Evaluating Liquid Manure as Nutrient Source in a Commercial Orchard

Final Report for FNC93-049

Project Type: Farmer/Rancher
Funds awarded in 1993: $4,551.00
Projected End Date: 12/31/1994
Matching Non-Federal Funds: $4,260.00
Region: North Central
State: Michigan
Project Coordinator:
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Project Information


Mr. Muma’s 180 acre operation consists of 100 acres of fruit with the remaining acres in vegetables, grains, and alfalfa. Fruit is generally sold fresh market or to processors, but a portion is sold at local farm markets.

During the past 5 years, with assistance from the Muskegon County Soil Conservation District several energy conservation practices have been adopted in this operation. Practices include chemical spry reduction through Integrated Pest Management (IPM), tree row volume sprayer calibrations, soil and nitrate testing. The implementation of erosion control practices such as proven to be of great benefit to this operation. With the recent addition of a small beef herd, rotational grazing pastures have been set up.

Because of interest in adopting new and innovative methods into this operation, an application was prepared for this producer grant program. Using manure to fertilize fruit crops seemed to be a good match but very little information could be found about the benefits or problems that might be realized from this practice.

The goal for this project is to evaluate whether liquid animal manures can be used as alternative nutrient source, replacing manufactured fertilizers, in a fruit orchard system. A three acre plot of “Improved Golden Delicious” trees on 106 rootstock received various nutrient treatments.

Some of the guidelines of the 1994 project are summarized below. Also refer to 1994 Grant Report dated December 30, 1994.

1) After comparison of various types of manure’s average nutrient values per gallon of liquid, available sources in the area, possible weed seed content, and consistency of liquids, liquid hog manure from closed pit systems was determined to be the best for this application
2) A concern in this project is soil phosphorus levels. Soil testing in late summer 1993 showed that test plot soil phosphorus levels at 0”-8” range from 64 to 112 pounds per acre and at 8”-16” range from 24 to 48 pounds per acre. These levels are below or near recommended rates in the upper soil layer and are far below levels under right to farm guidelines. Application will be monitored so that phosphorus levels do not build too quickly.

Potassium levels ranged from 220 to 348 pounds per acre at 0”-8” and 122 to 136 pounds per acre at 8”-16”. Potassium deficiencies are common in Michigan and orchardist regularly make potassium applications so this will not be considered a limiting factor. Levels will be monitored so that deficiencies and toxicities do not develop.

Nitrogen applications are extremely important in fruit production. Excessive applications can cause unwanted tree vigor, poor color, and decrease in fruit load. Michigan State University recommends the following initial guide for nitrogen applications for apples: for 6 to 7 year old trees, 10 to 12 ounces of N per tree. Since nitrogen is one of the most important nutrient application it has been chose as the limiting factor for the test plot applications.

3) The test plot was divided into six separate treatment rows of trees. Factors that will be used for comparison of these treatments will include soil sampling, leaf tissue sampling, harvest yields, and overall tree growth. The orchard was also monitored for insect and disease to make sure that treatments with the manure did not increase pest pressures which could be detrimental in the orchard system.

Soil samples were taken in August of 1993 and again in August of 1994. Soil samples were pulled at 0”-8” and at 8”-16” for each treatment row. Samples were tested at A and L Great Lakes Laboratories and then the analysis were used to develop MSU fertilizer recommendations. Leaf tissue samples were also taken August of 1993 and August of 1994 for analysis at Michigan State University Laboratories.

Below is a listing of the 1994 nutrient applications in the test plot, including the timing of applications, the manures or commercial fertilizers applied, and the calculated rates of nutrients for each treatment.

Test Plot Treatments:
Row 1: Check row, no applications

Row 2: Full application of N in spring, 4/23/94
Manure: 35.8 gal/tree, Waste Sample #1
Conversion: N, 2.28 oz/tree
P205, 71.19 lbs/acre
K20, 89.29 lbs/acre

Row 3: Half application of N in spring, 4/23/94
Manure: 15.3 gal/tree, Waste sample #2
Conversion: N, 2.28 oz/tree
P205, 9.47 lbs/acre
K20, 33.15 lbs/acre
Half application of N in summer, 6/27/94
Manure: 23.25 gal/tree, Waste Sample #3
Conversion: N, 3.52 oz/tree
P205, 65.48 lbs/acre
K20, 71.92 lbs/acre

Row 4: Calcium Nitrate(15.5%), 2#/tree on 6/28/94
Conversion: N, 4.96 oz/tree

Row 5: Full application of N in summer, 6/27/94
Manure: 30.25 gal/tree, Waste sample #3
Conversion: N, 4.58 oz/tree
P205, 85.90 lbs/acre
K20, 93.57 lbs/acre

Row 6: Full application in the fall. Not done in 1993 or 1994 due to late growth of trees. If nitrogen spurred late season growth trees could be more susceptible to winter damage. Late season applications of liquid manures may not be practical or beneficial as a regular practice. This row can be considered an additional check row for this project.

