Wet weather, higher precipitation, global warming

By Ken Williams

Waushara County Ag Agent

This past year has been a year of higher precipitation which has affected farmers and non-farmers. Wet fields have resulted in farmers planting crops later, which has the result of lowering the potential yields of those crops. Heavy rainfall after crops have been planted have resulted in ponding in many fields which reduces the yields in those ponded areas as a result of nitrogen loss due to leaching and  denitrification along with the negative effects on plant growth due to the loss of available oxygen for plant roots. Wet fields also affect the timely harvest of crops which affects the potential value or use of that crop.

Dairy producers rely on quality forage in order to maintain animal health and productivity. Wet weather has affected the timely harvest of hay and forage which results in lower feed quality. Uneven planting dates and uneven plant growth due to water ponding in corn fields results in a lowering of the feed quality of corn harvested for silage or grain.

Grain farmers are harvesting corn this year with higher than average moisture which could result in an additional cost for drying of $.50 per bushel.

Soybean producers face additional harvest issues. The moisture content in soybeans fluctuates considerably after a rain event occurs. Soybeans are harvested at a low moisture content and are not dried in a dryer as corn is. After it rains, it takes three or four days of dry weather for the moisture content in soybeans to fall back to thirteen or fourteen percent which is necessary for harvest.

Vegetable producers also face planting and crop growth issues due to wet fields. For vegetables such as carrots and potatoes wet fields can result in storage issues due to soft rot in those vegetables that may be started in the field and then be transferred with those crops into storage.

All agricultural crops have been faced with issues of wet fields causing harvest problems, which leads to higher harvest costs, more equipment breakdowns, as well as challenges meeting quality and production requirements.

Irrigation is affected somewhat but not to a great degree, the top foot of sand holds enough water for only about two days of plant growth for most vegetable crops because they are shallow rooted, corn can survive a day or two longer between rain or irrigation events due to a deeper root system.

The higher amounts of precipitation has also affected the area tourism economy as a result of many of our local lakes being posted as “no-wake’” for the major part of the summer season. Not long ago this area saw many of our lakes facing low water levels. Most of our local lakes are seepage lakes which have their water levels directly affected by the height of the water table in the surrounding ground. Now we have issues with the water levels in many of these same lakes being at record high levels.  Many of these lakes now have a circle of dead trees around them due to the higher water levels. Many of these trees are large enough to be perhaps 30 or 40 years old. This would indicate that the water levels are higher now than they have been in the past 30 or 40 years.

I looked at the precipitation records for The Hancock Research Station (HRS) from 1981 to 2019.

It appears that we have been in a pattern of higher precipitation throughout this time period. The USDA Soil Survey for Waushara County dated 1989 describes Waushara County as having a yearly rainfall amount of 29.44 inches. For the years 1981 to 2010 HRS received an average of 32.75 inches of precipitation per year. For the years of 2009 to 2019 HRS received an average of 35.92 inches of precipitation. (For October, November and December 2019 average values from 2009-2018 were used). For the years 2015 thru 2019 the yearly precipitation amounts at HRS were respectively; 35.1, 42.7, 38.3, 43.1, and 41.9 inches. Are these higher precipitation amounts the new normal?

Many people believe global warming is causing changes in our weather patterns. Various sources indicate that average temperatures have increased 1.5 to 2 degrees Fahrenheit in the past century. We are seeing weather patterns that point to longer growing seasons; earlier dates for the last frost in spring and later dates for the first killing frost in the fall. Higher air temperatures increase the rate of water evaporation from the ground and also increases the amount of water vapor that the air can hold. Some point to this as resulting in higher rainfall events during storm periods.

For whatever reason it does appear that our yearly precipitation amounts have been increasing over the past 40 years. If this is in fact the “new normal” it will have a serious effect on production agriculture, tourism and our daily lives in the future.