Fats cause digestion problems for the bacteria that work on your compost and that slows them down and that is why many people do not add fats to the compost. In small quantities fats should not be a problem, but what is a small quanity depends on the volume of compost. A cup of fat in a garbage can composter will be problematic while the same amount in a 4 x 4 x 4 compost pile will hardly cause the bacteria to blink. Bones are very dense and can take years for the bacteria in a compost pile to digest. Bones are more difficult then wood is to compost. Bones go into my compost and usually when that mix is pulled to use the bones are sorted out and run through the shredder. People have been putting bone meal into their compost, and soil, for years, but that is ground up bones not whole ones. There is no real problmne with composting bones either, just be aware they may stay around for several years in the form you put them into the compost.

My comments are in bold italic. My conclusion from this 1976 study is that 16% of soil microbes are completely wiped out by even small doses of these herbicides. These get kind of technical... http://www.springerlink.com/content/ng082l7058813182/ Influence of four herbicides on the algal flora of a prairie soil D. R. Cullimore1 and A. E. McCann1 (1) Department of Biology, University of Regina, S4S OA2 Saskatchewan, Canada Received: 11 May 1976 Summary Four herbicides (2,4-D, trifluralin, MCPA and TCA) were applied at two concentration levels to isolated cores of a grassland loam soil. After herbicide contact times of 1, 5, and 20 days, samples were taken and the algal population estimated both quantitatively and qualitatively using two selective mineral salts media. Thirty-one genera of algae were identified as occurring in the soil. Of these, Chlamydomonas, Chlorococcum, Hormidium, Palmella, and Ulothrix proved to be so sensitive to the four herbicides that they were rarely isolated from the cores after treatment. Other algal genera were found to be less sensitive, and the theoretical percentile sensitivity of fifteen genera was calculated. Chlorella, Lyngbya, Nostoc, and Hantzschia were found to be the most resistant algae, having percentile sensitivity to all four herbicides of less than 50%. Some algal genera varied in their sensitivity to each of the herbicides. Scytonema was sensitive to all of the herbicides except 2,4-D, while Tolypothrix showed a greater tolerance to MCPA. In the top cm of the soil, the reduction in cell numbers experienced by many algal genera after herbicide treatment was offset by an increase in the population of Chlorella. Stichococcus, Oscillatoria, and Spongiochloris all exhibited the ability to recover rapidly after a reduction in cell numbers resulting from the application of one of the herbicides. An overall reduction in cell numbers was noted for the algae growing preferentially on a nitrogen-free medium (i.e. potential nitrogen-fixers). re]19760511 Here's a 2005 study that showed similar results but not quantified... http://www.scielo.br/scielo.php?pid=S0100-83582005000400017&script=sci_abstract SANTOS, J.B., JAKELAITIS, A., SILVA, A.A. et al. Microbial activity in soil after herbicide application under no-tillage and conventional planting systems. Planta daninha, Oct./Dec. 2005, vol.23, no.4, p.683-691. ISSN 0100-8358. This study evaluated the effect of the herbicides fluazifop-p-butyl and fomesafen in five concentrations (0.0; 1.05; 2.10; 4.20 and 8.40 g g-1) and their mixture (Robust®) on microbial activity in soil submitted to no-tillage system (NTS) and conventional planting system (CPS). Samples in Erlenmeyer of 250 mL were treated with herbicide and wetted to field capacity. After every four days, microbial respiration was quantified through CO2 left by the soil. Metabolic quotient (qCO2) and carbon of microbial biomass (CMB) were determined 20 days after incubation. Under NTS, microbial activity increased with fluazifop-p-butyl and decreased with up to 4.20 µg g-1 of fomesafen. Herbicide effect on soil microbial respiration and CMB under CPS was below that observed under NTS.CMB increased with the increase of fluazifop-p-butyl concentration and decrease of fomesafen concentration. The mixture (Robust®) did not influence CMB under NTS, but it was reduced under CPS in higher concentrations. Under NTS, qCO2 increased with the herbicide concentrations, without, however, varying between them. Under CPS, herbicide mixture provided a higher qCO2. In general, the herbicides provided a negative effect on microbial biomass, proportional to the concentrations applied, being smaller in soil under NTS than in soil under CPS. This one you'll have to read. Some microbes increase, some decrease. Here's the final paragraph and the conclusion. http://www.ath.aegean.gr/srcosmos/showpub.aspx?aa=5462 EFFECT OF ATRAZINE ON MICROBIAL ACTIVITY IN SOIL AND MAIZE RHIZOSPHERE Milosevic Nada,* Govedarica Mitar** and Cvijanovic Gorica*** According to Greaves and Malkomes [7], most groups of microorganisms regain their population size 30 days after herbicide application. If inhibition of microbiological activity persists longer than 60 days, the ecological balance is considered to be disturbed. Microorganisms are constituting elements of the environment. Their abundance, enzymatic activity and biodiversity are good indicators of the balance in the agro-ecological system. CONCLUSION Atrazine affected the biological activity of the soil. The impact of atrazine depended on its dose and date of testing. It was observed that atrazine cause highest reduction in the total number of microorganisms, the number of azotobaters and DHA in the period of 60 days after application. The higher doses of the herbicide were more detrimental for the total number of microorganisms than the lower dose. Atrazine application increased the numbers of actinomycetes and fungi, especially the higher dose. This one shows a decrease in soil biomass after using a herbicide... http://www.springerlink.com/content/fu8wu864f6x0078r/ Relationship between rimsulfuron degradation and microbial biomass content in a clay loam soil Authors C. Vischetti, P. Perucci, L. Scarponi Abstract The present research was conducted to determine the relationship between the degradation of rimsulfuron and soil microbial biomass C in a laboratory-incubated clay loam soil (pH=8.1; organic matter=2.1%) under different conditions and at different initial dosages (field rate, 10 and 100 times the field rate). The half-life values varied between 0.4 and 103.4 days depending on temperature, soil moisture and initial dose. Evidence suggested that rimsulfuron could pose environmental risks in cold and dry climatic conditions. Significant decreases in microbial biomass C content in rimsulfuron-treated soil, compared to untreated soil, were observed initially, especially at higher temperatures and low moisture levels, but never exceeded 20.3% of that in control soil. The microbial biomass C content then returned to initial values at varying times depending on incubation conditions. The relationship between herbicide degradation and microbial biomass C content gave parabolic curves (P

Before you fertilize I'd recommend a soil test, especially for vegetable gardens so you will know exactly which nutrients your soil is lacking. This way you can add the appropriate organic fertilizer necessary. I like to say you get out of your garden what you put into it...in other words if you want organically grown vegetables use organic fertizers and if you want chemically grown vegetables use chemical fertizers. Plants really don't know the difference and they will take up what nutrients they need. But if a certain nutrient is missing that is needed for the plant to take up another that could be a problem, that is why soil tests are so important.

If you have sandy soil with very little to no organic matter any nutrients you apply, no matter the source, will flow through and into the ground water (causing pollution) and wasting your money because that food will not be feeding your plant. Adding organic matter to sand fills in the pore spaces and helps hold both nutrients and moisture in the root zone so the plants can uptake what they need. If you have clay soil with little to no orgnaic amtter in that soil any nutrients you apply, no matter the source, will be locked onto the clay particles and will not be available to the plants. Adding organic matter will seperate the clay particles, change the electric charge on the clay particles so the nutrients are not locked on, the plants roots will be able to move around to find both food and nutrients more freely so the plants grow stronger and healthier. You do not need to add organic matter to your soil but if you do you may just as well take the money you would spend for "fertilzier" and through it into the nearest landfill for all the good it will do.