Testing establishes exact fertiliser needs

Cust farmer Roscoe Taggart is using a handheld nitrogen tester in conjunction with nitrogen sensors to apply the right amount of fertiliser which results in cost savings and environmental benefits.


Investing in a handheld nitrogen tester and using variable rate nitrogen fertiliser has enabled Cust farmer Roscoe Taggart to significantly reduce the amount of fertiliser he applies to his family’s 730-hectare arable and sheep operation which has resulted in cost savings and environmental benefits.

Roscoe is participating in a farming innovation project, which examines how the next generation of farmers are using innovative approaches to improve their farming practices. Waimakariri Landcare Trust (WLT) and Waimakariri Irrigation Limited (WIL) have partnered with the Ministry for Primary Industries (MPI) for the project, with support from MPI’s Sustainable Food and Fibre Futures fund along with Environment Canterbury, Ballance, and DairyNZ.

Roscoe says the cost savings of applying variable rate nitrogen fertiliser compared to a traditional blanket approach are “astronomical”. He grid-sampled his paddocks and then determined the exact amount fertiliser required for each block via nitrogen sensors attached to the roof of his tractor.

“We have spread triple super for our phosphate and potash for our potassium as our base fertiliser. Where in the past we would have gone with a blanket approach we have been able to save a huge amount on fert this season by using variable rate.

“I think it’s incredibly worthwhile to invest in variable rate technology and it feels wrong now to put a blanket application across a paddock when I know how much variability there is within a single paddock.”

Roscoe has gone a step further to hone his precision techniques when applying fertiliser by purchasing a handheld nitrogen tester which he can use to fine tune applications throughout the growing season. Within ten minutes of the test, the nitrogen level of the plant is provided, and Roscoe and his team can then put this figure into the N sensor which then provides a starting point for the variable rate spreading of nitrogen.

“I have just purchased a Yara N-Tester which we will use to test rye grass, cereals, and brassicas to make sure we have the correct levels of nitrates. It is simple to use and allows us to find out what the N levels are and to see if we need to apply a little bit more or a bit less fertiliser.

“Hopefully, in combination with the N sensors on the tractor we will be able to be even more precise in how we do things. When it comes to managing the cost of inputs, I really believe that precision technology will help us to stay viable when looking ahead with rising costs and increasing environmental regulation.

“Anything that enables us to do more with less is better for our bottom line and for the environment.”

Crop sampling with the hand-held nitrogen tester will start in late August or early September and Roscoe says this will help to determine which elements are required by the plants, while avoiding a blanket application approach.

“We will get a good idea of where the crops are sitting early in the season and if there is anything missing, we can address that early on.”

This season Roscoe will continue with the same crops; however, he is considering trialling a regen paddock and comparing this to a conventional farming paddock to work out if there is a financial benefit to this type of farming.

“I want to have the two paddocks side by side and do a gross margin on both, so I have real data to show how they compare. I am a huge fan of on-farm comparisons and giving things a go because until you try something you never truly know if it works.”