For the extension of this 1994 project in to 1995 the first criteria evaluated is the results form leaf tissue sampling. The compressed chart of results shown below gives the 1993 level of nitrogen, the nitrogen applied during the 1994 season, and the 1994 levels of nitrogen.

Table 1:
Leaf Tissue Analysis for Nitrogen Levels
Row, 1993% in leaf, N/Tree app. 94, 1994% in leaf, Change
1, 2.31,-, 4.25, +.14
2, 2.59, 7.1 oz, 2.66, +.07
3, 2.38, 5.8oz, 2.52, +.14
4, 2.31, 4.96 oz, 2.45, +.14
5, 2.59, 4.59 oz, 2.31, -.28
6, 2.38, -, 2.52. +.14

Michigan State University in Extension Bulletin E-852 states the optimum range of nitrogen concentration in leaves of golden delicious is 1.7 to 2.0 percent, while Cornell Extension in Bulletin 219 recommends concentrations of 1.8 to 2.2 percent.

Based on 1994 nitrogen concentrations recommendations for 1995 nitrogen application adjustments would be as follows:
Row, N% 1994, MSU Adjust. Recommend (1), Cornell adjust. Recommend (2)
1, 2.45, <18%, <25%
2, 2.66, <27%, <46%
3, 2.52, <21%, <32%
4, 2.45, <18%, <25%
5, 2.31, <12%, <11%
6, 2.52, <21%, <32% (1) MSU recommendations taken from analysis of leaf samples tested at MSU. IT is unclear if the standard range of 1.9 to 2.6% N or if the range of 1.7 to 2.0% N for Golden delicious was used to determine the recommendations.
(2) Cornell Cooperative Extension in Information Bulletin 219 states in general, a 10 percent increase of reduction in nitrogen application is usually reflected as a 0.1 percent change in leaf nitrogen content.

Based on 1994 leaf analysis, recommended decreases in application rates, and nitrogen rates applied in 1994, estimated nitrogen applications for 1995 may be as follows:

Row, 1994 Est. Residual N Rate, Decrease % appl., Proposed 1995 rate, 1994 manures
1, 0, 18-25, 0, ----
2, 7.1 oz, 27-46, 5.2-3.8 oz, 1.775 oz
3, 5.8 oz, 21-32, 4.6-3.9 oz, 1.45 oz
4, 4.96 oz, 18-25, 4.1-3.7 oz, ----
5, 4.58 oz, 12-11, 4.0-4.1 oz, 1.145
6, 0, 21-32, 0, ----

Included in the above table is also the estimated residual nitrogen from the 1994 manure applications. Thus applications for the 1995 season would be very minimal. At this point other criteria were considered to help determine if 1995 manure application could be justified.

Next in consideration is phosphorus and potassium levels in leaf tissue and soil tests taken in 1993 and 1994. See Attachment #1 for phosphorus results and Attachment #2 for potassium results. Evaluation of both of these nutrients suggest that there is very minimal needs for applications of either nutrient.

[Editor’s note: There are many charts and tables that could not be posted on the website. If you would like to see these please email us at ncrsare@umn.edu or call us at 800-529-1342. Thanks]

So based on nutrient evaluations it was determined that the application of manures could not be justified. The minimal gallons of manure needed per tree (@ 10 gallons at most) could not be economically justified since nutrients were not near a deficient point.

Also evaluation of shoot growth, crop yield and fruit size in 1994 did not reflect any stress or possible deficiencies.

In conclusion it was determined that no nutrient applications, not even manufactured fertilizers, would be applied in the test plot for 1995.

In 1995, the test plot was observed weekly to visible signs of nutrient deficiencies, tree stress, and poor fruit sizing. No problems were noted during the growing season so no nutrients were applied.

Leaf tissue and soil samples were taken as there were in past years. Attachment 3a and 3b shows leaf tissue analysis results for all three years of sampling. Attachments 4a through 4f show results of soil sampling for the three years.

Leaf tissue analysis show that nitrogen levels fell slightly from 1994 to 1995. This was expected since no nitrogen was applied, but levels were still at the upper end of optimum percentage ranges.

Leaf potassium levels for 1995 tested just below the desired optimum range. The surprising point in this comparison is that from 1994 to 1995 the percentages actually increased.

