Cotton in many fields has started to bloom which is the most critical stage when it comes to amount of moisture that the cotton plant uses. Drought before bloom can reduce the number of fruiting branches produced by first bloom. However, drought is rarely severe enough to cause fruit shed before bloom. As the crop begins to bloom, it must begin filling bolls. This process causes the plant's demand for water to rise dramatically as more and more bolls are produced.
When cotton begins to bloom it can be using from 0.25 to 0.4 inches of water per day. The dry conditions that we have had early in the season have forced the cotton plant to send roots deep for moisture, which helps explain why some of the cotton looks as good as it does.
Drought following bloom has the greatest effect on cotton yield and lint quality, so we need this new rainfall trend to continue.
Grain sorghum is known as a drought-tolerant crop and that is why it is so well adapted to the local region. Grain sorghum's ability to perform under dry conditions can be attributed to the sorghum plants rolling leaves as they wilt, thus reducing transpiration, the waxy covering over the leaf protecting it from drying and the extensive root system. Much of our sorghum is at peak water use stage now, which can be as high as 0.4 inch per day during early bloom and then is reduced to just less than 0.3 inch per day during grain fill. Grain sorghum’s extensive root system, can extend to 6 feet in a friable soil. About 75 percent of water use will occur in the upper half of the root zone. Under stress conditions, when the upper zone becomes water-limited, the crop will use significant deep water, which thankfully we had some of that this year.
Corn has been hurt the most by the current drought. During the period of pollination the corn plant requires the most water and is most sensitive to drought stress. Grain is not produced without pollination because fertilization by pollen initiates seed (kernel) production. Drought stress can disrupt pollination in many ways, with the most frequent being by disrupting the "nick," or synchronization of pollen shed and silk emergence. Tassel and pollen formation take priority over silk and ear formation. Drought stress prior to tasseling will delay silk emergence. By the time the silks from the tip of the ear emerge from the husks, pollen shed may have ended. This leads to ears with barren tips (nubbins), or, in extreme cases, ears with no kernels at all. We have already seen some evidence of this locally.
