(1) Fertilization is shallow. Fertilizers are volatile, lost or difficult to reach the roots of crops, which is not conducive to crop absorption, resulting in low fertilizer utilization. Fertilizer should be applied to the seed or plant 16-20 cm below the side.
(2) Double chlorine fertilizer. The compound fertilizer produced by ammonium chloride and potassium chloride is called double-chlorine fertilizer, and contains about 30% chlorine. It is easy to burn seedlings and should be watered in time. Chlorine-free fertilizers cannot be applied to saline-alkali and chlorine-sensitive crops. Excessive application of potassium chloride to leaves (stem) vegetables not only causes the vegetables to be less tender and more fibrous, but also makes the vegetables taste bitter, with poor mouthfeel and low benefits. The urea-based compound fertilizer has high nitrogen content, and the biuret has a slightly high nitrogen content. It is easy to burn the seedlings, and attention should be paid to watering and fertilization depth.
(3) Improper application of chemical fertilizers to crops. May cause fat damage, burning seedlings, plant wilting and so on. Excessive application of nitrogen fertilizer, a large amount of ammonia or ammonium ions in the soil, on the one hand ammonia volatilization, the formation of alkaline small water droplets in the air droplets, burning crops, causing scorch spots on the leaves; on the other hand, ammonium ions in the drought The soil is easily nitrified and converted into ammonium nitrite under the action of nitrosating bacteria. The gasification produces nitrogen dioxide gas, which will poison the crops, and irregular water-like plaques appear on the leaves of the crops, and the veins gradually turn white.
(4) Excessive use of certain nutrients. It not only poisons crops, but also hinders the absorption of other nutrients by crops and causes deficiency. For example, excessive nitrogen application can cause calcium deficiency; excessive nitrate nitrogen can cause chlorosis in the absence of molybdenum; excessive potassium can reduce the effectiveness of calcium, magnesium, and boron; excessive phosphorus can reduce the effectiveness of calcium, zinc, and boron.
(5) Fresh human excrement is directly applied to vegetables. Fresh human excrement contains a large number of germs, toxins and parasite eggs. If it is not directly decomposed, it will contaminate vegetables and easily spread diseases. It can be applied after high temperature stacking fermentation or harmless treatment.
People's Daily - People's Daily
Steel hollow section:
Other names: Hollow steel
section, square
steel tube, rectangular steel pipe, rectangle Steel Hollow Section, galvanized
steel square tube, galvanized rectangular steel pipe, square hollow steel tube
Section Shape: square and rectangular
Material: carbon steel, Q195-Q215,Q345,20#,alloy
steel,ST37-2,ST52-3,S235,S355,A500,A106,A53
Standard: DIN EN 10210, DIN EN 10219, ASTM A 500 ,GB/T 3094-2000,GB/T 6728-2002
Length:
2m-12m
Technology: Cold rolled, cold drawn, hot rolled,
galvanized, annealed, ERW, EFW, DSAW.
Size of Steel hollow section:
Rectangular steel pipe: 10*20mm--800*1000mm
Square steel pipe:10*10mm-800*800mm,
WT: 2--30mm SCH 20, SCH30,SCH40,STD,XS,SCH80,SCH160,XXS etc
Packing: Painting, oil outside, steel strip then in Bundle or according to customer`s requirements.
Application: The Steel hollow section tubes are used for Tower cranes, pick and move cranes, crawler cranes, mobile cranes, road construction, folk lift, equipment manufacture, building, green house, handrail, furniture, structure building etc.
Payment terms:30% advance payment, the balance will be against the BL copy. Or LC irrevocable at sight.
Finish: Galvanization ,bared, oiled, black panting or as per the client's requirement, beveled edges
| Square pipe Specification(mm) | Rectangular pipe Specification(mm) | ||
| 16×16×0.4~1.5 | 380×380×8.0~14.0 | 10×20×0.6~1.5 | 250×150×6~12.0 |
| 18×18×0.4~1.5 | 400×400×8.0~14.0 | 14×21×0.6~1.5 | 250×100×6~12.0 |
| 20×20×0.4~1.5 | 420×420×10.0~14.0 | 15×30×1.5~1.5 | 250×200×6~12.0 |
| 25×25×0.6~2.0 | 450×450×10.0~14.0 | 15×38×0.6~1.5 | 300×150×6~12.0 |
| 30×30×0.6~4.0 | 480×480×10.0~14.0 | 20×30×0.6~2.0 | 300×200×6~12.0 |
| 34×34×1.0~2.0 | 500×500×10.0~14.0 | 20×40×0.8~2.0 | 300×250×6~12.0 |
| 35×35×1.0~4.0 | And the specifications based on the cold drawn process is as follows | 20×50×1.0~2.0 | 400×250×8~12.0 |
| 38×38×1.0~4.0 | 550×550×10.0~40.0 | 22×35×0.9~2.0 | 400×300×8~12.0 |
| 40×40×1.0~4.5 | 600×600×10.0~40.0 | 25×40×0.9~3.75 | 450×200×8~12.0 |
| 44×44×1.0~4.5 | 700×700×10.0~40.0 | 25×65×1.0~2.0 | 450×250×8~12.0 |
| 45×45×1.0~5.0 | 800×800×10.0~50.0 | 30×40×1.0~3.75 | 400×300×8~12.0 |
| 50×50×1.0~5.0 | 900×900×10.0~50.0 | 30×45×1.0~3.75 | 400×350×8~12.0 |
| 60×60×1.5~5.0 | 1000×1000×10.0~50.0 | 30×50×1.0~4.0 | 500×200×10~12.0 |
| 70×70×2.0~6.0 |
|
30×60×1.0~4.5 | 500×250×10~12.0 |
| 75×75×2.0~6.0 |
|
40×50×1.0~4.5 | 500×300×10~12.0 |
| 80×80×2.0~6.0 |
|
40×60×1.0~5.0 | 500×350×10~12.0 |
| 85×85×2.0~6.0 |
|
40×80×1.5~5.0 | 500×400×10~12.0 |
| 95×95×2.0~8.0 |
|
40×100×2.0~5.0 | 500×450×10~12.0 |
| 100×100×2.0~8.0 |
|
50×60×2.0~5.0 | And the specifications based on the cold drwan process is as follows |
| 120×120×4.0~8.0 |
|
50×80×2.0~5.0 | 600×200×10~28.0 |
| 150×150×6.0~10.0 |
|
50×100×2.0~8.0 | 600×400×10~28.0 |
| 180×180×6.0~12.0 |
|
60×80×2.0~6.0 | 600×500×10~28.0 |
| 200×200×6.0~12.0 |
|
80×100×2.0~8.0 | 800×400×10~28.0 |
| 220×220×6.0~14.0 |
|
120×60×2.5~10.0 | 800×600×10~28.0 |
| 250×250×6.0~14.0 |
|
120×80×2.5~10.0 | 800×700×10~28.0 |
| 280×280×6.0~14.0 |
|
150×100×2.5~12.0 | 1000×400×10~28.0 |
| 300×300×8.0~14.0 |
|
180×150×2.5~12.0 | 1000×500×10~28.0 |
| 320×320×8.0~14.0 |
|
200×100×4~12.0 | 1000×600×10~28.0 |
| 350×350×8.0~14.0 |
|
200×150×4~12.0 | 1000×800×10~28.0 |
Steel Hollow Section
Square Steel Tube,Rectangular Steel Tube,Galvanized Steel Hollow Section,Shs Carbon Steel
Cangzhou Fixed Star Steel Co.,Ltd , http://www.fixedstarpipe.com