A kind of exceed standard fertilizing method of vegetable plot leaf vegetables cadmium content of cadmium that reduces
Technical field
The present invention relates to the cultivation method of a kind of leaf vegetables, particularly a kind of exceed standard fertilizing method of vegetable plot leaf vegetables cadmium content of cadmium that reduces.
Background technology
Vegetables are one of indispensable vegetalitas agricultural product in people's daily life, maintain human normal physiological activity and improve health aspect there is very important nutritive value.In recent years, due to the unreasonable use of the irrational discharge of Industrial " three Waste ", high-load heavy metal agrochemistry input, motor vehicle exhaust emission etc., make vegetables home environment suffer to destroy to some extent, there is Accumulation of heavy metals in a considerable amount of vegetable field soils, particularly Cd content is apparently higher than soil background, surpass soil environment quality secondary standard, the vegetables particularly phenomenon of leaf vegetables Cd content overproof happen occasionally, health and ecotope are brought to potential threat, also become the Main Barrier Factors of vegetables industryization development simultaneously.
Fertilising is indispensable means in agricultural production, and happiness fertilizer and fertilizer requirement are greatly the nutritive peculiarities of vegetable crop.In recent years, along with vegetables produce the rapid expansion of area and developing rapidly of establishment planting technology, the degree that vegetables production depends on chemical fertilizer supply increases increasingly.In vegetables production at present, ubiquity the phenomenon of using in a large number blindly chemical fertilizer or partially executing certain chemical fertilizer for pursuing high yield, often ignore crop nutrient uptake feature, fertilizer variety and soil quality situation, cause fertilizer decline in benefits, vegetable field soil physicochemical property bad, and may cause the solvability of heavy metal in soil to increase, promote the absorption accumulation of vegetables to heavy metal, food chain risk strengthens.
Research shows, fertilizer type, form and follow ion different exist very big-difference to the impact of the solvability of heavy metal cadmium and biological effectiveness.What cadmium dissolubility was had the greatest impact is soil pH, mainly comprises the acid, the alkali that in fertilizer self acid, alkalescence and conversion process, produce, and it changes and Cadmium in Soil activity is remarkable negative correlation; Secondly be the metathesis of fertilizer components to cadmium on the complexing of heavy metal and fertilizer middle-jiao yang, function of the spleen and stomach ion pair soil colloid.The degree of strength that different fertilizer produces above-mentioned effect in soil determines that it is on the impact of cadmium solvability and biological effectiveness.As nitrogenous fertilizer, mainly the alkalization of the rhizosphere by nitre state, ammonium nitrogen and acidification effect affect the activity of heavy metal, use ammonium fertilizer NH
4cl and (NH
4)
2sO
4, because plant is to NH
4 +the absorption of-N, root system secretion H
+, make rhizosphere acidifying around, increase the solvability of Cd in soil, adsorption by soil Cd measures minimizing, and the biologically active of Cd significantly improves; Use nitrate fertilizer Ca (NO
3)
2, plant absorbs NO
3 --N, root system secretes OH
-, or HCO
-, make rhizosphere pH increase, cause rhizosphere alkalization, reduce solvability and the biologically active of soil Cd; The effect main manifestations of potash fertilizer is that potassium ion is to H on soil colloid
+displacement and follow anion and the complexing of metal cation, appropriate potassium sulfate is not remarkable on soil pH impact, potassium chloride can significantly reduce soil pH; MAP in phosphate fertilizer, diammonium phosphate physiology Acidity of Aikalinity are not obvious, mainly by three kinds of acid group (H
2pO
4-, HPO
4 2-, PO
4 3-) form affects soil surface electric charge, and then affect the absorption of soil to heavy metal.Therefore,, if ignore fertilizer variety and consumption on Cd exceeds standard vegetable plot, only rule of thumb fertilising, may cause the validity of Cd in soil to increase, and promote the absorption of vegetables to Cd.In addition, the rock phosphate of import and take in the P fertilizer that import P ore deposit is raw material much higherly more than domestic rock phosphate and P fertilizer containing Cd amount, is also one of potential Cd pollution source in vegetable plot.
