Spring Assessment Of Winter Wheat Stands

 

Spring assessment of winter wheat stands can be fairly difficult. The decision to replant or “wait it out” depends on various factors. First of all, assess the level of plant death. By this point in the spring, it is fairly easy to evaluate.

 

 

 

Earlier in the spring, the bag test – uprooting plants and placing them in a ziplock bag indoors for a few days – can give some indication. Live plants will begin to show new root growth with a healthy crown, whereas dead ones will show no growth or begin to decay. If the plants are dead, determine the cause of death: Is there any possibility of root rot, rather than winter-kill? Winter-killed plants should be in fairly large patches (Fig. 1). Stressed plants (low moisture or high moisture coupled with limited snow-cover and low temperatures) will have low winter survival. Plants killed by root and crown rots tend to be in smaller patches, especially in lows spots of the field. Another common symptom of root rot is stunted growth and/or thin stand.

 

 

If plants are dead in large patches, replanting may be an option. In replant situations, this year’s low soil moisture adds some complexity to the decision making process. Where soil moisture is inadequate, a newly planted crop may exhibit poor germination or face drought stress in its early growth stages. Thus the new crop may not produce sufficient yields to even cover the replant costs. Moreover, with some additional moisture and warmer temperatures, winter wheat has an exceptional tillering capacity, which compensates, to some extent, for thin stands. Uniformity should also be considered. Optimal plant population generally ranges from 20-30 plants per square foot, but adequate yields can be attained on much less density (see Table 1, Lafond and Gan, 1999). In smaller patches, lower stand counts are manageable.

 

 

 

 

Current forecasts do call for some rain in the future. But it may be sparse still. If the decision is made to replant, there are various options. In late April, it is fairly late to plant spring wheat in the patchy areas. This would not be recommended anyway due to disease concerns and lack of marketing options. In the western part of the state, millet and sorghum might be good options because they are planted much later in the growing season, which allows time to assess precipitation patterns. Both crops are fairly drought tolerant and millet, in particular, relies on in-season rains to a larger extent rather than soil water reserves.