Seasonally Averaged Temperature Fluctuation Penetrations into The Ground

Soil temperatures were analysed for the climatological station Pohořelice during the period of 1961–2000. According to the agroclimatic zoning, this region is a part of warm macroarea, mainly warm area, mainly dry subarea, and a district of mainly cold winter. The average annual air temperature is 9°C and the average year precipitation total is 475 mm. For the characterisation of the soil temperature were used the average monthly soil temperature determined from daily averages, maximal monthly soil temperature determined on the basis of daily maximums, and minimal monthly value determined on the basis of daily minimums. In the Czech Hydrometeorological Institute, the soil temperature was measured in the observation terms at 7:00, 14:00 and 21:00 local mean time. These temperature characteristics were assessed for the depths of 5, 10, 20, 50, and 100 cm. The longterm average annual temperature for the depths measured varies from 10.0°C (at 20 cm) to 10.4°C (at 100 cm). From the longterm viewpoint, the warmest month for the depths of 5, 10, and 20 cm is July, the coldest one is January, and for the depths of 50 and 100 cm the warmest month is August and the coldest one is February. For the classification of single months, the average monthly soil temperature for the respective month was compared with the longterm average soil temperature of 1961–2000. According to the average monthly soil temperature and its standard deviation, the months of the evaluated period were divided into seven categories: thermally normal months, warm months, very warm months, extraordinary warm months, cold months, very cold months, and extraordinary cold months.

Studies on how to counteract overheating caused by sun patch exposure in ventilated highly glazed spaces heated by floor heating systems

The different land uses influence to the soil temperature and humidity in the different soil depths. The objective of this study was to know the soil temperature and humidity in the different soil depths (5 cm, 10 cm, 20 cm, and 30 cm) in three land uses (young secondary forest, settlement area, and open area). The average soil temperature in the young secondary forest were 27.6°C, 27.4°C, 27.0°C, dan 26.9°C. The average soil temperature in the soil depths of 5 cm, 10 cm, 20 cm, and 30 cm were 27.5°C, 27.4°C, 27.0°C, and 26.8°C in the settlement area. The average soil temperature in the open area were 27.6°C, 27.4°C, 27.0°C and 26.9°C. The average soil humidity in the young secondary forest were in depth of 5 cm, 10 cm, 20 cm and 30 cm were 78.5%, 78.8%, 79.1% and 79.4%. The average soil humidity in the settlement area were 76.4%, 78.5%, 79.3%, and 80.2% in the depths of 5 cm, 10 cm, 20 cm, and 30 cm. The average soil humidity in the depths of 5 cm, 10 cm, 20 cm, and 30 cm were 69.2%, 69.6%, 70.3%, dan 70.8% in the open area.

A 1D microphysical cloud model for Earth, and Earth-like exoplanets: Liquid water and water ice clouds in the convective troposphere

Human activity has changed land surfaces by converting native ecosystems to urban and agricultural land uses. This conversion has caused increases in air and soil temperatures that influence soil C and N cycling. Efforts to model changes in soil temperature resulting from urban land use change have not accounted for changes in both plant cover and land use and thus fail to produce accurate predictions at high‐resolution spatial and temporal scales. We measured average daily soil temperature at a 10‐cm depth at urban and rural forest and grassland sites for 8 yr in the Baltimore, MD, metropolitan area and developed a model of the average daily soil temperature that accounts for two vegetation and two land use types. Average annual soil temperature was higher in urban than rural sites under both turfgrass (15.0°C vs. 13.5°C) and forest (12.6°C vs. 12.2°C). The application of climate‐change scenarios predicted by general circulation models to our soil temperature model suggested that the highest increases in mean soil temperatures will occur in August, September, February, and March, and will range from 1.2 to 2.0°C, while air temperature is predicted to change from 3.4 to 5.6°C between 2070 and 2099. The model can be used to predict the average daily soil temperature in the Baltimore area for sites with similar hydrologic and soil conditions, i.e., remote from the shoreline and characterized by loamy soils.

Ground temperatures were measured under two parking lots, one of which was cleared of snow in winter, and monthly and annual average surface temperatures were estimated by extrapolation. The surface temperatures were compared with monthly and annual surface and air temperatures measured at a nearby grassed site. A dependence of the difference between the monthly average surface and air temperatures on snow cover and convective loss was observed. A correlation was found to exist between the monthly average of the daily global solar radiation and the difference between monthly average air temperature and monthly average parking lot surface temperature. It was demonstrated that, because of a change in surface conditions, there was a change in annual average ground temperature beneath a parking lot. The observations are discussed with reference to the formation of sporadic permafrost.

