Bio slurry PPRE Oldenburg University April 26-28, 2011

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

Nutrient depletion in Africa Water & wind erosion = 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 ( % 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 phosphorus, potash and micronutrients. Helps for the growth and development of root of the plant Resist from wilting and lodging of plants

Soil Organic Matter 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 pH Resistance to erosion Small fraction of soils: < 2 % (in tropics)

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 OriginsCharacteristics Farm yard manurePartly decomposed mix of dung and urine with bedding material High NPK and OM content, handling is critical to prevent nutrient losses Animal manureDroppings and urine of animals Free ranging: nutrient loss through evaporation and washing CompostAerobically decomposed organic material High carbon content (humus) Bio-slurryAnaerobic decomposed organic material Lower OM component, high available N

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

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 Household system Animal production system Biogas plant Bio slurry

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 TreatmentGrain yield (kg/ha) Avg over 3 yrs Increment over control (kg/ha) Control1288 Bio-slurry dry Bio-slurry wet % dry slurry + 50% CF % dry slurry + 25% CF Chemical fertilizer 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