CN104350988A

CN104350988A - Rice field selenium application method for reducing Cd concentration in rice

Info

Publication number: CN104350988A
Application number: CN201410454263.XA
Authority: CN
Inventors: 刘建国; 瞿鹏; 柴育红
Original assignee: Changzhou University
Current assignee: Changzhou University
Priority date: 2014-09-05
Filing date: 2014-09-05
Publication date: 2015-02-18

Abstract

The invention relates to a rice field selenium application method for reducing Cd concentration in rice and belongs to the technical field of agricultural product heavy metal pollution prevention and control. The method comprises the following specific steps: in a Cd polluted rice field, applying Se for three times with the total amount of 60 g/hm2 of pure Se, namely applying 1/2 of the total Se applying amount one day before rice seedling transplanting, applying 1/4 of the total Se applying amount 20 days after rice seedling transplanting, and applying 1/4 of the total Se applying amount three days before heading. With adoption of the rice field selenium application method, the Cd concentration in rice can be greatly reduced, and the rice yield can be obviously increased.

Description

Selenium method is executed in a kind of rice field reducing rice cadmium concentration

Technical field

The present invention is that selenium method is executed in a kind of rice field reducing rice cadmium concentration, belongs to agricultural product Heavy Metal Pollution technology.

Background technology

Since the 1950's, along with increasing considerably of the size of population, the fast development of the industry such as mining, smelting and manufacture, a large amount of use of agricultural chemicals and the discharge of urban sewage dirt, the metallic element causing Cd, Pb, Hg, Cu etc. poisonous to biology accumulates in the environment fast, excessively, this problem of environmental pollution caused by mankind's activity attracts wide attention, the major part of these metallic elements is summarised in together, is referred to as " heavy metal (Heavy metals) " element.In each heavy metal element, cadmium (Cd) is one of element that the degree of receiving publicity is the highest, because Cd is easily absorbed by plants, and often through food chain to human body enrichment.

Cd is high to human toxicity, and the accumulation that is easily absorbed by the body.Have abundant result of study to prove, Cd has very strong carcinogenesis to the lung of animal, prostate, suprarenal gland, the multiple organ such as testis and hemopoietic system.According to Japanology, the rice that long-term edible Cd content is high can cause human kidney dysfunction, causes lethality to rise, the lost of life.Betide the Itai-itai diseases in magic basin, river, Toyama County, Japan, confirmed it is because local resident is for a long time caused by the edible rice polluted by Cd by Japanese Environment mechanism.Cd is defined as the carcinogen to the mankind by international cancer research institution (International Agency for Research on Cancer).

In Chinese industrial and mining area and developed area, along with the quick increase of the size of population, the using in a large number of industrial expansion and agricultural chemicals, the heavy metal pollution of agricultural land soil is on the rise.China digs up mine to 20 many places, smelt and the investigation of industrial wastewater pollution point shows, the farmland Cd in some areas pollutes very serious, and area and degree in rising trend.Agricultural land soil as Yang Shuo, Guangxi Pb-Zn deposits contaminated wastewater reaches 10-136mg/kg containing Cd amount; The contaminated farmland area 2800hm in Zhang Shi irrigated area, Shenyang ², soil Cd content 5-7mg/kg; The farmland of the chimney of the Daye, hubei Province copper works cadmium of discharging to around 10km scope pollutes, and polluted agricultural land area reaches 8700hm ²; The average cadmium content of agricultural land soil that the cadmium wastewater of Shanghai zine-smelting plant discharge pollutes reaches 7.7mg/kg; " world's tungsten all " Dayu County, Jiangxi spread all over tungsten ore factory, reach hm more than 5000 by rural sewage disposal farm area ², the average cadmium content of soil is 0.62mg/kg, similar to the cadmium pollution situation in Japan's remarkable ability basin, river.Above-mentioned contaminated region rice grain Cd concentration is 0.29-1.09mg/kg, all exceedes state health standards.Chinese Academy of Sciences Nanjing soil the sampling Detection in county of city of Jiangsu Province 8 28 is shown, Jiangsu Part area grain (rice, wheat, flour) Cd concentration over-standard rate reach 25%.And paddy rice has an outstanding feature to be to the absorption of Cd and accumulation: often grow and be not affected, but the Cd concentration of rice has exceeded sanitary standard several times, even more than ten times.Therefore, the movement of Cd in soil-rice-human system and accumulation are shown great attention to.

Cd concentration in rice not only can be subject to the impact of soil pollution situation and rice varieties, also can be subject to the impact of culture technique.In growth process of riceplant, the agronomic measures such as fertilising, water management can change the physics and chemistry situation of soil and the upgrowth situation of paddy rice, thus can change the existence of Cd in soil and the validity to plant, affect paddy rice to the absorption of Cd and distribution.There are some researches show, selenium is executed in rice field can reduce the absorption of paddy rice to Cd, reduces the Cd concentration in rice, but selenium level of executing about rice field and execute selenium period in the affecting of rice Cd concentration, yet there are no open report, thus lack the rice field reducing Cd concentration in rice and execute selenium method.

The present invention is on the basis that applicant studies for many years, and disclose a kind of in heavy metal Cd pollution rice field, significantly can reduce the Cd concentration of rice, selenium method is executed in the rice field that can significantly improve again rice yield.