Little information is available regarding the effects of biochar amendment on soil thermal properties and soil temperature, especially under field conditions. The possible changes in soil thermal conductivity, surface reflectance, and temperature resulting from biochar addition might affect other biophysical–chemical processes in the soil. We examined the effects of biochar amendment on the thermal conductivity, surface reflectance, and temperature of soil. Soil thermal conductivity, reflectance, and temperature at a 5-cm depth were measured and monitored in an experimental field using a portable soil thermal property analyzer, a portable full-range spectrometer, and temperature and water potential probes. The field was located in the North China Plain and had been cropped in a winter wheat (Triticum aestivum L.)–maize (Zea mays L.) system for 5 yr. With biochar amendment, soil thermal conductivity was decreased significantly by 3.48 and 7.49% with 4.5 (B4.5) and 9.0 t ha⁻¹ yr⁻¹ (B9.0) of biochar addition, respectively, which was consistent with a decrease in soil bulk density. Soil water potential slightly increased under B4.5 treatment but decreased under B9.0 treatment relative to the control. Reflectance increased in the near-ultraviolet and blue-light wavelengths (350–513 nm) and decreased in the infrared wavelength range (520–2350 nm) with biochar amendment. Biochar amendment reduced diurnal soil-temperature fluctuations on both daily and seasonal scales, although the annual average daily soil temperatures at a 5-cm depth showed no significant difference among treatments. Comparison with the control showed that biochar treatment moderated soil temperature extremes, lowering the temperature when soil temperature was high and raising it when soil temperature was low. This moderating capability was mostly within ±0.4 and ±0.8°C for mean daily temperature and mean diurnal temperature of soil, respectively. The effect of biochar amendment on soil temperatures can be explained by the combined action of changes in soil thermal conductivity and reflectance.

SynopsisApplied nitrogen increased the growth rate of the grass very little when the average soil temperature was below 45° F. Grass fertilized with nitrogen showed the greatest increase in growth compared with unfertilized grass when the average soil temperature was between 47° and 55°. When the temperature went above 55° the difference between unfertilized and fertilized grass decreased.

