How many tons of manure per acre

The rates below are the maximum amounts of N that should be applied when manure is used, whether it is all manure or a combination of manure and inorganic commercial fertilizers. Lower rates may be considered based on the productivity of the soils in your fields, economics, or environmental concerns. In all cases, all sources of N should be taken into consideration when estimating how much N to apply, including:.

Why is that? For example, once N leaches past the plant root zone into the ground water, it becomes a concern for drinking water and will eventually end up in lakes, rivers, and streams. On the other hand, excess N that is not taken up by crops can also be lost as a gas through denitrification. When manure N becomes plant available, it behaves exactly the same in the environment as N from commercial inorganic fertilizer, so it is important that all forms of N applied to the soil are taken into consideration.

The maximum rate of plant-available nitrogen PAN that should be applied with manure to non-irrigated corn, depending on the crops prior to corn, can be found in the table below.

Corn grown under irrigation is a special case because it is usually done on coarse-textured or sandy soils. Under these conditions, there is a higher risk of N loss due to the high leaching potential of these types of soils. With manure, there are other nutrients to consider that could potentially also be lost through leaching. See the table below for the total N rate guidelines. A good rule of thumb is to apply a lower rate of manure lbs of plant-available N [PAN] or lower , then add the remaining N as commercial fertilizer.

The maximum amount of PAN you should apply to non-legume crops with manure should follow University of Minnesota guidelines for nitrogen fertilizers. If manure is applied to a legume crop, you can apply as much PAN as the crop will likely take up in the harvested portion. Apply manure to distant or limited-access fields in early winter, then to nearer fields later in the season, when mud and snow make access and spreading more difficult. The use of conservation practices that reduce or slow runoff will help reduce the adverse effects of winter-applied manure.

If it is necessary to spread manure on soils subject to flooding, do so only at times when flooding is least likely to occur. An up-to-date, implemented farm conservation plan is an important component of farm management. Not only do conservation practices reduce soil and water loss, but they also can reduce the potential for nutrient loss.

Practices such as using a cover crop or crop residue management, as well as contour stripcropping, contour farming, cropland terraces, diversions, grassed waterways, and filter strips can effectively reduce the surface loss of soil and manure nutrients.

It is critical that the practices in the farm conservation plan be integrated into the nutrient management plan. This is not always simple and may require some compromise. For example, incorporating manure is recommended to reduce N loss by volatilization; however, incorporating manure also incorporates crop residues, which are critical to soil conservation.

Most of the emphasis of nutrient planning efforts has been placed on balancing nitrogen. It is important to recognize that phosphorus P also is a potential pollutant and to make every attempt to maintain adequate but not excessive P levels in the soil. When manure nutrient applications are balanced based only on N, an excess of P often will be applied. If only some of the crops in a typical crop rotation receive manure, this excess may be balanced out over the cycle of the rotation.

Continuous manure application, however, may result in excessively high P levels in the soil. Although potassium K usually is not considered an environmental problem, excessive K levels in soils can lead to nutritional imbalances in crops that can affect the health of animals. For example, high forage K levels have been linked to an increase in milk fever in dairy cows. A regular soil testing program should be followed to monitor the status of P and K in your fields.

The goal should be to maintain the P and K levels within the optimum range on the soil test report. Records of manure applications should be kept both as a management tool and as a verification that sound nutrient management practices are being followed, in case of a complaint related to nutrient applications on the operation.

It is difficult to make decisions about what practices to change in a farm's nutrient management program without having records such as soil tests, manure analyses, and crop yields.

Simple records of which fields manure was applied to, when manure was applied, how much was applied, and any other nutrient applications will meet most needs. Certain situations require rough estimates of manure application rates. These estimates can be especially helpful in planning a new or modified operation where soil tests and manure analyses do not exist. The accompanying tables can be used to estimate manure application rates for these purposes. For existing operations, although a nutrient management plan should be based on soil tests and manure analyses, using book values to develop a crude plan is better than having no plan at all.

Note, however, that a plan based exclusively on these tables would not meet the requirements for a nutrient management plan developed under the Pennsylvania Nutrient Management Law.

Whenever possible, manure rates should be determined based on soil test recommendations and manure analysis adjusted for actual incorporation and field history. A simple worksheet for making this calculation is included in this fact sheet. To use the following tables, you must know at least the type of manure and the crop to be grown.

Additional information that will help to improve the estimated application rate includes the actual expected crop yield, the anticipated time between spreading and incorporation, and some sense of the fields' manure history. In these tables, an estimated Nbalanced manure application rate is given for most crops commonly grown in Pennsylvania for an average yield.

This base application rate then can be adjusted for a different yield and for the field's manure history. Guidance for making these adjustments follows:. In the spring, even without mechanical incorporation, manure likely will be incorporated by rainfall. Yield Adjustment: These rates can be adjusted proportionally higher or lower based on your actual expected yield.

Adjustment for other nutrient sources: These rates assume that manure will be used to satisfy the entire N requirement or utilization for the crop.

If other sources of N, such as starter fertilzer, legume N, etc. Calcium carbonate lime is a common additive to livestock diets. Manure can contain between one and four percent calcium carbonate, depending on the diet formulation. One way to account for the liming effect of manure is to monitor the pH of the soil over time. The pH of manured soils should increase, or become more basic. Used in conjunction with a good liming plan, the amount of agricultural lime needed can be reduced on manured fields.

A more direct way to determine the amount of calcium carbonate in manure is to test it for effective calcium carbonate ECC , which is a commercial fertilizer test. Request an ECC test which will report the amount of calcium carbonate equivalent in the manure. Potassium content in soil, plants, and animal rations is expressed as potassium K content but potassium in fertilizers and manure intended for land application is expressed as potash, or more correctly, potassium oxide K 2 O.

Liming effect of manure: Assume a feedlot manure sample test returns two percent calcium carbonate. In this example, one ton of dry manure contained 40 pounds of available lime. Therefore, if the producer's soil test showed a 2, pound lime requirement, he would only need a 1,pound application after the manure application. Salt is an issue in certain soils and real dry areas, wet locations the salt flushes out.

Paul Yes that is a big problem here. Even with irrigation, years of manure applications can hurt yields. Dairies around here run out of places to spread after a while. They will even help pay some of the trucking to get rid of it.

We also can get too much K as our soils are already adequate. North Liberty and South Bend, Indiana. Beresford, SD. Same here.