Off-Road Equipment Management TSM 262: Spring 2016 LECTURE 13: Tillage Systems Off-Road Equipment Engineering Dept of Agricultural and Biological Engineering achansen@illinois.edu

Homework

Lab and Technical Sessions

Tillage Systems: Class Objectives Students should be able to: Understand the relevant ASABE standards Identify and apply soil textural classifications Analyze primary and secondary tillage systems Analyze the performance of tillage equipment Identify factors that cause soil compaction

ASABE Standards ASABE EP291.3 FEB2005 (posted on compass) Terminology and definitions for soil tillage and soil-tool relationships Basic tillage goals General tillage terms and kinds of tillage Tillage systems Specific tillage operation Nomenclature for tillage tools and implements Soil reaction nomenclature Soil nomenclature Soil and surface characteristics

ASABE Standards ASABE S414.2 MAR2009 (posted on Compass) Terminology and definitions for agricultural tillage implements Tillage implement categories Implement hitch classification Implement frame configurations Definitions and illustrations 5.18 Combination tillage implement for strip tillage 5.19 Tillage components

Properties of Soil Soil properties are very important consideration in tillage Soil texture (clay, silt, sand): Effects on Draft forces Soil compaction Crop growth Physical properties (porosity, bulk density, water content) Measures of readiness of soil for crop establishment and growth Mechanical properties (shear strength, friction, adhesion) Used to study mechanics and performance of tillage tools

Soil Textural Classification Soil Classification Clay, 2 micron, (0.002 mm) Silt, 0.002 – 0.05mm Sand, 0.05 – 2mm Gravel, 2- 64 mm SAND Textural Classification 8

Soil Physical Properties Porosity (n) is the ratio of the void volume (Vv) to the total volume (V) of the soil n = (Vv) / (V) Void Ratio (e) is the ratio of the void volume (Vv) to the solid volume (Vs) of the soil e = (Vv) / (Vs) Water Content (w) is the ratio of the mass of water (mw) to the mass of solids (ms) w = (mw) / (ms)*100 Degree of Saturation (Sr) is the percent of void space (Vv) occupied by water (Vw) Sr = (Vw) / (Vv) *100 Field Capacity: Field capacity is the water content of a soil at which the gravitational pull on the water is matched by the capillary action (33 KPa). Wilting Point: Is the moisture content at which the plant cannot remove any further water from the soil (1.5 MPa) Air (ma) Water (mw) Soil (ms) Vs Vw Va Vv V

Soil Physical Properties Bulk Density (γ) is the total mass (m) of the soil divided by the total volume (V) of the soil γ = (m) / (V) = (ms + mw) / V Dry Bulk Density (γd) is the mass (ms) of the solid constituents in the soil divided by the total volume (V) of the soil γd = (ms ) / V Particle Density (γs) is the mass (ms) of the solid constituents in the soil divided by the solid volume (Vs) of the soil γd = (ms ) / Vs Particle density is approx. constant at 2.6 – 2.8 g/cm3 Sand/Silt ≈ 2.65 g/cm3 Clay ≈ 2.75 g/cm3 Organic Matter ≈ 1.37 g/cm3 Acceptable range for dry bulk density, 1.2-1.4 g/cm3 Dry bulk density of 1.8 g/cm3 represents top end of bulk density Air (ma) Water (mw) Soil (ms) Vs Vw Va Vv V Root Limiting Bulk Density Sand ≈ 1.8 g/cm3 Loam ≈ 1.55 g/cm3 Clay ≈ 1.4 g/cm3

What is Tillage? The practice to develop a desirable soil structure or soil tilth for crop growth. Soil structure - the way in which soil particles are grouped or bound together to form lumps or aggregates. Pores are controlling factors governing water, air and temperature and there should be optimum soil water and soil aeration. Seedbed preparation Post-emergence cultivation Weed control Residue management Air (ma) Water (mw) Soil (ms)

Seedbed Preparation Place where seeds germinate & nourish young plants Seedbed must be firm to allow seed to come in contact with soil particles to absorb moisture Must be porous to allow for air and water movement and root development Have a crumb structure so that roots of seedling can penetrate it easily. The hard compact layer impedes root growth. Water will not easily penetrate hard soil to reach roots If soil is too loose, rain will wash away young plants Some soils have excess water Oxygen is needed by roots Air and water conduct heat more rapidly than soil, looser soils warm up sooner Plant residue on surface insulates, warms up slower, also provides buffer against wind

General Rules for Good Soil Tilth Till at proper time to maintain proper aggregation Too wet during tillage produces large clods Too dry during tillage makes soil too fine and likely to blow away Over tillage will destroy soil structure and lead to soil compaction

Types of Tillage (EP291.3) Tillage Conventional Primary/ Intensive Secondary Conservation Minimum/ Reduced Strip Till No-Till

What is Primary Tillage? First tillage operation of a season (after harvest) Loosen soil to permit air and water to penetrate Definitions Equipment used to break and loosen soil for a depth of six to 36 inches (15 to 90 centimeters) may be called primary tillage equipment. It includes moldboard, disk, rotary, chisel, and subsoil plows ASABE: Initial major soil working operation. Designed to reduce soil strength, cover plant materials, and re-arrange aggregates 15