PDF HTML阅读 XML下载 导出引用 引用提醒 西北旱地春小麦不同覆盖措施的温度和产量效应 DOI: 10.5846/stxb201403050373 作者: 作者单位: 甘肃农业大学生命科学与技术学院 甘肃干旱生境国家重点实验室 作者简介: 通讯作者: 中图分类号: 基金项目: 公益性行业(农业)科研专项(20130314);现代农业产业技术体系建设专项(CARS-3-2-49) Effect of mulching method on soil temperature and grain yield of spring wheat in rainfed agricultural areas of northwestern China Author: Affiliation: College of bioscience and technology, Gansu Provincial Key Lab of Aridland Crop Science Gansu Agricultural University, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:在西北半干旱雨养条件下,以春小麦为材料,研究了夏季覆膜(T1)、秋季覆膜(T2)、春季覆膜(T3)、小麦碎秆覆盖(T4)、小麦整秆覆盖(T5)、夏季覆膜+麦秆还田 (T6)和无覆盖对照(CK)7个处理间0-20 cm土壤温度、产量和重要农艺指标的差异。结果表明:处理间在不同生育时期、不同土层的土壤温度存在显著差异。生育时期间比较,处理间土壤温度差异以播种期-分蘖期最大、蜡熟期-成熟期次之、拔节期-灌浆中期较小;土层间比较,处理间土壤5 cm处的温度差异依次大于10 cm、15 cm、20 cm处。T6在各时期、各土层均表现出突出的增温效应,全生育期土壤平均温度较CK高0.57 ℃,以成熟期、播种期及分蘖期增温效果较大;其它覆盖处理存在增温和降温的双重效应,增温效应覆膜 > 秸秆覆盖,而降温效应则秸秆覆盖 > 覆膜,各处理的32个土壤温度测试点中,增温点次以T4最少(仅有9个),降温点次为23个,且T4降温幅度最大,全生育期0-20 cm土壤平均温度较CK低0.63 ℃,降温效果在播种期和分蘖期尤为突出。覆盖处理全生育期土壤平均温度表现为覆膜 > CK > 秸秆覆盖。温差最高值出现在分蘖期土壤5 cm处的T6与T4间,T6高出T4 4.23 ℃。T6可以平抑生育期间土壤温度的变化,其它5个覆盖处理则加剧土壤温度的波动,以T4处理的土壤温度波动最明显(CV为32.4%)。处理间产量、单位面积穗数、穗粒数间差异显著,而千粒重差异不显著。无论覆膜还是秸秆覆盖,都较CK穗粒数显著增加(17.4%-36.3%)。除T5较CK显著减产14.1%外,其它覆盖处理均较CK显著增产21.7%-37.3%,其中以全膜覆土穴播基础上的秋季覆膜 (T2)增产最显著,适宜在西北旱地春小麦产区推广应用。土壤温度主要影响营养生长,拔节-开花期0-20 cm的土壤温度与株高高度正相关(0.77*-0.92**),但覆盖引起土壤温度的变化最终对西北旱地春小麦产量没有关键影响。 Abstract:This study determined the effects of mulching method on soil temperatures in the 0-20 cm soil layer, and grain yield of spring wheat (Triticum aestivum L.) in a semiarid rainfed agricultural area of northwestern China. The experiment was conducted at Tongwei Research Station, Gansu Agricultural University (34°55'N, 104°57'E) in 2012. The following 7 treatments were evaluated: plastic film mulch applied in summer (T1), plastic film mulch applied in autumn (T2), plastic film mulch applied in spring (T3), mulching with chopped wheat straw (5 cm in length) on the soil surface in summer (T4), mulching with whole wheat straw in summer (T5), T1 in combination with harvested wheat straw returned to the field (T6), and control (no mulching, CK). Soil temperatures were measured and recorded at 32 points in each treatment. Soil temperatures differed significantly among mulching treatments, growth stages and soil layers. The largest difference in soil temperature occurred from the sowing to tillering period, followed by the dough stage to maturation period, whereas the smallest differences in soil temperature were in the jointing-middle filling stage. Soil temperature decreased with soil depth in the order 5 cm > 10 cm > 15 cm > 20 cm. Soil temperature in the T6 plots was significantly (0.57 ℃) higher than, and this effect was more pronounced in the sowing, tillering, and maturing stages than in the other growth stages. The other five treatments either increased or decreased soil temperatures depending on growth stage and soil layer. Soil temperature was consistently increased by plastic film mulch but consistently decreased by straw mulching. The T4 treatment had 9 points with soil temperatures higher than the CK, and 23 points lower than the CK. Mean soil temperature over the whole growth period was 0.63℃ lower in the T4 treatment than in the CK, with the difference being more obvious at the time of sowing and the tillering stage. Average soil temperatures over the whole growth period were in the order: plastic film mulch > CK > straw mulching. The highest difference occurred between T6 and T4 in the 5 cm soil layer at the tillering stage, with T6 being 4.23 ℃ higher than T4. The largest variation soil temperature among growth stages was found in the T4 treatment, with a coefficient of variation of 32.4%. Mulching increased the number of kernels per spike by 17.4% to 36.3% compared with the CK. Mulching increased wheat grain yield by 21.7% to 37.3% compared to the CK, with the maximum yield increase being with plastic film mulch applied in the autumn (T2). The exception was the T5 treatment which decreased grain yield by 14.1% compared to the CK. It appears that the T2 mulching method is the most suitable for spring wheat production in rainfed agricultural regions of northwestern China. There were highly positive correlations (r = 0.77*-0.92**) between soil temperature and plant height at jointing-flowering, but mulching method did not have a significant impact on spring wheat grain yield in the study area. 参考文献 相似文献 引证文献

This research aims to study the trends and patterns of average maximum temperature change data of monthly surface in Thailand during the 30 year-period from 1986 to 2015 that has already eliminated seasonal variations and autocorrelation. The data set obtained from Climatological center, Meteorological Development Division, Thailand Meteorological Department for 73 completed recording stations. The climatically regions of Thailand meteorology are divided into 5 regions: Central, Eastern, North, Northeast and South. After the process of parameter estimation using simple linear regression of average maximum temperature data that has already eliminated influences of variations, the study results showed that over the last 10 years, the northern, central, eastern, northeastern and southern regions of Thailand had trends of the average maximum surface temperature increasing by 0.164°C 0.137°C 0.127°C 0.194°C 0.068°C, respectively. For over the whole country, the average maximum surface temperature increasing by 0.141°C in the last 10 years at a significant level of 0.05.

Based on the available observation data from meteorological stations in Henan Province from 1981 to 2010, annual and seasonal average soil temperature of each station during the past 30 years was calculated, monthly, seasonal and annual sequence of average temperature of each layer was generated, climate trend rate of annual and seasonal average soil temperature was calculated as well as spatial distribution characteristics of average soil temperature of Henan Province and vertical change, monthly change, seasonal change, annual change and other temporal change characteristics.

