CN103460873A

CN103460873A - Rice field phosphate fertilizer application method capable of reducing cadmium content in rice grains

Info

Publication number: CN103460873A
Application number: CN2013103910860A
Authority: CN
Inventors: 刘建国; 马新美; 王明新
Original assignee: Changzhou University
Current assignee: Changzhou University
Priority date: 2013-08-30
Filing date: 2013-08-30
Publication date: 2013-12-25

Abstract

The invention relates to a rice field phosphate fertilizer application method capable of reducing the cadmium content of rice grains. The phosphate application level is high; the total phosphate application amount is 135kg/hm<2> based on effective constituents P2O5; phosphate fertilizers are applied for three times; the application amount of each of base fertilizers, tillering fertilizers and granular fertilizers is 1/3 of the total phosphate application amount. According to the method, the cadmium content in the rice grains can be effectively reduced and the rice yield can be increased.

Description

A kind of rice field phosphate fertilizer method that reduces the rice grain cadmium content

Technical field

The invention 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 uses of agricultural chemicals and the discharge of urban sewage dirt, cause metallic element that Cd, Pb, Hg, Cu etc. are poisonous to biology in environment fast, excessively accumulation, 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 easily is absorbed by plants, and usually by food chain to the human body enrichment.

Cd is high to human toxicity, and the accumulation that easily is absorbed by the body.Have abundant result of study to prove, Cd has very strong carcinogenesis to the multiple organs such as lung, prostate, suprarenal gland, testis and hemopoietic system of animal.According to Japanology, the edible high rice of Cd content can cause the human kidney dysfunction for a long time, causes lethality to rise, the lost of life.Betide the Itai-itai diseases in basin, magic river, Toyama County, Japan, by Japanese Environment mechanism, confirmed it is due to the local resident for a long time due to the edible rice polluted by Cd.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 using in a large number of quick increase, industrial expansion and the agricultural chemicals of the size of population, the heavy metal pollution of agricultural land soil is on the rise.China shows the investigation of 20 many places mining, smelting and industrial wastewater pollution point, and some regional farmland Cd pollute very serious, and area and degree in rising trend.As the agricultural land soil of the plumbous zinc ore contaminated wastewater in Yang Shuo, Guangxi is measured and is reached 10-136mg/kg containing Cd; The contaminated farmland area 2800hm in Zhang Shi irrigated area, Shenyang ², soil Cd content 5-7mg/kg; The cadmium that the chimney of Daye, hubei Province copper works is discharged pollutes the farmland of 10km scope on every side, and the 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; " Dayu County, Wu Dou” Jiangxi, the world spreads all over tungsten ore factory, is subject to the rural sewage disposal farm area to reach hm more than 5000 ², the average cadmium content of soil is 0.62mg/kg, similar to the cadmium pollution situation in basin, the magic river of Japan.Above-mentioned contaminated region rice grain Cd content is 0.29-1.09mg/kg, all over state health standards (<0.2mg/kg).Chinese Academy of Sciences Nanjing soil the sampling Detection in 28 counties, 8 city, Jiangsu Province is shown, the Cd content overproof rate of Jiangsu Part area grain (rice, wheat, flour) reaches 25%.And paddy rice has an outstanding feature to be to absorption and the accumulation of Cd: often growth is not affected, but the Cd content of rice has surpassed sanitary standard several times, even more than ten times.Therefore, movement and the accumulation of Cd in soil-rice-human system shown great attention to.

Summary of the invention

The technical problem to be solved in the present invention is to reduce the rice grain cadmium content.

In actual Rice Production, because the number of dropouts of paddy soil phosphorus is larger, the phenomenon of Deficiency Xn Rice Plants phosphorus is very general.But a lot of peasants' the phosphorus method of executing relatively blindly, often lack scientific.The present inventor finds by large quantity research: the Cd content 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.Different phosphate fertilizer amounts and application process have different impacts to the Cd absorption of paddy rice.If it is improper to execute phosphorus period or execute the control of phosphorus level, not only can cause the low rice quality that reaches of rice yield to descend, and can make in paddy soil the release of very strong heavy metal Cd to human toxicity increase and promote the absorption of paddy rice to these materials, result causes Cd content overproof in rice grain, in the rice field of particularly polluting at Cd, this situation is easy to occur.The present inventor shows by large quantity research, execute the phosphorus level and the disposable employed comparison using phosphate fertilizer as base manure with common adopt low of peasant, the phosphorus method of executing of suitable time, optimal level, can be when improving rice yield, the Cd content of energy decrease rice grain.