China's rice husk resource is very abundant, approximately produce every year the rice husk of 4,500 ten thousand tons, part, for generating, making sheet, biomass fuel etc., also has a considerable amount of rice husks be not fully used and lost as discarded object, this is the significant wastage to resource still not, and environment is also caused to larger pollution.Rice husk the most outstanding feature is high ash content (7%~9%) and high silicon content (20% left and right), and contents of heavy metal elements is extremely low, after carbonization, has good toughness, porous, low-density (112~144kg/m
3) and the character such as specific surface area is very big, for the heavy metal in contaminated soil, there is comparatively significant passivation suction-operated, effect stability, can not cause harmful effect to soil property, and expense is moderate, be easy to promotion and implementation, meet the needs of China's sustainable agriculture development.
Along with the development of economic society and the raising of people's environmental consciousness, the safety of victual and quality are more and more subject to people's common concern, on exceeding standard vegetable plot, Cd select suitable fertilizer variety to carry out the rational application of fertilizer, when obtaining high yield, effectively resistance control heavy metal enters in leaf vegetables body, reducing the heavy metal pollution of vegetables, improve quality of vegetable, is current the parties concerned problem demanding prompt solution.
Summary of the invention
In order to solve the problem of prior art, the embodiment of the present invention provides a kind of can reduce the cadmium Cd content in the leaf vegetables of vegetable plot that exceeds standard, and then improves the fertilizing method of its security quality.
The technical scheme that the present invention takes is to achieve these goals:
Reduce the exceed standard fertilizing method of vegetable plot leaf vegetables cadmium content of cadmium, comprise the following steps:
(1), using carbonization rice husk as base manure, before leaf vegetables sowing, spread fertilizer over the fields and even with soil rake, or transplant before leaf vegetables described carbonization rice husk buriing in planting ditch;
(2) with inorganic fertilizer as topdressing, after described leaf vegetables final singling or surviving, then using the inorganic fertilizer that is rich in nitrogen, phosphorus, potassium and drench and execute as topdressing.
In described step (1), use described carbonization rice husk 250~750kg for every mu.
In described step (2), described inorganic fertilizer is divided equally 3 parts or 4 parts of water-soluble pouring and is executed, and in leaf vegetables final singling or after surviving, drenches for the first time, within later 5~10 days, drenches once, drenches altogether 3 times or 4 times, and described inorganic fertilizer is given every mu and provided N5~15kg, P
2o
51.6~4.0kg, K
2o5.0~15.0kg.
Described carbonization rice husk is rice husk or the product of powdered rice hulls after smouldering, and containing abundant carbon, silicon and potassium, and contains a small amount of N, P, Ca, Mg, Fe and various trace elements.
Described inorganic fertilizer is by two or more simple substance or the mixed fertilizer that forms of binary compound fertilizer;
Described N is by containing more than N46% urea, containing nitrate of lime more than N11%, provide containing one or more in diammonium hydrogen phosphate more than N20%;
Described P is by containing P
2o
5diammonium hydrogen phosphate more than 50wt% or containing P
2o
5calcium dihydrogen phosphate more than 53wt% provides, and K is by containing K
2potassium sulfate more than O50wt% provides.
Described leaf vegetables is selected from romaine lettuce, cabbage heart, a variety of Chinese cabbage, leaf mustard, Lettuce, spinach, water spinach, cabbage, green water cress or three-coloured amaranth.
