Current Browsing: Vegetation


HiWATER: Dataset of fractional vegetation cover and biomass observed in the middle reaches of the Heihe River Basin (2014)

This data includes the coverage data set of vegetation in one growth cycle in five stations of Daman super station, wetland, desert, desert and Gobi, and the biomass data set of maize and wetland reed in one growth cycle in Daman super station. The observation time starts from May 10, 2014 and ends on September 11, 2014. 1 coverage observation 1.1 observation time 1.1.1 super station: the observation period is from May 10 to September 11, 2014. Before July 20, the observation is once every five days. After July 20, the observation is once every 10 days. A total of 17 observations are made. The specific observation time is as follows:; Super stations: May 10, 15, 20, 25, 30, 10, 15, 20, 20, 30, 30, 30, 30, 30, 7, 10, 10, 10, 10, 10, 15 1.1.2 other four stations: the observation period is from May 20 to September 15, 2014, once every 10 days, and 11 observations have been made in total. The specific observation time is as follows:; Other four stations: May 10, 2014, May 20, 2014, May 30, 2014, June 10, 2014, June 20, 2014, June 30, July 10, 2014, July 20, August 5, 2014, August 17, 2014, September 11, 2014 1.2 observation method 1.2.1 measuring instruments and principles: The digital camera is placed on the instrument platform at the front end of the simple support pole to keep the shooting vertical and downward and remotely control the camera measurement data. The observation frame can be used to change the shooting height of the camera and realize targeted measurement for different types of vegetation. 1.2.2 design of sample Super station: take 3 plots in total, the sample size of each plot is 10 × 10 meters, take photos along two diagonal lines in turn each time, take 9-10 photos in total; Wetland station: take 2 sample plots, each plot is 10 × 10 meters in size, and take 9-10 photos for each survey; 3 other stations: select 1 sample plot, each sample plot is 10 × 10 meters in size, and take 9-10 photos for each survey; 1.2.3 shooting method For the super station corn and wetland station reed, the observation frame is directly used to ensure that the camera on the observation frame is far higher than the vegetation crown height. Samples are taken along the diagonal in the square quadrat, and then the arithmetic average is made. In the case of a small field angle (< 30 °), the field of view includes more than 2 ridges with a full cycle, and the side length of the photo is parallel to the ridge; in the other three sites, due to the relatively low vegetation, the camera is directly used to take pictures vertically downward (without using the bracket). 1.2.4 coverage calculation The coverage calculation is completed by Beijing Normal University, and an automatic classification method is adopted. For details, see article 1 of "recommended references". By transforming RGB color space to lab space which is easier to distinguish green vegetation, the histogram of green component A is clustered to separate green vegetation and non green background, and the vegetation coverage of a single photo is obtained. The advantage of this method lies in its simple algorithm, easy to implement and high degree of automation and precision. In the future, more rapid, automatic and accurate classification methods are needed to maximize the advantages of digital camera methods. 2 biomass observation 2.1 observation time 2.1.1 corn: the observation period is from May 10 to September 11, 2014, once every 5 days before July 20, and once every 10 days after July 20. A total of 17 observations have been made. The specific observation time is as follows:; Super stations: May 10, 15, 20, 25, 30, 10, 15, 20, 20, 30, 30, 30, 30, 30, 7, 10, 10, 10, 10, 10, 15 2.1.2 Reed: the observation period is from May 20 to September 15, 2014, once every 10 days, and 11 observations have been made in total. The specific observation time is as follows:; 2014-5-10、2014-5-20、2014-5-30、2014-6-10、2014-6-20、2014-6-30、2014-7-10、2014-7-20、2014-8-5、2014-8-17、2014-9-11 2.2 observation method Corn: select three sample plots, and select three corn plants that represent the average level of each sample plot for each observation, respectively weigh the fresh weight (aboveground biomass + underground biomass) and the corresponding dry weight (85 ℃ constant temperature drying), and calculate the biomass of unit area corn according to the plant spacing and row spacing; Reed: set two 0.5m × 0.5m quadrats, cut them in the same place, and weigh the fresh weight (stem and leaf) and dry weight (constant temperature drying at 85 ℃) of reed respectively. 2.3 observation instruments Balance (accuracy 0.01g), oven. 3 data storage All the observation data were recorded in the excel table first, and then stored in the excel table. At the same time, the data of corn planting structure was sorted out, including the plant spacing, row spacing, planting time, irrigation time, except for the parent time, harvesting time and other relevant information.

