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Farming through the drought cycles

Soils and Crops: Even with modern ag technology, we’re still reliant on rain or soil moisture

As the combines started to roll this fall, many were very surprised at how hard the truckers had to work. While not a barn burner, the 2017 crop will go in the books for many as good, and considering the lack of rainfall some will say it is great.

We all like to point out that our crop management, crop varieties and overall soil health is much better than during past droughts like 2001-02, 1988 and way back to 1961 for old crocks like me. But, to find the main reason for the good crops you need to check out the February 17, 2017, issue of Grainews for our soil moisture map. It was the first year we did not map any “very dry” soils and significant areas were in the “super wet” category. The good crops of 2017 were no surprise to me. Remember, “water in the subsoil is like money in the bank.” It is going nowhere until a plant root sucks it up.

The first Stubble Soil Moisture Map as of freeze-up was made in Saskatchewan in 1978. For those who have Henry’s Handbook of Soil and Water check out page 109.

Historic wheat yields, RM of Milden

To illustrate drought cycles, I am using wheat yields for the Rural Municipality of Milden, Sask., No. 286. It is only nine townships with mainly clay/heavy clay soils on the eastern edge of the Kyle, Eston, Rosetown clay belt of west central Saskatchewan. I chose this RM because that is my homeland and I chose wheat because it has the best long-term records available.

Actually, much of the net worth of current Milden area farmers has been derived from lentils. A heavy clay soil full of water will produce a very good crop of lentils with very little rain. The dry growing season also makes for great crop quality — as was the case in 2017.

Wheat yields for RM of Milden, Sask. #286
photo: File

The chart starts at 1960, the year I crawled off the old Cockshutt combine on August 31 with the crop on Brunswick farm all in the bin. There were still two weeks left to get ready for my grand university experiment. It was a fair crop, but when the crop is off in August there has been little late summer/early fall rain.

Then came 1961. No rain, no soil moisture reserves equals no crop. It was my first experience with such a drought but it was old hat to Dad, who’d survived the 30s. The 1960s at Milden were on the dry side but summerfallow was still prevalent so most yields should really be divided by two. 1964 was an anomaly at Milden as a five-mile swath of big hail made summerfallow of crops through the center of the RM.

The 1970s were on the wet side with the big 1973-74 snow dump that recharged sloughs. The 1970s was the decade we worked hard in extension programs to convince farmers that summerfallow could be greatly reduced or eliminated. It has all come to pass in spades.

The 1980s were on the dry side. 1987 was a fair crop but there was no extra or post-harvest rain to recharge the soil. Our November 1, 1987, the stubble soil moisture map put much of Saskatchewan as “dry” or “very dry.” Winter snow was meager.

1988 was the biggest bust of all. In the spring, grass in ditches was as brown as fall. Any big wind raised big dust storms. In Saskatoon, when we finally did get a bit of a rain event, it was actually a “mud rain.” No kidding, mud was falling from the sky. Truckers had a very easy time of it in 1988.

Then comes 2001 to 2004. With no stored soil moisture, rains must be adequate and timely to make a crop. It is the second year of low rain that delivers the depression era yields. Beware 2018.

The big snow of 2004-05 was the flex point to our decade of adequate to excessive rains with water table rise to give sub-irrigation in parts of some landscapes. The 20 inches of rain in 2010 ushered in the era of combines stuck in the mud. That aggravation finally ended this year, in all but the far northwest of Saskatchewan and northeast Alberta.

The 2013 crop had just the right combination to deliver a record crop mostly of good quality.

2018 and beyond: Drought mitigation

As of mid-September we still have six weeks of calendar to deliver rains to at least partially recharge the soil. I have no idea what rain we can expect but I do know this: if the fall rains fail, the November 1, 2017, Soil Moisture map will have a lot of red ink (indicating “very dry”). In that event, timely and substantial rains will be needed to deliver an average crop.

We hear a lot of talk about drought mitigation with drought-tolerant crops and varieties and fertilization. But the only way I know of to mitigate a real drought is to irrigate. In the Allan Hills area south of Saskatoon we still have a lot of sloughs and some with quite a bit of water. If there was a practical and economic way to get that water onto the parched soil the response would be huge. However, there will be only about one year of that and the sloughs will be dry also.

My answer to dry soils is to minimize the money that is poured in.

A strategy for dry years

Chapter 7 of Henry’s Handbook of Soil and Water provides yield equations for CWRS wheat, feed barley and canola based on soil water at planting and the probability of receiving a given May, June, July total rainfall. Yields are given for a 75, 50 and 25 per cent chance of rain in a given soil zone.

In the past decade those equations have been irrelevant because Mother Nature has provided natural irrigation. The yield equations are now a decade old also so the yields, particularly for canola, are on the low side. For example for Thick Black, Grey Black and Grey soil zones the yield for six inches of stored soil water and 6.8 inches of growing season rain was only 52 bushels per acre of canola. Many in those soil zones have exceeded that yield often with modern hybrid canola varieties and other good management.

But the concept is still valid. Some of the coefficients need some tweaking and the equations would be correct. I have had phone conversations with young mathematically-inclined folks who have done just that.

The point is this: if you have little or no stored soil moisture at seeding time then you are banking on very timely and adequate rains to get a crop and much above-average rain to get a very high yield. It can happen, but be aware of the extra risk you are taking when pouring in large rates of nitrogen.

The upside of high rates of nitrogen in a dry year is that much of the N will still be in the soil for the next year. For high rollers with big bank accounts that might be OK. For the beginning farmer with a big mortgage it could be trouble.

We close by apologizing to the drowned out folks in the Meadow Lake area in the far northwest of Saskatchewan. I am sure all this talk of drought and looking for a rain makes them sick.


Clay soil cracks in a dry year

The extreme drought this summer in Regina has resulted in electrical meters being destroyed by the huge shrinkage of the clay soils. My dad often told stories about losing a crescent wrench at harvest down a crack in our clay land after a dry year.

I have been scanning the thousands of slides taken at University of Saskatchewan over the years and stumbled on these. The year is 1990 and the location is the clay lands right here in Saskatoon on university plots.

So you see, Grandpa was not kidding when he told you about big cracks in gumbo soils!

That is a Brown soil moisture probe with a four-foot handle. The cracks do run deep
photo: Les Henry

It is true, crescent wrenches can be lost in soil cracks.
photo: Les Henry

About the author

Columnist

J.L.(Les) Henry is a former professor and extension specialist at the University of Saskatchewan. He farms at Dundurn, Sask. He recently finished a second printing of “Henry’s Handbook of Soil and Water,” a book that mixes the basics and practical aspects of soil, fertilizer and farming. Les will cover the shipping and GST for “Grainews” readers. Simply send a cheque for $50 to Henry Perspectives, 143 Tucker Cres., Saskatoon, Sask., S7H 3H7, and he will dispatch a signed book.

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