Blue sky thinking for future farming

17 Aug, 2018 04:00 AM
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DISCONCERTING is probably an understatement about how you feel, when somebody tells you your livelihood may be in jeopardy.

But for retired researcher and soil scientist Paul Blackwell, there’s no point in massaging what he believes is a serious issue.

“Climate change may be a bigger threat to WA farmers than Ukraine wheat production,” Dr Blackwell said.

Given the extremes of heat and cold over the past 10 to 20 years, Dr Blackwell said watching how the future evolved was not an option.

Action is needed.

“The sooner we all try to test and modify new ideas that may save the farm budget, the sooner we learn what can work or fail on our own patch,” he said.

“Genetics offers real help, but it is not as direct as, and often slower than, changes in the way we farm with the biology we are familiar with.

“But the future climate for growing crops, pastures, fodder shrubs and anything else means planning for the future.

“And that should be starting today.”

One aspect of farming already is clear: monoculture farming is not working and diversity is the best bet.

That was addressed by Dr Blackwell earlier this month at a Northern Agricultural Catchment Council (NACC)-sponsored informal field walk at Perry St Quintin’s farm, Dartmoor, at north Yuna, to discuss ideas for future farming in the district.

The concept (see diagram) could have a general application that would see a more diverse approach to farming involving a mixed enterprise, and with self-sufficiency (power).

On the farm some of the ideas are based on the controlled traffic farming (CTF) system.

According to Dr Blackwell it seems unlikely that farms at family scale will easily survive a sequence of two very bad seasons (like 2017), relying on grain production alone.

“Livestock production and renewable energy offer two income streams that new CTF ideas can help,” he said.

With livestock production (not necessarily owned), strategies could include grazing pasture, sub-tropical grasses, fodder shrubs or failed crops, or selling failed crops or hayed crops to local feedlots.

On the renewable energy front, which could involve on-farm and integrated community planning, energy could be derived from:

p Stand-alone power generators powered by dry biomass from oil mallee processing.

p Chipped dried stems from harvested fodder shrubs (eg Acacias or good fodder saltbush species, harvested with a John Deere willow harvester or converted sugar cane harvester).

p Bales of hay or failed crop.

Of course, reliable economic modelling of the livestock and energy options would be a given before any major investment.

Dr Blackwell also spoke about several interesting observations he has made over his working life in the northern Wheatbelt.

p Heat stress

The consequences of heat stress (about a third reduction of yields of low rainfall crops per degree above 35oC, per day, at flowering) may be reduced by employing the following soil modification strategies between and in the design of permanent tramline layouts.

Get more of the afternoon sun’s heat between the rows and not on the crop by orientating the rows and tramlines north-south, or ideally north west-south east.

“This seems to work better with wider rows, more standing stubble and generally lower crop yield potential,” he said.

Cool the heads of flowering crops and pastures more efficiently by encouraging more root density in the subsoil – to bring up more cooling water on a hot afternoon.

This is achieved easiest by burying topsoil and appropriate organic matter in the subsoil by deep ripping, with topsoil inclusion.

This method also should be safer against wind or water erosion than other options such as inversion ploughing or spading, which also are beneficial in encouraging more root density.

Combine the above water supply benefits with the safer nutrient supply from buried topsoil or organic matter, to compensate for loss of nutrition when the real topsoil is bone-dry.

This is especially useful in low fertility status sands.

“Much of the above has been verified in GRDC (Grains Research and Development Corporation)-funded long-term field trials on CTF farms initialised by the agriculture department,” Dr Blackwell said.

“These and other on-farm trials in WA and South Australia have shown topsoil and organic matter inclusion slowing the self-settling of yellow sands, improving nutrition of poor sands and stabilising dispersive clay.

“This helps improve production from transiently saline clays and improving productivity from high pH soils.

“Direction change on some paddocks may be very challenging, but may be easier and less stressful as part of a farm layout re-think program.”

p Cold stress

Some increase of canopy temperature may be possible on cold nights following sunny afternoons if sunlight can heat the soil between rows and be released to warm the crop later at night.

The same guidelines of orientation of rows may apply – tramlines north-south, or ideally north west-south east – using wide rows and more standing stubble.

p Extreme dry (after summer rain)

Keep the subsoil moisture in better with a less compact profile to wick away the moisture and protective stubble to minimise evaporation.

Do early sowing between or next to old stubble rows to help conserve that benefit.

Also employ dry ridges of non-wetting sand between rows to further lower summer evaporation rates by using smart furrow sowing.

“These effects have also been verified by good soil modelling and experimental investigations by previous DAFWA research and The University of WA,” Dr Blackwell said.

p Extreme wet

Employ safe surface drainage with optimum stubble levels; slow overland flow along tramlines and furrows with less than three per cent slope (often a downhill direction); design drive-through drains in complex slope systems for safer water disposal.

Farmer and consultant experience in the southern Wheatbelt has substantiated these ideas, especially in combination with strategic tillage, usually some form of deep ripping, between permanent tramlines.

The field walk also included a demonstration of a John Shearer Trashworker converted to a deep ripper (with the help of Tuncoat and Nufab Engineering) and an experimental hopper and elevator system to directly insert organic matter or limes and sulphates behind ripper tines.

The hopper is to be used in later trials to insert inorganic (limes and sulphates) or organic (chaff or wattle eaves) directly into the inclusion zone formed by the exclusion plates behind the tines.

“This should waste less material than using top-dressing followed by inclusion helped by angled chains,” Dr Blackwell said.

One trial already established involves ameliorating a “challenging” red dune with combinations of deep ripping and limes and sulphates and another trial examined a high rate of dolomite sown to cereal rye.

According to Mr St Quintin, while many of the ideas appear blue sky, inevitable spin-offs can occur.

“You can’t ignore ideas and a lot of useful information is good to have in this environment,” Mr St Quintin said.”

“At the moment we’re focused on deep ripping and experimenting with ameliorating products to make sure what rain we get is more useable.

“We’ve got about 30pc really poor sand that needs structure with the majority being red sand going into reasonable yellow sand, but it’s pretty much rainbow country.

“When you’re dealing with soil it’s a slowly, slowly approach and in the context of cost effectiveness and practicality.”

FarmWeekly

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