Understanding and implementation

The implementation of soil and water conservation control measures not only changes the temporal and spatial distribution of runoff and sediment due to the change of underlying surface conditions, but also effectively intercepts surface runoff, improves the utilization rate of water resources and reduces sediment entering the river. At the same time, with the expansion of afforestation and grass planting area, the improvement of vegetation coverage, and the increase of high-standard terraces and dams, the properties and roughness of the underground surface of the project area have changed, which has also changed the regional microclimate and improved the local ecological environment. Objectively analyze and evaluate the effects of ecological environment before and after the implementation of soil and water conservation projects, and investigate the main factors affecting the ecological environment-soil, runoff, biology and microclimate. The ecological benefits of soil and water conservation mainly include improving the runoff on the surface, the physical and chemical properties of soil, the microclimate attached to the stratum and the plant coverage on the ground, and describing the increase of wild animals.

this paper introduces the ecological benefit monitoring method of soil and water conservation ecological environment construction in loess plateau proposed by Kang Lingling (24), which can provide reference for ecological benefit monitoring in other regions.

first, the ecological benefits of hydrosphere

The hydrosphere mainly monitors the surface runoff flood flow and normal water flow similar to the rainfall after treatment. Because soil erosion is an important carrier of non-point source pollution, monitoring and comparing the change of water quality can reflect the reduction of non-point source pollution load before and after the implementation of soil and water conservation measures.

1. Runoff monitoring

(1) Monitoring layout.

1) Monitoring layout of runoff plot.

a. comparison between measures and no measures: comparison between terraced fields and sloping farmland, comparison between afforestation, grass planting, orchards and wasteland or abandoned farmland.

B. The slope, aspect, length, width, soil quality, etc. of each comparison plot should be basically the same, located on the same slope, on the same contour line, and in similar positions.

C. a rain gauge is set between the communities, and a self-recording rain gauge can be added if conditions permit.

D. The pool under the residential area should have sediment to accommodate the maximum storm runoff, otherwise water diversion equipment should be added. The water gauge in the pool should be clearly marked, and the water level-capacity relationship curve should be well made.

2) Monitoring layout of comparison ditch.

a. When a single measure is fully implemented in a small gully (area < ＜1.km2) (usually mainly afforestation or terraced fields), the water storage benefit can be monitored by the comparison gully method.

B. Set up monitoring at the outlet of Xiaomaogou with measures and at the outlet of Xiaomaogou with similar natural conditions nearby.

(2) monitoring methods.

1) runoff plot monitoring.

a. after each rainstorm, check the rainfall, rainfall duration and water level in the pool in time, find out the corresponding water quantity and make records in time.

B. stir the muddy water in the pool evenly, take out the muddy water sample with a standard sampler (fixed capacity), and filter to obtain the water quantity.

2) comparison ditch monitoring.

a. after each rainstorm, timely monitor the water quantity, corresponding rainfall and rainfall intensity of two small watersheds with and without measures, and make records.

B. Different monitoring devices adopt different monitoring methods. ① Monitoring of weir (trough) and channel section. After each rainstorm, check the channel section, the water level near the measuring weir (trough) and the upstream and downstream water levels in time, make a good record, and calculate the outflow according to the water level-flow relationship. ② Dam monitoring without drainage facilities. After each rainstorm, check the water level on the water gauge in front of the dam in time and make a good record. According to the relationship between water level and storage capacity, deduct the original water in the reservoir before the rainstorm to calculate the basin water yield of this rainstorm. ③ Dam monitoring with drainage facilities. After the flood season every year or after each torrential rain, on the basis of the above monitoring work, check the water level on the horizontal pipe and the drainage situation of the intake hole (the opening number of the intake) and make a good record. According to the established calculation chart and table, calculate the drainage quantity, and add it to the measured inflow in the reservoir, which is the runoff in this rainstorm basin.

2. Water quality monitoring

(1) Monitoring layout.

1) layout principle.

a. combining with runoff plot monitoring and water sampling analysis, the plot with measures is compared with the plot without measures;

b, combining the monitoring of small watersheds and analyzing water samples, comprehensively managing small watersheds and comparing them with untreated small watersheds;

C. The Yellow River tributary hydrological station in the project area combines hydrological monitoring to take water samples at appropriate locations for analysis.

2) layout of monitoring points.

a. layout of monitoring station network. According to the characteristics of water system and the distribution characteristics of the project area. All rivers with project implementation should set up stations. In view of the scattered project area, representative stations should be set up at the outlet of the small watershed where the project area is located. The layout of station network should be combined with hydrological station, flow station or water and sediment monitoring station as far as possible.

B. layout of sampling section. ① Control section: set up a control section where the river enters the upstream of the project area and is not affected by pollution; Or choose a river outside the project area that is basically consistent with the conditions in the project area to set up a control section. ② Control section: in the downstream of the project area, the place that can reflect the pollution of the project area is generally located 5 ~ 1 m away from the project area. The number of control sections in a river section should be determined according to the project division and the actual situation of the river basin. ③ Cut-off section: set up a cut-off section at the downstream of the control section and the river section where the water quality is diluted, which is generally located 15m away from the project area. Fixed and obvious signs shall be set up on each sampling section, so that the samples collected each time are taken from the same position.

