Escape to the high canopy—thermal deficiency causes niche expansion in a forest‐floor ant

The small formicoxenine ant Temnothorax saxonicus was known from about 40 localities in Central Europe nesting in anorganic substrates on floor of xerothermous forests whereas investigations of 198 tree canopies in 19 forest sites of the same region provided no indication for arboreal nesting or foraging. We present the first evidence for canopy‐nesting populations of T. saxonicus on old Quercus trees in 3 sites having maximum calibrated topsoil temperatures of 17.9 ± 0.3 °C which were significantly (P < 0.007) lower than 22.8 ± 2.0 °C measured in 5 sites with ground‐nesting populations. The thermal deficit on forest floor inhibits brood development in ground nests and caused a moving to canopy were maximum calibrated temperatures of the, now wooden, substrates are at least 26.1 °C for the whole canopy and 30.8 °C in more sun‐exposed spots. T. saxonicus competed here successfully with the obligatory canopy ants T. affinis and T. corticalis. The distributional data of this rope‐climbing study support former results that highest nest densities of small arboreal ants occur in temperate climate over the entire canopy mantle of single trees situated in open land or in park‐like environments but occur in the top of the canopy in tree stands with high degree of canopy closure.     

不同耕作措施下冬小麦生长季农田二氧化碳排放通量及其与土壤温度的关系

利用长期定位试验研究了华北平原不同耕作措施下冬小麦生育期农田CO2排放通量,并对CO2排放通量和土壤温度进行了回归模拟.结果表明冬小麦生育期CO2排放速率表现为翻耕＞旋耕＞免耕,平均分别为343.69、337.54和190.47 mg·m-2·h-1.各处理冬小麦生育期CO2排放通量与土壤温度呈显著正相关;翻耕地CO2排放通量与10 cm地温相关性最高,旋耕地和免耕地则与10 cm和20 cm地温相关性较高.CO2排放通量和土壤温度呈指数函数关系(P＜0.01),利用10 cm地温对冬小麦生育期农田CO2排放通量进行估算表明,翻耕、旋耕和免耕地CO2排放分别为1.88、1.89和1.03 kg·m-2.     

Influence of Planting Date on Damage to Soybean Caused by Heterodera glycines

Bragg soybeans were planted in nematicide-treated and nontreated plots on 15 May, 15 June, 1 July, and 15 July in 1980 and 1981 to determine the influence of planting date on damage caused by H. glycines. Although earlier studies showed the nematode was sensitive to high soil temperatures (> 34 C), late planting did not reduce damage caused by the nematode. Yields from plots treated with 1, 2-dibromo-3-chloropropane (57.5 kg a.i./ha) were 48, 118, 395, and 403% higher than yields from nontreated plots with planting dates of 15 May, 15 June, 1 July, and 15 July, respectively, when data were averaged over the 2 years. Increase in both seed size and number accounted for the yield increases in treated plots. Soil temperatures were highest during July in 1980, averaging 8.9 and 6.5 hours per day above 34 C at 10- and 20-cm depths, respectively. Larvae populations of H. glycines were reduced by the nematicide but not by late planting. These results indicate that damage caused by H. glycines may actually increase with later planting and that nematicides may be more beneficial when soybeans are planted late in a double-cropped production system.     

Effect of Tylenchorhynchus robustoides on Growth of Buffalo Grass and Western Wheatgrass

Tylenchorhynchus robustoides reduced (P = 0.05) growth of Agropyron smithii (western wheatgrass) at soil temperatures of 20, 25, 30, and 35 C. Growth reduction increased with increasing soil temperatures. Highest populations of T. robustoides were recovered at 25 and 30 C. Clipping weights of Buchloe dactyloides (buffalo grass) were reduced at 25 and 30 C; however, root/crown weights were reduced at 15, 20, 30, and 35 C in nematode infested vs. noninfested soil. Reproduction of T. robustoides was greater at 25, 30, and 35 C than at 20 C on B. dactyloides. In a greenhouse study, T. robustoides reduced clipping and root/crown weights of both grasses 24-64%.     

