The need for potassium (K) fertilisers is increasing with intensive cropping and higher yields. And as the need for K increases, so will the dividends from supplying K to the crop effectively.

Cereal crops need adequate K within the first four to eight weeks to promote tillering, so early supply is critical. Many trials have shown that this is best achieved by banding it at seeding.

Potassium deficiency is becoming more common on loamy soils. Banding K on these soils is likely to yield the most benefits.

On a red brown loam near Beverley in 2015, a CSBP wheat trial showed a 1.8 t/ha yield response to 16 kg K/ha banded (supplied by 120 kg/ha K-Till Extra Plus), but only a 0.6 t/ha response to 30 kg K/ha top dressed pre-sowing (60 kg/ha Muriate of Potash) (Figure 1) – three times the response from banding half as much!

FIGURE~1

Figure 1. Wheat yields in response to potassium applied (kg/ha) in a CSBP trial near Beverley in 2015. All treatments received the same nitrogen and phosphorus inputs. Muriate of potash (MoP) treatments were topdressed before seeding.

It’s on these medium textured soil types that we can expect the greatest benefits from banding K co-granulated with nitrogen (N) and phosphorus (P), to get more granules containing K (and P) down the drill row.

A neighbouring site at Beverley in 2016 produced a similar result, when wheat yields from K-Till Extra Plus were 120 kg/ha higher than a MAP/MoP blend.

The potential efficiency gains from banding K and using compound NPK fertilisers on loams will be examined again in two trials, over the course of 2022, near York. Soil tests indicate both sites should be very responsive.

You can find out more about this trial at csbpresults.com.au or if you wish to find out more about our range of K products contact your local CSBP account manager.

 

James Easton
By James Easton
- Senior Agronomist

James has over 30 years’ experience working on soil and plant nutrition (crops and pastures).

He graduated from the University of Western Australia with a degree in Agricultural Science (Honours). He has in depth knowledge of historic fertiliser research trials and has worked closely with many growers, consultants, research institutions and farming groups over the years.

James gets a lot of satisfaction from sharing his knowledge with growers and those who support them. And he enjoys the fact that we are always learning.

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