C. determination of sampling point position. On a sampling section, when the water surface width is more than 1 m, three vertical lines are set: left, middle and right. 5 ~ 1 m, in addition to the Zhonghong line, set another vertical line; When it is less than ＜5m, only one vertical line is set in Zhonghong. On a vertical line, when the water depth is more than 5m, two points are set, namely one point at .3～.5m below the water surface and one point at about 1m on the river bottom; When the water depth is less than 5m, only one point is set at .3～.5m below the water surface.

(2) monitoring content. According to the characteristics of river water and the actual situation of the project area, pH value, BOD5, COD, NH3-N, NO2-N and organophosphorus pesticides are selected as the main monitoring items. Total hardness, CO2-3, SO2-4, Ca2+, Mg2+, K+, arsenic and cyanide are secondary monitoring items. At the same time, flow observation is carried out.

(3) water sampling method.

1) Collection quantity and preservation method. The amount of water samples collected should meet certain requirements and be analyzed and tested within the specified storage time. See Table 9-45 for the water sample consumption and preservation methods of common water quality monitoring projects. The determination method of water quality is carried out according to GB3838—22.

table 9-45 water sample consumption and preservation method

2) sampling frequency. The main monitoring items shall be collected once in January-February, and the sampling time shall not be less than 6-8 times a year, and they can be sampled twice or bimonthly in wet season (flood season), dry season (before flood season) and normal season (after flood season). Secondary monitoring items shall be sampled not less than 3 times a year, and may be sampled once each in the rainy, dry and normal periods.

3) sampling method. ① Ship sampling: Generally, small boats can be used for river sampling, and it is better to have special monitoring boats or sampling boats. In order to be safe and reliable, ships with appropriate tonnage should be selected in consideration of water regime and climatic conditions. You must wait for the ship to stop before taking samples. ② Bridge sampling: When determining the sampling section, convenient traffic should be considered, and the existing bridge sampling should be used as much as possible. (3) Wading sampling: Shallow rivers and shallow sampling points near the shore can be waded for sampling. However, it is necessary to avoid stirring the sediment at the bottom of the water and polluting the water sample. When wading for sampling, the sampler should collect water samples facing the upstream direction.

second, the ecological benefits of the soil circle

The ecological benefits of the soil circle mainly monitor the changes of soil moisture, nitrogen, phosphorus, potassium, organic matter, aggregate structure, porosity and other physical and chemical properties before and after the implementation of soil and water conservation measures.

1. Monitoring layout

(1) Layout principle.

1) Take the county (tributary) as a unit to control, and set up monitoring points in different soil types, different measures, different plot types (terraced fields, sloping farmland, woodland, orchard, grassland and wasteland) and different positions (upper, middle and lower);

2) The monitoring points at different levels should be compared horizontally with and without projects (the soil type should be the same) and vertically with different periods before and during the project implementation;

3) from the implementation of the project, the monitoring shall be fixed for a long time, and the observation shall be continuously recorded at different time periods (at least one growing season), and the annual point-by-point monitoring registration form and monitoring results table shall be submitted.

(2) layout of monitoring points.

1) in the non-project area, select the area adjacent to the project area with basically the same natural conditions and soil types as the control point;

2) take the county (tributary) as a unit, and each county (tributary) shall set up representative monitoring points according to the soil type and land use status, combined with the actual situation of the county (watershed).

2. Monitoring content

(1) Monitoring the basic situation of the project area.

1) types, quantities, proportion, application methods and yield-increasing benefits of pesticides and fertilizers;

2) Types, sources, application amounts, application methods, proportion with chemical fertilizers and yield-increasing effects of organic fertilizers;

3) After vegetation measures are implemented, the thickness of ground litter will be increased.

(2) Monitoring of soil basic conditions.

1) Soil type: soil species, parent material, basic fertility status and maturity;

2) Soil properties: soil configuration, effective soil layer thickness and soil texture.

(3) Physical properties of soil.

1) particle composition;

2) bulk density, specific gravity and porosity;

3) water content.

(4) chemical properties of soil.

1) total nitrogen, total phosphorus, total potassium, available phosphorus and available potassium;

2) pH;

3) cation exchange capacity (CEC).

3. Sampling method

(1) Sampling of soil physical properties. Select a representative position, dig a hole to collect undisturbed soil in layers or use a specific tool (such as a circular knife) to sample, and pay attention to keep the clods from being squeezed and deformed;

(2) Collection of soil mixed samples. According to the purpose of the test and the size of the test area, the sampling depth (generally 2cm) and the number of sampling points are determined. In the determined monitoring plots, different sampling points (5 ~ 2) were selected according to the area, and about 1kg of mixed samples were collected by layers. If the sample exceeds 1kg, it should be shrunk by quartering;

(3) Method of sample collection. Diagonal sampling method is used for small area, checkerboard sampling method (up, middle, down, left, middle and right) is used for moderate area, and snake (S-shaped) sampling method is used for large area. However, in order to avoid systematic errors, samples are usually taken along the S-shaped route. The determination methods of soil physical and chemical properties refer to the Analytical Methods of Soil Agrochemistry (2) compiled by China Soil Society.

third, the ecological benefits of the atmosphere

The ecological benefits of the atmosphere mainly monitor the changes of microclimate (temperature, humidity, wind power, etc.) in small watersheds or regions before and after the implementation of soil and water conservation measures, and increase crop yield due to the improvement of microclimate. In case of natural disasters such as frost, freezing and dry hot wind, we should further understand the role of improving microclimate in alleviating natural disasters.

