跨区域量化比较3种土壤类型坡面的拦蓄径流能力

[目的] 基于定量化数值建立一个跨区域评价不同土壤类型和管理措施坡面拦蓄径流能力的指标体系,为水土流失防治工作提供科学指导。 [方法] 在新疆维吾尔自治区伊宁市北山坡的灰钙土、棕红土坡面和贵州赤水市大石河小流域的紫色土坡面各布设了4种管理措施的径流小区,基于2019—2021年4—9月的自然降雨量和径流量观测数据,用径流系数、径流曲线数(CN值)和降雨产流阈值数据量化比较了12个径流小区的减流能力。 [结果] 不同土壤拦蓄径流能力排序为：灰钙土＜棕红土＜紫色土,其CN值分别为90.05,89.53和77.36;其降雨产流阈值分别为3.44,3.50和14.96 mm。不同评价指标结果均显示,灰钙土和棕红土管理措施坡面的拦蓄径流能力顺序为：枯草覆盖＞水平沟＞增渗孔＞对照;紫色土管理措施坡面减流能力的顺序为：园地＞草地＞耕地＞对照。对于对照小区,当径流系数增加1%时,灰钙土、棕红土和紫色土的径流深分别增加了1.73,2.61和6.79 mm;当CN值增加1时,3种土壤坡面的径流深则将分别减少1.00,1.00和0.71 mm。 [结论] 跨区域评价不同土壤类型坡面的减流能力时,推荐用CN值和降雨产流阈值指标,不宜使用径流系数。     

温度对西花蓟马生长发育的影响

西花蓟马为进境地植物检疫潜在性害虫。为了防治该入侵害虫的危害,在19℃、22℃、25℃、28℃和31℃5个恒温条件下,研究了西花蓟马Frankliniella occidentalis (Pergande)取食四季豆时各虫态的发育历期和存活率,并计算了其发育起点温度和有效积温。结果表明:西花蓟马各虫态的发育历期随温度的升高而缩短;发育历期与温度之间的关系为直线关系;19~28℃各虫态的存活率均为100%,在31℃时存活率只有60%;卵、一龄幼虫、二龄幼虫、预蛹、蛹的发育起点温度分别为14.2℃、14.8℃、5.3℃、12.7℃、6.7℃,其有效积温分别为28.5、23.5、77.7、14.6、40.7日度;未成熟期的的发育起点温度为10.7℃,有效积温为177.4日度。     

利用动态阈值决策树分类的华北平原冬小麦动态监测

华北平原是中国最大的粮食生产基地,准确监测其冬小麦种植面积及其变化对粮食产量预测和国家粮食安全具有重要意义。然而,不同土地利用产品所估算的小麦面积、空间分布及其动态均存在较大分歧,不能有效反映出冬小麦的长期变化特征。该研究结合作物物候特征和已有小麦专题数据产品,首先构建动态阈值决策分类算法,以降低传统方法在阈值设定和样本筛选方面的不确定性;进而分析了2003—2022年华北平原区冬小麦播种面积的长期变化规律。结果表明：1）该研究提出的动态阈值决策分类算法能准确地提取冬小麦面积,平均总体精度为93.44%,且与统计数据具有较高的一致性;2）2003—2022年华北平原冬小麦种植面积整体呈上升趋势,不同地区变化类型差异较大;3）研究时段内,持续种植冬小麦的耕地面积仅占各年份种植范围总面积的5%,种植次数低于10 a的面积占比达55%;4）河北中南部、山东省西部和河南省中北部冬小麦种植面积相对稳定,京津冀地区以及山区冬小麦播种面积变化相对频繁。该研究可为大尺度冬小麦动态监测提供了新的方法视角,并对科学制定耕地调控策略具有重要意义。     

Phenotypic variations of wheat cultivars from the North China Plain in response to cadmium stress and associated single nucleotide polymorphisms identified by a genome-wide association study

Understanding the genetic mechanisms for cadmium(Cd) uptake and translocation in common wheat(Triticum aestivum) is of significance in food Cd contamination control. In this study, a diverse panel of 132 wheat cultivars was collected from the North China Plain. The cultivars were evaluated in terms of their phenotypic variations in response to Cd stress and subjected to a genome-wide association study(GWAS) to identify single nucleotide polymorphisms(SNPs) associated with the phenotypic variatio...     

