Buying Lime, Fertilizer and Seed from a Soil Report: Cost for 1,000 Forage Pounds

STEP 1 · Reading the report

Converting recommendations into purchases

Your soil report gives pH and nutrient readings, followed by per-acre application recommendations expressed as lime tonnage and nutrient weight. Products on store shelves have different concentrations. Lime has a neutralizing value, fertilizer has nutrient percentages, and a seed tag reports pure live seed. Dividing each recommended application amount by the product's delivered fraction handles most of the conversion. Leave readings such as pH out of those calculations.

Before calculating purchases, consider two points. In its 2017 publication, Mississippi State lists $8 as the charge for its routine laboratory test and describes testing as a plot's best use of money. Sampling directions also vary by laboratory. Mississippi State requests 10 to 12 separate sub-samples within the upper 6 inches for plots covering 1 to 10 acres. Missouri's extension guidance instead describes four to six samples collected roughly 4 inches down, with at least three months between testing and planting. Use the sampling directions provided by your laboratory.

STEP 2 · Soil acidity

How the same recommendation changes by product

According to Mississippi State bulletin 3102, its laboratory assumes lime's relative neutralizing value (RNV) equals 100 percent when making recommendations. Most lime products have lower values. The bulletin illustrates this with 3 tons rated at 67 percent, which provide the same effect as 2 tons rated at 100 percent. Calculate the purchase amount by dividing the recommended tonnage by the product's decimal RNV. A rating of 65 percent becomes 0.65. For a recommendation calling for 1 ton, dividing 1 by 0.65 gives 1.54 tons. Confirm the assumption behind your own laboratory's report. The bulletin compares three products against a recommendation calling for 1 ton.

Finer materials can work faster. The bulletin cautions that their smaller application amounts also call for more frequent soil testing. For plots measuring 1 acre or more, it identifies bulk aglime as much more economical. Pelletized and liquid products are reserved for smaller plots or places beyond a spreader truck's reach. These costs exclude spreading. Alabama's price examples favor bulk material too: supplier-spread aglime runs roughly $30 to $40 per ton. Pelletized lime is around $4 per bag weighing 40 pounds, equivalent to $200 per ton.

The waiting period deserves as much attention as the application amount. According to Alabama, lime begins to raise soil pH within weeks, with the full response taking 6 months or longer. Missouri advises incorporating lime roughly six months ahead of planting. When the soil requires 4 tons or more for each acre, Mississippi State advises another sample the following year. Its usual testing schedule starts when the plot is established and repeats at 2-year intervals. Alabama recommends intervals of 2 to 3.

STEP 3 · Bag analysis

Converting nutrient requirements into product weight

A fertilizer bag's three values describe weight percentages. The middle value represents phosphate (P2O5); the last represents potash (K2O). Alabama calculates product weight by dividing the nutrient recommendation by that nutrient's decimal percentage. Its sample report called for phosphate at 70 pounds and nitrogen at 60 pounds for each acre. Triple superphosphate (0-46-0) and ammonium nitrate (34-0-0) meet those requirements with product weights of 152 and 176 pounds, respectively. Alabama labels its 70 pound recommendation "phosphorous." However, the grade 0-46-0 represents phosphate, consistent with the publication's statement that a bag weighing 50 pounds contains 23 pounds of phosphate.

The final row shows why this calculation belongs ahead of shopping. Alabama explains that soil reports frequently recommend only nitrogen. To supply 60 pounds, the required product weight is 176 pounds when using 34-0-0, versus 462 pounds when using 13-13-13. The additional bags also supply an unrequested 60 pounds apiece of phosphate and potash. Using Alabama's 2021 prices, nitrogen supplied by 13-13-13 has a per-pound cost 1.6 to 2.6 times that of the nitrogen-only option. Get a current quote and compare costs by the pound of nutrient your report requests. Matching units are necessary for the division: the report and bag must describe the same nutrient form. When a laboratory gives elemental phosphorus or potassium, have it convert the recommendation to phosphate or potash first.

STEP 4 · Planting expense

Low seed prices and low forage costs can differ

Mississippi State bulletin 3604 compares seed expense for every 1,000 pounds produced. First, it multiplies the sowing weight by the average seed price per pound. It then divides that acre's seed expense by the mean trial yield and adjusts the result to represent 1,000 pounds. The sowing recommendation uses pure live seed as its basis. Coating often leaves roughly half a clover bag as pure seed. In the bulletin's example, purity of 50 percent multiplied by germination of 90 percent yields a live-seed fraction of 45 percent. Meeting a recommendation calling for 25 pounds therefore requires a bag weight of 56 pounds.

Wheat ranks lowest in seed price by weight at $0.25 per pound and by area at $37.50 per acre. For every 1,000 pounds produced, it ranks fourth at $22.50. Red clover's per-pound seed price of $1.81 ranks fifth, while its expense for every 1,000 pounds produced ranks lowest at $13.14. That advantage comes from the trials' highest yield among the nine forages: 4,822 pounds from each acre.

The table's pH column identifies optimum growing conditions for each forage. Those ranges all begin at either 5.8 or 6.0. Soil testing below 5.8 falls beneath every one of the nine ranges. At pH between 5.8 and 5.9, three forages include that soil within their listed ranges: cereal rye, balansa clover and crimson clover. Balansa has the lowest cost among them, $21.80. Across pH values from 6.0 to 6.5, every one of the nine ranges applies, and red clover ranks lowest in cost. Mississippi State also reports poorer forage performance below pH 6.0 because plants absorb fertilizer and soil nutrients less effectively. Treat the listed ranges as guidance.

STEP 5 · Price context

What these calculations cover

These dollar amounts illustrate the calculations. Lime pricing comes from a publication dated 2017. Fertilizer and pelletized lime pricing comes from another dated March 2021. The seed figures average prices from 10 Mississippi retailers, and no year is shown. Substitute quotes from the current month while keeping the calculation methods. Yield figures average Mississippi variety trials conducted at two stations: annual trials dated 2017 and perennial trials dated 2016 to 2017. They describe forage mass. They do not establish deer consumption or show how results compare with your soil, rainfall or state. Expense for every 1,000 pounds produced includes seed alone. Missouri's extension guidance estimates combined food plot spending on seed, herbicide, fertilizer and lime at as much as $200 per acre.

We calculated all the conversions again. For all nine rows in Tables 1A and 1B of Mississippi State's seed bulletin, the calculations agreed with the published inputs. Seed quantities differed by no more than 0.6 pound, and costs agreed to the cent. For quoted text, 58 of 58 sentences agreed with the cached publications. Some lime figures reflect rounding: the unrounded bulk cost is $81.54, compared with $81.62 in print. Both approaches still produce 28 cases and 56 bags.

STEP 6 · Shopping order

Calculate quantities before comparing prices

Read the application recommendations as division problems. Before checking prices, divide each amount by the product's actual strength. Compare seed expense for every 1,000 pounds produced. Put that approach into five steps:

The designing food plots on a map guide identifies soil testing as the plot project's move with the highest return. This article supplies the calculations that come afterward.