Method for improving low organic soil
Technical Field
The invention particularly relates to a method for improving low organic soil, and belongs to the technical field of soil improvement.
Background
The soil improvement requires the application of the theoretical technologies of multiple subjects such as soil science, ecology and the like to improve the soil characteristics, improve the soil fertility and create a good soil environment. The soil improvement mainly comprises barren soil improvement, saline-alkali soil improvement, acidified soil improvement, soil structure improvement and the like. The barren soil, namely the low organic soil, is widely distributed in the northwest of China and has the characteristics of small viscosity, weak water and fertilizer retention capacity, low nutrient content and the like. The improvement of the low organic soil is an important component in soil improvement in China.
The soil organic matter not only can provide nutrition for plant growth, increase the effectiveness of the nutrition, retain water and fertilizer, and enhance the buffering capacity of soil to acid and alkali, but also can promote the formation of a soil granular structure, improve the physical properties of the soil and the like. Currently, there are several types of methods for improving low organic soil: 1) a large amount of organic fertilizer is applied, and the applied organic fertilizer is easy to form humus, so that the formation of granular structures and the improvement of organic matters are promoted; 2) foreign soil, which is low organic soil improved by using non-local native high organic soil such as river mud and pond mud; 3) applying agricultural biological measures including land leveling, soil fertility improvement, economic crop planting or green manure; 4) adopting deep autumn sand pressing on the low organic soil with a thinner sand layer to blend the clay at the bottom layer with the sand at the surface layer so as to increase the organic content of the clay; 5) the soil is improved by using chemical reagents such as soil conditioner.
The above-mentioned methods for improving low organic soil generally require complicated improvement measures and agents, and require a large investment in capital and time. Therefore, it is necessary to develop a method with simple operation and low cost to realize effective improvement of low organic soil.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a method for improving low organic soil, which utilizes the stable combination of the percolate of the domestic garbage landfill stored stably in a regulating and storing pool and the low organic soil under the aerobic condition, has simple and convenient operation, can realize the resource utilization of the percolate of the domestic garbage landfill, reduce the improvement cost of the low organic soil and the treatment amount of the percolate, improve the water and fertilizer retention capacity and the nutrient (organic matters and nitrogen) content of the low organic soil, and realize the effective improvement of the low organic soil.
In order to achieve the technical purpose, the technical scheme of the invention is as follows:
a method for improving low organic soil comprises the following steps: mixing low organic soil with organic content less than 1% and biochemical oxygen demand: the leachate of the domestic garbage landfill with the chemical oxygen demand B/C less than 0.1 is prepared from the following components in percentage by mass (2.5-5.3): 1, paving and placing the mixed soil under an aerobic condition, and continuously replenishing percolate into the mixed soil along with the reduction of water in the mixed soil so as to keep the water content in the mixed soil unchanged all the time until the organic matter content of the organic matter soil in the mixed soil is more than 3 percent.
Preferably, the leachate of the domestic refuse landfill reaches a stable state after being stored or treated by a storage tank.
Preferably, the leachate is characterized in that: the pH value is 7.5-8.3; alkalinity of 7000 to 9000mgCaCO3/L; CODCr4000~6500mg/L;BOD5120-200 mg/L, biochemical oxygen demand: chemical oxygen demand is less than 0.1; the low organic soil is characterized in that: the volume weight is 1.0-1.7 g/cm3The water holding capacity in the field is less than 25%, the pH value is 7.5-8.5, and the organic matter content is less than 1%.
Preferably, the aerobic condition refers to that the mixed soil is paved in the air at room temperature, the paving thickness is not more than 0.5m, and the soil is turned and stirred every 3 days.
Preferably, the leachate is irrigated to the surface of the low organic soil by an irrigation method to realize mixing with the low organic soil.
Further preferably, the irrigation means may be furrow irrigation or drip irrigation.
From the above description, it can be seen that the present invention has the following advantages:
1. according to the invention, the household garbage landfill leachate and the low organic soil are mixed and then are paved under an aerobic condition, so that organic matters and nitrogen in the leachate can be stably combined with the low organic soil, wherein humus in the leachate is transferred to the low organic soil to provide a better matrix environment for microorganisms in the low organic soil, and conversely, the microorganisms with the good matrix environment can better promote a large amount of ammonia nitrogen in the leachate to be converted into nitrate nitrogen to be used as a nitrogen fertilizer through nitrification, so that the water and fertilizer retention capacity and the nutrient (organic matters and nitrogen) content of the low organic soil are improved, and the effective improvement of the low organic soil is realized.
2. The method is simple and convenient to operate, can realize the resource utilization of the leachate of the domestic garbage landfill, and reduces the cost for improving the low organic soil and the treatment capacity of the leachate.
