Soil The most important portion of the whole program.

Soil The most important portion of the whole program. USDA EQUAL OPPORTUNITY STATEMENT The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, sex, religion, age, disability, political beliefs, sexual orientation, or marital or family status. (Not all prohibited bases apply to all programs). Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact the USDA's TARGET Center at 202-720-2600 (voice and TDD). To file a complaint of discrimination, write the USDA, Director, Office of Civil Rights, Room 326-W, Whitten Building, 14th and Independence Avenue, SW, Washington, D.C., 20250-9410 or call (202) 720-5964 (voice and TDD). USDA is an equal opportunity provider and employer. Soil Soil Formation Soil Texture Soil Color Organic Matter Soil Chemistry Soil Air Compaction/Shrink-Swell Drainage Erosion Safety References Practical Exercise Topics 1

Climate Living Organisms Parent Material Topography Time Forming Factors Temperature and precipitation Determines the nature and speed of soil formation Gulf Coast has year long growing season, high humidity, uniform rainfall Climate Climate on Soils Desert Major factor is lack of rainfall Cold Frozen soils and cold temps limit soil formation Tropical Hot, humid, and lots of rainfall causes extreme weathering Temperate Wide array of soils formed under these conditions 2

Effects of Living Organisms on Soil Formation Grasslands = dark soils Forest= light colored and acidic Marsh=high organic Crawfish=destruction of structure Recent Alluvium Beaumont Formation-Late Pleistocene Lissie Formation- Early Pleistocene Willis Formation- Pliocene Parent Material Gulf Coast was a fluvial deltaic system Soils are derived from loamy and clayey fluviomarine deposits Parent Material 3

Topography Nearly level Highly dissected Soils on flood plains and coast line are youngest Stable landscapes have older soils Takes about 500 years to form an inch of soil from hard parent material Time Texture USDA % of Sand, Silt and Clay Clay fraction key factor chemically and physically 4

Typical Soil 40 to 45% 25 to 30% 25 to 30% Air Water Mineral Organic Particle Size Comparison Clay Particles=Smallest Sand Particles=Largest High Shrink-Swell High Organic Content Agriculturally productive Difficult to manipulate when wet or dry Clayey Soils 5

Sandy Soil Low fertility Low water holding capacity Easy to work Large category of soils Characteristics vary About 15 to 35 percent clay; 25 to 70 percent sand Loamy Soil Fertility Drainage Past climate Heating, cooling and chemical reactions Soil Color 6

Color as Indicator of Fertility Dark Soils have higher organic content Organic content usually greater than 1 percent Higher fertility Color as Indicator of Fertility Light Colored Soils are less fertile <1 percent OC Drainage Indicator-Well Drained Usually found on convex landforms Ridges and sloping areas Yellow, red or brown show good internal drainage Black is usually well drained No grays due to wetness 7

Drainage Indicator-Poor Gray throughout Contains mottles (oxidized or reduced iron) Concave landforms Wet soils could be associated with wetlands! Past Climate Dominantly gray but no water Absence of hydrophytic vegetation and landform is convex Chemical and Physical Reactions Dark Colored Soils Absorbs light-warms quicker Light Colored Soils Reflects light-stays cooler 8

Humus What is left after decomposition Coats soil particles and gives dark soils their color Organic Carbon Organic Matter All things organic before it becomes humus Provides food for microbes and worms Organic Importance Loosens soil Nutrient source for plants Increases water holding capacity Food for microbes Regulates temperature Helps prevent erosion Soil Organic Matter Highest in the surface where the majority of biotic activity occurs Important to stockpile surface layer Easily destroyed when disturbed 9

Increasing Organic Content Gulf Coast climate ideal for year round microbial action Constant struggle to maintain in this climate Do not bag grass clippings, leaves, and twigs Add mulch Soil Characteristics and Chemistry Air and Water-pores,structure, compaction Tilth ph Cation Exchange Capacity Carbon to Nitrogen Balance Salinity Shrink and Swell Drainage Erosion Fertilizer use Pores Pores-voids in soils Types of Pores 10