Intensive Tillage (Primary) Leave less than 15% crop residue cover or less than 500 pounds per acre (560 kg/ha) of small grain residue. This system often involves multiple operations with implements such as a moldboard plow, disk, and/or chisel plow. 16

Residue Coverage 75% 25% 50% 90% CORN RESIDUE

Typical Equipment for Intensive Tillage (S414.2) Moldboard Plows (Mouldboard Ploughs) Gunnel, Share, Shin, Moldboard, Landside, Heel Down Suction from the plow Disk Plows Gang Angle, Disk Angle(42-45 deg), Tilt Angle (15-25 deg), 180-540 kg/disk Hard soils, non-scouring soils Chisel Plow / Subsoiler Shanks, straight shanks, curved shanks V-Frame Rotary Tillers PTO driven, High Power Requirements, Low Traction requirements Single pass operation 18

Moldboard Plow Typically bury 90-95% of the residue on each trip. These plows turn the surface soil upside down leaving only 5-10% surface residues. 19

Problems with Moldboard Plowing Moldboard plowing has become increasingly recognized as a highly destructive farming practice rapidly depleting soil resources. Foremost is the formation of hardpan, or the calcification of the sub layer of soil. Hardpan is impenetrable to the roots of plants and restricts growth and yields. Hardpan becomes impenetrable to water, leading to flooding and the drowning of crops. Rapidly depletes the organic matter content Promotes erosion Leads to increased soil compaction and loss of pore space within the soil. 20

Disk Plows 21

Chisel Plow and Subsoiler Series Type No. of Shanks Weight Lbs Track/Belted DBHP Wheel Tractor PTO-HP VRT towed 5 or 7 6,610-8,050 160-250 225-350 22

Rotary Tiller High PTO power required High wear part consumption Excellent residue incorporation 23

Secondary Tillage Objectives: Tillage that can take place on its own or after primary tillage and is less than 6" deep Objectives: Refine the seed bed – create a smoother surface with less clods Shape rows if necessary Control weeds Incorporate chemicals Manage residue 24

Cultivation Tillage Systems Post plant and shallow tillage Objectives: Weed control Aerate soil (moisture or crust) S-tine C-shank rolling

Secondary Tillage Equipment Harrows Disk Spring Tooth Cultivators Rotary Hoes Cultipackers

Disk Harrow

Spring Tooth Harrow Purpose: Final seedbed preparation, post-planting operations to break up soil crust and remove weeds

Cultivator

Rotary Hoe Purpose: Weed control in row crops, breaking soil crusts for better seed emergence, and mixing of fertilizer

Cultipackers Purpose: Break up hard clods and conserve soil moisture for better seed germination by increasing soil density in top few centimeters of soil

Conservation Tillage Leave minimum of 30% of crop residue on soil surface or at least 1,000 lb/ac (1,100 kg/ha) of small grain residue on surface during critical soil erosion period Slows water movement Reduces the amount of soil erosion Warms soil, enabling next year’s crop to be planted earlier in the spring Reduces fuel consumption Reduces soil compaction Reduces field traffic 32

Reduced Tillage Systems Leave between 15 and 30% residue cover on the soil or 500 to 1000 pounds per acre (560 to 1100 kg/ha) of small grain residue during the critical erosion period. This may involve the use of a chisel plow, field cultivators, or other implements 25% 33

Strip Till Combines soil drying and warming benefits of conventional tillage with soil-protecting advantages of no-till by disturbing only the portion of the soil that is to contain the seed row Requires special equipment Each row that has been strip-tilled is usually about eight to ten inches wide. Benefit of strip-tilling is that farmer can apply chemicals and fertilizer at the same time as tillage 34

Strip Till (S414.2) Leave surface ready for planting Loosen soil below row to be planted Cut surface residue Move surface residue away from seed row Planter can be attached to rear of machine for single pass tillage/planting operation

No Till Pros Increasing soil quality (soil function), Protecting the soil from erosion, evaporation of water, and structural breakdown. Residues left intact help both natural precipitation and irrigation water infiltrate the soil where it can be used. Residue left on the soil surface also limits evaporation, conserving water for plant growth. Reduction in tillage passes Reduced labor and related fuel and machinery costs. Less airborne dust, Often have more beneficial insects and annelids, a higher microbial content, and a greater amount of soil organic material. 36

No Till Cons Yield Equipment Yields can be impacted negatively. However, lower overhead cost may offset lower production, thus higher profits. Crops, like corn, do not tolerate the increased competition in early life well, and are not suitable for complete no-till agriculture. With precise fertilizer and seed placement, yields are never compromised. Equipment Requires specialized seeding equipment 37

No Till Cons Chemicals Erosion One of the purposes of tilling is to remove weeds. No-till farming does change weed composition drastically. Shrubs and trees may begin to grow eventually. Crop rotation is also more important Erosion Long-term erosion, drainage gulleys that do form get deeper every year Slight increase in soil bulk density 38

Management Goals of Tillage Minimize soil compaction rearrangement of soil particles and aggregate to reduce pore space and increase soil bulk density Soil Properties are a key factor soil composition - Sand, silt, clay soil texture - % sand, silt, clay soil aggregates Compaction clay soils are most compactible

Management Goals of Tillage Crop Residue Management Benefits erosion control soil tilth : improves both physical and chemical properties water holding capacity CEC is increased Conservation tillage (> 30% on surface)