End-of-summer thoughts on some crop issues
Sunday, October 5, 2014
A number of problems dogged us in 2014, ranging from white mould to sulphur deficiency. Some preliminary musings on how to deal with them
by PAT LYNCH
We tried a lot of things this year but, as I am writing this at the end of August, we are not really sure what worked. So here are some thoughts.
White mould. This was a big issue in 2014. Fungicides were sprayed with various levels of success. By mid-August, at the end of the mould cycle when the disease was well established, producers were desperately trying to spray various concoctions to stop the spread. Mould cannot be stopped once it is well established. It would be like spraying Dual on foxtails that are three inches high and expecting them to die.
There are varietal differences to white mould. I am not sure how current varieties attain tolerance. The old white bean variety Ex Rico 23 was very tolerant to white mould. When mould infected Ex Rico 23, it could not spread from one cell to the next like it can in susceptible varieties.
If you had mould in 2014, you could have it again in 2015. A good defence is to leave fields that had mould untilled. Do not work them. This allows the sclerotia, the overwintering part of this disease, to rot. Even if you do not plant soys for another two or three years in that field, leaving it unworked will help break down the overwintering structures.
Planting an earlier variety helps. But planting another crop is the best option.
Nitrogen (N) loss. This was not as big an issue in 2014 as in other years. Part of the reason is that more growers went to some type of strategy to prevent corn and wheat from running out of N. The different strategies included ESN (Environmentally Smart Nitrogen) nitrification inhibitors and split applications. It will be interesting to review the results of these trials in 2014. But even if there was little difference in 2014 between different strategies, this is something we have to continue to work at. We need ways to keep corn and wheat from running out of N without applying too much N.
Sulphur (S). S deficiency was widespread in 2014. It showed up in forages and beans and, to a lesser extent, in corn – probably because more corn growers used S in their 2014 corn program. The use of S as a common fertilizer material is relatively new to Ontario. The reality is that we are using up the S from the soil that was deposited as a pollutant. The excess rain in 2014 probably helped cause more deficiencies. It would be nice to variably apply S only to those areas of the field where it is needed, but the cost of variably applying is similar to the cost of applying S to the whole field or farm. And there may be areas that do not appear to be deficient but produce more because of S applications.
Crop rotation. Commodity prices will mean a shift back to more soybeans on soybeans, which is not a good trend. Soybeans add nothing to soil structure or organic matter and do less to prevent erosion than wheat or corn. At the same time, growing wheat after wheat has been considered a no-no.
The reality is that the yield hit by growing wheat after wheat will probably be less than growing wheat after a crop of soybeans that were harvested late, especially if wheat is mudded in. The option is to not do either and just plant soys after soys. Looking at the whole view of crop production, planting wheat after wheat on some acres and sowing red clover may be a better option.
Single-cut versus double-cut red clover. This year the single cut was a better option. If you are thinking of seeding more single cut next year, you'd better order your seed early. If a lot of acres switch, there could be a shortage. BF
Consulting agronomist Pat Lynch, CCA (ON) formerly worked with the Ontario agriculture ministry and with Cargill.