1. Monitoring layout

(1) Classification of monitoring points. Microclimate monitoring in the project area is different from that observed by general weather stations. When selecting observation points, the representativeness of the observation points and the comparability of observation data must be considered. Therefore, the selected measuring points are usually divided into basic measuring points and control measuring points.

1) basic measuring points. A fixed measuring point set up in a representative section of the project area.

2) control points. The measuring points located outside the project area, which are not affected by the climate of the project area, but also close to the project area and belong to the same climate type area as the project area.

(2) the principle of selecting points.

1) density of measuring point. (1) the layout density is generally controlled at one measuring point every 4km2; If the project area is relatively large and the control measures are single, the layout density can be relaxed to one measuring point every 6km2. ② At least two basic points and two control points should be arranged in any project area.

2) representativeness of measuring points. The basic measuring point is generally located in the downwind area of the prevailing wind direction in the middle of the project area. If the local weather station is entrusted as the basic point due to conditions, its location should also be in the project area.

3) comparison of measuring points. After the basic measuring point is selected, at the same time, the control point should be selected on the line perpendicular to the prevailing wind direction in the project area through the basic measuring point, so as to conduct parallel observation with the basic point. The distance between the control point and the project area should be controlled within 1 ~ 5 km.

4) Similarity of measuring points. The area where the control point is located should be consistent or basically consistent with the natural environment where the basic point is located except the factors that need to be compared (such as vegetation coverage, etc.).

(3) Selection of monitoring points.

1) entrust the weather station (park). In order to reduce investment and ensure data quality, existing meteorological stations (parks) that meet the above conditions should be entrusted as monitoring points as far as possible.

2) new measuring point. If there is no condition to entrust a weather station in the project area, or after entrusting a weather station, the layout density can not be reached, new monitoring points should be added.

2. Monitoring items

(1) Temperature-regular temperature and daily maximum and minimum temperature.

(2) precipitation-time period precipitation and daily precipitation.

(3) Humidity-absolute and relative humidity and daily minimum relative humidity.

(4) wind-wind speed and direction.

(5) weather phenomena-fog, frost, sandstorm, sand blowing and strong wind.

3. Observation time and instruments

(1) Observe regularly at 2: , 8: , 14: and 2: every day.

(2) The basic measuring points and the control measuring points should be observed synchronously.

(3) The thermometer, hygrometer, self-recording rain gauge and electric wind anemometer shall be recorded continuously for 24 hours.

4. Monitoring methods

(1) Temperature and humidity monitoring methods.

1) Procedure and accuracy of timing observation. ① Procedures for regular observation: dry bulb, wet-bulb thermometer, alcohol column of the lowest thermometer, cursor of the highest thermometer and the lowest thermometer, adjust the readings of the highest and lowest thermometers, thermometers and hygrometers and make time marks. ② Observation accuracy: The readings of various thermometers should be accurate to .1℃, and "-"should be added when the temperature is below ℃. The reading shall be recorded in the corresponding column of the observation book, and the device error shall be corrected according to the attached verification certificate.

2) observation and adjustment of the highest and lowest thermometers. (1) the highest and lowest thermometer observation once a day at 2 o' clock, must adjust the thermometer after measurement. ② Method of adjusting the maximum thermometer: Hold the thermometer body by hand, with the sensing part downward and the arm extending outward by about 3. Swing the thermometer back and forth with the big arm, and the mercury in the capillary can fall to the sensing part, so that the indicated temperature is close to the dry bulb temperature at that time. ③ Method of adjusting the minimum thermometer: raise the sensing part of the thermometer, tilt the body, and return the cursor to the top of the alcohol column.

3) Check the water vapor pressure and relative humidity. Using the dry and wet bulb temperatures corrected by the instrument, the water vapor pressure and relative humidity values are retrieved from the Meteorological Common Table.

4) Selection and determination of extreme value. The selection and determination of daily extreme maximum, minimum temperature and daily minimum relative humidity should be combined with the self-recording records of thermometer and hygrometer.

(2) methods of precipitation monitoring.

1) precipitation (mm) shall be 1 decimal place. Equipped with a self-recording rain gauge, make continuous records and sort them out.

2) Observe the precipitation in the first 12 hours at 8: and 2: every day.

3) For the observation of solid precipitation, it can be measured with a cup after melting, or it can be weighed with a platform scale.

4) when there is no precipitation, the column of precipitation is left blank.

(3) wind monitoring