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Transcript
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 • • • • • • 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 • • • • 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