C.o.R.n. to go....
A Supplement to the OSU Extension Agronomic Crops Team Online C.O.R.N. Newsletter ~ This version for Ohio’s Country Journal is by Harold Watters Harold Watters can be reached in the Logan County Extension office, at
watters.35@osu.edu or by phone 937-599-4227.
phosphorous Management
By GReG laBaRGe, aGRonoMy FielD speCialist The amount of press recently on water
quality problems in Lake Erie and Grand Lake St Mary’s has put a focus on nutrient management and making sure agriculture is implementing practices that reduce nu- trient loss both from an economic and envi- ronmental standpoint. The source of phosphorous issues in
2011 is a different issue than the problem of the 1970s when agriculture shifted tillage practices and reduced total phosphorous load going into Ohio’s waters by 50% which led to the dramatic recovery of Lake Erie. The situation today is being fueled by dissolved reactive phosphorous (DRP) lev- els, which are at levels that were seen in the 1970s while the total phosphorous load are still being maintained at target levels. There continues to be a lively scientific debate about the reasons for the measured in- creases in DRP. As the debate continues farmers can
reevaluate their management system to be sure they are getting full benefit out of the nutrients they apply which will limit the off flow of nutrients into Ohio’s water. BMPs for agriculture are going to be continued use of reduced tillage practices with a focus on nutrient utilization. There is a move- ment to utilize nutrients in the right way by selecting the combination of right source, right rate, right time and right placement in making nutrient applications. One of the highest potential losses of nutrients is from surface runoff after appli-
By Glen aRnolD, nUtRientManaGeMent FielD speCialists Saturated field conditions last fall and a
mild winter have resulted in pork produc- ers having more liquid manure on hand than normal as we approach spring. Research on applying liquid livestock
manure as a spring topdress fertilizer to wheat has been ongoing in Ohio for several years. There is usually a window of time, typically around the last week of March or first week of April, when wheat fields are growing and firm enough to support ma- nure application equipment. The key to applying the correct amount
of manure to fertilize wheat is to know the manure’s nitrogen content. Most manure tests reveal total nitrogen, ammonia nitro- gen and organic nitrogen amounts. The ammonia nitrogen can quickly be available for plant growth. The organic portion takes considerably longer and generally will not be available when wheat takes up the ma- jority of its nitrogen in the months of April and May. Some manure tests also list a “first year
availability” nitrogen amount. This number is basically the ammonia nitrogen portion of the manure plus about half the organic
cation. Avoiding surface applications to frozen or snow covered soil is one applica- tion timing to avoid. Frozen soil is gener- ally defined as frozen whenever incorporation cannot occur. Some Ohio data shows the right placement of nutrients is by incorporation; that can reduce losses of phosphorous by 60% more than surface application. For continuous no-till, using row placement, strip tillage or shallow tillage can be other options. The right rate should focus on a soil test-
ing program that divides up the landscape to represent yield response of the crop. Soil tests that are higher than 50 ppm or 100 pounds per acre are fields that can be tar- geted for drawdown of the soil bank of phosphorous. As the level of phosphorous increases from 50 ppm we see a higher po- tential for tile losses of DRP. The purpose for a soil sample should be to generate a fertilizer recommendation. The Tri-State Fertilizer recommendations were generated using calibration studies with a Bray P1 soil test result. Fertilizer recommendations for corn (Table 1), soybeans (Table 2) and wheat (Table 3) are listed on this page. The tables are updated to reflect the higher yield potentials utilizing the equations from the Tri-State Fertilizer Recommenda- tions publication which can be found at:
http://ohioline.osu.edu/ e2567/
index.html. The philosophy of these recommendations can be found in the orig- inal publication. Agricultural practices are always pro- gressing as we seek greater efficiency in
nitrogen portion. Again, for wheat, the or- ganic portion of the nitrogen should not be considered available in time to impact yields. Most deep-pit swine finishing manure
will contain between 35 and 50 pounds of ammonia nitrogen per 1,000 gallons. Fin- ishing buildings with bowl waters and other water conservation systems can re- sult in nitrogen amounts toward the upper end of this range. Finishing build- ings with nipple waters and surface water occasionally entering the pit can re- sult in nitrogen amounts toward the lower end of this range. Three years of on-farm wheat topdress
results (four fields) are summarized in Table 1. Each field trial was replicated four times. In each plot, manure ammo- nia nitrogen application rate was similar to the nitrogen amount in the urea; typically about 100 pounds per acre. Urea was applied using a standard fertilizer buggy. The manure was applied using a 4,800 gallon tanker with a Peecan toolbar. This toolbar cuts the soil surface with a straight coulter and a boot applies the manure over the soil opening.
