Superphosphate Alternatives

Rock Phosphate

• Fertilizer producers make superphosphate by adding acid to phosphate rock. This makes the phosphorous easily available to plants. Some gardeners do not want to use a fertilizer made through environmentally damaging industrial processes. They can add phosphate to their soils through the application of rock phosphate fertilizer. This is finely ground phosphate rock. However, this takes longer to break down in soil than superphosphate fertilizer. Rock phosphate breaks down faster in acidic soils.

Manure

• All forms of life contain phosphorous, so adding any plant or animal matter to the soil will supply phosphorous. Manure contains phosphorous and other elements essential to plant growth, such as nitrogen. The proportions of these nutrients vary according to the animal that produced the manure and what it was fed. Do not use fresh manure. Only apply manure that has been thoroughly composted.

Green Manure

• Some plants are rich in nutrients essential to plants' growth, including clover, peas, mustard and buckwheat. Growers can use these plants to increase the nutritional content of their soils. Plants grown for this purpose are called green manure. Growers cultivate these crops until they reach maturity then cut them down and dig them into the soil. They then release phosphorous and other plant nutrients as they decompose.

Crop Residues

• Another source of phosphorous is crop residue. Farmers and growers often remove all remains of a previous crop from their soil before sowing or planting another one. Yet the roots, leaves and stalks of previous plants contain nutrients that other plants can use to grow. They also contain fiber that adds structure to soils, and helps retain water and prevents soil erosion. To add crop residues to soils, chop up and dig in all plant matter rather than remove it.