Basic Soil Management

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Basic Soil Management Fertility

• Patricia Steinhilber
• Agricultural Nutrient Management Program
• University of Maryland College Park
• psteinhi_at_umd.edu
• www.anmp.umd.edu

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Major Topics

• lime
• organic matter
• soil loss
• soil sampling and testing

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Why is it important to lime?
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How Does a Producer Know When Lime is Needed?
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How Does a Producer Know When Lime is Needed?

• He asks himself two questions
• What is the pH of Field X now?
• What is the target pH of the crop or crop
  rotation in Field X?
• If there is a considerable gap between the two,
  its time to lime.

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Lime Requirement (LR)

• the quantity of pure fine ag limestone needed to
  increase the pH of a soil to the optimal pH
  (target pH) for the crop or crop rotation
• this information is included in your nutrient
  management plan

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Target pHs in Maryland

• pH 7.0
• asparagus
• pH 4.5
• blueberries
• pH 5.2
• Irish potatoes, sweet potatoes
• pH 6.2
• blackberries
• pH 6.5
• most vegetable crops , tree fruit, raspberries

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Maintain Organic Matter (OM)

• organic matter is multifaceted
• often is not part of a standard analysis at a
  soil test lab
• Pay extra. Its worth the .
• if you change labs, you may see a change in OM
  because of differences in techniques
• burn off OM with very high heat or very strong
  acids

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Adequate organic matter is important for

• nutrient holding capacity
• water holding capacity
• water stable aggregates
• resistance to erosion
• high water infiltration rates
• greater water storage in root zone
• greater oxygen supply in root zone oxygen
• better tilth

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Biomass Composition

• the living component of the soil
• consists of a range of creatures
• as small as microscopic bacteria
• as large as worms and other creatures that are
  visible to the unaided eye
• and everything between

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Biomass Functions

• nutrient cycling
• digest plant and animal materials (residues),
  using what they need and leaving behind what they
  do not
• mineralization
• creation of biopores
• larger organisms move through soil creating
  channels
• channels promote water infiltration and create a
  healthy balance between large and small pores
• large pores (which allow rapid infiltration of
  rainfall and replenishment of oxygen in the root
  zone) and
• small pores (which store water for plant use)

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Residues and By-productsComposition

• dead stuff - crop residues, dead roots and bodies
  of dead soil creatures
• by-products - materials that plant roots and soil
  creatures release or exude into the soil

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Residues and By-productsFunctions

• fuel and nutrients for soil creatures
• energy and nutrient source for most of the soil
  creatures
• formation and maintenance of soil aggregates
  (structure)
• sticky and gummy by-products of residue
  decomposition hold soil particles together into
  clumps or aggregates

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Humus Composition

• stable end product of residue decomposition
• composes the majority of organic matter
• resists further decomposition (1 per year)
• it is not a good nutrient or energy source for
  soil creatures

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Humus Functions

• high surface area
• charges at many locations on the surface
• effective at holding water and nutrients

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Adequate organic matter is important for

• increased nutrient holding capacity
• increased water holding capacity
• water-stable aggregates
• resistance to erosion
• high water infiltration rates
• greater water storage in root zone
• greater oxygen supply in root zone oxygen
• better tilth

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Minimize Soil Loss

• Keep soil loss to T, the tolerable soil loss
• Topsoil is a better growing medium than subsoil
  dont let it get away!
• If you do not have a soil conservation plan,
  request one. If you have a soil conservation
  plan, follow it.

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Tool for Estimating Erosion

• Revised Universal Soil Loss Equation (RUSLE)
• erosion estimates use
• rainfall (R)
• soil erodibility (K)
• slope length and steepness (LS)
• crop and crop management (C)
• conservation practices (P)

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Lets Look at Some C Factors

• grass hay - 0.005
• corn grain, no-till 0.02
• corn grain, conventional till 0.15
• soybeans, conventional till 0.30
• peas-pumpkins, dc, clean till 0.34
• cukes, fs, clean till 0.54
• cukes, fs, clean till, winter cover crop 0.44

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Cover Crops, Organic Matter (OM)and Erosion

• cover crops are a sustainable source of OM
• both summer annuals and winter annuals are
  useful
• extremely important in organic operations!
• with leguminous cover crops, get N with no P

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sunn hemp
crimson clover
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Soil Sampling for High Value Crops

• consider sampling every year
• be careful about delineating management units
• if any of these factors differ, sample separately
• soil complex
• previous fertility regime
• cover crop and its management
• previous crops

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Soil Testing

• chemical solutions are used to extract some
  portion of plant-available nutrients
• labs differ in the chemical solution they use
• choose one that can be used to develop your
  nutrient management plan

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Value of Soil Tests

• best pre-plant indicator we have of potential
  nutritional products
• mine them for information!
• excellent investment

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Soil Test Value and Response to Nutrients
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Soil Tests

• best if maintained in the high end of the
  optimum range or low end of excessive range

0
25
50
100
low
medium
optimum
excessive
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Questions?