The rice field phosphate fertilizer method that the present invention reduces the rice grain cadmium content is:

(1) execute the phosphorus level: height is executed the phosphorus level, and phosphorus application amount is 135kg/hm ²(with active ingredient P ₂o ₅meter, close every mu of 9kg).

Execute low (low phosphorus level, the 45kg/hm of executing of phosphorus level ²), rice yield is low, and seed Cd content is high, easily surpasses state health standards; Execute the phosphorus level medium (in execute the phosphorus level, 90kg/hm ²), although rice yield also higher (output only than height execute phosphorus level low 1% less than), seed Cd content is also higher, also easily surpasses state health standards; Height execute the phosphorus level with in, low execute the phosphorus level relatively, seed Cd content has significantly and descends, and rice yield improves (see attached list 1 and table 2).

(2) execute phosphorus period: minute 3 fertilisings, 1/3 of base manure, tillering fertilizer, the total phosphorus application amount of each Shi of granulated fertilizer., base manure, tillering fertilizer, granulated fertilizer are illustrated in paddy rice transplant seedlings first 3 days, transplant seedlings latter 20 days, the fertilising in first 5 days of earing.

If disposable employed as base manure, rice yield has obvious decline, with the highest minutes 3 times fertilisings of output relatively, rice yield 5% left and right that can descend.If divide, use for 2 times, respectively 3 days (base manure) and 1/2 of the latter 20 days total phosphorus application amounts of (tillering fertilizer) each Shi that transplant seedlings before paddy rice is transplanted seedlings.Although rice yield higher (than output the highest minute 3 times fertilisings descend 4% less than), seed Cd content is also higher, also easily surpasses state health standards.

The technical scheme of this application patent is after rice field Cd contaminated region is implemented, and Cd concentration that can the decrease rice grain, also can promote the increase of rice yield.With the commonly used low phosphorus level (45kg/hm that executes of paddy rice actual production Peasants ²) and the disposable employed comparison using phosphate fertilizer as base manure, seed Cd content fall is (long-grained nonglutinous rice descends 55.3%, and japonica rice descends 56.3%) significantly, and rice yield be significantly improved (long-grained nonglutinous rice increases by 11.5%, and japonica rice increases by 13.3%).In the heavy metal Cd of rice field, slight pollution area (soil Cd concentration≤10mg/kg), by the enforcement of this application patented technology scheme, can control rice grain Cd content and meet state health standards (seed Cd concentration<0.2mg/kg).

Embodiment

1, the phosphorus application amount in the present invention is the active ingredient P with phosphorus ₂o ₅meter, because the phosphorus content of different fertilizer kind is variant, will calculate according to the phosphorus content of concrete fertilizer variety concrete fertilizing amount during fertilising.

2, first rice field is filled with to thin water layer (about 3cm) before the fertilising, fertilizer is evenly executed in water layer, pour water after allowing water layer naturally fall to do again, water layer falls to do the front draining of not wanting.During fertilising, try not to make fertilizer to adhere on rice leaf, in order to avoid blade is produced and burns.

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

4, execute phosphate fertilizer and add up cadmium content, rice yield according to different fertilizing methods

Seed cadmium content under the different phosphate fertilizers application process of table 1 rice field is (unit: mg/kg) relatively

Rice yield under the different phosphate fertilizers application process of table 2 rice field is (unit: kg/hm relatively ²)

Annotate: phosphorus code in period is executed in rice field

A: disposable employed as base manure.

B: divide and use for 2 times, respectively 3 days (base manure) and 1/2 of the latter 20 days total phosphorus application amounts of (tillering fertilizer) each Shi that transplant seedlings before paddy rice is transplanted seedlings.

C: minutes 3 times fertilisings, i.e. 3 days (base manure), transplant seedlings latter 20 days (tillering fertilizer), 1/3 of the first 5 days total phosphorus application amounts of (granulated fertilizer) each Shi of earing before paddy rice is transplanted seedlings respectively.

The paddy rice that the paddy rice that table 1,2 result show to adopt the method kind of high phosphate fertilizer fertilizing standards, minute three fertilisings to go out goes out with the additive method kind compares that output improves, cadmium content reduces.

Claims

1. a rice field phosphate fertilizer method that reduces the rice grain cadmium content: height is executed the phosphorus level, and total phosphorus application amount is with active ingredient P ₂o ₅meter 135kg/hm ², minutes 3 times fertilisings, 1/3 of base manure, tillering fertilizer, the total phosphorus application amount of each Shi of granulated fertilizer.

2. the rice field phosphate fertilizer method of reduction rice grain cadmium content claimed in claim 1 is characterized in that: first rice field is filled with to thin water layer before fertilising, fertilizer is evenly executed in water layer, pour water after allowing water layer naturally fall to doing again, not draining before water layer falls to doing.