Summary of the invention

Technical problem to be solved by this invention is: provide a kind of rice field reducing rice Cd concentration to execute selenium method, and significantly can reduce the rice Cd concentration in Cd pollution rice field, rice yield is also significantly improved.

The technical solution adopted for the present invention to solve the technical problems is: selenium method is executed in a kind of rice field reducing rice cadmium concentration, it is characterized in that: within the whole Rice Production cycle, always executing selenium amount is 60g/hm2 (in pure Se), divide and use for 3 times, respectively before paddy rice is transplanted seedlings 1 day total selenium amount of Shi 1/2, after transplanting seedlings 20 days and heading the first 3 days total selenium amounts of each Shi 1/4.

Before executing selenium, first rice field is filled with thin water layer (about 3cm), spray fertile soluble in water for selenium, per hectare water consumption is about 450kg, and fertilizer evenly sprays application in rice field after dissolving mixing, pours water after allowing water layer naturally fall to doing again.

The invention has the beneficial effects as follows: after Cd contaminated region, rice field is implemented, significantly can reduce the Cd concentration of rice, rice yield is also significantly improved.Do not execute compared with selenium (contrast) with conventional in paddy rice actual production, rice Cd concentration fall is large, and (long-grained nonglutinous rice declines 80.4%, japonica rice declines 72.7%), and rice yield is significantly improved (long-grained nonglutinous rice improves 6.0%, and japonica rice improves 5.4%).Heavy metal Cd serious pollution area, rice field (soil Cd concentration is about 10mg/kg), by the enforcement of this application art solutions, the Cd concentration that can control rice lower than or significantly lower than state health standards Limited Doses (rice Cd concentration <0.2mg/kg).

Embodiment

Embodiment 1: selenium method is executed in a kind of rice field reducing rice cadmium concentration, within the whole Rice Production cycle, always executing selenium amount is 60g/hm ²(in pure Se), amounts to every mu of 4g.Point to use for 3 times, respectively before paddy rice is transplanted seedlings 1 day total selenium amount of Shi 1/2, after transplanting seedlings 20 days and the heading first 3 days total selenium amounts of each Shi 1/4.Because the selenium content of the fertile kind of different selenium is variant, when executing selenium, concrete fertilizing amount to be calculated according to the selenium content of concrete fertilizer variety.

First rice field is filled with thin water layer (about 3cm) before fertilising, spray soluble in water for fertilizer, per hectare water consumption is about 450kg, and fertilizer evenly sprays application in rice field after dissolving mixing, pours water after allowing water layer naturally fall to doing again, not draining before water layer falls to doing.

In the selection of rice varieties, the japonica rice variety more weak to Cd absorbing capacity in soil should be selected, should not select the stronger long-grained nonglutinous rice of Cd absorbing capacity or Hybrid Rice Varieties.

Mode below by list proves that the present embodiment significantly can reduce the Cd concentration of rice further, and rice yield is also significantly improved.In table, data obtain under soil Cd concentration is 10mg/kg (serious pollution degree) condition, and its nitrogen, phosphorus, Potassium Fertilizer Application are medium Fertilization Level, and other control measures are undertaken by Rice Production routine.

The rice cadmium concentration that table 1 rice field difference is executed under selenium method compares (unit: mg/kg)

Note: selenium code in period is executed in rice field

A-is disposable employed as base manure (paddy rice is transplanted seedlings first 1 day).

B-divides 2 fertilisings.1 day (base manure) and 1/2 of the latter 20 days total selenium amounts of (tillering fertilizer) each Shi of transplanting seedlings before paddy rice is transplanted seedlings respectively.

C-divides 3 fertilisings.Before paddy rice is transplanted seedlings 1 day total selenium amount of (base manure) Shi 1/2, after transplanting seedlings 20 days (tillering fertilizer), ear first 3 days (granulated fertilizer) respectively the total selenium amount of Shi 1/4.

The rice yield that table 2 rice field difference is executed under selenium method compares (unit: kg/hm ²)

From executing selenium level and executing selenium aspect in period two, it is visible that his-and-hers watches 1 and table 2 carry out analysis:

(1) execute selenium level, execute selenium amount in pure Se.

Executing selenium level, too high (height executes selenium level, 120g/hm ²), rice Cd concentration with in execute selenium level and there is no notable difference, rice yield with in execute that long-grained nonglutinous rice compared with selenium level declines to some extent, japonica rice is remained basically stable, but execute selenium cost and can increase substantially;

Execute that selenium level is too low (lowly executes selenium level, 30g/hm ²), rice Cd concentration with in execute compared with selenium level and be improved largely, rice yield with in execute compared with selenium level and have obvious decline.

(2) selenium period is executed

Point using for 3 times disposable employed with as base manure (paddy rice is transplanted seedlings first 1 day) or to use for 2 times with tillering fertilizer (transplanting seedlings latter 20 days) point as base manure and compare, the Cd concentration of rice has and significantly declines, and rice yield is significantly improved.

Claims

1. a selenium method is executed in the rice field reducing rice cadmium concentration, it is characterized in that: pollute in rice field at Cd, always execute selenium amount and count 60g/hm with pure Se ², point to use for 3 times, respectively before paddy rice is transplanted seedlings 1 day total selenium amount of Shi 1/2, after transplanting seedlings 20 days and the heading first 3 days total selenium amounts of each Shi 1/4.