Berkely Hot Composting Method

Berkeley is a fast, efficient, high-temperature, composting technique which will produce high quality compost in 18 days. This fast method of composting was introduced by Robert D. Raabe, a plant pathology professor at the University of California, Berkeley. The common names for this method are “Berkeley method,” “fast composting,” or “hot composting.”The Berkeley method produces more yields of finished compost than the traditional method. With a little more effort and hard work, one can establish usable, finished compost in as little as two to three weeks. Rather than waiting up to six months to a year or longer for the traditional compost to cure and be ready to use, one can have finished compost in under a month. Berkely composting works in such a short time period because of its having the right ratio of carbon to nitrogen, 30:1. For every unit of nitrogen used by the bacteria in compost, they also use about 30 units of carbon. To keep the pile working efficiently, the compost pile needs to be 30 parts carbon to 1 part nitrogen. The compost microbes and bacteria use the carbon for energy and the nitrogen for protein synthesis. Green materials are sources of nitrogen and include grass clippings, manure, vegetable waste, or green prunings. Brown materials are carbon sources and examples include straw, cardboard, dead leaves, dried grass, or paper.
Trial on Berkely Hot Method of composting was conducted at BRDC Experimental farm, Laitmynsaw, using Paddy straw as brown biomass, grass clippings and garden weeds and cow dung as green biomass. The biomass was chopped into sizes of 1 to 1.5 inch pieces to increase the surface area where the decomposing bacteria can act upon, thus enhancing the rate of decomposition. The ratio has been theoretically estimated below;

C.N Ratio:         Paddy straw + Grass clippings + garden weeds + garden weeds
4
(70: 1) +  (20: 1) + (20: 1) + (16: 1)          =     126           =       33: 1
4
The size of the compost pile has been setup at an optimum size of 1m x1m x 1m. To ensure that aeration takes place, twigs and branches are kept at the bottom of the compost pile for proper supply of oxygen to the aerobic decomposers. 50% moisture is being maintained. This is done by watering the compost pile from above till the compost is just moist enough when squeezed by hand.The temperature of the compost pile has been maintained between 55-65oC.The heat is provided by the respiration of the microorganisms that are breaking down the organic matter. Alternate layer ofgreen and brown biomass is compiled along with cow dung slurry topping at every layer to generate optimum heat in thecompost pile. The compost pile is turned after 4 days from charging and after every two days thereafter till harvest.  Monitoring has been carried out every alternate day for maintaining optimum temperatureand moisture.

Observation and Result:
The compost has been observed to produce a very foul smell at 5 Days after charging. This is due to the loss of nitrogen into the atmosphere through volatilisation. About 1 Kg of sawdust (brown biomass) has been added by sprinkling over the compost while turning in order to increase the carbon substrate for the microbes in order to tap the loss of nitrogen.
The moisture content of the compost was observed to have decreased at a faster rate in the first 10 days. This may be due to the heat generated by the microorganism while breaking down the organic matter.Watering has been done every alternate day while turning to keep it moist. The heat generated from the compost was very high during the first  7-10 days due to the breakdown of green biomass. After 12 days, about 10 Kg of green biomass (nitrogen substrate) has been added in order to maintain generation of heat in the compost pile.

Table 1: Observation table of the Berkely Hot Compost


Particulars

Compost pile 1

Compost Pile 2

Cover

Under thatch house

Under polythene sheet

Amount of green biomass

100 Kg

100 Kg

Amount of brown biomass

50Kg

50Kg

Cowdung

50 Kg

50 Kg

No. of turning

8 times

8 times

No. of days to harvest

18

17

Yield

139 Kg

143 Kg

Unit cost of production

Rs. 5.19/Kg

Rs. 4.8/Kg

Conclusion: The Berkely hot compost is indeed a fast composting method taking about 17-18 days which is feasible even in temperate regions of Meghalaya. The yield in terms of biomass is higher in Berkely hot compost as compared to other conventional composting methods. However, the composting method is labour intensive and requires continuous monitoring. The cost of production is lower in berkely hot compost prepared in an open area using polythene sheet as a cover which also enhances compost pile temperature in temperate areas.

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