Fertilizer và những con số N-P-K

PostTue Jul 05, 2011 10:08 pm

E mua 2 loại fertilizers dùng cho mấy cây bông, "All-Purpose-Plant-Food" and "Bloom-Booster", hình ở dưới. E thấy mấy cây bông nào nhìn héo héo, không thấy lớn, thì E pha tưới cho nó. Bloom Booster thì E dùng mới có một lần cho cây bông, nó ra nụ nhiều lắm, nhưng E không (chưa) dùng nữa, vì thấy bình thường nó cũng ra bông, nên để nó ra bông tự nhiên cho cây được mạnh.

E hay nghe ACE nói đến N P K và số của nó, nên E cũng tìm hiểu để biết thêm.

E đọc vài bài viết trên net, đặc biệt là bài viết này, ACE nào muốn đọc chi tiết thì đọc ở đây nhe:
http://www.learn2grow.com/gardeningguides/fertilizer/basics/understandingfertilizernumbers.aspx

E xin tóm tắy mấy điểm chính về N P K:

- N=Nitrogen, P=Phosphorus, K=Potassium
- E nghĩ mình nhớ rõ thứ tự N P K hơn khi mình nhớ rằng mấy chất này đi theo thứ tự của bản chữ cái (Alphabetical order), Nitrogen, Phosphorus rồi cuối cùng đến Potassium.
- Những con số như 24-8-4, có nghĩa là loại fertilizer đó chứa 24% nitrogen, 8% phosphorus và 4% postassium.
- N: cho cây mau lớn, xanh hơn. Ví dụ fertilizer cho sân cỏ thì tỷ lệ của N cao.
- P: Giúp rễ phát triển, bông trái nhiều và to hơn. Dùng tỷ lệ P cao khi cây đã vững vàng (established).
- K: Giup chống bệnh (diseases), giúp giữ cây khi thời tiết nóng hay lạnh, giúp rễ phát triển. Có thể dùng tỷ lệ K cao khi bắt đầu mùa đông hay mùa hè, lúc thời tiết quá lạnh hay quá nóng, hoặc lúc cây bị nhiều bệnh (diseases).

Nói tóm lai, E nghĩ như vậy dễ nhớ hơn, N cho cây mau lớn, P cho nhiều bông trái, và K để chống bệnh và bảo vệ cây (khi thời tiết quá nóng hay quá lạnh).

Đây là Kinh nghiệm của E. Lúc mùa đông, có 2 cây xanh cây bị cắt sát gốc. Đầu mùa xuân, lá non ra rất nhiều, E pha All-Purpose-Plant-Food tưới cây, kết quả thì cả hai cây đều đi xa hết. Trong đám cây xanh cùng loại đó, cây nào không tưới lúc đó thì bây giờ xanh lắm, nên sau này khi muốn tưới fertilizer, E tưới cây bàng nước trước, rồi tưới fertilizer, rồi tưới lại bằng nướcva` tưới fertilizer lúc thời tiết mát mẻ như vào buổi sáng.

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Sau này E để ý thì thấy N P K là 24-8-16 (N% cao cho cây mau lớn, xanh)


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N P K là 15-30-15 ( P% cao cho nhiều hoa trái)
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PostWed Jul 06, 2011 8:53 am

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Nếu mình không chắc chắn cây mình cần chất nào, thì có thể mua loại tỷ lệ N P K bằng nhau như 10-10-10.

Source:learn2grow
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PostWed Nov 16, 2011 1:40 pm

Plant Nutrients
Sixteen chemical elements are known to be important to a plant's growth and survival. The sixteen chemical elements are divided into two main groups: non-mineral and mineral.

Non-Mineral Nutrients
The Non-Mineral Nutrients are hydrogen (H), oxygen (O), & carbon (C).

These nutrients are found in the air and water.
In a process called photosynthesis, plants use energy from the sun to change carbon dioxide (CO2 - carbon and oxygen) and water (H2O- hydrogen and oxygen) into starches and sugars. These starches and sugars are the plant's food.

Photosynthesis means "making things with light".

Since plants get carbon, hydrogen, and oxygen from the air and water, there is little farmers and gardeners can do to control how much of these nutrients a plant can use.
Mineral Nutrients
The 13 mineral nutrients, which come from the soil, are dissolved in water and absorbed through a plant's roots. There are not always enough of these nutrients in the soil for a plant to grow healthy. This is why many farmers and gardeners use fertilizers to add the nutrients to the soil.
The mineral nutrients are divided into two groups:
macronutrients and micronutrients.

Macronutrients

Macronutrients can be broken into two more groups:
primary and secondary nutrients.
The primary nutrients are nitrogen (N), phosphorus (P), and potassium (K). These major nutrients usually are lacking from the soil first because plants use large amounts for their growth and survival.

The secondary nutrients are calcium (Ca), magnesium (Mg), and sulfur (S). There are usually enough of these nutrients in the soil so fertilization is not always needed. Also, large amounts of Calcium and Magnesium are added when lime is applied to acidic soils. Sulfur is usually found in sufficient amounts from the slow decomposition of soil organic matter, an important reason for not throwing out grass clippings and leaves.

