Value of Manure

Is manure a “Waste” that pollutes our water resources and creates undesirable nuisances for communities? Or, is manure a “Resource” that reduces the demand inorganic fertilizers and improves the health of our soils? A team of university educators and agricultural organizations would like to learn more about the issues most important to you as you make decisions for the use of manure in cropping systems.

Many Nebraska farmers are experienced with using beef feedlot and swine manures as fertility products. Over the next few years, Nebraska crop farmers may have opportunities to consider using broiler poultry litter as a soil amendment and fertilizer. Other regions of the US have a history of using poultry litter in crop production from which we can take away a few lessons.

Animal agriculture often endures criticism from neighbors and consumers relative to sustainability. But when it comes to management of carbon and nutrients, animal agriculture has a positive story to share. Many environmental and sustainability organizations promote the importance of a “circular economy” for increasing sustainability. Those engaged with Nebraska agriculture should help our neighbors and consumers recognize agriculture’s long term practice of implementing this circular economy. This article will help introduce agriculture’s circular economy for nitrogen (N), phosphorus (P), carbon (C), and other nutrients and messages you might share with neighbors and consumers about the Nebraska Advantage for sustainability.

On a brisk April day, I was traveling with a group of adventurers through the wilds of the Minnesota country side. We came upon a steep embankment and climbed it so that we might see what lay beyond. When I reached the top, and the crowd around me had parted, I thought for a moment I might suddenly have traded places with Samwise Gamgee, hobbit, because I was gazing out onto a field of what reminded me very much of the steaming slag pits of Mordor.  However, rather than an apocalyptic hell-scape I was instead looking at a premier example of sustainable agriculture.

In sugar beet production, most farmers do not have an option of manure as an alternative N source since N availability from manure can occur too late in the season and affect sugar quality. Composted cattle manure as different as it is from fresh manure might be a viable alternative N source for sugar beet production.

Iowa State University researchers concluded from a long-term field study that poultry manure, when applied at a rate to meet the crop nitrogen (N) requirements, can reduce nitrate loss and achieve equal or better yields in corn soybean production systems. While this research focused on nitrate (NO­3-N) loss by field-tile drains (typically placed 3 to 6 feet deep), similar trends would be anticipated in Nebraska for nitrate leaching below the crop root zone and the eventual impacts on surface and ground water quality.

Spring manure applications may provide environmental and crop production advantages compared to fall manure applications. These benefits include reduced nitrogen leaching, increased crop yields, and higher phosphorus and potassium nutrient soil storage.

Cedar trees are spreading into grasslands and reducing forages that support cattle grazing. The Nebraska Forest Service is promoting management practices to keep the trees from spreading outside of their usual habitat and into grasslands and areas along the banks of rivers and streams (called ‘riparian forests’). So what do cedar trees have to do with manure? Since 2015, two resourceful farmers have generously given up a few acres of their fields for UNL researchers to test various applications of mulch alone or co-mingled with cattle or swine manure.

Our “instant” culture gravitates to testimonials about how to rapidly increase soil organic matter by 1% within 1 to 3 years. Conversations with lenders and landlords regarding rewards on manure applications and multi-species cover crops investments would likely be easier if financial rewards or measured soil physical properties came quickly.

Manure is a valuable source of nutrients offering agronomic and soil health value. Most manure nutrients (e.g. phosphorus) can be managed successfully with traditional soil analysis. However, nitrogen in manure requires some simple advance planning to insure that it is given proper credit for offsetting commercial fertilizer inputs.

Manure is often viewed by many as an environmental liability. However, if manure is applied at rates equal to or less than the nitrogen (N) requirement of a crop, can manure produce environmental benefits over commercial fertilizer? This was the focus of an Asian research group which summarized the results of 141 published studies from Asia, Europe, and the U.S. comparing manure substitution for fertilizer. This article summarizes the “Take Home Messages” from this research paper.

Land application of organic materials for soil management in Nebraska is important. The availability of applied organic N and the fertilizer N substitution values of applied organic materials is not well predicted. The uncertainty of applied organic N availability leads to over-application of fertilizer N resulting in low efficiency of applied N use. Research has been done to validate or adapt canopy sensor guided in-season N application practices for fields with manure or other organic material applied, and to improve the prediction of the fertilizer N substitution values for organic materials.

Soil health management refers to the preservation and improvement in soil physical, chemical, and biological properties to maximize the productive capacity of soil. Cover crops and reduced tillage are promoted for improving soil health; however, soil amendments such as application of livestock manure and municipal biosolids have received less attention as a soil health improvement practice. A literature review, funded by the North Central Region Water Network and the Soil Health Institute, was conducted to summarize and discuss results of studies reporting chemical, physical, and biological soil properties from application of livestock manure, animal by-products (i.e. compost), and municipal biosolids and to identify further research needs.

Manure has value. That value may result from improvements in soil quality, increases in yield, and replacement of commercial nutrient required for crop production. This article will focus on the economic benefits of manure.

This article reviews the value that results from changes to soil’s physical characteristics. Charles Wortmann and Dan Walters, faculty with the University of Nebraska-Lincoln monitored soil erosion, runoff, and phosphorus (P) loss from replicated field plots over three cropping seasons immediately after manure application and four subsequent years when no manure was applied. Significant erosion and runoff benefits were observed for sites receiving animal manures.

Manure increases formation of larger and more stable soil aggregates. Several benefits result for fields fertilized by manure compared to commercial fertilizer including reduced runoff and soil erosion and increased water infiltration leading to greater drought tolerance.

Farmers and ranchers are becoming increasingly aware of the importance of soil quality/health to the productivity and sustainability of their agricultural system. Research and field observations have demonstrated that carefully managed manure applications can contribute to improved soil quality with limited environmental and social risks. However, a comprehensive assemblage of outputs and conclusions from research studies, field trials, soil labs databases, and other sources has never been developed.

With ground opening up for manure application following wheat harvest, this is a good time to ask about the fit for manure with wheat? There are some good opportunities to use manure following wheat harvest.

When a swine lagoon is abandoned, the owner has the choice of decommissioning the lagoon or maintaining the integrity of the lagoon. Decommissioning means dewatering the lagoon and land applying the sludge at the bottom. One cannot just fill in the hole. The process of removing the water and the sludge is time consuming and takes resources and planning to complete properly. One aspect of the process does have some cost recovery and that is utilizing the sludge in a beneficial way.

This article is Part 1 of a two-part discussion on the value of manure. Part 2 focuses on soil quality benefits provided by manure and appeared in the March 6, 2017 CropWatch.