Safe utilization method for cadmium and arsenic combined pollution rice fields

Abstract

The invention discloses a safe utilization method for cadmium and arsenic combined pollution rice fields. The method includes the following steps: S1, applying 100-300 kg / mu of a weakly alkaline soilconditioner 5-10 days before rice is sowed or transplanted; S2, spraying a leaf surface resistance-control agent containing silicon and selenium on the rice for one time at the peak tillering stage ofthe rice; S3, at the late tillering stage and filling stage of the rice, performing moistening irrigation so as to make fields have no stagnant water; and S4, spraying the leaf surface resistance-control agent containing the silicon and the selenium on the rice for one time at the late booting stage of the rice, wherein the soil conditioner consists of, by mass percentage, 18-28% of water slag powder, 25-35% of biochar, 15-25% of organic fertilizer and 25-35% of bentonite. The provided method for governing cadmium and arsenic combined pollution rice fields is low in cost and high in efficiency; and cadmium and arsenic content in the rice can be greatly reduced, substances used during treatment have no harm to human bodies, so that the method is safe and environment-friendly.

Description

technical field [0001] The invention belongs to the technical field of agricultural environment conservation and restoration, and in particular relates to a method for safely utilizing cadmium-arsenic compound polluted paddy fields. Background technique [0002] In 2014, the Ministry of Land and Resources and the Ministry of Environmental Protection jointly issued the "National Soil Condition Survey Bulletin", pointing out that the soil environment of my country's cultivated land is not optimistic, and the rate of points exceeding the standard reaches 19.4%, of which cadmium (Cd) and arsenic (As) are two a major pollutant. In the specific farmland environment, domestic relevant scientific research institutes and enterprises have developed many more mature products and technologies for the safe utilization of these two types of polluted farmlands, cadmium single pollution and arsenic single pollution. In recent years, with the detailed investigation of soil pollution and the ...

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Problems solved by technology

[0006] (1) Affect normal agricultural production

During the implementation period of phytoremediation technology (usually lasting for several years), ordinary crops can no longer be planted, which will seriously affect local agricultural production, which is not in line with the reality of my country's large population and small land

[0007] (2) The effect of simultaneously reducing the accumulation of cadmium and arsenic in agricultural products needs to be improved

Some products or technologies can reduce the content of cadmium in agricultural products very well, but they will increase the soil pH or reduce the redox potential of the soil, resulting in poor effect on reducing arsenic; some products or technologies can reduce the content of arsenic in agricultural products very well content, but it will reduce the soil pH or increase the redox potential of the soil, resulting in a poor effect of reducing cadmium in agricultural products

[0008] (3) The cost is too high

For example, phytoremediation technology, which uses planting and removal of castor and centipede grass to reduce cadmium and arsenic content in the soil, will cost 30,000 to 80,000 yuan / mu to achieve the expected goal, and it is difficult to promote it on a large scale

[0009] (4) Some raw materials have certain toxicity to organisms and have a strong risk of secondary pollution

If some invention patent products contain ferrous sulfate as the raw material, this substance has strong biological toxicity and is irritating to the human respiratory tract, eyes, skin and mucous membranes. Liver damage, shock, coma, etc., can be fatal in severe cases. In addition, it is highly toxic to soil and aquatic organisms and has poor safety

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