Drawings
FIG. 1 is a schematic process diagram of the process of the present invention;
Detailed Description
The features of the invention will be further elucidated by the following examples, without limiting the claims of the invention in any way.
In the following embodiments of the present invention, the low organic soil is loess from northwest China; the percolate is taken from a percolate storage tank of a certain landfill.
Example 1:
(1) low organic matter soil characteristics
The improved object of the embodiment is barren soil with soil organic matter content below 1%, and the typical characteristics are as follows: the volume weight is 1.0-1.2 g/cm3The water content is 3-5%, the pH is 7.5-8.0, and the organic matter content is 0.5-0.75%.
(2) Stabilization of leachate characteristics
The leachate selected by the embodiment is a domestic garbage landfill leachate stored stably in a storage tank, and is characterized in that: pH: 8.0 to 8.3; alkalinity: 8000-9000 mgCaCO 3/L; CODCr:4000~ 4200mg/L;BOD5: 120-150 mg/L, and B/C (biochemical oxygen demand: chemical oxygen demand) is 0.03.
(3) Composition ratio
The invention requires that the mass ratio of the low organic soil to the percolate is 2.5-5.3, namely the water content of the mixed soil is 16-28 percent, and the content of the low organic soil is 72-84 percent. In this embodiment, the mass ratio of the low organic soil to the leachate is 5:1, the water content of the mixed soil at this time was 16.7%.
(4) Improvement method
Sprinkling the percolate of the household garbage landfill site with the characteristics to the surface of the low organic soil with the characteristics to realize the mixing of the percolate and the low organic soil, wherein the mass ratio of the low organic soil to the percolate is 5:1 (namely the water content of the mixed soil is 16.7%), paving the mixed soil in the air at room temperature, the paving thickness is not more than 0.5m, turning and stirring the soil every 3 days, continuously replenishing the percolate into the mixed soil along with the reduction of the water content of the mixed soil to always keep the water content of the mixed soil unchanged, taking a sample every ten days in the paving and placing process for detection, detecting that the organic content of the organic soil in the mixed soil is more than 3% when sampling for the sixth time (namely the improvement time is 60 days), and stopping improvement.
(4) Improved effect
The soil properties before and after the improvement of the low organic soil are shown in table 1, and the heavy metal content in the soil is shown in table 2;
TABLE 1 soil Properties before and after improvement of Low organic soil
TABLE 2 heavy metal content in soil before and after improvement of Low organic soil
The data show that the leachate improved low organic soil can effectively improve the organic content and the nitrogen element content of the leachate improved low organic soil, and the heavy metal content of the soil can not be obviously improved. Therefore, the method for improving the low organic soil by using the stable leachate is an economic and effective scheme.
Example 2:
(1) low organic matter soil characteristics
The improved object of the embodiment is barren soil with soil organic matter content below 1%, and the typical characteristics are as follows: the volume weight is 1.2-1.5 g/cm3The water content is 6-8%, the pH is 7.8-8.2, and the organic matter content is 0.7-0.9%.
(2) Stabilization of leachate characteristics
The leachate selected by the embodiment is a domestic garbage landfill leachate stored stably in a storage tank, and is characterized in that: the pH value is 7.5-8.0; alkalinity of 7000 to 8000mgCaCO3/L;CODCr5000~5500mg/L; BOD5150~200mg/L;B/C 0.03。
(3) Composition ratio
The invention requires that the mass ratio of the low organic soil to the percolate is 2.5-5.3, namely the water content of the mixed soil is 16-28 percent, and the content of the low organic soil is 72-84 percent. In this embodiment, the mass ratio of the low organic soil to the leachate is 4:1, and the water content of the mixed soil is 20%.
(4) Improvement method
And (2) drip-irrigating the percolate of the household garbage landfill site with the characteristics to the surface of the low organic soil with the characteristics to realize the mixing of the percolate and the low organic soil, wherein the mass ratio of the low organic soil to the percolate is 4:1 (namely the water content of the mixed soil is 20%), paving the mixed soil in the air at room temperature, the paving thickness is not more than 0.5m, turning and stirring the soil every 3 days, continuously replenishing the percolate into the mixed soil along with the reduction of the water content of the mixed soil to always keep the water content of the mixed soil unchanged, taking a sample every ten days for detection in the paving and placing process, detecting that the organic content of the organic soil in the mixed soil is more than 3% when sampling is carried out for the fifth time (namely the improvement time is 50 days), and stopping improvement.