Micronutrients
Micronutrients are those elements essential for plant growth which are needed in only very small (micro) quantities . These elements are sometimes called minor elements or trace elements, but use of the term micronutrient is encouraged by the American Society of Agronomy and the Soil Science Society of America. The micronutrients are boron (B), copper (Cu), iron (Fe), chloride (Cl), manganese (Mn), molybdenum (Mo) and zinc (Zn). Recycling organic matter such as grass clippings and tree leaves is an excellent way of providing micronutrients (as well as macronutrients) to growing plants.

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Soil
In general, most plants grow by absorbing nutrients from the soil. Their ability to do this depends on the nature of the soil. Depending on its location, a soil contains some combination of sand, silt, clay, and organic matter. The makeup of a soil (soil texture) and its acidity (pH) determine the extent to which nutrients are available to plants.
Soil Texture (the amount of sand, silt, clay, and organic matter in the soil)

Soil texture affects how well nutrients and water are retained in the soil. Clays and organic soils hold nutrients and water much better than sandy soils. As water drains from sandy soils, it often carries nutrients along with it. This condition is called leaching. When nutrients leach into the soil, they are not available for plants to use.
An ideal soil contains equivalent portions of sand, silt, clay, and organic matter. Soils across North Carolina vary in their texture and nutrient content, which makes some soils more productive than others. Sometimes, the nutrients that plants need occur naturally in the soil. Othertimes, they must be added to the soil as lime or fertilizer.


Soil pH (a measure of the acidity or alkalinity of the soil)


Soil pH is one of the most important soil properties that affects the availability of nutrients.

Macronutrients tend to be less available in soils with low pH.
Micronutrients tend to be less available in soils with high pH.
Lime can be added to the soil to make it less sour (acid) and also supplies calcium and magnesium for plants to use. Lime also raises the pH to the desired range of 6.0 to 6.5.
In this pH range, nutrients are more readily available to plants, and microbial populations in the soil increase. Microbes convert nitrogen and sulfur to forms that plants can use. Lime also enhances the physical properties of the soil that promote water and air movement.


It is a good idea to have your soil tested. If you do, you will get a report that explains how much lime and fertilizer your crop needs.


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Macronutrients
Nitrogen (N)
Nitrogen is a part of all living cells and is a necessary part of all proteins, enzymes and metabolic processes involved in the synthesis and transfer of energy.
Nitrogen is a part of chlorophyll, the green pigment of the plant that is responsible for photosynthesis.
Helps plants with rapid growth, increasing seed and fruit production and improving the quality of leaf and forage crops.
Nitrogen often comes from fertilizer application and from the air (legumes get their N from the atmosphere, water or rainfall contributes very little nitrogen)

Phosphorus (P)
Like nitrogen, phosphorus (P) is an essential part of the process of photosynthesis.
Involved in the formation of all oils, sugars, starches, etc.
Helps with the transformation of solar energy into chemical energy; proper plant maturation; withstanding stress.
Effects rapid growth.
Encourages blooming and root growth.
Phosphorus often comes from fertilizer, bone meal, and superphosphate.

Potassium (K)
Potassium is absorbed by plants in larger amounts than any other mineral element except nitrogen and, in some cases, calcium.
Helps in the building of protein, photosynthesis, fruit quality and reduction of diseases.
Potassium is supplied to plants by soil minerals, organic materials, and fertilizer.

Calcium (Ca)
Calcium, an essential part of plant cell wall structure, provides for normal transport and retention of other elements as well as strength in the plant. It is also thought to counteract the effect of alkali salts and organic acids within a plant.
Sources of calcium are dolomitic lime, gypsum, and superphosphate.

Magnesium (Mg)
Magnesium is part of the chlorophyll in all green plants and essential for photosynthesis. It also helps activate many plant enzymes needed for growth.
Soil minerals, organic material, fertilizers, and dolomitic limestone are sources of magnesium for plants.

Sulfur (S)
Essential plant food for production of protein.
Promotes activity and development of enzymes and vitamins.
Helps in chlorophyll formation.
Improves root growth and seed production.
Helps with vigorous plant growth and resistance to cold.
Sulfur may be supplied to the soil from rainwater. It is also added in some fertilizers as an impurity, especially the lower grade fertilizers. The use of gypsum also increases soil sulfur levels.


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Micronutrients
Boron (B)
Helps in the use of nutrients and regulates other nutrients.
Aids production of sugar and carbohydrates.
Essential for seed and fruit development.
Sources of boron are organic matter and borax

Copper (Cu)
Important for reproductive growth.
Aids in root metabolism and helps in the utilization of proteins.

Chloride (Cl)
Aids plant metabolism.
Chloride is found in the soil.

Iron (Fe)
Essential for formation of chlorophyll.
Sources of iron are the soil, iron sulfate, iron chelate.

Manganese (Mn)
Functions with enzyme systems involved in breakdown of carbohydrates, and nitrogen metabolism.
Soil is a source of manganese.

Molybdenum (Mo)
Helps in the use of nitrogen
Soil is a source of molybdenum.

Zinc (Zn)
Essential for the transformation of carbohydrates.
Regulates consumption of sugars.
Part of the enzyme systems which regulate plant growth.
Sources of zinc are soil, zinc oxide, zinc sulfate, zinc chelate.

http://www.ncagr.gov/cyber/kidswrld/plant/nutrient.htm
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