Large seasonal changes in Q10 of soil respiration in a beech forest

We analyzed one year of continuous soil respiration measurements to assess variations in the temperature sensitivity of soil respiration at a Danish beech forest. A single temperature function derived from all measurements across the year (Q₁₀ = 4.2) was adequate for estimating the total annual soil respiration and its seasonal evolution. However, Q₁₀'s derived from weekly datasets ranged between three in summer (at a mean soil temperature of 14 °C) and 23 in winter (at 2 °C), indicating that the annual temperature function underestimated the synoptic variations in soil respiration during winter. These results highlight that empirical models should be parameterized at a time resolution similar to that required by the output of the model. If the objective of the model is to simulate the total annual soil respiration rate, annual parameterization suffices. If however, soil respiration needs to be simulated over time periods from days to weeks, as is the case when soil respiration is compared to total ecosystem respiration during synoptic weather patterns, more short‐term parameterization is required. Despite the higher wintertime Q₁₀'s, the absolute response of soil respiration to temperature was smaller in winter than in summer. This is mainly because in absolute numbers, the temperature sensitivity of soil respiration depends not only on Q₁₀, but also on the rate of soil respiration, which is highly reduced in winter. Nonetheless, the Q₁₀ of soil respiration in winter was larger than can be explained by the decreasing respiration rate only. Because the seasonal changes in Q₁₀ were negatively correlated with temperature and positively correlated with soil moisture, they could also be related to changing temperature and/or soil moisture conditions.     

耕作和覆盖对黄土高原果园土壤水分和温度的影响

研究了几种不同耕作方式（免耕、旋耕和翻耕）和覆盖措施（覆草、生草和覆膜）对黄土高原果园土壤水分和温度的影响.结果表明：5月不同耕作方式下0～1 m土层土壤水分差异极显著,表现为免耕（14.28%）>旋耕（14.13%）>翻耕（13.57%）,9月差异不明显;不同覆盖措施中,覆草处理的土壤水分最高,且与生草、覆膜、裸地处理间差异极显著;不同耕作方式和覆盖组合处理中以免耕覆草保水效果最好.不同覆盖处理白天土壤平均温度表现为覆膜>裸地>生草>覆草,土壤温度变幅表现为裸地>覆膜>生草>覆草.各覆盖处理的蓄水量与其土壤温度并不都呈负相关,而是由不同覆盖物的保水效果和保温性质共同决定.综上所述,黄土高原果园的保护性耕作体系应以免耕覆草为主.     

不同地表覆盖方式对苹果园土壤性状及果树生长和产量的影响

以黄土高原9年生红富士果园生态系统为对象,研究不同地表覆盖模式（清耕、生草覆盖、地膜覆盖、秸秆覆盖和砂石覆盖）对果园土壤性状及果树生长和产量的影响.结果表明：生草覆盖土壤水分剖面分异最低,砂石覆盖土壤水分剖面分异最高;砂石覆盖提高了根层水分含量,有利于果树对水分的利用.不同地表覆盖模式土壤热量状况变化显著,处理间差异明显,极端最高温度下降,但地膜覆盖处理夏季地温超过果树根系生长的上限温度,对果树根系生长和生理功能发挥不利.除地膜覆盖外,其他地表覆盖模式均能提高土壤CO₂释放速率,其中生草覆盖的效果最为显著.不同地表覆盖模式对果树枝条类型比例及产量影响较大,砂石覆盖处理的中短枝比例和果实产量最高;生草覆盖处理的果实产量最低.因子分析结果表明,对于黄土高原沟壑区盛果期果园,砂石覆盖处理是较为适宜的地表覆盖模式.     