2020-03-14

Canopy interception dataset of Picea crassifolia in Tianlaochi watershed of Qilian Mountain

The data are from 2011 to 2012. A 30m×30m Picea crassifolia canopy interception sample plot was set up in the Picea crassifolia sample plot at an altitude of 2800m m. A siphon raingauge model DSJ2 (Tianjin Meteorological Instrument Factory) was set up on the open land of the river about 50m from the sample plot to observe the rainfall outside the forest and its characteristics. Penetrating rain in the forest adopts a combination of manual observation and automatic observation. Automatic observation is mainly realized through a penetrating rain collection system arranged in the interception sample plot, which consists of a water collecting tank and an automatic recorder. Two 400cm×20cm water collecting tanks are connected with DSJ2 siphon rain gauge, and the change characteristics of penetrating rain under the forest are continuously recorded by an automatic recorder. Due to the spatial variability of the canopy structure of Picea crassifolia forest in the sample plot, a standard rainfall tube for manual observation is also arranged in the sample plot to observe the penetrating rain in the forest. Ninety rainfall tubes with a diameter of 20cm are arranged in the sample plot at intervals of 3m. After each precipitation event ends and the penetrating rain in the forest stops, the amount of water in the rain barrel will be emptied and the penetrating rain in the barrel will be measured with the rain cup.

2020-03-14

Coverage data of Picea crassifolia sample in Tianlaochi watershed of Qilian Mountain

The data is a fisheye photo above the interception barrel of the Picea crassifolia plot in the Tianlaochi small watershed of Qilian Mountain. The plot has a latitude and longitude of 38.44N, 99.91E, and an altitude of 2793m. Photo DSC_0008——DSC_0097 corresponds to Fisheye photos above interception barrels 1 to 90 respectively. The camera is directly above the interception barrel and the lens is 1m above the ground. It is used to estimate the cover or LAI of Qinghai spruce forest, and the pictures are processed with Gap Light Analyzer software.

2020-03-13

Grassland interception dataset of Tianlaochi watershed in Qilian Mountain

This data includes experimental data of grassland interception control and observation data of maximum water holding capacity of grassland. The maximum water holding capacity experiment was carried out in 2011. The main vegetation types selected are Carex, Polygonum viviparum, Plantago asiatica and Potentilla chinensis. The maximum water holding capacity experiment was carried out on each type of samples and the samples were photographed. The specific data obtained are shown in the document. The grassland canopy interception was carried out in the growing season of 2012, and was completed by artificial rainfall control experiment. At the end of the growing season, the main types of grassland in the basin were sampled according to grazing and grazing ban. During artificial rainfall, rainfall and penetrating rainfall are recorded every 1min. Finally, the grassland canopy interception is calculated by the difference between rainfall and penetrating rainfall.

2020-03-12

The data of canopy photosynthesis measurements of desert plants (2013)

In the middle of August 2013, photosynthesis of population was measured, and plant species: red sand. The group photosynthesis measurement system consists of li-8100 closed-circuit soil carbon flux automatic measurement system (li-cor, USA) and assimilation box designed and manufactured by Beijing ligotai science and Technology Co., Ltd. li-8100 is an instrument produced by li-cor company of USA for soil carbon flux measurement. The concentration of CO2 and H2O is measured by infrared gas analyzer. The length, width and height of assimilation boxes were all 50 cm. The assimilator is controlled by li-8100. After the measurement parameters are set, the instrument can run automatically.