(4) Improved effect
The soil properties before and after the improvement of the low organic soil are shown in table 3, and the heavy metal content in the soil is shown in table 4;
TABLE 3 soil Properties before and after improvement of Low organic soil
TABLE 4 heavy metal content in soil before and after improvement of Low organic soil
The data show that the leachate improved low organic soil can effectively improve the organic content and the nitrogen element content of the leachate improved low organic soil, and the heavy metal content of the soil can not be obviously improved. Therefore, the method for improving the low organic soil by using the stable leachate is an economic and effective scheme.
Example 3:
(1) low organic matter soil characteristics
The improved object of the embodiment is barren soil with soil organic matter content below 1%, and the typical characteristics are as follows: the volume weight is 1.4-1.7 g/cm3The water content is 8-10%, the pH is 8.2-8.5, and the organic matter content is 0.6-0.8%. .
(2) Stabilization of leachate characteristics
The leachate selected by the embodiment is a domestic garbage landfill leachate stored stably in a storage tank, and is characterized in that: the pH value is 7.5-7.8; alkalinity of 7000 to 7500mgCaCO3/L;CODCr:6000~ 6500mg/L;BOD5150~170mg/L;B/C 0.025。
(3) Composition ratio
The invention requires that the mass ratio of the low organic soil to the percolate is 2.5-5.3, namely the water content of the mixed soil is 16-28 percent, and the content of the low organic soil is 72-84 percent. In the embodiment, the mass ratio of the low organic soil to the percolate is 3:1, and the water content of the mixed soil is 25%.
(4) Improvement method
And (2) drip-irrigating the percolate of the household garbage landfill site with the characteristics to the surface of the low organic soil with the characteristics to realize the mixing of the percolate and the low organic soil, wherein the mass ratio of the low organic soil to the percolate is 3:1 (namely the water content of the mixed soil is 25%), paving the mixed soil in the air at room temperature, the paving thickness is not more than 0.5m, turning and stirring the soil every 3 days, continuously replenishing the percolate into the mixed soil along with the reduction of the water content of the mixed soil to always keep the water content of the mixed soil unchanged, taking a sample every ten days for detection in the paving and placing process, detecting that the organic content of the organic soil in the mixed soil is more than 3% when sampling for the fourth time (namely the improvement time is 40 days), and stopping improvement.
(4) Improved effect
The soil properties before and after the improvement of the low organic soil are shown in table 5, and the heavy metal content in the soil is shown in table 6;
TABLE 5 soil Properties before and after improvement of Low organic soil
TABLE 6 heavy metal content in soil before and after improvement of Low organic soil
The data show that the leachate improved low organic soil can effectively improve the organic content and the nitrogen element content of the leachate improved low organic soil, and the heavy metal content of the soil can not be obviously improved. Therefore, the method for improving the low organic soil by using the stable leachate is an economic and effective scheme.
Comparative example 1:
taking the household garbage landfill leachate and the low organic soil which are the same as those in the embodiment 1, sprinkling the household garbage landfill leachate onto the surface of the low organic soil with the characteristics to realize the mixing of the leachate and the low organic soil, wherein the mass ratio of the mixed low organic soil to the leachate is 6:1 (namely the water content of the mixed soil is 14%), paving and placing the mixed soil in the air at room temperature, continuously supplementing the leachate into the mixed soil along with the reduction of the water content of the mixed soil to always keep the water content of the mixed soil unchanged, and stopping good soil after paving and placing for 60 days. The soil properties before and after the improvement of the low organic soil are shown in table 7, and the heavy metal content in the soil is shown in table 8;
TABLE 7 soil Properties before and after improvement of Low organic soil
TABLE 8 heavy metal content in soil before and after improvement of Low organic soil
When the mass ratio of the low organic soil to the percolate is 6:1, after 60 days of improvement culture, the content of organic matters in the organic soil in the mixed soil is detected to be still less than 3%, and meanwhile, the improvement of nitrogen is only 5.6%, and the improvement effect is far less than that of the embodiment 1.
Comparative example 2:
and mixing the low organic soil with the percolate, wherein the mass ratio of the low organic soil to the percolate is less than 2.5: 1.
When the mass ratio of the low organic soil to the percolate is 2.5:1, the water content of the mixed soil is 28.6%, the maximum field water capacity of the adjacent soil (the maximum field water capacity after the low organic matter soil is improved is measured by an experiment to be 280-290g/kg, namely the water content at the moment is about 28-29%), and therefore, when the mass ratio of the low organic matter soil to the percolate is less than 2.5:1, the risk of pollution to the surrounding environment due to overflow of the percolate exists.
It should be understood that the detailed description of the invention is merely illustrative of the invention and is not intended to limit the invention to the specific embodiments described. It will be appreciated by those skilled in the art that the present invention may be modified or substituted equally as well to achieve the same technical result; as long as the use requirements are met, the method is within the protection scope of the invention.