imafan26
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Compost is Good Stuff

I think we all agree that compost is good for the garden.

It adds organic matter that feeds the soil

Anecdotetally plants seem healthier with compost added? Or does is it mainly and adjunct by feeding the soil organisms the soil organisms in turn improve the growth and in turn keep the plants looking healthier.

https://www.uvm.edu/vtvegandberry/facts ... sttea.html

People have passionate opinions about compost and organic vs synthetic but research is difficult to do because of the inconsistent quality of most organic composts and fertilizers. It creates too many variables to control and makes the experiments difficult to repeat. Conclusions based upon a single test that is not reproduceable with many uncontrolled variables can be misleading or do not take into account that some other variable may be responsible for the result.

There can be a middle ground. organic and synthetic can cooexist and can be better together than used separately provided they are used correctly.


There is little composting research that is based on a long term study but I found one
https://www.ct.gov/caes/lib/caes/documen ... s/b966.pdf

1 Compost and some synthetic fertilizer usually a reduced rate had the highest yields followed by organic + organic fertilizers and no compost + synthetic fertilizer and the control was no compost
2 compost needs to be added every year and yields are best after three years of adding compost. However yields drop quickly if compost is not added. More needs to be added to sandy soils
3. On vegetable plots where compost alone was added for at least 3 consecutive years, yield was only 1 percent less than the unamended but fully fertilized control plot.
4. Compost added in the Spring was best. Soil organisms activity varies with temperature so they are less active in the fall and winter so release fewer nutrients.
5. Compost improves water holding capacity, but in soil that are wet when planted in the Spring they warm up slower and can hold too much water and increase seed rot.
6. 2 inches of compost can be applied as mulch for weed control although not 100% effective it does reduce weeds for up to a year.
7 Undecomposed leaves can be used as soil amendments. There is no gain over using composted leaves but no real detriments. However as the leaves decompose they may need more nitrogen fertilizer.
8. leguminous cover crops planted in the fall and compost applied with full rate fertilizer had the greatest yield in corn crops.
8 Manure based composts should be limited to 1 inch for 3 consecutive years to prevent nitrogen leaching. No manure in the fourth year.
9. Sheet mulching can grow a sufficient crop with the advantage of not having to maintain a compost pile. However yields are not as great as when compost is used.
10. Compost is not a fertilizer. Unlike inorganic fertilizers the nutrients in composts are not readily available to plants. However, soil organisms release nutrients from compost at a slower rate over a longer period of time. Nutrient release is dependent on organizms activity. Soil organisms release nutrients quicker in warm weather when plants are actively growing.
11. Synthetic fertilizers can be reduced by almost half if compost is also added every year.

12. Synthetic fertilizers increase yields but can also be detrimental to soil life in some circumstances but synthetic fertilizers are compatible with a healthy soil if everything is in balance.
https://www.agriculturesnetwork.org/maga ... ertilizers
Happy gardening in Hawaii. Gardens are where people grow.

toxcrusadr
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Re: Compost is Good Stuff

Great stuff, thanks for posting. The stuff is almost magic!

I did find these two to be a little bit contradictory:

3. On vegetable plots where compost alone was added for at least 3 consecutive years, yield was only 1 percent less than the unamended but fully fertilized control plot.

10. Compost is not a fertilizer. Unlike inorganic fertilizers the nutrients in composts are not readily available to plants. However, soil organisms release nutrients from compost at a slower rate over a longer period of time. Nutrient release is dependent on organizms activity. Soil organisms release nutrients quicker in warm weather when plants are actively growing.

Compost obviously has nutrient value because if you test it similar to a soil for NPK, it will have some. Not very much, but then again you add it by the wheelbarrow load rather than sprinkling like you do with chemical fertilizers. The test methods used (extraction into a solution) give a result for 'soluble' or 'available' nutrients. So I would not agree that the nutrients in compost are not available to plants. I added tons of compost to my clay for 20 years and the P and K levels got so high (again, based on lab tests), I had to cut back to avoid excessive levels.

