Composting in the Desert

Transcription

1 Composting in the Desert nmcomposters.org Objectives Overview Describe and discuss influences of climate. Delineate science, materials, methods, choices and best practices for high desert composting. Describe and delineate hot and cold methods. Understand the basics of soil amending. High Desert Climate Considerations Sparse rainfall Low humidity Frequent drying winds. Frequent sunshine. Intense UV radiation in summer. (altitude) Day to night wide temperature variations Seasonal temperature variations 1

2 Desert Composting Considerations Organizing & Managing feedstock to moderate moisture evaporation to enhance decomposition. Shady locations on top of soil Low porosity bins / containers Soak dry before adding Cover the top Sprinkle water as needed Composting? Organizing and Managing organic material so that it decomposes. Decomposition is the transformation of organic material to humus. Accomplished by naturally occurring microorganisms in presence of air & moisture. Plant Nutrient Recycling Decomposition in Nature 2

3 Finished Compost Contains Humus Dormant, living & dead microorganisms Undecomposed organic material Plant nutrients Organic Material Anything that was once alive will decompose. Green & Brown Materials Browns-carbon, provide microbial nutrition. Alone they decompose slowly. Greens-nitrogen, provide microbial nutrition and protein for reproduction / cell wall formation. When mixed together then decomposition goes well. A handful of carbon with a pinch of nitrogen. Ideal C:N ratio for microbial nutrition is 25:1 3

4 Greens and Browns The NTG requirement for decomposition of browns is why in general we put: Undecomposed organic mulches on top of the soil. Decomposed organics (compost) on top of or in the soil. How Do We Get There? Organics + Water + Air + Time = Compost Moisture in Composting About 50% throughout process. Similar to moisture content of fresh coffee grounds. Moist but not dripping. Manage evaporation! Always cover the top. Add moist materials then maintain moisture. Sprinkle with water as necessary. 4

5 Moisture Microorganisms can only function in a thin film of moisture on organic materials. Within that moisture film they secrete enzymes which transform organic material to humus. No moisture = No decomposition Maintain 50 % moisture throughout process. Organizing Let s organize and manage organic material so that it decomposes. Let s consider some choices. Containment Options in the Desert On top of soil bins, sheet, pile, bag In the soil pit, trench, blend & bury, worms 5

6 Containers - Bins Easy to add to; easy to harvest from - usually Neat / tidy Facilitate air & moisture management Movable many styles / choices Reduce flying insects, sometimes vermin Organizing Containers Customize for desert. Too Porous Customize for Desert Cover holes with tape or caulk 6

7 Containers Add May be useful for entomophobes Containers Too porous Better > Appropriate for Desert 7

8 Block Bins Cover the top. Wire Bins Too porous for Desert Lined Wire Bin 8

9 Bale Bins Cover the top Piles Cold / Hot Cover it. Sheet Composting on top of Soil Moisture Cover the top Static: cold/hot 9

10 Containment in the Soil Moisture, mulch, cover Pit / trench Cold / static Bags - closed Leaf mold Shred, moisture, bag, wait - anaerobic Cold / static Bokashi Closed Bucket Method First stage Second stage Entomophobes Cold / static 10

11 Blend and Bury Dump & Run Easy no turn, static, cold Coarse bulking added Maintain 50% moisture months Choices 1. Choose organizing method bin, pit, sheet, bag, etc.. 1. Then a process hot or cold 1. Then a management style active or passive: Active - turning & churning with coarse bulking. Usually hot process. Passive - static with coarse bulking. Often cold process. 11

12 Hot Process Composting Batch mixed all at once. Intention - heat Minimum size - 1 cu. yard: 3 x3 x3 Attention to the C:N ratio- 2lbs. brown with 1lb. Green is in the range of 30:1 Needs turning & churning active management Hot Process Add bulking material at bottom, then more after every 5 of greens & browns Soak dry materials before adding. Mix greens & browns before adding. Once desired temp. (about 150F)- turn, churn, sprinkle, add more nitrogen every 7-14 days. Hot Process High energy process uses up O2 & Ntg. Heat comes from microbes releasing energy from carbohydrates. Moist heat softens the organics. Destroys pathogens & seeds. Sprinkle pile before tuning & churning. Turn & add more Ntg. as necessary 12

13 Hot Process Original pile will decompose to +/- ½ original size. End product: 3 6 months. Screen out coarse bulking materials. End product requires a curing (cold) phase: 2 6 weeks. Actinomycetes > humification & produce geosmin > earthy scent. Hot Process Evaporation happens with uncovered pile. Large Scale Hot Composting 13

14 Seed2Need Garden Corrales, NM C:N Ratio Ideal 25:1 So what? It is a guideline - a goal for feedstock blend. Ideal ratio for microbial nutrition and so Important for heat generation with hot composting process. C:N Ratio For every 2 parts of brown mix in 1 part green, by weight. This mix of feedstock will be in range of 25:1. Bulking material not part of calculation. Use compost mix calculator. nmcomposters.org 14