中国水蚀区5种典型土壤的侵蚀性降雨阈值比较

[目的]准确拟定侵蚀性降雨阈值,区分侵蚀性与非侵蚀性降雨事件,为有效减少土壤侵蚀预报的工作量以及区域土壤侵蚀防治提供科学参考。[方法]在北京市房山区布设中国5个水蚀二级区典型土壤休闲小区,收集各小区2006—2019年的产流产沙监测资料,利用降雨侵蚀力偏差法分析各小区的侵蚀性降雨量(P)和最大30 min雨强(I₃₀)阈值。[结果](1)相比P阈值,I₃₀在识别侵蚀性降雨方面更为有效。(2)黑土和褐土小区侵蚀性降雨阈值较高,二者P阈值均为10.0 mm,I₃₀阈值均为10.2 mm/h;黄土小区次之,其P和I₃₀阈值分别为9.5 mm和8.9 mm/h。紫色土与红壤小区较低,二者的P阈值分别为5.4和6.1 mm,I₃₀阈值分别为3.2和5.2 mm/h。(3)各径流小区的监测资料年限达到12 a时,侵蚀性降雨阈值才可达到稳定。[结论]不同地区土壤的侵蚀性降雨阈值存在较大差异。侵蚀性降雨阈值不仅受土壤自身特性如粒径分布和有机质含量的影响,还与当地的气候状况如降雨雨型有关。     

镜鲤体重的QTL定位

本研究利用217个微卫星标记和336个SNPs标记对德国镜鲤F2代68个个体基因组DNA进行基因型检测。其中507个标记共组成62个连锁群,覆盖基因组总长度为2805．85cM,标记问平均距离为6-31cM;利用软件MapQTL4．0采用区间作图法对体重性状进行QTL定位分析。研究结果共检测到14个与体重性状有关的QTLs,分布于9个连锁群。其中BIV-5-J有最大的LOD值,为4．46;BIV—I-1的LOD值最小,为2．25。单个QTL平均解释表型变异介于14．10％～45．50％之间,其中贡献率大于20％的主效QTLs有9个。通过BLASTX与斑马鱼蛋白质序列数据库进行序列比对,找到了与斑马鱼酰基辅酶A脱氢酶蛋白、胰淀粉酶仅2蛋白、Apoebprotein和甘油醛-3-磷酸脱氢酶蛋白同源的分子标记。本研究结果对分子标记辅助育种具有重要应用价值。     

电解质浓度对土壤吸附铜离子时氢离子释放的影响

研究了不同铜离子浓度、不同电解质浓度情况下,吸附铜离子时氢离子释放对两种可变电荷土壤和4种恒电荷土壤悬液pH的影响。研究结果表明,除了黄棕壤外,含铁量越高,由于吸附铜离子后所引起的土壤ΔpH最大值越小。加入的铜离子浓度为10-4 mol L-1时,铜离子吸附对中和曲线形状没有根本影响。在较低浓度时,铜离子吸附时氢离子的释放较少;而在较高浓度时,当体系pH大于一临界值时,开始释放大量氢离子。氧化铁是引起恒电荷土壤和可变电荷土壤在吸附铜离子时氢离子释放差异产生的主要原因。电解质浓度的变化对恒电荷土壤和可变电荷土壤吸附铜离子后中和曲线变化影响有很大的区别,含铁量越高,电解质浓度对土壤吸附铜离子后的氢离子释放的影响越小。     

不同农垦地下垫面对风蚀起沙风速的影响分析

以新疆塔里木盆地垦区为例,研究不同地表粗糙度下垫面对风蚀起沙的临界摩擦速度和起沙风速的影响。根据Shao的方法计算不同下垫面起沙风速,结果表明:塔里木盆地垦区所选的小麦、棉花、红枣这3种地类2m高度临界摩擦速度(u*t)分别为棉花地0.40m/s,红枣地0.43m/s,小麦地1.85m/s;2m高度临界起沙风速(ut)分别为棉花地5.3m/s,红枣地5.7m/s,小麦地7.5m/s,小麦地较其他2种地类更具有抵抗风蚀的作用。     

