分别减少了78.5%和58.9%,香樟、柏树减流效果不明显,但产沙量分别减少了44.7%和79.3%;坡度为18°时,经济林地(梨树)、水保林地(香障)、水保林地(柏树)、坡耕地(农作物)4种地类的产流量减少45.8%,4.9%,3.8%,16.6%,产沙量分别减少了91.3%,81.1%,77.4%,61.6%。25°的坡耕地产沙量是对照的8.9倍,土壤侵蚀量大幅度增加。产流产沙量与降雨量(P)、最大30min雨强(I30)和坡度(s)均呈幂函数关系,产沙量与产流量呈线性关系。     

荒漠草原人工柠条林重建的土壤养分效应

采用时空互代方法,构建了由天然草地和7,12,27a柠条林组成的序列,对其下土壤有机质、全氮、碱解氮、有效磷进行了研究。结果表明:(1)0—200cm土壤剖面上的有机质含量由草地、幼龄林、中龄林、老龄林依次增加,有机质含量增加的显著程度随着林龄的增加在更深土层上体现。(2)全氮含量由草地到幼龄林阶段显著增加,由幼龄林到中龄林再到老龄林依次减少。幼龄林、中龄林、老龄林之间全氮含量减少的最大幅度随林龄增加向土壤深层移动。碱解氮与全氮具有一致的规律。(3)整个土壤剖面上有效磷含量依次为:老龄林<幼龄林<中龄林<草地。(4)3个不同林龄的柠条林的有机质、全氮、有效磷在柠条行内和行间的空间差异均不显著。柠条行内与行间的有机质和全氮相关程度很高,有效磷相关性不显著。     

Film fully-mulched ridge-furrow cropping affects soil biochemical properties and maize nutrient uptake in a rainfed semi-arid environment

Abstract

This study evaluated the effects of plastic mulched ridge-furrow cropping on soil biochemical properties and maize (Zea mays L.) nutrient uptake in a semi-arid environment. Three treatments were evaluated from 2008 to 2010: no mulch (narrow ridges with crop seeded next to ridges), half mulch (as per no mulch, except narrow ridges were mulched), and full mulch (alternate narrow and wide ridges, all mulched with maize seeded in furrows). Compared to the no mulch treatment, full mulch increased maize grain yield by 50% in 2008 and 25% in 2010, but reduced yield by 21% in 2009 after low precipitation in early growth. Half mulch had a similar grain yield to no mulch in the three cropping years, suggesting half mulch is not an effective pattern for maize cropping in the area. Mulch treatments increased aboveground nitrogen (N) uptake by 21?34% and phosphorus (P) uptake by 21?42% in 2008, and by 16?32% and 14?29%, respectively, in 2010; but in 2009 mulching did not affect N uptake and decreased P uptake. Soil microbial biomass and activities of urease, β-glucosidase and phosphatase at the 0?15 cm depth were generally higher during vegetative growth but lower during reproductive growth under mulch treatments than no mulch. Mulching treatments increased carbon (C) loss of buried maize residues (marginally by 5?9%), and decreased light soil organic C (15?27%) and carbohydrate C (12?23%) concentrations and mineralizable C and N (8?36%) at harvest in the 0?20 cm depth compared with no mulch, indicating that mulching promotes mineralization and nutrient release in soil during cropping seasons. As a result of these biological changes, mineral N concentration under mulch was markedly increased after sowing in upper soil layers compared with no mulch. Therefore, our results suggest that mulched cropping stimulated soil microbial activity and N availability, and thus contributed to increasing maize grain yield and nutrient uptake compared with no mulch.     

Effects of long-term treatments of different organic fertilizers complemented with chemical N fertilizer on the chemical and biological properties of soils

Continuous cultivation has been known to decrease soil organic matter content. Application of organic matter to cultivated soil is an important practice from the point of view of maintaining an adequate amount of soil organic matter. Soil organic matter content significantly affects soil microbial activity, which is an important index of soil quality. In this study, a field experiment was conducted to examine the long-term effects of different kinds of organic matter in combination with inorganic nitrogen (N) fertilizer on chemical and biological properties of soils. There were seven treatments, namely (1) CK (without fertilization), (2) Chem-N (applying chemical N fertilizer only), (3) Comp (applying compost with the same rate of N as the Chem-N treatment), (4) Comp + l/3 N (applying compost complemented with 33% of the chemical N fertilizer of the Chem-N treatment), (5) Comp + 2/3 N (applying compost complemented with 66% of the chemical N fertilizer of the Chem-N treatment), (6) GM + 1/3 N (applying green manure complemented with 33% of the chemical N fertilizer of the Chem-N treatment) and (7) Peat + 1/3 N (applying peat complemented with 33% of the chemical N fertilizer of the Chem-N treatment). After continuous treatment for 12 years and with cultivation of 24 crops on the same area, soils were sampled for analyses of chemical and biological properties, enzymatic activities and phospholipid fatty acid (PLFA) profiles. The results showed that compared with CK and Chem-N treatments, applications of compost and peat increased soil organic carbon (SOC) content and altered microbial activities and microbial community structure. However, application of green manure for 12 years had no effect on SOC content. Both microbial activities and PLFA profiles were clearly dependent on the characteristics of the applied organic amendments. In summary, a peat application led to the highest increase in SOC content compared to compost and green manure; however, compost-treated soil had a higher microbial population and higher microbial and enzyme activities, while the effects of both green manure and chemical N fertilizer on soil properties were similar.