Download Chapter 15

Chapter 15
• Tillage: working the soil to
provide a good environment
for seed placement,
germination, and crop growth
August 2008
3 goals for Tillage
• 1. Weed Control
– Before Planting
• Kill weeds
• weakens perennials
– After Planting
• destroys weeds
• covers seedlings
August 2008
2. Alteration of Physical Soil
Conditions
• Structure, Moisture, and Temperature
– Stirs and loosens soil
– improves aeration
– creates suitable medium for growth
– may breakup soil compaction
August 2008
2. Alteration of Physical Soil
Conditions
• Causes long term decline in Structure
– loss of organic matter
– crushes soil aggregates
• Moisture and Temperature
– tilled warms earlier, causes earlier
seeding and better germination
August 2008
Crop Residue Management
• amount depends on crop
– 8500 lbs/acre off of 150 bu corn
– 5600lbs/acre off of 100 bu corn
August 2008
Crop Residue Management
• amount depends on type of tillage
– Plowing 5%
– Field Cultivator 80%
– Chisel 80%
– Disc 6” 25%, 3” 50%
– Harrow 65%
August 2008
Seedbed Preparation
• Culmination of all 3 aspects
• Meets requirements for seed to grow
– moisture, temperature
– aerated, yet compacted
– free of clods
• Type of seed determines how smooth you
need seedbed
August 2008
Conventional Tillage
• Primary Tillage
– Breaks up soil and buries crop residue
– inverting equipment
• Plowing, time consuming, no residue
• Discing
August 2008
Conventional Tillage
• Secondary Tillage
– Produces fine seedbed that breaks up
into smaller chunks
– mixing implements
August 2008
Conservation Tillage
• Leaves 30% of residue
– reduces erosion by 40-50%
– reduced tillage
– fewer trips, compaction less
August 2008
Conservation Tillage
• Mulch Till
– Chisel, Secondary, 30-50% residue
• Strip Till
– No Primary tillage
– planter tills band of soil and plants
– bares 1/3 of soil
– 50% residue
August 2008
Conservation Tillage
• Ridge Till
– plants cleaned strip
– seed planted on ridge
– 2/3 residue
August 2008
Conservation Tillage
• No Till
– specialized planters
– 90% untouched ground
– Herbicides used to control weeds rather
than tillage
August 2008
Differences between
Conservation and Conventional
• Yields
– slightly lower in Conservation
• Equipment
– conservation needs specialized, but fewer
• Fertility
– Conservation remains moist longer,
– N needs to be deeper incorporated in
Conservation
– PH may be higher
August 2008
Drawbacks to Conservation
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Management
Adapted for select soils
Perennials can be a problem
Compaction in No Till can be a problem
PH lowers
Use of herbicides
August 2008
Cropping Systems
• 3 Different ways to decide what to plant
August 2008
Plant the Market
• Plant what the market wants you to,
highest price
August 2008
Suit to Operation
• Plant what you will use in ag operation
August 2008
Crop Rotation
• 1.Continuous Cropping
– grows same crop every year
– yields decline after several years
August 2008
Crop Rotation
• Disadvantages
– planting less profitable crops
– do not use crops that you need to plant
August 2008
Crop Rotation
• Advantages
– Control disease and insects
– Control weeds
• allelopathy: chemical emitted by a crop that kills
weeds in next crop
– supplies N
– Improves O.M.
– Reduces erosion
August 2008
Dryland Farming
• No irrigation
• Summer Fallow
– left fallow for 1 crop season
– control weeds and crop on field
– 25% of rain will be stored in ground
August 2008
Dryland Farming
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3 Problems
1. Wind erosion
2. Decline in O.M.
3. Saline Seeps
August 2008
Dryland Farming
• Saline Seeps:
– Deep rock layer stops water and pushes it
downhill
– water carries salt with it
– comes out at low spots of hill
– water evaporates leaving salt behind
August 2008
Dryland Farming
• Avoid saline seeps by moving the water
before it can evaporate
August 2008
Rangeland
• Four SCS ranks
– 1.
– 2.
– 3.
– 4.
August 2008
Excellent
Good
Fair
Poor
Rangeland
• Things to do to make rangeland more
productive
• 1. Control grazing
• 2. Fertilize
• 3. Seed out new plants
August 2008
Organic Farming
• No inorganic fertilizers or synthetic
pesticides are used
• Usually use rotation w/legumes to supply
N
• Rely on tillage and cultivation
– rotary hoe
August 2008
Organic Farming
• Results of O.F.
– better bean and oats yield
– erosion is reduced
– use 1/3 of energy
– sell to regular markets
– some utilize only part organic
August 2008
LISA
• Low Input Sustainable Agriculture
– Maximizes profits by reducing costs
– Minimizes off farm inputs
August 2008