Midwest Vegetable Guide - 2022 - 18

Soil Fertility and Nutrient Management
only 20 to 50 percent of the total N before planting. Apply
the remaining N with regular drip irrigation at 5 to 10 pounds
of N per week until the total recommended for the season has
been applied. K may also be applied through drip irrigation if
the crop needs more than has been applied to the soil before
planting.
If you apply only part of the recommended N before planting,
apply the remainder as a sidedressing when the plants are still
young, or apply N through fertigation before and during the
period of rapid crop growth. Early sidedress applications are
especially important with crops such as sweet corn, broccoli,
and cabbage. The total N applied during the growing season
(broadcast, plus banded, plus transplant starter, plus
sidedressed, plus fertigated) should equal the recommended
N rate. Applying more than the recommended rate of N may
be necessary when there are leaching rains.
Transplanted crops often respond to a small amount of watersoluble
fertilizer in the transplanting water. Special fertilizer
grades (such as 14-28-14, 10-52-10, 23-21-17) are used at a
rate of 3 pounds per 50 gallons of water. The high-P liquid
10-34-0 can also be used at the rate of 2 quarts per 50 gallons
of water. Apply starter solutions at 8 ounces per plant. If dry
weather is prevalent, irrigate after setting the plants.
Fertilizer Rates per Linear Bed Foot
You can apply fertilizer in a band while shaping beds or
laying plastic. You can also apply it dissolved through
irrigation water and delivered by drip tape to the base of the
plants. In these systems, it is helpful to calculate the fertilizer
rate per linear bed foot (LBF) based on the fertilizer rate per
acre. To do so, you will need to know:
* Bed spacing (BS): distance in feet between bed centers
* Fertilizer rate in lb./A (RatePerA)
Use this equation to determine the fertilizer rate in pounds per
LBF:
(RatePerA X BS) / 43,560 = RatePerLBF
Example:
Bed spacing (BS) = 5 ft. between centers of beds
Fertilizer rate in lb./A (RatePerA) = 100 lbs./A
(100 X 5) / 43,560 = 0.0115 lb./LBF
For a crop on six 100-foot beds, there would 600 LBF to
fertilize. The amount of fertilizer needed to supply 100 lbs./A
would be:
600 LBF X 0.0115 lb./LBF= 6.9 lbs.
The Rate per Linear Bed Foot for Various Bed Spacings and
Rates table provides conversion of lb./A to lb./LBF for a
number of bed spacings and fertilizer rates.
18
Rate per Linear Bed Foot for Various
Bed Spacings and Rates
Bed
Spacing
(ft)
3
4
5
6
7
8
9
10
Linear Bed
Feet (LBF)
in 1 Acre
14,520
10,890
8,712
7,260
6,222
5,445
4,840
4,356
Fertilizer Rate (lbs./A)
20
40
60
80
Fertilizer Rate (lb./LBF)
0.0014 0.0028 0.0041 0.0055 0.0069 0.0083
0.0018 0.0037 0.0055 0.0073 0.0092 0.011
0.0023 0.0046 0.0069 0.0092 0.0115 0.0138
0.0028 0.0055 0.0083 0.011
0.0138 0.0165
0.0032 0.0064 0.0096 0.0129 0.0161 0.0193
0.0037 0.0073 0.011 0.0147 0.0184 0.022
0.0041 0.0083 0.0124 0.0165 0.0207 0.0248
0.0046 0.0092 0.0138 0.0184 0.023 0.0275
Soil pH and Adjustment
Soil pH describes whether the soil solution is acidic or
alkaline. The native pH of Midwest soils varies from quite
acidic (pH 5.0 or lower) to quite alkaline (pH 7.5 or higher).
Most vegetable crops prefer a pH range of 6.0-6.8 on mineral
soils. On muck soils, a pH of 5.5-5.8 is considered adequate.
Vegetables grown under acid soil conditions lack vigor and
yield poorly. Acid soils restrict the uptake of nutrients such as
P and K. Acid soils also make elements such as aluminum
(Al) and manganese (Mn) more available to plants so that the
plant may absorb enough to be toxic to the plant. Under
severe conditions, visible foliage injury can result from
magnesium (Mg) deficiency and/or Mn toxicity.
Physiological disorders such as blossom end rot are more
common on acid soils. In contrast, when soil pH is high, Mn,
B, iron (Fe), and certain other micronutrients become less
available for plant uptake. Deficiencies of these
micronutrients are most likely to occur on mineral soils with
pH greater than 7.4.
Lime neutralizes soil acidity and supplies Ca and Mg,
elements necessary for plant growth. A soil test determines
how much lime you need. Liming may be necessary every
few years because soil pH tends to decline over time. The
decline is caused by ammonium-releasing N fertilizers, the
crop's removal of Ca, and the leaching of Ca and Mg by rain.
Soil pH and Plant Nutrients
Nitrogen (N)
Plants can take up N in the form of ammonium (NH4
nitrate (NO3
+) or
-). In the soil, ammonium is converted into
nitrate, and vice versa, by particular sets of microbes. When
soil pH is near neutral (pH 7), and the soil is moist and warm,
the microbial conversion of ammonium to nitrate
(nitrification) is rapid, and crops generally take up nitrate. In
acid soils (pH lower than 6), nitrification is slow, and plants
will take up a higher percentage of N as ammonium.
Soil pH also plays an important role in N loss due to
volatilization. Volatilization occurs when N compounds turn
Midwest Veg Guide 2022
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Midwest Vegetable Guide - 2022

Table of Contents for the Digital Edition of Midwest Vegetable Guide - 2022
