Bio slurry PPRE Oldenburg University April 26 28

Bio slurry PPRE Oldenburg University April 26 -28, 2011

Soil fertility Cultivation: Soil air: • • Air / water critical Respiration: roots & micro organisms • • Crop rotation Slash & burn Fallowing Population pressure! Mineral matter: • • • Biological population: • • Climate: Worms, insects, spiders Fungi, bacteria, algae 20% SOM Physical & decomp • • Soil water: • • Held by clay & humus Transport nutrients Micro-organism activity Mineral weathering Clay: < 0. 002 mm Silt: 0. 002 – 2 mm Stone: > 2 mm Temp: chemical reaction for weathering Rainfall: washing out weathering products Organic matter: Larger organisms: • • Vegetation, animals Tropical soils: low Ccontent • • Decomposing organisms Humus, back (C) jelly, in mineral matrix

Nutrient depletion in Africa • Water & wind erosion = 16 - 300 x soil development through weathering • Nutrient export by product export

Plant growth Nutrient levels: • Deficient: Severely limited growth and yield • Critical: Growth and yield below average, good response on added nutrients • Sufficient: Added nutrients result in added nutrient in produce rather then increased yields • Excessive: Reducing yields, causing nutrient imbalances, toxic

Plant nutrients Macronutrients (0. 2 - 4% DW) • Primary: nitrogen (N), phosphorus (P), potassium (K) • Secondary: calcium (Ca), magnesium (Mg), sulphur (S) • Silicon (Si) Micronutrients (trace elements, 5 – 200 ppm) • boron (B), copper (Cu), iron (Fe), chlorine (Cl), manganese (Mn), molybdenum (Mo), zinc (Zn) Non-Mineral Nutrients • hydrogen (H), oxygen (O), carbon (C)

Macro nutrients Nitrogen (N) Phosphorus (P) Potassium (K) Increases growth and development of all living tissues. Helps in early maturing by stimulating flowering Enhances the plant's ability to resist diseases Improves the quality of leafy vegetables and fodder and the protein content of the food grains and makes them green. Helps in seed and fruit development. Assists carbohydrate translocation and water utilization by stomatal regulation. Helps uptake of Helps for the growth and phosphorus, potash and development of root of the micronutrients. plant Resist from wilting and lodging of plants

Soil Organic Matter Small fraction of soils: < 2 % (in tropics) OM: • Living organisms: roots, fungi, earthworms, etc. • Dead material: plant residues, fym, compost, humus, etc Positive effects: • Soil structure (roots, air) • Water retention capacity • Soil fertility (CEC = cation exchange capacity) • Buffers soil p. H • Resistance to erosion

Fertilizers Organic fertilizer: – Broad range of nutrients – Low in N-P-K – Long term effect (indirect) – High soil organic matter content Chemical fertilizers: – Short term effect (direct) – High in N, P or K Integrated Soil Fertility Management: – Optimal combination of organic and chemical fertilizers

Sustainable agriculture Ecologically sound, economically feasible, socially acceptable Origins Characteristics Farm yard manure Partly decomposed mix of High NPK and OM dung and urine with content, handling is critical bedding material to prevent nutrient losses Animal manure Droppings and urine of animals Free ranging: nutrient loss through evaporation and washing Compost Aerobically decomposed organic material High carbon content (humus) Bio-slurry Anaerobic decomposed organic material Lower OM component, high available N

Anaerobic Digestion Process Acid Production Liquefaction Liquefying Bacteria Acid-Forming Bacteria Liquefied soluble organic compounds Manure Insoluble Compounds (organic, inorganic, water) Biogas Production Methane-Forming Bacteria Simple organic acids End Products Biogas (Methane, CO 2, misc. ) Effluent

Bio-slurry characteristics An example of Nutrient contents of slurry at different situations/practices (Gurung, 1997)

Factors affecting nutrient content • • Species, age, and condition of the animal from which the dung is drawn Nutrition - composition of diets Environmental factors The way the slurry is stored, treated and applied to the field

Farm system Crop production system Bio slurry Biogas plant Household system Animal production system

Economic benefits of slurry • • Higher yield kg/ha Better quality, higher price/kg Savings chemical fertilizer Savings on pesticides Financial benefits of bioslurry is far greater than that of biogas! (Vietnam, India, China)

Effect of biogas slurry Dry and wet slurry on wheat Treatment Grain yield (kg/ha) Avg over 3 yrs Increment over control (kg/ha) Control 1288 Bio-slurry dry 1450 162 Bio-slurry wet 1842 554 50% dry slurry + 50% CF 2706 1418 75% dry slurry + 25% CF 1744 456 Chemical fertilizer 3503 2215 Source: Maskey, 1978 in Gurung, 1997

Slurry application methods • • Slurry as a ready-made manure Application of slurry with irrigation water Slurry used as dried dust Use after composting

Other applications • Soil conditioning • Starter for composting • Enriched with organic fertilizer (urea, super phosphate) • Feed (fish culture, animal husbandry) • Pesticide application • Seed pelleting • Mushroom cultivation • Earthworm rearing

Wet Storage

Shading

(semi) Dry Storage

Slurry hut

Wet application

Wet application II

Dry Application

Challenges of Bio-slurry utilization • Storage has significant deterioration effect on the slurry quality • It is expensive and labor intensive to transport composted slurry, particularly, to fields far away from homesteads • Determining specific plant requirement and soil test is required • Determining optimum time and season for slurry application – Lack of knowledge and skill in the value and use of the slurry

Thank you