The beneficial effect that the technical scheme that the embodiment of the present invention provides is brought is:
The technical solution used in the present invention, be in view of: suitable chemical fertilizer kind and amount of application can effectively reduce the Phyto-availability of heavy metal in soil, reduce the absorption of plant to heavy metal.Select urea, nitrate of lime, diammonium phosphate, calcium dihydrogen phosphate and potassium sulfate etc. as N, P, K fertilizer, rationally use can improve soil pH to some extent, reduce the content of exchange state Cd in soil, the activity that suppresses Cd in soil, reduce the absorption of leaf vegetables to heavy metal, thereby reduce the accumulation of Cd in leaf vegetables.Carbonization rice husk contents of heavy metal elements is extremely low, has the character such as good toughness, porous, low-density (112~144kg/m3) and specific surface area be very big, and heavy metal Cd is had to stronger absorption passivation; The Si wherein containing can increase crop and vegetables rhizosphere oxidability, reduce the ratio of exchange state heavy metal in soil, and because having hindered heavy metal in the deposit of above-ground plant parts, moves to acrial part silicon, make heavy metal be trapped in plant root, thereby suppress the absorption of plant to heavy metal, effectively prevented the pollution of heavy metal to vegetables.Therefore, carbonization rice husk and inorganic fertilizer Reasonable being executed is the effective measures that reduce Cd content, improve leaf vegetables security quality.
Therefore, fertilizing method of the present invention can lower 20%~65% by leaf vegetables edible part Cd content, and can improve leaf vegetables commodity output and mineral nutrient, vitamin C and soluble sugar content, make soil pH improve 0.2-0.5 unit, soil available cadmium content reduces by 18%~46%, the nutrient imbalance situations such as the soil organic matter and phosphorus potassium be improved significantly, soil property improves good, soil ecology function is restored.
Embodiment
For making the object, technical solutions and advantages of the present invention clearer, below embodiment of the present invention is described further in detail.
Reduce the exceed standard fertilizing method of vegetable plot leaf vegetables cadmium content of cadmium, comprise the following steps:
(1), using carbonization rice husk as base manure, before leaf vegetables sowing, spread fertilizer over the fields and even with soil rake, or transplant before leaf vegetables described carbonization rice husk buriing in planting ditch;
(2) with inorganic fertilizer as topdressing, after described leaf vegetables final singling or surviving, then using the inorganic fertilizer that is rich in nitrogen, phosphorus, potassium and drench and execute as topdressing.
Adopt method of the present invention, carbonization rice husk and inorganic fertilizer are joined and executed, than existing method, improve leaf vegetables security quality, reduce Cd content in leaf vegetables.
Following examples carbonization rice husk used is smouldered and is formed by the rice husk of taking from meter factory, and inorganic fertilizer used is commercially available fertilizer, and fertilizer amount is the consumption of a mu.
Described carbonization rice husk be by rice husk in the airtight container of 400-600 ℃, insulation 6-7 hour.In insulating process, can in airtight container, offer an air admission hole, guarantee the minimum air inlet demand of airtight container, air admission hole diameter is 1-3cm.
Carbonization rice husk preparation method: rice husk is pulverized rear or directly rendered in the body of heater of the brick one-tenth of use, and inboard wall of furnace body is covered with the fire-resistant tile of one deck, and lower portion of furnace body is provided with grate and air inlet, and upper of furnace body is provided with bell.Grate and bottom of furnace body arrange certain space, the body of heater of grate bottom is provided with air inlet, rice husk drops into body of heater from top, and rice husk is positioned on grate, lights rice husk, when in body of heater, temperature rises to 400-600 ℃, cover bell, and cover seal cover at air inlet, keep the interior temperature of stove at 400-600 ℃, after carbonization 6-7 hour, after naturally cooling Powdered or shell shape carbonization rice husk.Seal cover is provided with air admission hole, guarantees minimum intake requirement in stove, and the diameter of air admission hole is preferably 1-3cm.