Anyway, I'm only griping about 1 point out of 12 which is pretty darn good. :cool:
Tox

Mr green
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Re: Compost is Good Stuff

The biggest problem i see is the focusing on large yields, and no focus on quality tho.

And yes 3 and 10 is very contradictory, but then again this test doesnt seem to consider soil health. And for example bacteria that binds nitrogen from the air into the soil and these bacteria run from synthetics like it was the pest.

Number 7 is also very badly stated, there is lots of gain adding leaf mulch, worms that areate the soil and gives you wormcastings for example. Saying there is no gain is very untrue tho, but again they are only focusing on yields it seems. And for example adding compost and covering it with leaf mulch would be beneficial and increasing the amount of nutrients from the compost that stay in the soil.

12 Is also a bit contradictory by itself.

Will read the whole report when i have more time. Lots of things to do now that spring has come!
Nature does not hurry, yet everything is accomplished - Lao Tzu

imafan26
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Re: Compost is Good Stuff

The multi year study measured yields to determine the effectiveness of synthetic vs organic fertilyzers

If you design a study you have to set parameters and control as many variables as possible so you can make a reasonable conclusion. The multiyear study used yields as a measure of effectiveness.

If you wanted to measure soil health you would have to set up different measures such as soil microbe counts, soil tests, yields for example. A good test has a hypothesis that is specific and parameters that weed out as many variables as possible. A good design is a fair test. You start with the same virgin field with the same soil and soil microbia counts, same rainfall, temperatures, crops and the test must be repeatable multiple times. It isn't a fair test to use microbe counts as a measure if one field has a clear advantage over the other from the outset or if the fields are planting different crops at different times of the year or in different locations with different soil types. Too many variables. Organic composts and fertilizers are also variable from batch to batch so you would have to test each batch to get comparable data. I would like to see a soil health test that measure not only organic, synthetic, but also include the hybrid organic + synthetic.

Compost is not considered fertilizer because of the low NPK (usually less than one) . The nutrients in organic fertilizers and composts are not all readily available to plants just as soil tests measure total amounts of the elements present but unless they are only measuring the available elements, some may be locked up. The study did say that it was actually the activity of the soil microbes that releases the nutrients and since a lot more compost and organic fertilizer needs to be added to be comparable to synthetic NPK and most people do add a lot more, by volume so the total nutrients added will be determined by the volume added and the NPK in the batch of compost you have. The NPK of compost looks to be determined based on a cubic yard.
https://soiltest.umass.edu/fact-sheets/ ... st-results

It is actually the soil microbes' activity that makes most of the nutrients available to plants. It can take years for all of the nutrients in compost and organic fertilizers to be released, but the effects are cumulative, so the more you add the more is available. It also explains why it takes about 3 years for the nutrient release to be maximized. Not all the nutrients come from composts and fertilizers. There are soil microbes that fix additional nitrogen from the air as well as denitrifying bacteria that return it back to the air.

It is why the statements are not really contradictory if you take into account the cumulative effects of the slow release by soil organisms and the volumes of compost that have to be added every year to have enough enough available nutrition for plants.

Phosphorus is one of those elements that is plentiful in the soil but not readily available to plants. One of the drawbacks of using organic materials is that you will have a different analysis from batch to batch and if you use different feedstocks, different time of the year and different stages of the composting process, it will analyze differently. There are very few pure organic sources for elements. It is hard to get a phosphorus free compost for example. Blood meal comes the closest to pure nitrogen.

