Get your ducks in a row for liming this spring and summer

15 Sep 2021

AG ADVICE - September 2021

Phil Cranney - Senior Land Services Officer, Pastures

There are two liming rate demonstration sites on the Central Tablelands. One at Lyndhurst and other at Toogong. Helen Burns and Jason Condon from NSW DPI have set up these two sites to demonstrate the effect of different liming rates, surface applied vs incorporated on two very different soil types.

While it is early days for both sites since set up before a winter crop in 2020 and a new pasture planted this year, we hope to be able to compare legume nodulation across treatments this spring.

While we wait for some more conclusive results from these important demonstration sites that are yet to be fully funded, there are some compelling reasons for incorporating lime this year. Here is a list of the ducks that all seem to be lining up:

“Huey” the rainfall duck

While most farmers take 3-month rainfall outlooks from the BOM with a massive grain of salt, the outlook is positive, with the chance of exceeding 151mm median rainfall for Canowindra being “High” and past accuracy is “High”. While erosion risk must always be considered, the rain should help amelioration process

The wet winter has meant some traffic (vehicles and livestock) damage on pastures and cropping paddocks. This is an ideal opportunity to return these paddocks to a level playing field with cultivation

“Dewey” the money matters duck

When the NSW DPI masters acid soil experiment was being conducted in the early 2000’s the average price for a heavy lamb was $83. Livestock prices are 3-4 times that now on average, whereas the cost of lime has barely moved from $50/tonne to still less than $100/tonne spread

A similar trend in land prices, 3-4 times the price of 20 years ago, therefore the cost of liming/Ha is a miniscule capital cost now

The cropping gross margin in the masters experiment economic analysis showed a three year payback period for a wheat price of $120/tonne and with a $80/tonne lime cost and wheat at $150 it was still only a three year payback period. IMAGINE these figures when we plug in today’s canola price!

“Lewy” the labile soil carbon Duck

Labile soil carbon is the fraction of soil carbon with the most rapid turnover, therefore the most easily built up and the easiest to lose.

NSW DPI retired soil scientist Mark Conyers found that while cultivation did initially damage the soil and increase its risk of erosion, the soil structure basically returned to normal within 1-4 years under zero/min till practices, and two years under pasture.

Soil microbes do not like the acid soil conditions, therefore the more we eliminate Aluminium from the soil by increasing the pH (CaCl) to above 5.5, the better chance we have of increasing soil carbon

And finally...

Let us not forget that pesky little mouse duck that is lining up nicely for another plague this summer. Why not dig up their homes while incorporating the lime to increase their risk of exposure to baits and disease this spring and summer.

The take home message for when all your ducks are in alignment is - LIME PAYS, do it this year.