Specifics of soil temperature under winter wheat canopy (original) (raw)
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The course of soil temperature under wheat stand
The course of soil temperature was determined under the wheat stand during the main growth season in 2010 and 2011years. Automatic sensors were positioned at two levels (50 and 100 mm) under the soil surface. The range of temperatures was more pronounced in the depth 50 mm in comparison with 100 mm. The distinct differences were not obvious between two evaluated years. The dependence of soil temperature under wheat canopy on the temperature under grass cover in particular depth was high in the first two stages of wheat development (tillering till the end of flowering) in both years evaluated, the coefficient of determination reaches values from 0.80 to 0.96.The regression between soil temperature and air temperature in the wheat stand was established, also. As it was found out by cross correlation analysis, the best interrelationships between these two variables were achieved in 3 hours delay for the soil temperature in 50 mm and 5 hour delay for 100 mm. After the time correction the determination coefficient reached values from 0.76 to 0.88 for 50 mm and 0.61 to 0.74 for 100 mm. These findings can be used in making more accurate prediction models of pathogens and pest occurrence on winter wheat.
The temperature in the ground of wheat canopy was compared with those measured on standard climatological station by regression analysis. Measurements in the wheat stand were carried out on two localities – Žabčice (site Obora and Písky) and Branišovice from year 2015. The course of temperature in the wheat stand ground differed meaningly, the length of particular winter wheat vegetation stages was different, too. The regression equations reveal the differences of standard environment and the ground of wheat canopy. These differences were dependent on the growth stage of winter wheat and experimental site. These differences can be caused by different conditions of experimental localities on results.
Crop and Soil Temperature Difference an Additional Factor for Analysis of the Condition of Crops
E3S Web of Conferences
The study aims to study changes in land surface temperature (LST) of soil and vegetation on agricultural land planted with barley based on unmanned LST data. Simultaneously with the LST data, the spectral characteristics (NDVI) of crops were measured using the DJI P4 Multispectral. The paper shows the variability of vegetation indices and radiation temperature during the growing season. A significant relationship was found between the dynamics of NDVI and the dynamics of radiation temperature. The features of the variability of the spatial distribution of temperatures depending on precipitation are shown. The paper gives an example of a temperature map of the studied areas in the middle of the growing season, which shows the features of the spatial distribution of temperatures.
Acta Agriculturae Scandinavica, Section B - Plant Soil Science, 2009
Modelling of ecosystem processes often requires soil temperature as a driving variable. Since soil temperature measurements are seldom available for regional applications, they have to be estimated from standard meteorological data. The objective of this paper is to present a general, simple empirical approach for estimating daily depth profiles of soil temperature from air temperature and a surface cover index (LAI; leaf area index) mainly focusing on agricultural soils in cold temperate regions. Air and soil temperature data measured daily or every fifth day at one to six different depths was acquired from all meteorological stations in Sweden where such records are available. The stations cover latitudes from 55.65 to 68.42 N and mean annual air temperatures from +8.6 to -0.6 o C. The time series spanned between two and ten years. The soils at the stations cover a wide range of soil textures, including two organic soils. We calibrated the model first for each station and then for all stations together and the general parameterization only slightly decreased the goodness of fit. This general model then was applied to two treatments in a field experiment: bare soil and a winter rape crop. The parameters governing the influence of LAI on heat fluxes were optimized using this experiment. Finally, the model was validated using soil temperature data from two barley treatments differing in LAI taken from another field experiment. In general, the model predicted daily soil temperature profiles well. For all soils and depths at the meteorological stations, 95% of the simulated daily soil temperatures differed by less than 2.8 o C from measurements. The corresponding differences were somewhat higher for the validation data set (3.9 o C), but bias was still low. The model explained 95% of the variation in the validation data. Since no site-specific adjustments were made in the validation simulations, we conclude that the application of the general model 3 presented here will result in good estimates of soil temperatures under cold temperate conditions. The very limited input requirements (only air temperature and LAI) that are easily obtainable from weather stations and from satellites make this model suitable for spatial applications at catchment or regional scales.
2019
Object of this study is the regime of soil surface temperatures down to 20 cm depth during the period of sowing and initializing stages of spring crops development. The area to the west of Burgas is on the border of the Black Sea sub region of the Continental-Mediterranean region. The annual course of rainfall is characterized by maximum during November and minimum in August. Less pronounced is the continental influence with a secondary maximum in June. The area is generally classified as dry but mitigated compared to the interior of southern Bulgaria and with higher relative air humidity. In terms of temperature conditions, the spring is a cooler and the sharp decreases are lower. The аgro-ecological resources of the region during the last 30 years have defined it as dry, moderately hot. Increasing tendencies last 30 years in air temperature have been established compared to 1961-1990. In recent years, scientists have focused their research mainly on air temperature. It is known th...
