Effect of compost mixed with native soil animals and microorganism

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Chipped wood and cattle manure were made into three different composts with native microorganisms (compost M), native soil animals (compost A) and both native microorganisms and animals (compost MA). For comparison, compost without adding these was also made (compost C). The composts were evaluated in terms of growth performances of Komatsuna (Brassica rapa var. peruviridis), sorghum and orchard grass. The komatsuna and sorghum grew slightly better with the composts M and MA. Although the orchard grass performed best with the compost M, the growth was not as well as those with a conventional chemical fertilizer. Species of soil animals were compared among composts that were made of manures of cattle, deer, pigs and chickens and were either turned every 3 days (S-turn) or every month (L-turn) for three months. While mites were far abundance as occupying more than 90% of soil animals in all the S-turn composts, collembola were dominant as 20-30% in the L-turn composts made of cattle and deer manure. Roles of soil animals for nematodes in composts were also investigated in a lettuce field. The more the increase of soil animals in the composts the less the number of nematodes and there was a negative correlation (r=0.695) between the numbers of soil animals and nematodes in the composts. The fields fertilized with composts which were abundant in soil animals had higher numbers of soil animals but less nematodes compared with the fields fertilized with commercially prepared composts. Analyses of soil animals suggested that oribatida and gamasida mites might have suppressed increase of nematodes. These results indicate that fertilizing with composts which are abundant in soil animals will encourage diversity of soil animals and may suppress nematodes in the fertilized field.