Cover Cropping Benefits – Lessons from the Mallee

Nuffield Scholar, Craig Duffield speaks to us about cover cropping benefits in the South Australian Mallee. Craig has trialled this system and plans to increase cover cropping into the future.

Craig and Nicole Duffield continuously crop 2,000 hectares around the Waikerie area. Craig has done extensive research on the benefits of sowing cover crops. What I’m trying to do is grow a rotational crop in the summertime where we can’t grow one here in the winter time so we’re trying to start with some nutrients and soil and try and change the water holding capacity of our soil. So by growing some warm season broad-leaves and some warm season grasses and I’m even throwing in some cold season broad leafs into the summer mix to try and get some diversity back into our soil.

I saw all this stuff in North Dakota and some in South Dakota and I was lucky enough to meet up with Rick Beber who has actually came out to the SANTFA conference in 2009. And I emailed him and went across and stayed with them for a week and he put me into contact with a lot of other people there, and spent some time with Gabe Brown and a few other people who have actually spoken at the SANTFA conferences. And seeing what they’ve done over there they’ve actually doubled their yields in the last five years just through cycling nutrients in the soil.

Overcoming the Summer Moisture

What we are trying to overcome is the moisture that we receive in the summer time, when we actually don’t need it and which is only growing weeds anyway. We might as well be growing something in there that could actually be feeding the bugs under the soil and start to build organic matter in the soil at a time when we’re not using the soil.

So we can utilize that moisture and grow a cover crop, put some residue, shade the soil from the hot sun that we receive here. And at the end of it because we’re not taking the cover crop to maturity, we’re not actually using that much moisture than what you think you would, because we’re not taking that through to the grain.

We did have some moisture probes done and we’ve now got the results back of those moisture tests. It looks like there was about 10 millimeters of different moisture between where there was a crop and where there wasn’t a crop. What they haven’t been able to tell me at this stage is what that is equating to available moisture for plants given the fact that since that covered crop was desicated out.

Using Cover Crops for Livestock Feed

We virtually had no rain since then so I’m guessing that when we get the opening rain, available moisture’s going to be about the same. Well it can provide two benefits. One, we can get a rotational crop in the summertime when we haven’t actually got anything growing. And the other thing is once we get into the system and running after a couple years I think we can actually provide a food source for livestock.

I’ve been at livestock for 3 years now and all the Americans that I visited while I was in the States are telling me that I will be going back into livestock because I just have too much residue there. It was interesting we did a feed test on that particular mix that we had, and it looks like it’s going to be a very viable option for a livestock.