# Maximising The Effectiveness Of Phosphate Fertilisers

- Link: https://rd2.co.nz/maximising-the-effectiveness-of-phosphate-fertilisers/
- Published: 2022-06-06T06:07:45+00:00
- Author: RSF Admin

As one of the three macronutrients, Phosphorus is a critical part of any crop’s 
nutritional profile. It is a major contributor to pasture/plant growth, as well 
as healthy flowering and root development in all crops.

Crops can exhibit phosphorus deficiency symptoms when soils have plentiful levels
of P and this is because phosphorus has a unique characteristic of low availability
due to slow diffusion and high soil fixation properties. i.e. phosphorus can be 
tied up very quickly in low pH soils with Aluminum and Iron and in high pH soils
with Calcium. Phosphorus is also difficult for plants to access under hot and dry
conditions. Cold and wet conditions can lead to phosphorus loss through the soil
profile causing environmental damage. These P characteristics can be a major limiting
factor for plant growth, not through under fertilisation but under utilisation.

Prices for phosphate fertilisers have skyrocketed over recent years, and this has
put a significant financial strain on farmers. To mitigate the financial impact 
of increasingly expensive fertilisation regimes, farmers should look to improve 
techniques and alternative methods, including soil conditioning amendments, that
allow for more efficient use of Phosphorus as well as Mycorrhizal fungi which are
specifically adapted to plants for phosphorus acquisition from soils. This will 
decrease the levels of fertiliser needed, and thereby provide more cost-effectiveness.
The key here is more efficient fertilisation, as opposed to current methods of simply
adding more products which is ecologically and financially unsustainable. 

## Why is Phosphorus so expensive?

It’s tempting to lay the blame on COVID-19, along with every other business disruption,
but there are a number of factors at play. The mineral phosphate is obtained through
rock mining and 70% of the world’s Phosphate reserves are located in North Africa.
China, Russia, South Africa and the United States all have limited quantities of
the mineral rock which are being used to shore up their own domestic food production.
Political issues and the increased cost of fuel, and the price of hiring bulk carriers
to transport the fertiliser, is also contributing to price increases. This has pushed
farmers to find alternative sources of phosphate locally.

![person holding brown and black frog](https://rd2.co.nz/wp-content/uploads/2022/
06/q13zq1jufks-1024x683.jpg "Maximising The Effectiveness Of Phosphate Fertilisers
1")

## What can we do about it?

Phosphorus use has declined since its high in 2003 to 2005. Price hikes due to economic
difficulties around 2008 encouraged farmers to refine on-farm practices and increase
the efficiency of phosphorus use, which has paid dividends. Moving forward, finding
better ways to increase the bioavailability of phosphorus in the soil will be a 
primary focus.

New Zealand farms have long struggled with losing phosphorus to the environment.
Not only does this represent money out of the farmer’s pocket, it also causes the
development of toxic algal blooms in precious freshwater bodies. 

Best practice for phosphorus application requires that it be applied in the right
amounts at the right time.

## Right amounts

The amount of phosphorus needed is highly individualised. Many things need to be
considered, including the type of crop, stocking rates if applicable, and the condition
of the soil. Soil properties like pH levels, iron content and water retention capacity
also play a major role. A high iron content tends to fix phosphorus, rendering it
unavailable for uptake. This is a particular issue in volcanic ash soils. Meanwhile,
low water retention, such as that in sandy soils, can lead to excessive phosphorus
loss through leaching. 

Conduct soil tests to ascertain what nutrients are currently in the soil, and consult
with your soil scientist to get a better understanding of what may be required in
your particular circumstances. 

## Right time

When maintaining phosphorus levels, it is best to hold off in times of increased
rainfall to prevent leaching. If heavy rainfall cannot be avoided, a slow release
form like reactive phosphate rock will reduce the risk of runoff. If soil testing
indicates low levels of phosphorus, and an increase in production is required quickly,
soluble phosphorus should be applied sooner rather than later. 

## How Roots, Shoots and Fruits can help

Increasing the bioavailability of nutrients to crops can be achieved, in large part,
by better conditioning of the soil. Think of adding Phosphorus applications with
soil amendments such as [Humic acid](https://rd2.co.nz/?s=humax&post_type=product)
to hold the P in the soil and [Fulvic Acid](https://rd2.co.nz/?s=mobilizer&post_type=product)
to move the Phosphorus to the plant quickly. 

Look at different forms of Phosphorus fertiliser such as a highly systemic foliar
phosphorous acid.

RSF’s [Rootella](https://rd2.co.nz/?s=rootella&post_type=product) products provide
an excellent solution. Rootella contains mycorrhizal fungi, which work symbiotically
with your crops. Mycorrhizal fungi form complex networks of fine strands that connect
with your crop’s roots and extend their effective reach. These organisms have grown
and adapted to optimise plant phosphorus uptake requirements from soils, they prefer
low soil phosphorus levels and achieve excellent results. 

Mycorrhizal fungi additionally increase the stability of the soil which improves
water retention. Plants transpiration rates increase via inoculation of these organisms
achieving higher water use efficiency (another important factor moving forward).
By holding water closer to your crop’s roots, nutrients become easier to absorb.
This allows for more effective use of phosphate fertilisers, meaning less fertiliser
is needed, which saves on costs.

It’s clear that, while phosphates can be a significant cost factor for farmers, 
increasing the efficiency of phosphorus utilisation by crops through soil amendments
can reduce this financial burden.

If you have questions, send me an email – rsf@rd2.co.nz