南京城市公园绿地不同植被类型土壤呼吸的变化

子2007年10月-2008年9月,利用Li-6400便携式光合作用仪配合土壤呼吸气室对南京中山植物园内草坪、疏林和近自然林3种植被类型的土壤呼吸速率的季节变化及其影响因子进行了测定.结果表明:不同植被类型土壤呼吸速率具有明显的季节变化,夏季(8月)较高,近自然林、疏林和草坪类型分别为3.28、4.07和7.58 μmol·m~(-2)·s~(-1),冬季(12月)最低,近自然林、疏林和草坪类型分别为0.82、0.99和1.42 μmol·m~(-2)·s~(-1);不同植被类型的年均土壤呼吸速率有显著差异(P＜0.05),平均土壤呼吸速率大小排序为草坪>疏林>近自然林;不同植被类型的土壤呼吸速率与土壤温度呈显著性指数相关关系,与土壤含水率无显著相关关系;Q_(10)值均随着土层深度的增加而增加;不同植被类型的Q_(10)值存在一定程度的差异,近自然林类型的Q_(10)值大于草坪和疏林类型的Q_(10)值.研究表明,城市如果大量发展草坪可能增加土壤CO_2的排放.

Abstract：

By using Li-6400 portable photosynthetic apparatus connected to soil chamber,the soil respiration rate under three vegetation types(lawn,open woodland,and close-to-nature forest)in Nanjing Zhongshan Botanical Garden was measured from October 2007 to September 2008,with related affecting factors analyzed.The soil respiration rate had obvious seasonal fluctuation,being the highest in summer(August)and the lowest in winter(December).For the close-to-nature forest,open woodland,and lawn,their soil respiration rate in summer was 3.28,4.07,and 7.58μmol·m~(-2)·s~(-1),and that in winter was 0.82,0.99,and 1.42μmol·m~(-2)·s~(-1),respectively.The annual mean soil respiration rate differed significantly with vegetation type(P＜0.05),which was in order of close-to-nature forest＜open woodland＜lawn.The soil respiration rate had significant exponential correlation with soil temperature,but no correlation with soil moisture.The Q_(10) value increased with increasing soil depth,and was larger in close-tonature forest than in open woodland and lawn.Our results indicated that the rapid development of lawn in urban green space could increase the urban soil CO_2 emission.     

川西平原灌区不同水旱轮作模式周年土壤呼吸特征

水旱轮作是川西平原灌区重要的稻田种植模式,为探究本区域不同水旱轮作模式对周年土壤呼吸的影响,在四川崇州设置蒜-稻(GR)、麦-稻(WR)和油-稻(RR)三种水旱轮作模式,采用静态箱-气相色谱法测定不同模式周年土壤呼吸,并同步测定温度、水层高度等水热生态因子。结果表明:三种轮作模式周年土壤呼吸累积排放量表现为GRRRWR,分别为193.36、160.27、157.28 kg/hm~2;土壤呼吸速率日动态规律基本一致,均表现为单峰型变化趋势,最高值出现在12:00—15:00,6—8月的日变幅高于其余月份;土壤呼吸速率季节动态均呈双峰型变化趋势,在6月和9月达到峰值,其中GR模式土壤呼吸速率年均值最高;三种模式土壤呼吸速率均受0—10 cm、10—20 cm土壤温度的显著影响,而与土壤含水量无显著相关性。土壤温度是旱季土壤呼吸速率季节变化的主要影响因素,土壤水层深度和土壤温度共同作用影响了稻季土壤呼吸速率的变化。     

