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Spreader Calibration Worksheet for Biosolids Application

by Dan Sullivan, Extension Soil Scientist, Oregon State University

Version 1.0, March, 1999

 

Introduction

Before using this worksheet, you need to calculate an agronomic biosolids applicaton rate (dry ton/acre) A step by step agronomic rate calculation procedure is given in a companion worksheet: "Calculating biosolids application rates in agriculture", Pacific Northwest Extension Bulletin 511.

This worksheet calculates the "feet of travel for a full spreader load". You will need to determine how to adjust your speader to meet the "feet of travel" calculated here. You can adjust either the speed of the spreader vehicle (mph) or the biosolids discharge rate.

The worksheet assumes a rectangular spreading area with by a truck or tractor-mounted spreader.

To meet regulatory requirements, some biosolids applicators choose to apply a rate slightly lower than the permitted "agronomic rate". So, you might want to calibrate your spreader to deliver approximately 90 % of the agronomic rate. This will allow for some variation in application rate across the field.

Re-calibration is needed on a daily basis if you are dealing with liquid biosolids that vary in percent total solids. Biosolids with 4 % total solids should be applied at half the rate of biosolids with 2 % solids, to maintain the same rate of application (dry ton/acre).

Biosolids application rates should be verified on a daily basis by measuring the area spread and keeping a log of the number of spreader loads applied.

How to use this worksheet

Download this worksheet as an excel spreadsheet

Fill in your measurements in the yellow highlighted cells.
The calculations in the blue highlighted cells will be done for you.
The tan highlighted cells are for record-keeping. They are not part of the calculations performed by this spreadsheet
         
Date __________________________________________________________  
Operator __________________________________________________________  
Site __________________________________________________________  
Spreader ID __________________________________________________________  
Speed __________________________________________________________  
Gear etc. __________________________________________________________  
         

 

Line
Number		   Your
Calibration		 Example Formula
  Step 1. Calculate spreader capacity
1.1 Weight of empty spreader vehicle (lb) 12000  
1.2 Weight of spreader vehicle loaded with biosolids (lb) 30000  
1.3 Weight of biosolids in spreader vehicle (lb) 18000 line 1.2 - line 1.1
1.4 Total solids analysis of biosolids (percent) 20  
1.5 Dry weight of biosolids (dry ton per full spreader load) 1.8 (line 1.4/100 * line 1.3)/2000
         
  Step 2. Calculate biosolids application rate on an "as-is" basis
2.1 List target biosolids application rate (dry ton/acre) 3.0  
2.2 Calculate target biosolids application rate (wet ton/acre) 15 line 2.1 * 100 / line 1.4
         
  Step 3. Calculate feet of travel for a full spreader load
3.1 Calculate target area to cover per spreader load (ft2) 26136 line 1.5 / line 2.1 * 43560
3.2 Measure width of spreader application swath (ft) 20.0  
3.3 Calculate feet of travel for application of full spreader load (ft) 1307 line 3.1 / line 3.2
         
  Step 4. Calculate the number of spreader loads to apply per field
4.1 List net acreage available for biosolids application (acres/field) 30.0  
4.2 Calculate number of spreader loads to apply per field 50.0 line 4.1 *43560 / line 3.1