No. 12 could be stated better, but if you read the link it does say that organics are needed for a healthy productive soil but especially where non-native crops are grown synthetics plus organic works better and organic inputs reduce the amount of expensive fertilizer that needs to be added. Nothing about soil is either or, everything in nature interacts. Organics do help the soil but does not get the highest yield to feed a hungry population. Expensive fertilizers are beyond the reach of poor farmers and everyone agrees that conventional farming in the long run uses soil only to support the plants and depends on water and fertilizer to get yields. Ignoring the soil in the long run hurts yields and ruins the soil. However, poor eroded soils can't even supply enough nutrients for a green manure crops without some fertilizer added and heavy monocrop farming with heavy use of synthetic fertilizers eventually will cause crop failure but can be redressed by adding organic matter and micronutrients to make the fields productive again.
Balance is the key to healthy productive soils. Ecological recovery can be achieved with a balance between organic and synthetic inputs. The soil is an ecosystem in itself and part of the larger environmental ecosytem. Everything interacts and each component has an effect on the system and a response is generated. The real trick is to balance inputs and outputs to keep things running smoothly.
Happy gardening in Hawaii. Gardens are where people grow.

Mr green
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Re: Compost is Good Stuff

I still think its contradictory, just because its slowrelease (specially with low microbial activity) does not mean its not fertilizing the soil, as you stated it clearly does just that. The difference is feeding the soil, not the plants directly.

And it can take years yes, specially if you have a soil in bad "health" thats why its an important factor to count with. To leave such factors out is making it easier to do the study yes thats true, but its not making it a better study in anyway, i would say the opposite removing important factors is abit like shooting in the dark.

Only considering NPK is also quite stoneage in my humble opinion, we all know by know that healthy food contains alot more, but does not require alot more to grow big economic yields and here lies the problems, most big farmers don't give a EDITED - PLEASE REPORT THIS POST what the food contains they are interested in the maximum weight per acre, and this study seems to support just that. Thus their interested in taking out more than they actually give back to the soil, wich in the end is bad for all of us. Nutrient deficient food is the biggest concern and is proven in many studies that its about 50% of the nutrients in many crops today as compared to 50-70 years ago when modern agriculture really began (atleast where im at) that means you need to eat 2 carrots instead of 1 to get the same amount of nutrients while having to digest twice the amount of fibers etc (waste) thus wasting more energy in the process big problem in my opinion, unless you like to be tired and overeat.

As stated before i care little about growing big crops if their nutrient deficient compared to abit smaller crops. And as proven in in many studies about nutrients in the food today versus 50-70 years ago is half, i rather have a bit smaller yields and get them packed with all the nutrients my body desires, thus having to eat less to get the same its actually a win then with the smaller yields.
Nature does not hurry, yet everything is accomplished - Lao Tzu

toxcrusadr
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Re: Compost is Good Stuff

@imafan: I understand your analysis. This is advance composting and soil science, and my comments were along the lines of trying to make sure that the less experienced don't get the wrong ideas about compost because some of this stuff is pretty technical.

@Mr green: Interesting that you interpret the study as "fertilizer is just as good as compost" because I saw it as "compost is just as good as fertilizer," and therefore the bottom line was pro-compost for me. :)
Tox

imafan26
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Re: Compost is Good Stuff

Thankyou Mr. Green and Toxcrusadr for your input.

Mr. Green there are government studies that have said that nutritionally there isn't a lot of difference nutrient wise between organic and synthetic crops if they are growing the same thing. What was said that plant breeding concentrated more on looks and disease resistance not on nutrition, so it is possible to haver bred out some of the more healthy factors. Unfortunately most of these conclusions were from sources that are either pro organic or non-scientific (New York Times ). They refer to studies without referencing them so they cannot be tracked back. Most of the information comes from pro organic organizations rather than government or scientific sources.

Organics do have an edge over safety because they are limited in the pesticides that they are allowed to use. However, conventional pesticide residues are within safe limits if the days to harvest are adhered to. Even organic produce can have pesticide residues. Organic products are not statistically significantly different from conventional produce in terms of nutrient values, however organic produce has something like 30% less likely to have pesticide residues. Healthwise, less exposure to pesticides is better. There is no statistically significant difference between an organic or conventional diet. Organic foods may reduce diseases associated with antibiotic resistance, but there is no real proof to say it is so. Doctors and nutritionists agree regardless of source a diet rich in a variety of fruits, vegetables, whole grains and low fat foods was what was the most important thing for children's health.

