Given the recent weather pattern........

I thought I would copy and paste an article from the May 23rd NDSU Crop and Pest Report.  This article was written by Joel Ransom, NDSU's Extension Agronomist for Cereal Crops, and addressed the issue of waterlogged soils and plant establishment/development.

Joel writes; "The recent rainfall has curtailed planting at a critical time as the last planting date approaches for many crops and regions of the state. In many areas, excessive rainfall has caused localized flooding, ponding and saturated soils. For fields previously planted, excessive moisture can be damaging to the germination process and to plant development. Waterlogging (flooded/ponded/saturated soils) affects a number of biological and chemical processes in plants and soils that can impact crop growth in both the short and long term. Waterlogging deprives plants of oxygen. Plants need oxygen for cell division, growth and the uptake and transport of nutrients. Since oxygen diffuses through undisturbed water much more slowly than a well-drained soil, oxygen requirements rapidly exceed that which is available when soils are saturated. The rate of oxygen depletion in a saturated soil is impacted by temperature and the rate of biological activity in the soil. Moisture is required for germination. Once the seed has absorbed enough water to start germination, however, excessive water in the soil can deprive the emerging seedling of oxygen and kill it before it can emerge from the soil. Germinating seeds/emerging seedlings are very sensitive to waterlogging as their level of metabolism is high.
The cooler temperatures that have been associated with the recent wet weather will help delay the adverse effects of waterlogging on any emerged crops. Generally, the oxygen level in a saturated soil reaches the point that is harmful to plant growth after about 48-96 hours (longer when temperatures are cooler). In an effort to survive, tissues growing under reduced oxygen levels use alternate metabolic pathways that produce by-products, some of which are toxic at elevated levels. Crops like small grains and corn tend to be more sensitive to waterlogging when their growing point is still below the surface of the soil (before the 5-6 leaf stage). With the exception of winter wheat, all of the small grain and corn crops in the state are still in these sensitive stages (if planted at all) and can be killed if soils are saturated beyond 48 hours when soil temperatures exceed 65 degrees.
Crops can differ in their tolerance to waterlogging. Data from differing sources suggest a possible ranking of waterlogging tolerance as follows (most tolerant to most susceptible): rice, soybean, oats, wheat, corn, barley, canola, peas, dry beans and lentils.
Waterlogged conditions also reduce root growth and can predispose the plant to root rots, so the ultimate effect of excess moisture may not be known until late in the season. It is common to observe plants that have experienced waterlogging to be especially sensitive to hot temperatures and display nitrogen and phosphorus deficiencies later in the season due to restricted root development. Yield losses can occur even if these obvious visible symptoms are not observed.
Waterlogging can also indirectly impact cereal growth by affecting the availability of nitrogen in the soil. Excessive water can leach nitrate nitrogen beyond the rooting zone of the developing plant, particularly in well-drained lighter textured soils. In heavier soils, nitrate nitrogen can be lost through denitrification. The amount of loss depends on the amount of nitrate in the soil, soil temperature, and the length of time that the soil is saturated. Losses of up to 75% of the soil applied N have been reported when soils are saturated for 5 days and soil temperatures are 75 to 80 F."