Use respectively the fertilizing method of following examples, and the fertilizing method of planting leaf vegetables of the same race with existing method as a comparison, picking time, gathers in the crops leaf vegetables acrial part, tests respectively leaf vegetables output, overground part Cd, vitamin C and soluble sugar content.Existing fertilizing method is to using chicken manure and peanut press pulp to impose on plantation ditch as fertilizer base, and inorganic fertilizer is Norway composite fertilizer 15-15-15kg/ mu, and inorganic fertilizer is executed 1 time in leaf vegetables final singling or after transplanting as topdressing for every 3~5 days.
The leaf vegetables short for vegetative period and fertilizer requirement is relatively little, generally topdresses 3 times; The leaf vegetables that vegetative period is long and fertilizer requirement is relatively large, topdresses 4 times.
Embodiment 1
Field trial is carried out in the vegetable plot that is 0.52mg/kg in soil Cd full dose.Base manure using shell shape carbonization rice husk 400kg as 1 mu, plants two batches of romaine lettuce continuously, and before first batch of romaine lettuce dish seedling transplanted, buriing is in planting ditch.Inorganic fertilizer topdresses, and every mu of fertilizing amount is N12kg, P
2o
54.0kg, K
2o10kg.By the urea (26.1kg) containing N46.0%, containing P
2o
555.2% calcium dihydrogen phosphate (7.3kg) and containing K
2the potassium sulfate of O 50% (20kg) is divided into 4 parts as one mu topdress, and the water-soluble pouring of gradation is executed, and in romaine lettuce, survives rear pouring for the first time, within later every 6 days, drenches once, has drenched for totally 4 times.Second batch of romaine lettuce fertilising is with first batch.
Use after the fertilizing method of the present embodiment, first batch of romaine lettuce per mu yield increases by 5.64%, and acrial part cadmium content reduces by 55.5%, and romaine lettuce vitamin C and soluble sugar content increase respectively 1.2% and 4.3%; Second batch of romaine lettuce per mu yield increases by 12.1%, acrial part cadmium content reduces by 62.5%, romaine lettuce vitamin C and soluble sugar content increase respectively 2.1% and 4.0%, and soil pH is increased to 5.40, DTPA-Cd content by original 4.99 and is down to 0.16mg/kg by original 0.28mg/kg.
Embodiment 2
Field trial is carried out in the vegetable plot that is 0.46mg/kg in soil Cd full dose.Base manure using Powdered carbonization rice husk 300kg as 1 mu, plants two batches of cabbage hearts continuously, spreads fertilizer over the fields and harrow even with soil before cabbage heart sowing.Inorganic fertilizer topdresses, and every mu of fertilizing amount is N8kg, P
2o
53.4kg, K
2o6.4kg.By the nitrate of lime (60.9kg) containing N11%, containing N20%, containing P
2o
552.5% diammonium hydrogen phosphate (6.5kg) and containing K
2the potassium sulfate of O50% (12.8kg) is divided into 3 parts as one mu topdress, and the water-soluble pouring of gradation is executed, and after cabbage heart final singling, drenches for the first time, within later every 5 days, drenches once, has drenched for totally 3 times.Second batch of cabbage heart fertilising is with first batch.
Use after the fertilizing method of the present embodiment, first batch of cabbage heart per mu yield increases by 10.3%, and acrial part cadmium content reduces by 44.0%, and cabbage heart vitamin C and soluble sugar content increase respectively 5.2% and 8.7%; Second batch of cabbage heart per mu yield increases by 12.8%, acrial part cadmium content reduces by 51.0%, cabbage heart vitamin C and soluble sugar content increase respectively 3.3% and 5.6%, and soil pH is increased to 5.66, DTPA-Cd content by original 5.28 and is down to 0.25mg/kg by original 0.32mg/kg.
