Published September 24, 2012 | By admin
Now that those of us who are looking at harvesting the 2012 crop, be it corn, soybeans, dry edibles or cotton we seem to have a common theme of thought – let’s look forward to next year. Why? The 2012 year just has a taste about it that is bitter and salty (salt due to all the sweat I think!). As an agronomist I am reflecting how can we cope with anything like this in the future. Several key measures come to mind; first off taking care of all the residue– to not let it leave the field, use it to blanket the soil and hold valuable moisture. How that is done with the corn fields that had three feet high shriveled stalks at best? Or beans that barely came up to the knee in height? If fall tillage is your only considered method (even in this super dry soil condition we are in right now), then look to strip-till or direct seed next spring.
The first benefit of strip-till is you can apply the needed dry fertilizers in a band this fall to those soils that call for it from your soil testing program. The P and K into a band is a long-time proven method that works to supply nutrients for the next crop. It is much more difficult in the direct seeding method unless then you are banding it somehow with a knife (and then is that really direct seeding or no-till?)
Secondly, we want to leave crop residue, and minimize tearing it loose from the soil. Every little bit of crop aftermath has a gaining effect for slow release of K, S, N and a little P back to the soil. Residue protects the soil surface from oxidizing the readily broken-down carbon particles to the atmosphere. Those residues are like a blanket to reflect sunlight and cool the soils in the heat of the summer. Keeping the shallow portion of the root zone cool will help root function and water uptake so the plant can cope with the heat. Why? When soils are far above 85 degrees F (28 C) roots are nearly stopped in function and the smaller diameter roots are dying. Those small roots are incredibly important to nutrient uptake as well as soil moisture. Residues are food for the microbial life and microorthopod insects in the upper 10 inches (25 cm) of the soil, maintaining the aftermath as long as possible feeds the soils inhabitants. Residues do act like a plastic barrier to reduce evaporation of precious soil moisture that is drawn to the soil surface. Every little twig, leaf, cellulosic fiber is worth maintaining on the soil surface in as long of a form and not all cut up into smaller pieces because we perceive they are unsightly and farming like that is untidy.
Third, minimizing tillage has far reaching benefit on soil moisture. Each tillage pass releases soil moisture to the atmosphere and the loss of 0.75 of an inch (19mm) potentially. What could all of us had with another 3 inches (75mm) of moisture? In some instances just another 20 days of watching in agony I am sure. Consider the dollars spent in diesel to till, your time on the tractor, maybe a breakdown, overhead and more.
In some locales, it is said that broadcast fertilization is the only way to distribute commercial or organic manures. If I may, I challenge that way of thinking. It is obvious that roots do not grow on the ground surface, and research shows that roots can tolerate only so much heat and then they wither and die. Even gravity is a major factor in plants rooting. It was long-thought that tillage was the best way to mix nutrient products into the soil surface, spreading it all in a totally random fashion on the soil surface. But modern science shows that P and K products (as well as some of the micronutrients) move so little, and knowing that roots grow downward – how do we connect the dots folks? Place these nutrients strategically in the path of where the plant roots will grow and we are developing the solution to the age old problem of feeding our plants to perform. Strip-tillage and methods of banding nutrients gives you the grower of foodstuffs, fiber and forage a better solution. Along with this piece of the puzzle is selecting the right hybrid to fit your soils, management, fertility program and weed control system.
Another piece of the puzzle to handle long duration dry periods (especially with maize / corn) is to look at hybrids with better genetic selectivity for handling heat stress and when pollination will occur. Now corn breeders have seen the effects of better selectivity for deeper rooting has been a help. Getting the crop to have early vigor will make a positive difference too. We are in a period of climate warming similar to what came after the last glacial period of 9,000 years ago – so our crop management techniques must adapt to cope with such.
Pest control, those venerable and pesky weeds are on the minds of growers everywhere. How do I control them from robbing moisture? Indeed as an agronomist the weed species are a nuisance and bugger to deal with, whether they are many or few. Herbicides and tillage or the lack of have their problems for farmers all over the globe.
One of the last facets of real integrated farming systems is water management. That does not only mean this important to the irrigated farmer, but also to the rain-fed farmer, the grower that relies upon the clouds to deliver precious moisture for the crops they grow. Residues, minimizing tillage passes, keeping weeds controlled from taking all the soil moisture from our crops all play a strong role in this system.
More of us in the industry want growers to consider the great value of how to think of a fully integrated approach to be successful.
by: Michael Petersen, Lead Agronomist for Orthman Mfg., Inc