Irrigation an important tool for increasing profits, managing risk and utilizing applied nutrients

Irrigation plays an important role in Michigan agriculture, contributing the rich diversity of crops grown and ensuring that short-term water deficits do not reduce yields and quality of crops produced.

Weather station in a corn field.
Photo by Younsuk Dong, MSU

The Michigan Department of Agriculture and Rural Development (MDARD) estimates that the food and agriculture industry contributes $104.7 billion to the Michigan economy each year. According to Michigan Farm Bureau, Michigan has the second most diverse agriculture in the country, behind only California in the number of crops produced (over 300). The lake-moderated climate, wide range of climatic zones and the diversity of soil types contribute to Michigan farmers being able to produce the wide variety of crops that fuels the state’s robust agricultural economy.

Irrigation plays an important role in Michigan’s agricultural production. A Michigan State University Extension fact sheet developed in 2014, “Value of Irrigation to the Southwest Michigan Economy,” utilizing USDA National Agriculture Statistics Service data, vegetable, fruit, ornamental, seed corn and commercial corn industry resources outlined the economic impacts of irrigation on Michigan agriculture. MSU Extension is scheduled to update this paper during the summer of 2021. These are some of the examples.

Commercial corn—commodity corn that is used for feed and processing—is the largest single acreage irrigated crop in Michigan. Commercial corn plays an important role in Michigan agriculture by providing feed for the state’s dairy industry and other livestock.

Vegetable, fruit, ornamental. The vast majority of the state’s vegetable, fruit, ornamental and nursery stock crops are produced under irrigation. This is because grower’s investment in producing some of these crops often reaches into the thousands of dollars per acre, and even a short-term drought can reduce yields and quality resulting in losses significant enough to create a potential for business failure. Irrigation water is sometimes used in the fruit industry for early season frost protection as well as providing water for crop growth and development.

Seed corn. Irrigation is critical to the hybrid seed corn industry. Southwest Michigan produces seeds for the next generation of much of the world’s corn crop. Two of the largest seed corn processing plants in the world are located south of Constantine, Michigan, in St. Joseph County. Irrigation and the seed corn industry have transformed the agricultural landscape of southwest Michigan and northern Indiana into one of the most productive and valuable local agricultural economies in the Midwest. The seed industry is located here primarily because water can be managed effectively, reducing the chance for flooding injury and production losses caused by drought conditions.

There are several benefits of irrigation in Michigan that are not generally understood. Michigan’s humid climate means that irrigation water supplied is supplemental to natural summer rainfall. This situation is much different than in western areas of the Midwest. Michigan producers use less water to produce an equivalent yield due to our high humidity and higher summer rainfall amounts which reduces crop water demand. Western regions may require two to three times the amount of irrigation to be able to produce a full crop. This is true of commercial corn as well as other crops produced under irrigation.

Irrigation also allows the crops produced to more fully utilize the fertilizer nutrients applied. For example, dryland commercial corn can have wide swings in yields based on the duration of drought stress conditions. In years with adequate soil moisture, yields often run above 200 bushels per acre. With drought stress, these yields can drop more than 60–80 bushels per acre causing obvious issues with profitability. However, it can also result in not fully utilizing all inputs necessary to raise a crop, including energy, water, pesticides and fertilizers.

For example, not using all the nitrogen applied when anticipating full yields can result in leaching, causing water quality issues. Irrigation water application allows the plants to utilize the applied nitrogen more fully, reducing the risk of leaching losses to groundwater resources as well as producing economic returns. The ability to apply nitrogen fertilizer through irrigation water also allows producers to apply the nutrient closer to the time of maximum uptake by the crop, further reducing the risk of loss to the environment. Additionally, nitrogen can be applied later in the season to make up for losses that can occur following excessive rainfall through leaching and denitrification (loss of nitrogen to the atmosphere as N2 gas under extreme wet soil conditions).

The excellent study conducted by Bruno Basso et al. (2021) as discussed in a Journal Nature Communications article provides new insights into the implications of increased humidity on crop water needs and corn production. The study showed that the demand for increased water needed for corn production due to climate change is much less than predicted by other studies. Their models predict that the impact of increased water demand caused by increased temperatures is offset by increased humidity in the Midwest corn growing region. Basso points out that increased climate variability demand can also be offset by “regenerative practices, genetics and digital technology solutions.”

In interpreting the results of the study, it is important to note that the study covers only commercial corn production over a wide area of the Midwest. The manuscript noted that, “Irrigation is indeed a valuable tool for managing risks and boosting profits and will continue to play an important role in adapting production systems to increased weather variability under climate change.” This is especially true in the sandier regions of southwest Michigan and northern Indiana.

Irrigation scheduling is an important step to maximize the benefit of water applications and increase water use efficiency. Maximum efficiency protects the watershed from nutrient leaching, excess water usage and maximizes economic output for the growers. Often in Michigan, irrigation is used to be able to provide short-term drought relief with timely water applications. MSU is continuing the development of irrigation scheduling tools, low-cost soil moisture monitoring systems and improved access to weather forecast and data through the MSU Enviroweather network to provide information that is easy for irrigators to use and tailored to meet Michigan needs. This effort is being led by Younsuk Dong, MSU irrigation specialist, and Lyndon Kelley, irrigation educator for MSU and Purdue.

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