Title: What is the title of this lecture?Speaker: Amit DhingraCreated by: (remove if same as speaker)

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Title: General Principles of Soil Fertility and Soil ProductivitySpeaker: William Pan

Unit 1, Lesson 2

General principles of soil fertility and soil productivity

http://soils.usda.gov/education/resources/k_12/lessons/profile/

1.2 Learning Objectives Define soil, soil fertility, soil

productivity, essential plant nutrients Recognize interactions between

fertility and productivity factors Go Extraterrestrial in Assignment 1.2

Soil Definition

What is soil? What are the key parts of the definition with respect to its i. function and ii. its location, and iii. its formation?

SOIL (i) The unconsolidated mineral or organic material on the immediate surface of the earth that serves as a natural medium for the growth of land plants. (ii) The unconsolidated mineral or organic matter on the surface of the earth that has been subjected to and shows effects of genetic and environmental factors of: climate (including water and temperature effects), and macro- and microorganisms, conditioned by relief, acting on parent material over a period of time. A product-soil differs from the material from which it is derived in many physical, chemical, biological, and morphological properties and characteristics.

Definitions of “soil” according to SSSA: https://www.soils.org/publications/soils-glossary#

The status of a soil with respect to its ability to supply the nutrients essential to plant growth

Soil Fertility:

What Defines the Essential Plant Nutrients?

The nutrient: is needed for the plant to

complete growth cycle performs a function that cannot

be done by another element is directly or indirectly involved

in plant metabolic processes.

Essential Elements for Plant Growth

C, H, O

Macronutrients (0.2-5%) N P K Ca Mg S

Micronutrients(0.01-100 ppm)

Fe Mn Cu Zn B Mo Cl Ni

Other Non-essential Elements Absorbed by Plants

CoSiSeNa

PbCdHg

From orchard to golf course: different systems, same SOIL

The status of a soil with respect to its ability to supply the nutrients essential to plant growth

Soil Fertility =

Soil Productivity: The capacity of a soil, in its normal environment, for producing a plant or crop sequence under a specified system of management.

A productive soil is one in which the chemical, physical, andbiological conditions are favorable for plant growth.

Soil Productivity Factors

Precipitation Temperature Humidity Light Altitude Wind CO2

…

Organic matter Texture Structure Cation exchange Slope,

topography Temperature Water regime Depth …

Climate Soil

Soil Productivity vs. FertilityExamine two soil profiles Can you describe the

major differences you see between Central WA, Basin irrigated soil: Quincy sand vs. Eastern WA, dryland Palouse silt loam?

Which soil has more native fertility? Despite this difference, are they both potentially productive? Why? (Think of the crops grown in the Basin)

Quincy Palouse

http://www.cals.uidaho.edu/soilorders/

Hawaii example

Oxisol

Lahaina Series, Maui

Oxisols generally contain low activity clays, highly weathered, tropical soils are nonsticky and workable. Nutrient cations, such as calcium, magnesium, nitrate, and potassium, must be added to the soil. Phosphorus may also be limited, because it tends to form strong bonds with the oxides.

Write examples of situations where…

A fertile soil may not be productive

A potentially productive soil is not fertile

Nutrient interactions with productivity factors have shaped our production oriented approaches in Soil Fertility:

Identify essential nutrients.

Establish nutrient relationships to desired plant growth characteristics (yield, quality, etc.) in the context of other productivity factors (soil, environmental and management).

Define nutrient conditions for desired growth, yield, quality.

Leibig’s “Law of the Minimum”

The most limiting fertility or productivity factor determines plant productivity.

Producers need to first optimize the most limiting factor, then the second most limiting factor and so on to improve overall yield potential.

Synergism According to von

Liebig’s Law of the Minimum, growth is controlled not by the total of resourcesavailable, but by the scarcest resource (limiting factor). Therefore, all nutrients are synergistic with one another to a certain degree.

Interaction between two growth factors -Example: Water and N

N Applied (lb/a)

Dryland

Irrigated100

50

70 110

Two rainfall zones

Y = A * ( 1 – e – C ( X))Where:

Y – yieldX – N supplyA – Max yieldC – efficiency factor

0

500

1000

1500

2000

2500

3000

0 100 200 300 400

Yie

ld (k

g gr

ain/

ha)

N supply (kg N/ha)

PullmanDavenport

(Hammac and Maaz)

Soil Depth and Soil Productivity

Soil Depth (ft) Relativeproductivity (%)

1 352 603 754 856 100

Factors responsibility for 2x corn yield increases between 1930 and 1980.

Genetics: 59% Agronomic advances: 68% Crop rotation shifts: -6% Manure: -15% Insects:-15% Organic matter decline: -13% Soil erosion: -8% Other negative soil factors: -23%

Table 1-5 HBTN

Productivity and Fertility Needs are Correlated

Productivity Factors Fert

ility

Req

uire

men

ts

Assignment 1.2. Do Mars and comet 67 P/C-G have evidence of soil or conditions to create soil?

Do a web search on these space projects. Consider the definition of soil and soil fertility.

Do you think we can state that there is soil or past/present conditions and components to create soil on Mars and comet 67 P/C-G? Explain and give specific examples to support your case, and cite your sources in a 1-page essay.

See ESA simulation and pictures of comet landing : https://www.youtube.com/watch?v=fHzvl3QVyhg