Specifics of soil temperature under winter oilseed rape canopy
The aim of this study was to evaluate the course of soil temperature under the winter oilseed rape canopy and to determine relationships between soil temperature, air temperature and partly soil moisture. In addition, the aim was to describe the dependence by means of regression equations usable for pests and pathogens prediction, crop development, and yields models. The measurement of soil and near the ground air temperatures was performed at the experimental field Zabcice (South Moravia, the Czech Republic). The course of temperature was determined under or in the winter oilseed rape canopy during spring growth season in the course of four years (2010 – 2012 and 2014). In all years, the standard varieties (Petrol, Sherpa) were grown, in 2014 the semi-dwarf variety PX 104 was added. Automatic soil sensors were positioned at three depths (0.05, 0.10 and 0.20 m) under soil surface, air temperature sensors in 0.05 m above soil surfaces. The course of soil temperature differs significantly between standard (Sherpa and Petrol) and semi-dwarf (PX 104) varieties. Results of the cross correlation analysis showed, that the best interrelationships between air and soil temperature were achieved in 2 hours delay for the soil temperature in 0.05 m, 4 hour delay for 0.10 m and 7 hour delay for 0.20 m for standard varieties. For semi-dwarf variety, this delay reached 6 hour for the soil temperature in 0.05 m, 7 hour delay for 0.10 m and 11 hour for 0.20 m. After the time correction, the determination coefficient (R 2) reached values from 0.67 to 0.95 for 0.05 m, 0.50 to 0.84 for 0.10 m in variety Sherpa during all experimental years. For variety PX 104 this coefficient reached values from 0.51 to 0.72 in 0.05 m depth and from 0.39 to 0.67 in 0.10 m depth in the year 2014. The determination coefficient in the 0.20 m depth was lower for both varieties; its values were from 0.15 to 0.65 in variety Sherpa. In variety PX 104 the values of R2 from 0.23 to 0.57 were determined. When using multiple regressions with quadratic spacing (modelling of hourly soil temperature based on the hourly near surface air temperature and hourly soil moisture in the 0.10–0.40 m profile), the difference between the measured and modelled soil temperatures in the depth of 0.05 m was –3.92 to 3.99 °C. The regression equation paired with alternative agrometeorological instruments enables relatively accurate modelling of soil temperatures (R2 = 0.95).
Climate sensitivity of the main Hungarian soil types
Cereal Research Communications
We present a study on the impact of soil and climatic variability on the yield of winter wheat in Hungary. The study was based on the use of National Pedological and Crop Production Database (NPCPD). The analysis was performed using the data of two climatic soil zones (17 selected climatic districts). The brown forest soil area was represented by Lessivated brown forest soils and the chernozem area was characterized by Chernozem soils. Statistical classification methods were used to distinguish significantly different climate categories and winter wheat yield groups. The calculated climate sensitivity factors described the aggregated effects of soil and climate heterogeneity on the crop production.
Influence of winter wheat on soil thermal properties of a Paleudalf
International Agrophysics
Soil thermal properties can influence several soil processes important for crop productivity. This study was conducted to evaluate the influence of cover crops on selected soil physical and thermal properties. The field site was set up using a randomized complete block design with two levels of cover crops (cover crops versus no cover crops). The soil thermal properties measured included thermal conductivity, volumetric heat capacity, and thermal diffusivity. The physical properties of the soil studied included bulk density, volumetric water content, total pore spaces, water-filled pore spaces, air-filled pore spaces, gas diffusion coefficient, and soil pore tortuosity factor. Soil organic carbon was also measured. The results showed that soil organic carbon was 26% higher under cover crops management compared to no cover crops management. Thermal conductivity and thermal diffusivity were positively correlated with soil bulk density and these properties (soil thermal conductivity and soil thermal diffusivity) were higher under no cover crops management compared with cover crops management probably due to the proximity between soil particles. The volumetric heat capacity was positively correlated with soil organic carbon, with soil organic carbon being higher under cover crops management compared with no cover crops management. Results from the current study show that cover crops can improve soil physical and thermal properties which may benefit crop productivity as corroborated via laboratory measurements. K e y w o r d s: thermal conductivity, volumetric heat capacity, thermal diffusivity, soil organic carbon
A new approach to predict soil temperature under vegetated surfaces
Modeling Earth Systems and Environment, 2015
In this article, the setup and the application of an empirical model, based on Newton's law of cooling, capable to predict daily mean soil temperature (T soil ) under vegetated surfaces, is described. The only input variable, necessary to run the model, is a time series of daily mean air temperature. The simulator employs 9 empirical parameters, which were estimated by inverse modeling. The model, which primarily addresses forested sites, incorporates the effect of snow cover and soil freezing on soil temperature. The model was applied to several temperate forest sites, managing the split between Central Europe (Austria) and the United States (Harvard Forest, Massachusetts; Hubbard Brook, New Hampshire), aiming to cover a broad range of site characteristics. Investigated stands differ fundamentally in stand composition, elevation, exposition, annual mean temperature, precipitation regime, as well as in the duration of winter snow cover. At last, to explore the limits of the formulation, the simulator was applied to non-forest sites (Illinois), where soil temperature was recorded under short cut grass. The model was parameterized, specifically to site and measurement depth. After calibration of the model, an evaluation was performed, using *50 % of the available data. In each case, the simulator was capable to deliver a feasible prediction of soil temperature in the validation time interval.
Simulation of Soil Temperature Dynamics with Models Using Different Concepts
The Scientific World Journal, 2012
This paper presents two soil temperature models with empirical and mechanistic concepts. At the test site (calcaric arenosol), meteorological parameters as well as soil moisture content and temperature at 5 different depths were measured in an experiment with 8 parcels realizing the combinations of the fertilized, nonfertilized, irrigated, nonirrigated treatments in two replicates. Leaf area dynamics was also monitored. Soil temperature was calculated with the original and a modified version of CERES as well as with the HYDRUS-1D model. The simulated soil temperature values were compared to the observed ones. The vegetation reduced both the average soil temperature and its diurnal amplitude; therefore, considering the leaf area dynamics is important in modeling. The models underestimated the actual soil temperature and overestimated the temperature oscillation within the winter period. All models failed to account for the insulation effect of snow cover. The modified CERES provided ...