soil health & fertility

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Soil Health & Fertility. Healthy Soil Performs Five Vital Functions:. Regulates water - Soil helps control where rain, snowmelt, and irrigation water goes. Water and dissolved solutes flow over the land or into and through the soil. - PowerPoint PPT Presentation

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Soil Health & Fertility1Healthy Soil Performs Five Vital Functions:Regulates water - Soil helps control where rain, snowmelt, and irrigation water goes. Water and dissolved solutes flow over the land or into and through the soil.Sustains plant and animal life - The diversity and productivity of living things depends on soil.Filters potential pollutants - The minerals and microbes in soil are responsible for filtering, buffering, degrading, immobilizing, and detoxifying organic and inorganic materials, including industrial and municipal by-products and atmospheric deposits.Cycles nutrients - Carbon, nitrogen, phosphorus, and many other nutrients are stored, transformed, and cycled in the soil.Supports structures - Buildings need stable soil for support, and archeological treasures associated with human habitation are protected in soils.

2To determine the level of nutrients found in a soil sampleAccurate account of nutrient removal and replacementCrop production statisticTo manage fertilizer applicationsWhy We Need a Soil Analysis

3A soil analysis is only as good as the soil sample submitted.* Sample problem areas and good areas* Sample different soil types* Sample for different crops* Use appropriate sampling techniques- probe 6 to 7 for tilled soil- probe 4 for untilled soil- minimum of 1 sample per 20 ac.

4First Principle - Feed the soil and let the soil feed the plant.Second Principle The fertility level we are working to achieve is the right amount of each nutrient. (Soil Balance)True soil balance means determining and adding the proper amount of each nutrient.

5Fertilizers must have a positive charge to be held to the soil colloid.Positive charged elements are called cations.Colloids come from clay and organic matter and carry a negative charge.Negative sites on a clay particle will attract and hold positives.

6Negatively charged elements such as nitrogen, phosphorus, and sulfur are called anions.Negative ions do not hold to the clay colloid and remain free to move in the soil solution or water.

7The first thing to do for your land is to correctly measure the amount of clay and humus the soil has in it.That measure is cation exchange capacity, or CEC.CEC is a measure of the capacity of the soil to exchange nutrients or holding power.A CEC of 10 will hold twice as many pounds of nutrients as a CEC of 5.

8First: You must know the total exchange capacity (capacity of soil to hold plant nutrients)

< 15 Low CEC Sandy Soil 15 25 or Ideal CEC >25 High CEC Clay SoilSoil Fertility

9What this means for us?High levels of one nutrient can affect the uptake of another nutrientExample:Too much calcium in a soil can limit the uptake of potassiumToo much potassium can limit the uptake of magnesium even if magnesium levels in the soil are high.Cation Exchange Capacity

10Second: The base saturation percent (Specific % of nutrients needed for optimal plant growth)What the soil is composed of in terms of cations calcium, magnesium, potassium, and sodium)Also tells the availability of these nutrients to plantsAn excess of any one of these four makes it the weakest link in the chainSoil Fertility

11Ideal for Ca & Mg is total 80%Clay soils need more Ca, sandy soils need more MgCation Calcium should be 60% to 70%60% in sandy soils70% in clay soilsCation Magnesium should be 10% to 20%20% in sandy soils10% in clay soilsSoil Fertility

12Yield and quality are determined by the percentages, not the pounds.

Calcium60 70%Magnesium10 20%Potassium 3 5%Hydrogen10 15%Other Bases 2 4%

13Too much Calcium ties up all other nutrients (every other nutrient has to ride over the back of Ca to get to the plant).Too much Nitrogen ties up Calcium and other elements; even Zinc.Too much Phosphorus ties up Zinc and Copper.Too much Potassium ties up Boron.Nutrient Imbalance

14pH refers to how acidic or alkaline the soil is.pH potential HydrogenRange of 0 to 14 with 7 as neutralA change of one unit in the pH scale represents a 10-fold change in acidity or alkalinitypH

15Affected by:FertilizersRainOrganic MatterSoil microorganisms

pH

16Influenced by:CalciumMagnesiumPotassiumSodiumpH

17pH

Global variation in soil pH. Red = acidic soil. Yellow = neutral soil. Blue = alkaline soil. Black = no data.

