Monday, August 27, 2012

Not So Common

Brian brought home this specimen one day last week.  It was supposed to be an ear of corn.
The ear is totally infested by common smut.  Common smut is a fungal disease that attacks plants in the grass family and flourishes under a variety of conditions.  The disease overwinters in the soil and on plant trash.  The overwintering stage is known as a teliospore and can survive for several years, so there is always a ready supply of inoculum.  It will infect a plant through wounds or holes in the plant's physical structure.  In this case the smut attacked the plant through the silk channels, which provide openings into the plant.  Normally, pollen grains germinate and grow down the silk channel.  Droughts often delay pollen production and the silks will remain viable for several days.  In this case the fungus grew down the silk channel first and blocked out the pollen.  The fungus is NOT toxic to livestock.  In fact the early growth stages of the fungus are edible.
The reason this field is affected is due to timing of fungal spore production and drought stress.  The ability of a hybrid to withstand drought stress at pollination can be a factor, but hybrid susceptibility differences are small. 

Monday, August 20, 2012

Dialing 1-800-POTASH!

As mentioned in last week's Ontario Farmer potash deficiency symptoms are showing up many soybean fields.   You do not have to drive very far to see lots of examples.

Many farmers just assume the drought was too severe and the plants are starting to ripen.  The reason for the deficiency showing up now is because potash demand peaks during the pod fill stage. Most assume there is nothing they can do.  Very few farmers actually ask about potash deficiency.  Take a close look at your fields.

If you see symptoms that look like this you have potash deficiency.  There are two main reasons for the symptoms to appear.  Either the soil has low potash reserves to begin with or the ground is so compacted the plant cannot forage for the available potash in the soil.  Most of the time in our neighbourhood it is caused by low potash reserves in the soil.  It is a worry that despite spending big dollars on land purchases and rent, farmers are not keeping up with basic soil maintenance.  The solution is simple, but you have to get off your wallet one more time. 

A good explanation on the benefit of potash and phosphate applications in soybeans from the University of Wisconsin can be found at the following link.

Friday, August 10, 2012

Down The Back Stretch

I posted a while back about our planting date trial in soybeans.  I thought it was time to update our observations.  There is a lot we can learn about growth stages of soybeans and the effect of weather during the later development stages of the crop.

For a refresher these are the reproductive stages of a soybean plant.  The stages seem complicated, but you just have to look at the top of the plant to make the assessment.

R3 - Beginning pod, short pods visible in top 4 nodes of the plant.

R4 - Full Pod, pods 2 cm long at top 4 nodes of the plant.

R5 - Beginning Seed, seed .3 cm long at top 4 nodes of the plant. 

R6 - Full Seed, seed in upper pods fills the cavity.

The R5 stage is the most critical for yield development. The soybean plant can shake off earlier problems and still produce high yields if weather co-operates during this stage. It is why Horst Bohner will say it does not matter what happens to the crop until August.  He is right.  What is sometimes not mentioned however, is the effect of maturity in the yield equation.  That is why we are looking at full season soybeans planted early, May 11 and late (for this year), May 26. 

Pioneer variety 92Y12 is an early group 2 bean.  Early group 2 is approxmately 3050 CHU.  A lot of you would not consider plantring a bean this late.  Some of you do not want to plant corn hybrids in this maturity range either.  That is ok.  Very full season crops are not for everyone.  You have to feel comfortable with your maturity choice. 
The reason we looked at 92Y12 is purely yield.  This is one of the highest yielding group 2 varieties on the market.  Last year in our strip plot it yielded 72 bu/acre harvested on October 12.  We would not be doing our job as a Pioneer rep if we did not push the edge of maturity to see if it makes sense for some of us to try it on a larger scale. 

The May 11 planted 92Y12 were still producing a few flowers at the top pf the plant last week.  This is the late stages of R4.  The upper pods are forming.
Further down in the canopy the pods are flat.
The 92Y12 planted on May 26 is in the R3 stage of early pod formation.  A long way to go, but the growing season is not over. 

The other variety that is being evaluated in the planting date trial is 91Y61.  It is a mid group I variety which is  approximately 2900 CHU.  This is closer to the maturity that, at least in corn, many of you are comfortable with.
The May 11 planting date is just entering the R5 stage.   
The 91Y61 planted May 26 is close to the same maturity stage, late R4, as the May 11 planted 92Y12. 

For comparison we also have late group 0 soybeans planted on May 11.  A late group 0 variety is approximately 2750 CHU.
90Y90 is an example of this maturity. 
Soybeans in this maturity are well along in R5 and approaching R6.  These beans have had extreme heat and drought stress to contend with.  The R5 and R6 stages are both about 2-3 weeks in duration under normal circumstances.  Where the drought is worse it appears the early varieties have rushed through the R5 period quicker than normal.  What effect will this have on yield?  Probably negative. 
It is way too early to make many predictions.  August and September weather will decide who wins the gold in this race.

Saturday, August 4, 2012

Does Anybody Know A Good Crop Consultant?

I blew it, big time.

Spider mites have been lingering in the area and I had seen some evidence starting to show up.  I had even taken some shots from a neighbour's field early last week.

I kept telling myself we have never seen major outbreaks before in this area and it was going to rain.  This problem would be isolated.  My soybeans did not have any spider mites.  Meanwhile Peter Johnson was yelling at everyone to spray for spider mites.  Populations will explode he warned.  Yeah Peter, you were right.  I was wrong.  Now there is injury in many fields and Brian has started spraying.  The problem is once you see this degree of injury it is almost too late.  It is like closing the gate after the cattle have got out.  We let a week go by and did not react.  Now it is a long weekend, retail outlets are closed and the supply of dimethoate is almost gone. 

Thursday, August 2, 2012

Sometimes It Is Not As Bad As It Seems

I was out yesterday looking at more stressed corn.  The picture below is how the field looked.
Customers have been asking about corn plants burnt up to the ear and what to expect.  We all assume the worst.  A week ago this crop would make you cry.  It was shrivelling in the heat because the rains continued to go around.  3/4 of an inch arrived on Friday night.  I went about 10 rows from the edge and picked the ears shown below from 7 consecutive plants in the same row. 
Five of the seven are respectable.  And with a little more moisture it may surprise.  We all have been in a combine and seen a lot of little ears coming in the header and corn piling in the bin.  The season is not over and the plant can pack a lot of test weight into these kernels.  A week ago you would want to plow it under.  Yesterday, not so fast.