黄土高原四种人工植物群落土壤呼吸季节变化及其影响因子

以黄土高原侧柏、柠条、沙棘和油松人工植物群落为对象,土壤呼吸日动态和季节变化及其与环境因子之间的关系,结果表明:4种植物群落土壤呼吸速率具有典型的日变化和季节变化模式, 4种群落中,以侧柏6月土壤呼吸日变幅最大,沙棘6月土壤呼吸日变幅最小,大部分群落不同月份最大土壤呼吸与最小土壤呼吸倍数在1.1～1.6之间.4种群落中,以柠条土壤呼吸季节变幅最大,侧柏最小,最大土壤呼吸与最小土壤呼吸的倍数为1.5～2.2倍之间.同一植物类型土壤呼吸具有明显的季节变化特征,其具体变化趋势因植物类型而异.4种植物群落土壤呼吸速率与土壤和大气温度以及土壤含水量的关系在不同季节表现为不同的关系,其中侧柏和柠条土壤呼吸与土壤温度均呈乘幂关系,与大气温度为指数关系.沙棘土壤呼吸与土壤温度和大气温度均为乘幂关系,油松土壤呼吸与土壤温度和大气温度均为线性关系.这表明土壤呼吸与土壤和大气温度之间的关系及其紧密程度因植被类型而异.综合分析表明,同一气候区相同环境因子对不同植物群落土壤呼吸的影响作用不同,且因其自身具有明显的季节变化,从而导致对土壤呼吸的调控作用也具有明显的季节变异模式.     

草毡寒冻雏形土CO2释放特征

研究了植物生长季节海北高寒草甸生态系统高寒嵩草草甸覆被下草毡寒冻雏形土的 CO2 释放速率。其结果表明 :CO2 释放速率有明显的日变化和季节动态。日最大排放速率多出现在 1 4 :0 0～ 1 6:0 0时 ,最小排放速率在 6:0 0～ 8:0 0时。植物生长季日最大振幅为 797.75mg/m2·h,最小振幅 1 97.33mg/m2·h。CO2 排放白天大于夜晚。不同物候期 CO2 释放速率不同 ,其顺序为草盛期 >枯黄期 >返青期。生长季土壤 CO2 释放速率的范围是 4 41 .72 mg/m2 · h± 1 55.2 9mg/m2· h,最大日均值为 681 .0 6mg/m2 · h( 7月 1 6日 ) ,最低值 1 76.65mg/m2 · h ( 6月 1日 )。退化草地土壤 CO2 释放速率明显低于未退化草地 ,生长季平均日均值低 1 37.4 7mg/m2·h。相关分析表明 :土壤 CO2 排放速率与气温、地表温度、土壤5cm、1 0 cm、1 5cm、2 0 cm、30 cm地温均呈显著和极显著相关关系。温度是影响土壤 CO2 释放速率的主要因子。     

Effect of soil moisture at different temperatures on Rhizoctonia root rot of wheat seedlings

The effect of soil moisture at different temperatures on root rot of wheat seedlings caused by Rhizoctonia solani AG-8 was studied in temperature controlled water tanks under glasshouse conditions. Four moisture levels (15, 30, 50 and 75% of soil water holding capacity at saturation which were equal to –10, –7, –5 and –3 kPa, respectively) were tested in tanks maintained 10, 15, 20 or 25 °C. The role of microbial activity in the effect of soil moisture and temperature on disease severity was also studied by including treatments of steam treated soil. Results showed that at soil moisture levels optimum for plant growth (50 and 75% WHC) disease was more severe at a lower temperature (10 °C), but under relatively dry conditions (15% WHC) disease levels were similar at all temperatures tested. In warm soils (20 and 25 °C) at high soil moisture levels (50 and 75% WHC), disease was more severe in steam treated soil than in non-steam treated soil, indicating that the suppression of disease in natural soil under these conditions was associated with high soil microbial activity.     

土壤湿度对中国南部热带森林土壤甲烷吸收的影响

森林土壤是一个重要的大气甲烷的汇。然而,相较于寒带和温带,在热带尤其是东南亚地区,森林土壤甲烷通量的观测较少,这限制了目前对热带森林土壤甲烷通量与环境因子之间关系的认识,也给热带森林土壤甲烷汇的估算带来了一定的不确定性。在中国海南省吊罗山国家森林公园的热带森林土壤,采用激光光谱法测量了2016年9月至2018年9月逐月的土壤甲烷通量,并分析了其与周围环境因子的关系。结果表明：研究区土壤是甲烷的汇,山顶样地的年平均吸收量为0.95 kg CH₄-C hm^-2 a^-1,山脚样地的年平均吸收量为1.93 kg CH₄-C hm^-2 a^-1。干季(11月—次年4月)的甲烷吸收通量明显高于湿季(5—10月),占到全年甲烷吸收的68%。山顶样地年平均土壤湿度为19.2%,年内的波动较小(2.8%)。而山脚样地的年平均湿度相对较低,为12.7%,且年内波动大(5.4%)。土壤湿度是控制甲烷吸收最主要的环境因子,可以解释月际甲烷吸收变化的76%,甲烷吸收通量与土壤温度的相...     