Threshold of Soil Olsen-P in Greenhouses for Tomatoes and Cucumbers

Phosphorus (P) accumulation is a common phenomenon in greenhouse soil for vegetables. Excessive P accumulation in soil usually decreases the yield and quality of vegetables as well as potentially polluting water environments. Ninety-eight tomato and 48 cucumber greenhouses were investigated in the eight main vegetable production areas of Hebei Province, China. Soil Olsen-P, the electrical conductivity (EC), the pH value, the organic matter of the soil, and the cropping years of these greenhouses were investigated and analyzed in order to better understand the status of soil P accumulation and positively find effective ways to solve the excessive phosphate accumulation problem. The investigation showed that the ratio was above 70% for all of the greenhouses where the soil Olsen-P exceeded 90 mg·kg^?1 (upper bound of soil Olsen-P optimum value in greenhouse) in the 0–20 cm surface soil in the investigated greenhouses. There was a significant positive correlation between the soil Olsen-P content and the soil EC, between the soil Olsen-P and the cropping years, and the Olsen-P had a significant negative correlation with the soil pH value. It is concluded that supplying phosphate fertilizer excessively induced the soil EC to ascend and the pH value to descend, which increases the possibility of the soil secondary salinization and soil degeneration. The significant positive correlation between the soil organic content and the soil Olsen-P contents suggests that supplying organic fertilizer might mobilize soil residual phosphate. This also provides a good way to solve the problem of soil P accumulation. In order to further explore the threshold content of soil Olsen-P demanded by tomato and cucumber under the high soil Olsen-P condition, two tomato greenhouses (T1, T2) in Dingzhou and two cucumber greenhouses (C1, C2) in Wuqiang were researched. All of the greenhouses had ranges of soil Olsen-P content that were between 150 and 300 mg·kg^?1, which far exceeded the 90 mg·kg^?1 ideal. The P fertilizer application rates showed positive correlations with the soil Olsen-P contents and EC values in cucumber and tomato greenhouses in the current season. Analyzing T1 and T2 results showed that tomato was sensitive to the high soil Olsen-P contents ranging from 230.64 to 729.42 mg kg^?1 at the seedling stage (15 days after transplanting; DAT) and from 199.41 to 531.42 mg kg^?1 at the fruiting stage (90 DAT), because the yields correlated negatively with soil Olsen-P contents at each growth stage. It is suggested that the maximum soil Olsen-P threshold content for tomato should be lower than 230 mg·kg^?1 at the seedling stage and lower than 199 mg·kg^?1 at the fruiting stage. But cucumber yield did not change significantly as soil Olsen-P content rose from 248.75 to 927.62 mg kg^?1, 212.40 to 554.07 mg kg^?1, 184.48 to 455.90 mg kg^?1, and 128.42 to 400.96 mg kg^?1 at the seedling stage (15 DAT), early fruiting stage (50 DAT), middle fruiting stage (140 DAT), and late fruiting stage (235 DAT), respectively, suggesting that the maximal soil Olsen-P threshold content was lower than 249, 212, 185, and 128 mg·kg^?1 at each growth stage, respectively. The relationship between fruit qualities and soil Olsen-P contents at each growth stage was not evident. Activities of soil alkaline phosphatase (ALP) decreased as soil Olsen-P supply was raised in T1, T2, and C1 at the seedling stage. It is concluded that in an excess soil Olsen-P condition tomato yield decreases strongly as soil ALP activity decreases, whereas ALP activity has little direct effect on cucumber yield.     

灌水量和时期对不同品种冬小麦产量和耗水特性的影响

为明确品种更替过程中冬小麦的耗水特性、产量和水分利用效率(WUE)的变化规律,以及对水分胁迫的响应,于2010-2012两个生长季选取河南中北部建国以来不同年代的7个主栽品种为试验材料,在田间设置三个水分处理下(W0,返青后不灌水;W1,拔节期灌水;W2,拔节和灌浆期分别灌水),研究了冬小麦的耗水特性、产量构成因素、收获指数和水分利用效率的变化过程。研究结果表明:在冬小麦更替过程中,冬小麦总耗水和土壤贮水消耗与年代差异不显著,而受降雨和灌溉影响较大。从20世纪50年代至现在,90年代及以后的冬小麦品种千粒重在41g以上,明显高于早期品种。两年生长季冬小麦籽粒产量增加58.4%和41.8%,平均每次更替增加396和362kg/hm2;收获指数增加37.0%和18.0%,平均每次更替增加0.2和0.1;WUE增加55.3%和40.8%,平均每次更替增加0.11和0.10kg/m3。现代品种源、库关系得到改善,千粒重大幅度增加和收获指数增加是籽粒产量提高的主要原因。籽粒产量和WUE由品种和水分互作效应决定,在拔节期和灌浆期灌水可明显提高籽粒产量水平,并在一定程度上提高了水分利用效率。