Strip Intercropping Results Are IN!!!

I've done a really bad job keeping this blog current over the last 2 months but we haven't had a rainy day to catch up and allow me to post anything.  There's a lot to talk about as it's been a really interesting and surprising harvest with some of the things we've evaluated this year.  I'll start off with some observations about my strip intercrop yield results which was really interesting and a lot of fun to do this year. 

I was worried that my test of intercrop strips vs conventional solid block planting would be skewed all year as the conventional block was on flat black ground and about 1/2 of my intercrop strips were on a lighter Clarion soil type that under moisture stress would have a disadvantage from not being apples to apples.  Beggers can't be choosers as I didn't have a lot of say in where I put this plot....pretty much had to beg my Dad to let me do it in the first place.  Because of this, I wanted to go out and do some pre-harvest yield estimates on the intercrop corn strips that were closest to normal solid planting block and on the same soil type.  To do this I went out and hand harvested 17.5 ft of ears 6 rows wide in the intercrop and then harvested the same from the conventional block.  What was amazing like some of the pictures earlier in the year showed was how the outside rows even at 45-50k plants/A still had torpedo ears on nearly every plant despite the drought stress we were under.  I laid out the harvested ears on a trailer so that you could see what 17.5 ft of ears looked like in the both the intercrop and conventional settings. 

Grain Cart

Strip Intercrop 17.5 ft of row 6 rows wide

Conventional Planting Block 17.5 ft of row 6 rows wide

I had one row #2 on my planter that wasn't dropping enough seed in both the conventional block and strip intercrop so in both cases I had a light population in that row.  Although it's not scientific, I went ahead and grandfathered in the ear counts from the opposite side of the planter on row #5 to offset this equipment variable problem when making my yield estimates for both treatments.  I estimated yield by ear weight by weighing each individual ear in each row and recording that weight.  There was little variance in the ear weights of the conventional planting block but it was really interesting in the strip intercrop block as the middle four rows all had ear weights of 7.6-8 oz where as the outside row on the east side of the strip had an average ear weight of 8.76 oz while the outside row on the west side of the strip had an average ear weight of only 7.2 oz.  This confirmed what I witnessed visually that the outside west row's ears looked smaller throughout the last half of the season most likely from the increase in temperature and winds being higher with the full exposure to the afternoon sun.  Here is the breakdown of each row's yield estimate in the intercrop strip along with final ear counts/a. 

West row 1 - 277 bu/a 45k ears
Row 2 - 246 bu/a 37 k ears
Row 3 207 bu/a 32 k ears
Row 4 227 bu/a 37k ears
Row 5 246 bu/a 37 ears
East row 6 - 360/bu/a 48k ears

Overall Intercrop Average for 17.5 ft of row 6 rows wide = 261 bu/A estimate

I weighed the regular block as well but there wasn't enough variance to see anything really interesting so here's what the yield estimate was from that.

Overall Regular Planting Average for 17.5 ft of row 6 rows wide = 199 bu/A estimate

Keep in mind that both treatments were corn on corn that was strip tilled last fall and freshened this spring.

So now it was pretty apparent by the estimates that we had a difference on apples to apples soils that we'd see a difference between he 2 systems.  Time to combine and see the real story. 

We combined the beans off the headlands on a Sunday afternoon and could tell right away that the yields of the beans were significantly less than what we'd been combining in our normal bean fields.  The biggest difference that I could guess why was the fact that we hadn't sprayed them with fungicide and insecticide as we had our big fields. I could see quite a bit of spider mite damage late in the season in both the corn and the soybeans so I'm guessing that was part of the reason.  Our fungicide check on one of our big fields was 6-7 bu/A better than the untreated as well so our bean yields on this field were not likely representative as to what they were if we were managing them normally. I didn't have a wagon to put the beans from the end rows available as I was in a hurry trying to beat the sun going down so I used the next best thing in the yard...my Dad's old Gleaner M2.  My Dad won't get rid of it as he says "you never know when we're going to need that thing."  I guess he was right.

Once the beans on the ends were off, I started combining the corn in the normal block of 36 rows that I planted.  I weighed each 6 row pass across the field and took the average weight of the middle 4 passes to eliminate the advantage that the outside passes would have with the increased light on the edges.  The average yield of the conventional block was 196 bu/A...not too far off from the estimate. 

I had 3, 6 row strips of intercrop corn under the high management system that were on the same soils and that I felt were relative to the same conditions that the conventional planted block had.  I harvested those 3 strips weighing each pass and then averaging them and which resulted in a avg yield of 249 bu/A.  

Here's some video of harvesting one of the 6 row intercrop strips.

So our early estimates weighing ears turned out to be pretty close to the final actual numbers.  It makes sense that they're a little less as the sampling didn't take into account the spider mite damage on the south edge of both treatments.  It was nice to see though the same relative differences held true.  So we realized a 53 bu/A advantage to our new practice in this system.  The question remains would this be economic when you do the math comparing growing continuous corn vs having 50/50 corn soybeans with intercropping as well as taking into consideration that the soybeans will likely do less than normal yields?  My answer this year is that I don't know just yet.  While raising potential corn revenues by $375/A with $7/bu corn sounds great, you have to factor in the extra cost in inputs between seed and fertilizer which I've estimated at nearly $100/A along with decreased revenue likely on the soybeans of potentially $100/A compared to what normal yields would be.  Add to this that continuous corn, if yields were decent this year, was likely $100-200/A more profitable than soybeans. 

So in the end, I have more questions than answers.  I do want to do this again on more acres in a bigger field setting and figure out a way to be able to spray and manage the soybeans like we do the rest of our acres to give them the best shot possible for yielding well.  I also want to plant the soybeans the same time I plant the corn to get as much plant growth going before they get shaded out by the corn on the outside rows.  It's quite obvious that we can grow more corn this way but it has to make economic sense across the board if we're going to adopt on a widespread basis.  I'm really glad I took the time and went through all the hassle to do this though...it really opened my eyes to what can be possible if you farm outside the box.  Thanks to those who helped me in my efforts including Sheldon Stevermer of Easton, MN and Bob Recker of Ceder Valley Consulting. 

More blogs to come quicker in the future I promise!!!