Deicing performances of a road unit driven by a hydronic heating system in severely cold regions of China

Core Ideas Plastic mulch increased soil temperature and water, thus increased wheat yield. High soil temperature by plastic mulch and planting legume reduced wheat yield. Incorporation of legume increased soil temperature of next wheat growing season. Planting legume increased soil water use in summer and decreased evapotranspiration in wheat season. In the Loess Plateau of northwestern China, soil water shortage is the main factor constraining dryland wheat (Triticum aestivum L.) production. Soil mulching is considered an effective practice to improve wheat yield due to increased soil water storage, but the information related to integrated understanding of soil temperature and water is scarce. We conducted a location‐fixed field experiment with two soil mulching (plastic mulch and planting legume) treatments to confirm the effects of soil temperature and water on wheat yield under different precipitation levels. In 2014–2015 with higher than average precipitation, plastic mulch increased soil water storage by 13% at sowing and average soil temperature by 0.4°C, which in turn increased yield by 13%, compared to the control. In 2012–2013 with extremely lower than average precipitation, the high daily maximum soil temperature during wheat reproductive period decreased grain number per spike and grain weight by 16 and 4%, respectively, thus reduced yield by 16%. For planting legume, the lower soil water storage at sowing and high daily maximum soil temperature during the wheat reproductive period decreased the number of spikes per hectare and grain weight by 29 and 4%, respectively, resulting in a 37% decrease in yield in 2012–2013. In other years with relatively higher precipitation, the proper soil temperature and extra N input under planting legume alleviated the negative impact of yield decline. Overall, planting legume did not show any benefit for wheat yield, while plastic mulch provided an opportunity for increasing wheat yield in dryland.

Although it is well established that soil temperature has substantial effects on the agri-environmental performance of crop production, little is known of soil temperatures under living cover crops. Consequently, soil temperatures under a crimson clover and white clover mix, hairy vetch, and red clover were measured for a cool, humid Brookston clay loam under a corn–soybean–winter wheat/cover crop rotation. Measurements were collected from August (after cover crop seeding) to the following May (before cover crop termination) at 15, 30, 45, and 60 cm depths during 2018–2019 and 2019–2020. Average soil temperatures (August–May) were not affected by cover crop species at any depth, or by air temperature at 60 cm depth. During winter, soil temperatures at 15, 30, and 45 cm depths were greater under cover crops than under a no cover crop control (CK), with maximum increase occurring at 15 cm on 31 January 2019 (2.5–5.7 °C) and on 23 January 2020 (0.8–1.9 °C). In spring, soil temperatures under standing cover crops were cooler than the CK by 0.1–3.0 °C at 15 cm depth, by 0–2.4 °C at the 30 and 45 cm depths, and by 0–1.8 °C at 60 cm depth. In addition, springtime soil temperature at 15 cm depth decreased by about 0.24 °C for every 1 Mg·ha−1 increase in live cover crop biomass. Relative to bare soil, cover crops increased near-surface soil temperature during winter but decreased near-surface soil temperature during spring. These temperature changes may have both positive and negative effects on the agri-environmental performance of crop production.

We designed and tested a soil temperature control system for plant ecophysiological experiments in greenhouses and growth chambers. The system consists of a plywood box, polyethylene liner, insulation, seedling containers, a water pump, and a flow-through heater or chiller. One hundred and twelve seedling containers (11cm diameter, 13.5 cm high) are mounted in the plywood box. There is a hole at the bottom center of each container to allow the free drainage of irrigation water and fertilizer solution. The space between containers is filled with water that is circulated through the chiller/heater. The water is also circulated within the plywood box by a water pump to increase the uniformity of temperature. The system was tested for three soil temperatures (5, 20, and 30°C) over a period of four months. The containers were filled with a peat-moss vermiculite mixture and planted with tree seedlings. The test showed that the soil temperature was almost equal to the water temperature for all three soil temperatures (regression slop = 0.99, intercept = 0.12,r2 = 1.00). The average soil temperatures were within (0.41°C of the set values. The soil temperature of the 112 containers within the same box followed a normal distribution with a small standard deviation (0.34°C for the 30°C treatment). There was a temperature gradient from the top to the bottom of the container (< 1°C). The direction of the temperature gradient was determined by the direction of temperature difference between the soil and the ambient air. When the soil temperature was lower than air temperature, the soil temperature decreased from the top to the bottom of the container, and vise versa. The soil temperature was higher during the day than at night (difference < 1.5°C).