2020-03-12

The experimental data of water consumption and water consumption pattern of desert plants (2012)

A small lysimeter was made by ourselves, which simulated the natural conditions and selected typical desert plants as the object to study the water consumption and its law. Repeat 3 times for each plant. In 2011, the experiment of physiological water demand and water consumption of desert plants was carried out with the soil water content kept at (50 ± 10)% of the field water capacity; in 2012, the experiment of physiological water demand and water consumption was carried out with the soil water content kept at (20 ± 5)% of the field water capacity under stress.

2020-03-12

The experimental data of water consumption and water consumption pattern of desert plants (2011)

A small lysimeter was made by ourselves, which simulated the natural conditions and selected typical desert plants as the object to study the water consumption and its law. Repeat 3 times for each plant.

2020-03-12

The data of photosynthetic organ level gas exchange measurements of desert plants (2012)

In July and mid August 2012, plant species: Caragana. Using Li-6400 portable photosynthesis system (li-cor, USA) and li-3100 leaf area meter, the photosynthetic physiological characteristics of desert plants were observed. The symbols in the observation data have the following meanings: Obs, number of observations;Photo, net photosynthetic rate, moles of CO2 times m minus 2 times s minus 1; Cond, stomatal conductance, mol H2O•m -- 2•s -- 1;Ci, intercellular CO2 concentration, moles of CO2 times mol-1; Trmmol, transpiration rate, mmol H2O•m -- 2•s -- 1;Vpdl, water vapor pressure deficit, kPa; Area, leaf Area, cm2;Tair, atmospheric temperature, ℃; Tleaf, leaf surface temperature, ℃;CO2R, CO2 concentration in the reference chamber, moles of CO2•mol-1; CO2S, sample chamber CO2 concentration, moles of CO2•mol-1;H2OR, water in the reference chamber, mmol H2O•mol-1; H2OS, sample chamber moisture, mmol H2O•mol-1;PARo, photon flux density, mole •m -- 2•s -- 1; Rh-r, reference room air relative humidity, %;Rh-s, relative humidity of air in sample room, %; PARi, photosynthetic effective radiation, moles •m -- 2•s -- 1;Press, atmospheric pressure, kPa; Others are the state parameters of the instrument at the time of measurement.

2020-03-12

The data of photosynthetic organ level gas exchange measurements of desert plants (2011)

In the middle of July, 2011, 1. Elaeagnus angustifolia, 2. Blister. Using Li-6400 portable photosynthesis system (li-cor, USA) and li-3100 leaf area meter, the photosynthetic physiological characteristics of desert plants were observed. The symbols in the observation data have the following meanings: Obs, number of observations;Photo, net photosynthetic rate, moles of CO2 times m minus 2 times s minus 1; Cond, stomatal conductance, mol H2O•m -- 2•s -- 1;Ci, intercellular CO2 concentration, moles of CO2 times mol-1; Trmmol, transpiration rate, mmol H2O•m -- 2•s -- 1;Vpdl, water vapor pressure deficit, kPa; Area, leaf Area, cm2;Tair, atmospheric temperature, ℃; Tleaf, leaf surface temperature, ℃;CO2R, CO2 concentration in the reference chamber, moles of CO2•mol-1; CO2S, sample chamber CO2 concentration, moles of CO2•mol-1;H2OR, water in the reference chamber, mmol H2O•mol-1; H2OS, sample chamber moisture, mmol H2O•mol-1;PARo, photon flux density, mole •m -- 2•s -- 1; Rh-r, reference room air relative humidity, %;Rh-s, relative humidity of air in sample room, %; PARi, photosynthetic effective radiation, moles •m -- 2•s -- 1;Press, atmospheric pressure, kPa; Others are the state parameters of the instrument at the time of measurement.

2020-03-12

The experimental data of water consumption in drought stress of desert plants (2013)

A small lysimeter was made to simulate the natural conditions and select typical desert plants as the objects to study the water consumption of drought stress treatment. Repeat 3 times for each plant. In 2012, the soil water content was kept at (20 ± 5)% of the field water capacity, and experiments on physiological water demand and water consumption were carried out under stress. In 2013, the soil water content was kept at (10 ± 3)% of the field water capacity, and further experiments on water consumption and water consumption law were carried out under drought stress.

2020-03-12