华北平原地区麦田土壤呼吸特征

2008年4-6月利用LI-8100及LI-6400-09测定了华北平原典型冬小麦田土壤CO_2通量,并分析了麦田土壤呼吸变化规律及其影响机制.结果表明:土壤呼吸日变化呈明显的单峰曲线,最高值出现在12:30-14:30,最低值出现在5:00-6:30;在不同的天气条件下,土壤呼吸速率晴天最高,多云其次,阴天最小;观测期间冠层内各高度CO_2浓度与麦田土壤呼吸速率白天呈显著线性负相关,夜间正相关;土壤呼吸速率与5 cm地温的季节变化趋势基本一致,二者显著指数相关;在田间持水量范围内,土壤呼吸速率与土壤湿度正相关,当土壤相对湿度低于30%时,土壤呼吸受到抑制而通量降低;综合考虑土壤温度与湿度的双因素指数回归模型能较好地解释土壤呼吸的变化情况,土壤温度低于15 ℃时效果更好.

Abstract：

By using LI-8100 and LI-6400-09, the soil CO_2 flux of a winter wheat field in North China Plain was determined from April to June 2008, with its change patterns and affecting fac-tors analyzed. The soil respiration had a single-peak diurnal variation, with the maximum at 12: 30-14:30 and the minimum at 5:00-6:30, and the respiration rate was higher in sunny days than in cloudy or overcast days. There was a significant negative correlation between the CO_2 con-centrations at all canopy heights and the soil respiration rate at daytime, but a significant positive correlation at night. The soil respiration rate presented a seasonal variation similar to the soil tem-perature at 5 cm depth, and had a significant exponential relationship with the soil temperature. Significant correlation was also found between the soil respiration rate and soil humidity when the soil moisture content was within the range of field capacity. Soil humidity less than 30% would limit the soil respiration, inducing a decrease of soil CO_2 flux. A multiple exponential regression model of soil temperature and moisture could better explain the variation of soil respiration, espe-cially when the soil temperature was below 15 ℃.     

黄土旱塬裸地土壤呼吸特征及其影响因子

于中国科学院长武生态试验站(始于1984年),采用动态密闭气室法(Li-8100,USA)于2008年3月至2009年3月监测了裸地土壤呼吸日变化、季节变化以及0-60cm土层的温度和含水量,研究了裸地土壤呼吸的日变化、季节变化特征及其与土壤温度和含水量之间的关系。结果表明:裸地土壤呼吸四季的日变化和季节变化均呈单峰型曲线,与气温变化趋势一致;日变化峰值出现在14:00左右或16:00左右,最低值出现在0:00左右或者6:00左右;季节变化表现为夏季最高,冬季最低,春秋季无明显差异,年平均呼吸速率为0.94μmolCO₂·m^-2·s^-1。土壤呼吸与温度具有极显著(P<0.01)的正相关关系,且可以用R_s=ae^bx形式的指数函数很好地拟合,其中与5cm深度的土壤温度相关性最好。水分对土壤呼吸的影响复杂。裸地土壤呼吸的双变量模型关系显著(P<0.01),比相应的单变量模型更好地解释了土壤呼吸变异。     

东北羊草草原土壤微生物生物量的季节变化及其与土壤生境的关系

本文研究东北羊草草原土壤微生物生物量的季节变化规律。根据实测数据,利用ＭＶ／６０００电子计算机构造了趋势方程,并作了Ｆ检验,Ｆ０．２５＝２．６８,Ｆ０＝１９３．９９,效果良好。以此为基础可以进行预测预报。同时利用ＭＶ／６０００电子计算机绘制三维空间趋势面图形,直观地反映了东北草草原土壤分解微生物生物量的季节变化规律。实验结果证明,土壤温度、水分对土壤微生物的生物量影响同等重要。     

