Effect of drying method as a pretreatment of compost samples on the test results and their causes were examined, when plant growth inhibition by animal waste compost was evaluated by germination tests in petri dishes. The plant inhibition of extraction liquid from compost was investigated by using the elongation of the root of Komatsuna (Brassica campestris L.). 1) Germination tests were carried out to evaluate the plant growth inhibition of cattle feces, hog feces, chicken manure and their composts treated with draft drying at 50℃ and freeze-drying. Some samples, especially pig feces and its compost after draft drying showed lower plant inhibition than the undried samples. On the contrary, when the freeze-dried samples were used, the results of the germination test were similar to those for the non-dried samples. Draft drying causes a larger decrease in lower fatty acids, phenolic acids and ammonium nitrogen in the samples than freeze-drying. When the results of the germination test were different according to the drying methods, there were considerable differences in lower fatty acids, ammonium nitrogen and electric conductivity of the aqueous extracts of the compost. 2) Germination tests using solutions with lower fatty acids, phenolic acids and ammonia were carried out. Within the analysis values in extraction liquid of the compost used in above-mentioned experiment, lower fatty acids showed the most remarkable plant inhibition. 3) Germination tests and analysis of components were done on the fractionation of aqueous extract of pig feces which was divided by gel chromatography. The fractions which showed plant inhibition contained high levels of lower fatty acids. Also a highly negative correlation was observed between the elongation of the root of Komatsuna and lower fatty acid concentrations. 4) In conclusion, freeze-drying seemed to be a desirable method of drying samples for evaluating plant growth inhibitory of the animal waste compost by germination test, because it can decrease the loss in volatile phytotoxic substances represented for lower fatty acid.

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Exchangeable bases and related properties were important indicators of soil conditions. Under natural conditions, most Japanese upland soils are acid and have low exchangeable bases. However, on arable land, soil acidity had been reclaimed by liming and chemical fertilizer application. Under those kinds of agricultural practices, imbalance of bases, for example low Mg-K ratio, have been warned against in recent decades. General monitoring survey of soil properties of arable land were carried out by the Ministry of Agriculture and prefecture agricultural experiment stations from 1979 to 1997. In this report, we describe the state of exchangeable bases and related properties from the monitoring survey data. Exchangeable Ca switched from increase to decrease during the monitoring period in upland crop fields and orchards. The pH showed decreasing trend on orchards and tea gardens. Exchangeable Mg also showed decrease on paddy fields and orchards. On the other hand, exchangeable K showed rather higher increasing trend than Ca and Mg. Exchangeable Mg was clearly decreased in fine textured Gley soils of paddy fields. On the balance of exchangeable bases, ratio of Mg/K was decreased and stayed at low level in most land uses. Base saturation stayed at rather high level during the period, especially on greenhouses and vegetable fields.

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The morphological, physical, chemical and mineralogical properties of Red-yellow soils (paleo-Red soils) in southern Kyushu were investigated, and the forming period of these soils was deduced from the relationship between distribution pattern and geomorphic history. The results obtained were as follows : 1. In the Miyazaki Plain, the Izumi Plain and Tanegashima, the distribution of the paleo-Red soils was limited to the old aged geomorphic surface, such as the higher terrace and the hilly terrain. On the higher terrace, the paleo-Red soils were buried under the brown loam layer in the Miyazaki Plain and Tanegashima. 2. The paleo-Red soils were characterized by high clay content, low organic carbon content, and, except for the buried portions, low base saturation of cation exchange capacity (CEC). The clay mineral composition included mainly kaolin mineral, the value of CEC per clay was low. The free iron oxides had an activity ratio of less than 0.4 and a crystallinity ratio of more than 0.5. These values ranged within those of the paleo-Red soils in other areas of Japan. 3. To estimate the formation period of the paleo-Red soils based upon the latest data on the landform evolution, it was clarified that the paleo-Red soils were formed from 400-500 to 110-130 ka.

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A lysimeter study in combination with ^<15>N-tracer method was carried out for 3 years and 9 months to investigate the fate of nitrogen derived from cattle manure sawdust compost and coated fertilizer which were applied to vegetables grown in upland Andosol. Of total amount of input nitrogen derived from cattle manure sawdust compost, 1.15% was leached as nitrate, 12.8% was taken up by plants, 68.1% remained in soil, and 18.0% was unaccounted-for which was estimated to be the result of denitrification and volatilization. Of total amount of input nitrogen derived from coated fertilizer, 2.55% was leached as nitrate, 65.3% was taken up by plants, 16.2% remained in soil, and 15.9% was unaccounted-for which was estimated to be the result of denitrification and volatilization.

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The influence of nitrogen application rate on the behavior of inorganic nitrogen in the tea field of yellow soil was examined. Four experimental plots were prepared in August 1998, nitrogen application amounts of which were 0, 30, 60, and 90 g m^<-2> respectively. The soil pH, inorganic nitrogen of surface soil, and inorganic nitrogen of soil solution at the depth of 50 cm between the tea hedges were measured sinbe August 1999 to August 2000. 1) The pH of the surface soil between tea hedges appeared to be lower in the plots with high applications amount of nitrogen fertilizer than those of no or low nitrogen treatments. The ammonium in the surface soil increased immediately after applying compound fertilizer and ammonium sulfate in spring. The increments rose with the amount of nitrogen applied. Nitrate in the surface soil differed between the plots of no nitrogen and those of nitrogen treatments, but the difference among the N-treatments was not significant. 2) The ammonium in the soil solution differed in the two period.s of September and from March to July. In the soil solution of the plot with much nitrogen application higher concentration of ammonium occurred. 3) The CEC of the soil was measured under different pH in the laboratory. The CEC of the surface soil decreased apparently under low pH condition, which enhanced the ammonium mobilization in the plots with much nitrogen application. 4) The leached nitrogen collected by the ion exchange resin at the depth of 50 cm between the hedges was examined after one year's experiment. The collected ammonium and nitrate increased with the increase of fertilizer nitrogen, and so did the ratio of ammonium to nitrate. 5) The results suggested that in the tea field of yellow soil, not only nitrate but also ammonium became mobile with the increase of nitrogen fertilizer application, and more ammonium was absorbed by tea roots, especially at subsoil. But the remaining nitrogen might leach and consequently put a heavy load on the environment.

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