The highest levels of residues found were in canned and fresh beans, strawberries, celery, peaches and nectarines. The majority were still within acceptable levels. It was a long PDF but it did not separate out organic from conventional production. Samples came from markets in several states. Most of the samples showed 0 residues.

https://www.health.harvard.edu/blog/orga ... 1209055264
https://www.ams.usda.gov/sites/default/ ... tStudy.pdf
https://ehp.niehs.nih.gov/120-a458/

Compost is low in nutrients by itself but it does have some nutrients. If you add enough volume you will get more just not all at once. If you started a new garden and just added compost; no manure and no supplements of compost tea, fish emulsion, kelp meal, bokashi, bone meal, blood meal, bat guano, etc. your plants would not fare very well for very long.
The value of compost is not in its nutrient content but in its ability to improve soil tilth, moisture holding capacity,aeration, make nutrients more available, buffer pH, attract more soil microbes, earthworms and other creatures, and contains micronutrients ( so does a complete fertilizer with micros like citrus food), and plants appear healthier.
https://web.extension.illinois.edu/homec ... nefits.cfm
Happy gardening in Hawaii. Gardens are where people grow.

toxcrusadr
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Re: Compost is Good Stuff

Awesome post imafan. I like when things are backed up by real science. I also feel OK conceding (based on science) that in some ways compost or organic gardening methods don't produce a superior product. The reason is that there are so many good reasons to compost our wastes and feed our soils this way that it's just the right thing to do, regardless of whether my peppers have more vitamin C than my neighbors'. If we can't find a dozen good reasons to do it, there is no point in clinging to unproven reasons. But we do have the other reasons, so there's no need.
Tox

imafan26
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Re: Compost is Good Stuff

I totally agree. That is why compost is good. It does not by itself contain a lot of nutrients unless you add a lot of volume, but it does feed the soil community and whether you use synthetic or organic gardening methods in the long run it is a healthy soil community that makes it sustainable.

In the dust bowl days of the 1930's farms just blew away because they did not do anything to conserve or maintain the health of the soil. They kept planting the same crops over and over and not putting back in what they took out. Extended, drought, high winds and the lack of deep rooted grass to hold the soil because of over grazing. Mechanized farming and farming practices that did not conserve soil from erosion led to the collapse of the region. They started with fertile soil, but exploited it over 4 generations, when the drought hit, they bare soil just blew away.
https://www.history.com/topics/dust-bowl

Climate change is now and we have to do what we can to be good stewards of the land. This means keeping the soil healthy and for many changing what we grow and the way we grow them. A hotter climate, in some areas more drought while others will experience more storms, we have to all adapt by selecting plants that will be more heat and drought resistant and conserve water in the soil when water becomes scarce. Adding compost to feed the soil and to hold on to moisture and store nutrients. Rain gardens and natural sumps to prevent and slow runoff that pollutes streams and oceans; fertilizer management to prevent pollution of ground water sources. Dairies, stables, farms that keep animals concentrated in a small area need to manage manure wastes to prevent pollution from that source. Planting diverse gardens that provide habitat for beneficial insects and animals and changing the way we garden to keep things in balance. Less monocropping and more interplanting and no til or minimal tilling to avoid disturbing the soil community as much as possible. Mulching to conserve soil moisture and eventually to add more organic matter. By supporting the soil community and feeding the soil and for me a soil test every few years to see how I am doing, I can successfully grow a number of different crops in my small gardens using less commercial fertilizer and fewer pesticides yet getting good yields and minimal damage by selecting the most suitable plants.

Adding compost is one of the easiest things to do (well, not on my back). It is the food that feeds the soil that eventually feeds us.
Happy gardening in Hawaii. Gardens are where people grow.



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