Embodiment 3
Field trial is carried out in the vegetable plot that is 0.67mg/kg in soil Cd full dose. the base manure using Powdered carbonization rice husk 250kg as 1 mu, and first batch of plantation a variety of Chinese cabbage, second batch of plantation leaf mustard spread fertilizer over the fields and harrows even with soil before a variety of Chinese cabbage sowing.Every mu of fertilizing amount of a variety of Chinese cabbage is N8kg, P
2o
52.9kg, K
2o6.0kg, every mu of fertilizing amount of leaf mustard is N10kg, P
2o
52.9kg, K
2o9kg.By the urea (15.0kg) containing N46%, containing N20%, containing P
2o
552.5% diammonium hydrogen phosphate (5.5kg) and containing K
2the potassium sulfate of O50% (12kg) is divided into 3 parts as one mu topdress, and the water-soluble pouring of gradation is executed, and after a variety of Chinese cabbage final singling, drenches for the first time, within later every 6 days, drenches once, has drenched for totally 3 times.After a variety of Chinese cabbage results, turn over, harrow even soil, plantation leaf mustard.By the urea (21.7kg) containing N46%, containing P
2o
555.2% calcium dihydrogen phosphate (5.2kg) and containing K
2the potassium sulfate of O50% (18kg) is divided into 3 parts as one mu topdress, and the water-soluble pouring of gradation is executed, and after leaf mustard final singling, drenches for the first time, within later every 8 days, drenches once, has drenched for totally 3 times.
Use after the fertilizing method of the present embodiment, a variety of Chinese cabbage per mu yield slightly increases, and acrial part cadmium content reduces by 38.3%, and Vitamin C content slightly increases, and soluble sugar content increases by 10.5%; Leaf mustard per mu yield increases by 13.9%, and acrial part cadmium content reduces by 44.7%, and Vitamin C content increases by 2.9%, and soluble sugar content increases by 6.5%, and soil pH is increased to 6.20, DTPA-Cd content by original 5.72 and is down to 0.21mg/kg by original 0.38mg/kg.
Embodiment 4
Field trial is carried out in the vegetable plot that is 0.83mg/kg in soil Cd full dose.Base manure using shell shape carbonization rice husk 700kg as 1 mu, first batch of plantation three-coloured amaranth.Second batch of plantation Lettuce, spreads fertilizer over the fields and with soil harrows even before planting with three-coloured amaranth.Every mu of fertilizing amount of three-coloured amaranth is N10kg, P
2o
52.9kg, K
2o8.0kg, every mu of fertilizing amount of Lettuce is N15kg, P
2o
54kg, K
2o10kg.By the urea (21.7kg) containing N46%, containing P
2o
555.2% calcium dihydrogen phosphate (5.2kg) and containing K
2the potassium sulfate of O50% (16kg) is divided into 3 parts as one mu topdress, and the water-soluble pouring of gradation is executed, and after three-coloured amaranth final singling, drenches for the first time, within later every 5 days, drenches once, has drenched for totally 3 times.After three-coloured amaranth results, transplant Lettuce.By the urea (17.4kg) containing N46%, containing the nitrate of lime (50kg) of N11%, containing N20%, containing P
2o
552.5% diammonium hydrogen phosphate (7.6kg) and containing K
2the potassium sulfate of O50% (20kg) is divided into 4 parts as one mu topdress, and the water-soluble pouring of gradation is executed, and in Lettuce dish seedling, survives rear pouring for the first time, within later every 10 days, drenches once, has drenched for totally 4 times.
Use after the fertilizing method of the present embodiment, three-coloured amaranth per mu yield increases by 10.2%, and acrial part cadmium content reduces by 44.5%, and Lettuce Vitamin C content and soluble sugar content increase respectively 4.3% and 3.9%; Lettuce per mu yield increases by 17.3%, acrial part cadmium content reduces by 64.5%, Lettuce Vitamin C content and soluble sugar content increase respectively 4.3% and 3.9%, and soil pH is increased to 6.77, DTPA-Cd content by original 6.43 and is down to 0.13mg/kg by original 0.24mg/kg.
The foregoing is only preferred embodiment of the present invention, in order to limit the present invention, within the spirit and principles in the present invention not all, any modification of doing, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.