Efficiency of fertiliser N products on calcareous and sandy soil types

Jan 10, 2018

Background

Glasshouse trials funded by SAGIT (AS116) conducted by Agronomy Solutions in late 2016 using soils collected from Loxton, Karoonda and Condowie have revealed the efficiency of urea in prompting biomass production was lacking compared to other N products. The results from these trials showed UAN, MAP and SOA on a sand and calcareous soil type to be more efficient. Wheat plants where urea was banded revealed micronutrient deficiencies possible due to the process of urea breakdown causing a hostile environment near the plant seeds.

These outcomes have led to subsequent field trials beginning this year (2017) assessing the efficiency of four commercial nitrogen (N) products in generating wheat yields by applying products at both sowing and at GS30  (five rates).

Agronomy Solutions recognises many growers are reliant on nitrogen application at sowing to provide plant nutrition. This highlights the need for the correct form of N being used at this time to deliver the crop’s nutritional needs.

Very little recent information (post last century) is available that compares the efficiency of each N product in terms of overall crop uptake and subsequent yield benefits when banded below the seed at sowing. The components of each N product vary and therefore efficiency of conversion from organic N (urea) to ammonium and then nitrate may be different with respect to time and different soil environments in addition to effects on other soil properties (e.g. soil pH).

Project Details

Timing
Two year field trial

Project participants 
SAGIT (AS317), University of Adelaide

Locations 
Karoonda, Condowie

Karoonda

Condowie

R

We want to provide growers with accurate and recent information to assist in making cost-effective N fertiliser decisions.

Project Objectives

Large input costs are associated with ensuring crops have adequate N, particularly in lighter textured soils in southern Australia. Agronomy Solutions works within the industry and has identified a need to know the efficiency of N products in this area beyond the more traditionally used urea when products are banded.

The reality is urea’s efficiency is largely assumed and has not been explored for these sandy soils. Results would have significant industry impact around the most efficient N source with respect to the timing of application (sowing vs in-crop).

Results

Field trials aimed at assessing if results from glasshouse trials performed by Agronomy Solutions are translated to field environments is currently underway.

As results become available they will be uploaded to our website.

Figure 1

Wheat yields (@ GS33) in response to various forms of N application (20 mg/kg) using a Calcareous soil type. Different letters denote significant differences (p < 0.05), error bars represents standard errors from 4 replicates).