Importance of Pores Provides a space for air, water and roots Formed by roots, worms, burrowing animals, voids between soil particles Clays have small pores Sands have large pores Destroyed by compaction Root pore lined with oxidized iron Water Infiltration and Movement Function of gravity, pore space, structure and texture Water Movement Structure Texture 11

Soil Water Terminology Saturation-free water, all voids filled with water Field Capacity-water remaining in soil after free water is gone Wilting Point- water only in the smallest micropores When to Water Use of tensiometer (maintain 1/3 bar water, field capacity) when foot leaves a track in a lawn, it is time to water poke finger into soil. If no soil on finger, too dry. If some soil, ok. If mud, walk away Drip Watering Techniques Sprinkler Hand Rain 12

Structure Types Formed by roots Aggregation of soil particles Water movement Angular blocky Soil Structure Subangular blocky Granular Prismatic Single Grained Soil Structure Massive Columnar Wedge 13

Improving Structure Increase organic matter Avoid working soil when too wet Establishment of cover crops Deep rooted plants Reduce traffic Compaction Soil particles are compressed closer together Eliminates pore space which restricts air and water Soil Compaction Occurs in high traffic areas Occurs when soils are manipulated when wet Plowing or incorporating organic matter decreases compaction Minimize hazard of compaction by having a good thick layer of mulch on surface 14

Soil Compaction Plow pan Restricts water and air movement and root development Tilth The physical condition of soil as related to its ease of tillage, fitness as a seedbed, and its impedance to seedling emergence and root penetration Good tilth-usually a loamy soil with high organic content Poor tilth- hard to dig usually low organic content Ideal ph range is 5.5 to 7.5 ph >8.5 could mean high salt content ph<4 Aluminum and Iron toxicity ph meters or test strips Add lime for soils less than 5.5 and sulfur for soils above 7.5 Local soils are in good ph range Soil ph 15

ph Related to Plant Available Nutrients Cation Exchange Capacity CEC 16

CEC Values for Common Soil Attributes -clays and organic matter have higher CEC values Material CEC, meq/100g Organic matter 130-500 Vermiculite 100-500 Montmorillonite 29-150 Kaolinite 3-15 Sand 0.8-4 Sandy loam 7-16 Loam 10-15 clay loams 20-50 Carbon to Nitrogen Ratio Consideration when adding mulch vs soil amendment Microbes use nitrogen to eat carbon Grass clippings and manure have more nitrogen and will decompose fastest Woody material has less nitrogen and harder to decompose Could cause a temporary nitrogen deficiency in plants Add nitrogen (fertilizer or green organic matter) Will correct over time Use good compost C:N of Various Soil Amendments The closer to 1:1 is better Manures, grass clippings, and food scraps are good Sawdust not good High C:N acts as a better mulch than a soil amendment Material C to N Ratio Food Scraps 15:01 Grass clippings 19:01 Rotted manure 20:01 Vegetable trimmings 25:1 Oak leaves 26:1 Peat moss 58:1 Corn stalks 60:1 Straw 80:1 Pine Needles 60 to 110:1 Newspaper 170:1 Sawdust weathered 2 months 625:1 17

Salinity A localized problem on Gulf Coast Almost all soils have some salinity Causes soil to become hard Damages roots and stunts plants Corrodes steel Gypsum helps Shrink and Swell Function of many micropores and clay type swell when wet and shrink when dry Causes $$ in damage Maintain moisture level Use of mulch Drainage Poorly drained soils are gray with oxidized iron zones Concave landscapes Usually have water loving plants Best to avoid but raising the surface works Beware of altering wetlands! 18

Drainage Well drained are brown, yellow or red and most black soils Convex landscapes Avoid making depressions if you want the soil to stay well drained Soil moved by wind or water Occurs in high traffic areas where surface vegetation is gone Areas with more than 3 percent slope are susceptible Erosion Erosion Control MeasuresTerraces Mulches Grassed Waterways Rip rap Windbreaks 19