15 Coarse Bulking Material Decreases compaction of wet organics & provides for air flow throughout the pile. Woody, recalcitrant slow to decompose. Very useful in desert composting practice. Screen out of end product, then reuse them. Gather & Store Bulking Material Coarse Bulking Decreases compaction, allows for air flow Cover the top. > After every 6, then add 4 bulking > > 6 12 at bottom > 15

16 Chimney Effect Cold Process Any decomposition process that does not generate appreciable / sustainable heat. Often static composter s choice. Usually less labor than hot process. Temperature in pile is variable. Time to end product: months Cold Process Often occasional additions of whatever organics are available. Avoid compaction of each addition. Bulking & moisture maintenance required. Composting worms may be added. Hybrids are possible. 16

17 Review Influencing Factors Time Temperature C:N ratio Bulking Moisture Air Insects, worms Surface area Compost Food Web Nutrient Recycling Insects Dark, moist, food, undisturbed stay where there s food. Detritivores Make organics smaller. Add to biology. Useful to the process. 17

18 Composting Worms Eisenia fetida red wigglers Surface dwellers ingest decomposing organics Castings ( manure ) = humus Soil aerators, mucous binds soil particles Surface Area of Feedstock Increasing surface area improves water absorption which fosters microbial activity. Smaller decomposes faster ( better ) > > > Avoid Adding Discussion Diseased plants, weeds with seeds Wood ash - inorganic, alkaline Coal ash high sulfur & iron content Meat, fish, dairy Lard, margarine, oil, nut butters 18

19 Avoid Adding Chemically treated wood products Dog, cat, pig, pet bird manure Glossy colored & waxed paper Metal, glass, plastic, synthetic fibers Pesticides, herbicides, fungicides, vermicides Avoid Adding Manures containing vermicides. Need 3 months in sun / air for biodegradation. Manures containing persistent broadleaf herbicides which need 3 years for biodegradation. Clopyralid, Aminopyralid, Picrolam Fragrances When compaction of moist feedstock occurs in an aerobic composting process, then the decrease in 02 allows anaerobic bacteria to proliferate. Putrefaction / putrescent Anaerobes produce methane & hydrogen sulfide gases which are unpleasant. Maintain 50% moisture. Bulk to decrease compaction. 19

20 Microbial Inoculants Composter s choice Not required Finished compost may be used as an inoculant. Choices for Entomophobes Bokashi bucket process Deep pits, blend & bury Raised tumblers/ bins Choices for East Mountains Indoor worm bins Bokashi bucket Pits deep, blend & bury Avoid food scraps in out door piles, containers 20

21 Finished Product Looks like coffee grounds after bulking removed. Unable to identify original ingredients. Pleasant fragrance Does not generate heat Solvita test / maturity Amending Desert Garden Soil Texture no change Ideal Soil Structure - modifiable Amending Desert Garden Soil Feed the soil that feeds plants. Poke holes the soil Broad fork 21

22 Poke Spread Amending Soil Rake Water Mulch Mulch and Shade Amend in spring and fall. Maintain moisture in all seasons. May add composting worms Compostholing 22

23 Plant in native soil Trees & Shrubs Amend on top Safety Discussion Wear gloves. Cover wounds. Sprinkle before turning / churning. Consider tetanus booster. Scrub hands & vegetables Controversial Ideas All composting operations: Have to be turned. Have an unpleasant odor. Have to have soil, inoculant & worms added. Have to generate appreciable & sustained heat. Have a rigid set of rules to follow. Take a lot of time & effort. 23

24 Composting Literature Often written by people who do not live & practice in the high mountain desert.. Some of their advice may not be useful to us. Often create confusion about the hot & cold processes - not clearly distinguishing them. Rationale / Benefits Recycles plant nutrients rather than land fill. Humus in finished compost: Improves nutrient exchange in root zone. Absorbs water. Contains plant nutrients. Provides beneficial microorganisms & food for them. Helps improve soil tilth. Mycobacterium vacce Microorganisms in soil and compost. Produce a sense of well being in humans. 24

25 Composters Choices What might work for you / family? Pick a method. Get started. Practice! Keep notes. Ask questions. Be patient and compost on. Read & research. Attend another class. Good Practices in the Desert Moderate & manage evaporation: Use low porosity bins/containers. Block holes in manufactured bins. Always cover the top of pile then the top of bin. Wet dry material before adding. Sprinkle to maintain 50% moisture throughout. Place operation on soil in shade in summer months. 25

26 Good practices Chop, shred, cut before adding. Add what you have on hand all will decompose. Mixing browns with greens is helpful. Do not compact additions. Always add coarse bulking material as you build. Discussion 26