What makes fertiliser

Phosphate rock is primarily treated with sulphuric acid to produce phosphoric acid, which is either concentrated or mixed with ammonia to make a range of phosphate P2O5 fertilizers. Potassium is the third major plant and crop nutrient. Over time, the concentration of these ions decreases, so farmers and gardeners add fertilisers to the soil. Fertilisers may contain nitrogen, phosphorus and potassium compounds to promote plant growth.

Fertilisers that supply all three elements are often called NPK fertilisers, after the chemical symbols for these three elements. Fertiliser compounds must be soluble in water so they can be absorbed by the root hair cells:. They improve water movement into the soil and, in time, add structure to the soil. Organics feed beneficial microbes, making the soil easier to work.

But they may cost more than chemical, or inorganic fertilizers, because they are less concentrated, supplying fewer nutrients pound for pound. Fresh, non-composted manure can damage your plants as well, because some manure contains harmful amounts of salts.

They can also be a source of weed seeds. Penhallegon has collected information about the nitrogen N , phosphorus P and potassium K content of many of the organic substances commonly used as fertilizer in Oregon.

In simple terms, this means each pound bag of the fertilizer would contain 12 pounds of nitrogen, 11 pounds phosphorus and two pounds nitrogen. Burned eggshells To boost the nitrogen content of your soils, apply nitrogen-rich urea percent N , feathers 15 percent N , blood meal Organic amendments highest in phosphorus include rock phosphate percent P , bone meal percent P and colloidal phosphate percent P.

High in potassium are kelp percent K , wood ash percent K , granite meal percent K and greensand 5 percent K. To make soil less acidic, gardeners want materials rich in calcium, including clamshells, oyster shells, wood ashes, dolomite and gypsum all are at least 30 percent calcium carbonate or straight calcium. As you clean the fireplace, do your plants a favor and sprinkle the ashes in the garden instead of throwing them in the garbage.

Oct 22, News story. Gardeners tend to think of fall as the time to put bulbs in the ground, but the warm soil and increasing moisture make it a great time to plant most anything. Information about garden planning, maintenance, cleanup, pest management, houseplants and indoor gardening for the month of November. Information about garden planning, maintenance and clean up, pest monitoring and management, houseplants, and indoor gardening for the month of October.

This publication addresses the common misconceptions associated with products labeled "natural" and "organic," and describes related insecticides intended for home gardening. For food chain crops, farming can occur on land where hazardous constituents are applied as long as the agricultural producer receives a permit from the EPA Regional Administrator. Agricultural producers must demonstrate that there is no substantial risk to human health caused by the growth of such crops.

Skip to main content. Related Topics: Agriculture. Contact Us. EPA offers guidance and technical assistance for the beneficial recycling of biosolids as soil amendments and fertilizer. The use of these valuable materials can enhance:. Sewage sludge that is used in agriculture is regulated under the Clean Water Act, and is currently subject to concentration limits for the following metals:.

Commercial Fertilizer Purchased - Fertilizer is a primary source of nitrogen and phosphorus. Fertilizer use and run-off can be significantly reduced by appropriate fertilizer application through:.