Fertilizers Proper Use Inorganic or Organic Fertilizers Macronutrients- plant essential nutrients needed in large quantities Nitrogen, phosphorous, potassium, calcium, magnesium, and sulfur Micronutrients-plant essential nutrients required in small amounts. N-P-K N= Nitrogen-first number P=Posphorous as phosphate (P2O5)-actual phosphorous is 44% of the second number K=Potassium (aka potash)-not really potash but K2O-83% of the third number 20

Fertilizers Label has analysis and tells what is in the bag Complete fertilizers have N-P-K Incomplete fertilizers are missing one May or may not contain important micronutrients Soil Testing Best way to determine nutrient needs for a certain crop Conducted by Texas Agrilife Extension Service Soil, Water, and Forage Testing Laboratory Instructions for sampling found in handout Organic Fertilizers Texas AgriLife Extension Service, Texas A&M System Fertilizer N P K Remarks Blood 10 1.5 0 A very rapidly-available organic fertilizer Fish scrap 9 7 0 Do not confuse with fish emulsives which are generally quite low IN FERTILIZER content Guano, bat 6 9 3 Partially decomposed bat manure from caves 21

Organic Fertilizers Guano, bird 13 11 3 Partially decomposed bird manure from islands off coast Kelp or seaweed 1 0.5 9 Bone Meal, raw 4 22 0 Main value is nitrogen since most of the phosphorus is not soluble Organic Fertilizers Bone Meal, steamed 2 27 0 As a result of steaming under pressure, some nitrogen is lost, but more phosphorus is soluble for use by plants Cocoa shell 2.5 1 3 Cotton seed meal 6 2.5 2 Primarily a conditioner for complete fertilizers Generally very acid; useful in alkaline soils Hoof and horn meal 14 0 0 The steam-treated and ground material is a rather quickly- available source of nitrogen Organic Fertilizers Cattle manure 0.5 0 0.5 IMPROVES soil structure. Chicken manure 0.9 0.5 0.8 Careful! Burns plants easily. Horse manure 0.6 0.3 0.6 IMPROVES soil structure. Sheep manure Swine manure Manure (spent) 0.9 0.5 0.8 0.6 0.5 0.4 1 1 1 22

Organic Fertilizers Oyster shells 0.2 0.3 0 Because of their alkalinity, oyster shells are best used for raising ph rather than as a fertilizer Peat (reed or sedge) 2 0.3 0.3 Best used as a soil conditioner rather than as a fertilizer; breaks down too rapidly Rice hulls (ground) 0.5 0.2 0.5 Sewage sludge 2 1 1 Examples of activated sludge are Milorganite (Milwaukee, WI),ÊHu- Acinite, (Houston, TX),Chicagrow (Chicago, IL) and Nitroganic (Pasadena, CA) Organic Fertilizers Cocoa tankage 4 1.5 2 Garbage tankage 3 3 1 Process tankage 8 2 0 Wood ashes 0 2 6 Quite alkaline; do not use on high ph soils Fertilizer Considerations Calculate the exact amount needed to avoid excessive use High phosphorous amounts are generally unnecessary except in early establishment of transplants High nitrogen amounts promote vegetative growth (good for lawns and leafy vegs) Handout has more information on application methods and timing 23

Important to Remember 1. TO CORRECT MOST SOIL PROBLEMS, INCREASE ORGANIC CONTENT 2. MINIMIZE HAZARDS OF EROSION AND COMPACTION 3. KEEP HANDOUT FROM CLASS Safety and Health Soil pits are hazardous Know what your putting into the soil Know the history of the area (superfund sites probably don t make good gardens) Read labels Good Online Resources www.nrcs.usda.gov/ Aggie-horticulture.tamu.edu/ http://websoilsurvey.nrcs.usda.gov/ http://soiltesting.tamu.edu The Science of Soil Health (a series of Youtube videos) 24

Contacts USDA-Natural Resources Conservation Service Rosenberg Soil Survey Office=281-232-4668 jon.wiedenfeld@tx.usda.gov 25