22 Crops • Ohio’s Country Journal •
ocj.com • March 2012
Table 1. Fertilizer P Recommendations for Corn. (adapted from Tri-state Fertilizer Recommendations for Corn, Soybeans, Wheat and Alfalfa)
Soil Test Level PPM (lb/acre) 5 (10)
10 (20)
15-30 (30-60) 35 (70)
120 95
70 45 20
Realistic yield Goal (bu/acre) 145
lbs P2O5/acre recommended 105 80 55 25
170 115
90 65 30
40 (80) 00 0
200 125
100 75 40 0
Soil Test Level PPM (lb/acre) 5 (10)
10 (20)
15-30 (30-60) 35 (70)
30 75
50 25 10
Realistic yield Goal (bu/acre) 40
lbs P2O5/acre recommended 80 55 30 15
50 90
65 40 25
40 (80) 00 0
100 75 50 25 0
Soil Test Level PPM (lb/acre) 15 (30) 20 (40)
25-40 (50-80) 45 (90)
50 80
55 30 15
Realistic yield Goal (bu/acre) 65
80
100 75 50 25
95
lbs P2O5/acre recommended 90 65 40 20
50 (100) 00 0
producing crops. Nutrient management is one area where we can continue to progress in using nutrients more
topdressing wheat with liquid swine manure
Table 1. Wheat Yield (bu/ac) of On-farm Swine Manure Topdressing Trials swine manure
year 2009 2008 2008 2007
(surface applied)* (incorporated) 127.5a 63.1a 58.2a
swine manure 125.4a
102.2a
61.4a 58.2a 98.0a
To capture the most nutrients from ma-
nure farmers should consider incorpora- tion. Incorporation can result in less nitrogen loss and can especially reduce the loss of dissolved reactive phosphorus. Dis- solved reactive phosphorus has been iden- tified as a major contributor to water quality problems in lakes across Ohio and is present in all fertilizer sources. In addition to the Peecan toolbar,
OSU Extension as also conducted manure research on wheat using the both the Veenhuizen toolbar and Aerway toolbars. All toolbars cutting through the soil cause some disruption to the growing wheat but side-by-side yield comparisons with conventional surface applied fertilizer have rarely shown any difference in yields.
Urea
128.2a 62.9a 61.0a 96.5b
Date of
nutrient application April 7th April 3rd April 2nd March 28th
*Incorporation was performed with a modified Peecan toolbar attached to a 4,800 gallon tanker Dairy manure has also been utilized in
on-farm research plots when topdressing wheat. Dairy manure contains far less am- monia nitrogen per 1,000 gallons than swine finishing manure and does not con- sistently produce yields similar to commer- cial fertilizer. Research on dairy manure as a topdress to wheat is ongoing and adding 28%UAN to the dairy manure to increase its fertilizer value does show promise. When applying livestock manure to
wheat it’s recommended to follow the NRCS #633 Waste Utilization Standard to minimize potential environmental impacts. Additional on-farm manure topdress of
wheat plot results can be obtained by click- ing on the On-farm Research link on the OSU Extension Agronomics Crops team website at
http://agcrops.osu.edu/.
110 85 60 30 0
60
225 135
110 85 45 0
250 145
120 95 50 0
275 155
125 100 50 0
Table 2. Fertilizer P Recommendations for Soybean. (adapted from Tri-state Fertilizer Recommendations for Corn, Soybeans, Wheat and Alfalfa)
70
105 80 55 30 0
80
115 90 65 35 0
Table 3. Fertilizer P Recommendations for Wheat. (adapted from Tri-state Fertilizer Recommendations for Corn, Soybeans, Wheat and Alfalfa)
110 120
95 70 35 0
125 130
105 80 40 0
efficiently and keeping them on our fields where they will benefit us in crop production.
90
125 100 70 35 0
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