塔克拉玛干沙漠腹地冬季土壤呼吸及其驱动因子

利用Li-8150系统测定了塔克拉玛干沙漠腹地冬季(1月)土壤呼吸,分析了环境驱动因子对极端干旱区荒漠生态系统土壤呼吸的影响。结果表明:(1)冬季土壤呼吸日变化呈现出显著的单峰曲线,土壤呼吸速率最大值出现在12:00,为0.0684μmol CO2m-2s-1,凌晨04:00附近出现最小值,为-0.0473μmol CO2m-2s-1;(2)土壤呼吸速率与各层气温,0cm地表温度均存在着极其显著或显著的线性关系,且都具有正相关性;(3)土壤呼吸速率与5cm土壤湿度存在着较为明显的线性关系,该层湿度能够解释土壤呼吸的69.5%;(4)0cm地表温度对土壤呼吸贡献最大,其次是5cm土壤湿度;(5)以0cm地表温度、5cm土壤湿度为变量,通过多元回归分析表明:土壤温度-湿度构成的多变量模型能够解释大于86.9%的土壤呼吸变化情况;(6)研究时段内土壤呼吸速率的平均值是-1.45mg CO2m-2h-1。     

不同耕作措施下旱地农田土壤呼吸及其影响因素

为探讨耕作措施对旱地农田土壤呼吸的影响,采用动态气室法在山西寿阳地区对秸秆还田、免耕覆盖、浅旋耕、常规耕作4种耕作措施下玉米生长季土壤呼吸及影响因子进行了测定和分析。结果表明,4种耕作措施下土壤呼吸速率的日和季节变化规律明显,均呈单峰型,呼吸速率的日峰值出现在11:30 13:30,呼吸速率的季节峰值出现在7月上旬至中旬。浅旋耕、秸秆还田、常规耕作、免耕覆盖措施整个生长季平均土壤呼吸速率分别为2.82、2.77、2.64μmolCO.2m-.2s-1和2.49μmolCO.2m-.2s-1,处理间无显著差异。研究结果还显示土壤温度和湿度是影响旱地农田土壤呼吸的主要因子,二者分别解释了土壤呼吸季节变化的55%78%,20%43%。4种措施下土壤呼吸的温度敏感系数Q10值在2.19 3.07之间,大小依次为免耕覆盖浅旋耕秸秆还田常规耕作。对水分的敏感性依次为免耕覆盖秸秆还田浅旋耕常规耕作。     

Meloidogyne hapla in Organic Soil: Effects of Environment on Hatch,Movement and Root Invasion

Using new techniques, hatch and movement of Meloidogyne hapla and nematode invasion o f lettuce roots growing in organic soil were studied under controlled soil conditions of temperature, moisture, O₂ and CO₂. When O₂ levels of 2.7, 5, 10, 21 and 40% with CO₂ maintained at 0.03% were used, O₂ below 21% or at 40% reduced nematode activities compared with those at 21%. When CO₂ levels of 0.03, 0.33, 2.8, 10 and 30% with O₂ maintained at 21% were used, all levels above 0.03% CO₂ resulted in less activity than at 0.03% except for more invasion at 0.33% than at 0.03%. Results suggested M. hapla was tolerant of CO₂ below 10% but adversely affected by 30% CO₂. Effect of O₂ was influenced by the level of CO₂ present. No larvae invaded roots at 3.2% O₂ and 18.6% CO₂ but hatch and movement occurred. Night and day temperatures of 21.1 and 26.7 C were more favorable for movement and invasion than 15.5 and 21.1 C, 26.7 and 32.2 C or 26.7 and 32.2 C. Optimum moisture for movement was 80 cm suction and for invasion was 100 cm.