Soil potassium levels showed increases in both high and low soil samples with only one exception. In Row 1, where no manures were applied, the upper sampling showed a decrease of 30 pounds of phosphorus per acre but the lower sample shoed an increase of 34 pounds per acre. There were no other significant differences in changes between rows with or without manure applications.

Phosphorus tissue levels proved to be a little more interesting. The 1995 levels in each row are near the bottom end of the desired range. In rows 2, 3, and 5, where manures were applied in 1994, phosphorus percentages decreased. In rows 1, 4, and 6, where no manures or phosphorus fertilizers were applied in 1994, levels actually increase slightly.

Soil phosphorus test results were more erratic. In row 1 and 4 where no phosphorus was applied, there were only slight changes in year to year comparisons. Row 6 though showed a doubling of phosphorus levels in both the high and low samples even though no phosphorus was applied either year. In general, rows 2, 3, and 5 where manures were applied in 1994, showed slight overall increases in soil phosphorus levels. These changes do not correlate to any significant differences.

When considering fertilizing recommendations based on 1995 testing, leaf sampling calls for no phosphorus applications while soil test results vary. Soil recommendations (see attachment #5) are erratic and no correlation is see as related to manure applications of phosphorus.

Potassium recommendations based on 1995 leaf tissue sampling are to apply 120-180 pounds of K20 per acre on Rows 1 through 5 and 60 to 90 pounds of K20 per acre on Row 6. Soil sampling recommendations (attachment #5) that only Row 1 should receive 40 pounds per acre of K20 based on the high sampling. Based on low soil sampling Row 1, 2 and 4 should receive applications varying from 20 to 70 pounds of K20 per acre.

At this point, at best it can be said that the test results are very confusing since no strong correlations have been found.

Besides nutrient sampling other factors must be observed to determine the overall orchard conditions. This leads to our next evaluation criteria, crop yields. At harvest each row was harvested separately and yields were recorded on a per tree basis. The chart below shows the yields for three seasons.

Harvest Yields
Row, 1993 Bushel/tree*, 1994 Bushel/tree*, 1995 Bushel/tree
1, .63, 1.16, 1.12
2, .58, 1.16, 1.23
3, .51, .95, 1.10
4, .51, .98, 1.08
5, .50, 1.05, .97
6, .51, .93, 1.05

* The entire row for each test was harvested and then the total bushels for that row was divided by the number of tree in the row.

Comparing the harvest yields per row in the same year show no significant difference in yields. The overall yields for 1994 and 1995 are about double of the 1993 yields. In 1993 the season was very dry and apple size was poor, while in 1994 and 1995 the seasons were close to the average type of season. Apple size was not an evaluation measure in this project.

From looking at the harvest yields and the treatments that each row received there are no strong conclusions that can be drawn from this data.

Similar lack of evidence was found when comparisons of tree shoot growth were made. The length of 100 shoots from each row were measured in August each year. From row to row there was no difference in the average length of growth in these shoots between the three years. The growth averages of each row in each year ranged from 10.78 inches to 11.34 inches. Bearing apple trees supplied with adequate nitrogen usually produce 8 to 12 inches of shoot growth.

The 1995 testing has not given rise to any significant insights. If any thing the results have made things more confusing. From the three years of this project the following general trends could be suggested.

1) Fall applications of Nitrogen in any form are not feasible as late season nitrogen applications may spur unwanted growth.
2) Manures may be a substitute for commercial fertilizers but this study did not show this conclusively
3) Manure nutrient contents can vary drastically so testing just prior to application is a must so that proper nitrogen applications can be made.
4) Weather conditions may have dramatic influences on how nutrients are stored and used by trees.

Probably the most significant aspect of this project is how it might be conducted to obtain better results. Below is listed some observations that may provide better comparisons to help determine if manures can be used in an orchard system to replace commercial fertilizers.

a) It might be better to start with a orchard that has very poor nutritional status so that any positive effects of manure treatments would show more dramatically.
b) Include test rows that include commercial fertilizer applications of recommended phosphorus and potassium not just nitrogen
c) If possible, include irrigation so that available moisture can be controlled from year to year since seasonal rains can vary drastically. This could provide more consistent movement and uptake of nutrients.
d) Must include agitation of manures in orchard delivery tank so that solids do not settle and plug delivery systems.

This study was very enlighten and it seems like there is good potential for the use of manures in orchard systems but much more work needs to be done to make this a feasible way to fertilize orchard systems. The response to manure applications is extremely critical as over fertilization can be as big of a problem as under fertilization.

The continuation of research in this area would not only be beneficial to orchardist but also to livestock producers who are having difficulty finding places to dispose of manures.


Participation Summary
Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.