18Limestone is the most effective and inexpensive aid to adjust soil pH.Dolomitic limestone magnesium and calciumCalcitic limestone calcium Lime

19Calcium influences pH, as does magnesium, potassium and sodium.Lime increases microbial activity, manages decomposition and overcomes the potential for Ca and Mg deficiencies.Lime

20The pH will adjust to the proper level when all nutrients are corrected.Any nutrient required takes precedence over pH. When all nutrients are balanced, the pH will be right.As Ca concentration increases, it takes less nitrogen, phosphorus and potassium to do the same job.Every other nutrient has to ride over the back of calcium to get into the plant.

21Organic MatterSoil microorganisms decay organic matter and cycle nutrients back into forms that plants can use.The valuable link between soil carbon and your crop are soil microorganisms.OM effects nutrient cycles by chelating (chemically holding on to) nutrients, and preventing them from becoming insoluble and therefore unavailable to plantsWithout microbes, vital soil nutrients like Phosphorus remain present but unavailable to your crop.

22Enhanced development of soil aggregatesIncreased pore spaceIncreased infiltration and percolation ratesIncreased water holding capacity andOrganic Matter

23Organic matter is anything that once was alive. Bacteria, fungi, insects, and earthworms (among other creatures) use fresh organic matter as food. Their digestive processes convert the fresh residue in humic substances and nutrients. The nutrients in fresh organic residue are largely unavailable to plants before this conversion. The organic matter ranges from very simple to very complex chemical compounds. These includes sugars, starches, carbohydrates, nucleic acids, etc.Living organisms are also included in organic matter considerations.

Increasing organic matter enhances the nutrient providing capacity of a soil and enhances its ability to function as a rooting environment.Organic matter is lowered by over-cultivation of natural soils. Management changes and additions are often needed to optimize productivity of over-worked soils.

REVIEW: Is increasing organic matter in soils desirable?Greater capacity to hold and release nutrientsNutrient storageImproved cultivation ease (tilth)Promotes further biological activityOrganic Matter

24Organic matter is anything that once was alive. Bacteria, fungi, insects, and earthworms (among other creatures) use fresh organic matter as food. Their digestive processes convert the fresh residue in humic substances and nutrients. The nutrients in fresh organic residue are largely unavailable to plants before this conversion. The organic matter ranges from very simple to very complex chemical compounds. These includes sugars, starches, carbohydrates, nucleic acids, etc.Living organisms are also included in organic matter considerations.

Increasing organic matter enhances the nutrient providing capacity of a soil and enhances its ability to function as a rooting environment.Organic matter is lowered by over-cultivation of natural soils. Management changes and additions are often needed to optimize productivity of over-worked soils.

REVIEW: Is increasing organic matter in soils desirable?Five Ways Organic Matter Resists Soil Compaction

Surface residue resists compaction. It acts like a sponge to absorb weight and water.Organic residues are less dense than soil particles.Roots create voids and spaces for air and water.Roots act like a biological valve to control oxygen in the soil.Roots supply exudates to glue soil particles together to form macro-aggregates and supply food for microbes.Organic Matter

25HumusHumus refers to any organic matter that has reached a point of stability, where it will not break down any further.Improves the structure of soil and contributes to moisture and nutrient retention.Humus can hold the equivalent of 80-90% of its weight in water.Allows soil organisms to feed and reproduce and is often described as the life force of the soil.

26NitrogenPart of every living cell; important component of proteins, DNA, RNADirectly involved in photosynthesisNecessary component of vitaminsAids in production and use of carbohydratesNutrient Functions

27Why are these things important?Nitrogen helps make us what we are.DNA, RNAPhosphorus makes us happen.ADP-ATP: energy transferPotassium keeps us from falling down.Important for cell walls

REVIEW: Can plants live without N, P, or K?

NitrogenHas a negative charge and attracts a positive charge.Excess N causes weakness in the plant.Ties up copper and zinc.Takes either sodium or calcium as a passenger.For every % Ca taken out by N, Mg goes up 1%Anhydrous Ammonia (free ammonia) is toxic to living organisms and raises pH.

28PhosphorusEnergy exchangePromotes early root formation and growthVital to seed formationIncreases water use and efficiencyHastens maturity

Nutrient Functions

29PotassiumEssential for plant growthIncreases photosynthesisEssential to protein synthesisImproves quality of seed and fruitsImproves winter hardiness

Nutrient Functions

30CalciumContinuous cell division and formationReduces plant respirationIncreases fruit setStimulates microbial activityNutrient Functions

31MagnesiumKey e

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