We have talked enough about weather this year to last us for quite some time, but it continues to dominate everything we do to produce this crop. While some have received enough rain in recent weeks to keep the crop on track others have not.
The corn harvest has begun and yields are quite good so far, but when we get into some of the later plantings the story may change unless we receive a rain for those fields that have not reached black layer. So far it seems that corn pollination has been good, but drought stress can still lead to kernel loss if there is insufficient water to fill them.
The story for soybeans is quite different here in the Hills where we are able to irrigate only a few of our fields. Drought and heat stresses have arrived at a very difficult time since many of our fields are planted to late MG4 varieties which are now in the later phases of R5 maturity. At this point soybean plants require large amounts of moisture to sustain the reproductive processes leading up to physiological maturity.
In simple terms this is not the time when soybeans tolerate moisture stress well. Later maturing MG5 varieties are also reaching the R5 stage now if they were planted in late April or early May. Other fields that where planting was delayed or that were planted after the wheat harvest are not making the kind of progress they need to be on track for good yields, but if we can get rain within the next week or so they may be able to recover to some degree before they start setting pods.
Cotton and grain sorghum, our traditional drought tolerance winners, are now showing the signs of moisture deficiency as well. Peanuts are also suffering, especially on the very sandy soil areas where organic matter levels are low. As in other crops, peanuts show us definitively where soils are less capable of supplying water to the crop. Old fill areas and streambeds that have been filled with deep sand over the years are easily seen in many of our fields.
There is however something that we should recognize as important with regard to drought tolerance in many fields around the state. This is that soils that have been managed best with rotation, cover crops, no-tillage, strip tillage, or other forms of reduced tillage are showing less apparent symptoms of moisture deficit. Those fields where soil pH and nutrient levels have been maintained well are actually still looking fairly good. Fields where poultry litter has been applied recently along with whatever other liming and fertility needs are holding up to the challenge of moisture and heat stress amazingly well.
These days we have a term for the combination of factors and practices which lead to soils that support crops well during periods like this. It is a term that was not used when I first entered this profession, but I believe it is very appropriate for describing our most productive soils. This term is “soil quality” and it brings together all of the traditional traits of soil fertility plus some that are only now becoming more commonly recognized.
These include all kinds of organic activity from earthworms to actinomycetes and mycorrhizae. Mycorrhizae alone are capable of helping crops utilize a much greater portion of the water contained in the soil, but they are often not able to reach effective levels because of extensive tillage, reduced organic matter levels, and incorrect fertilization practices that suppress their development.
The sad fact is that we seldom accept just how critical all these factors are to our success with crops until we get into situations like the one we are in now. Too few people make the connection between soil quality and yield until it’s too late as it may be for some this year. We just go on being amazed at how well some producers fare in spite of stresses that cause big losses for others. There really is not much mystery to it. It’s not too late to change to better methods – I hope.