Exploring How Composts Affect the Soil s Plant and Microbial Community

Transcription

1 Exploring How Composts Affect the Soil s Plant and Microbial Community

2 Review of paper from South Korea Analysis of paper Outline of my research plan for 2- year field study of compost applied to an established grass pasture

3 Review of paper: Effect of food waste compost on microbial population, soil enzyme activity and lettuce growth Jae-Jung Lee, Ro-Dong Park, Yong-Woong Kim, Jae-Han Shim, Dong-Hyun Chae, Yo-Sup Rim, Bo-Kyoon Sohn, Tae-Hwan Kim, Kil-Yong Kim Department of Agricultural Chemistry, Institute of Biotechnology, Chonnam National University, South Korea, in Bioresources Technology

4 Introduction Food wastes are significant part of the waste stream in South Korea but they can be high in Na due to cooking practices Disposal of food wastes: Landfilling creates groundwater problems Incineration costly, environmental problems Feeding to animals not healthy or practical Composting: good feedstock high in Nitrogen, low in salts, high moisture, but elevated levels of Na

5 Description of methods Lettuce germinated in commercial medium Lettuce transplanted to pot, 4 kg soil Amendments added to pots Lettuce grown 6 weeks Biological measurements, lettuce weights taken at end 9 authors!

6 Treatment name CON Description No amendments added Pounds N/A 0 MF Mineral fertilizer 134 lbs N/A (15 kg N/10a)* CC Commercial Compost (1800 kg/10a) 107 lbs. N T /A ( lbs. N A /A)** FW0.5 Food Waste Compost (900 kg/10a) 300 lbs. N T /A ( lbs lbs. N A /A FW1.0 Food Waste Compost (1800 kg/10a) 600 lbs. N T /A ( lbs. N A /A) FW1.5 Food Waste Compost (2700 kg/10a) 1200 lbs N T /A ( lbs. N A /A) * an a is an are, 10a =.1 ha ** Assume compost is % available in year 1 *** Agronomic rate of N for lettuce is reported in lbs. N/A

7 Fig. 1. Population of fungi in rhizospheres of lettuce in pots as affected by CON, CC, MF, FW0.5, FW1.0, FW1.5.

8 Fig. 2. Population of bacteria in rhizospheres of lettuce in pots as affected by CON, CC, MF, FW0.5,FW1.0,FW1.5. Means with same letters are not sig. different at p<0.05 when compared by LSD, means avg. 3 reps.

9 Fig. 3. Microbial biomass in rhizosphere of lettuce in pots as affected by CON, CC, MF, FW0.5, FW1.0, FW1.5

10 Enzymes measured Acid phosphatase & Alkaline phosphatase Hydrolases which catalyze the hydrolytic cleavage of chemical bonds Dehydrogenase Calalyze oxidation-reduction reactions important in fermentation and respiration pathways

11 Fig. 4. Acid phosphatase activity in rhizospheres of lettuce in pots as affected by CON, CC, MF, FW0.5,FW1.0,FW1.5. Means with same letters are not sig. different at p<0.05 when compared by LSD, means avg. 3 reps.

12 Fig. 5. Alkaline phosphatase activity in rhizospheres of lettuce in pots as affected by CON, CC, MF, FW0.5, FW1.0, FW1.5. Means with same letters are not sig. different at p<0.05 when compared by LSD, means avg. 3 reps.

13 Fig. 6. Dehydrogenase activity in rhizospheres of lettuce in pots as affected by CON, CC, MF, FW0.5, Fw1.0, FW1.5.

14 Fig. 7. Fresh weight of lettuce in pots as affected by CON, CC, MF, FW0.5,FW1.0,FW1.5. Means with same letters are not sig. different at p<0.05 when compared by LSD, means avg. 3 reps.

15 Nutritional Needs of Lettuce* N: #/A P2O5: 200#/A K2O: 200#/A * From litterature, not site specific

16 Measurable Parameters that Indicate Quality in Compost CO2 evolution: maturity C:N NH 4 -N:NO 3 -N ph EC

17 Comparison of CC and FW Commercial Compost Composted 4 months High C:N (38:1) Low Total N Made with a high proportion of sawdust (probably high in C, difficult to degrade) Food Waste Compost Made in a lab Unknown additative Miracalous Soil Microorganisms Composted for 1 year C:N = 12:1

18 Analysis of Paper Objective: Look at change in soil microbial population? Information about soil? Silty clay from a wheat field at Ag Ext. Station no data about initial fertility of soil to understand control with no amendments added No background data on population of soil microorganisms in soil used in pots Unclear about how rates of soil amendments xwere chosen Description of sampling of rhizosphere soil lacking

19 Applying Composted Horse Manure to Grass Pasture Pasture planted in spring, 2004 Compost made fall, 2004 and present Compost to be tested for quality, first batch: C:N = 12:1 Spring 2005 application of: mineral fertilizer (MF) at agronomic rate based on fall soil tests and expected yield of hay (185 lbs N/A, 0 lbs. P2O5/A) Compost at same rate of N as MF uncomposted horse manure at same rate of N as compost compost tea (split plot?), 5 gal/a weekly May - September

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22 Challenges To compare equivalent rates of available N among treatments Unknown mineralization rate of compost Assume manure = 50% in year 1 Unknown effects of compost tea may affect mineralization rates of N Border effects from tea applications

23 More Challenges Little good qualatitive info available about compost tea How to measure quality of tea How to replicate tea every week over summer

24 More Challenges Measuring changes in soil microbial community! Explore effect of microbial soil life on plant response both biomass and nutritional quality