ロータリ耕うんにおける耕土の移動に関する研究

第2報 耕土の移動割合推定への電気伝導度法の適用

抄録

We discussed two methods to calculate displacement ratio of the soil tilled by rotary tillage in our first report. The present report is concerned with the results of application for the estimation of displacement ratio of the soil tilled by down-cut and up-cut rotary tillages. This paper also deals with the distribution of electrical conductivity on the soils in various upland fields.
The results are as follows.
1) The electrical conductivity of soil at the upland fields under the natural condition showed the value of 74.6-399.0μS/cm and the each field differed remarkably in electrical conductivity. This result was caused by the remaining rate of electolyte produced by chemical fertilizer.
2) From the comparison of electrical conductivity before tillage with one after tillage, the soil displacement in the backward and forward by rotary tillage was confirmed.
3) The large variation of displace-ment ratio of the tilled soil was observed between mesuring points [b₂-b₄ points to stabilize originally] in up-cut rotary experiment. The variation was also remarkably larger than one of down-cut rotary tillage, because of the variation of electrical conductivity of soil mixing KCI.
4) In case of the method by conditional inequality, the ratio of soil displacement is calculated with a certain range. According to the results of this experiment, its range was the value within ±1.1%. This degree of ranges are practically negligible.
5) The difference of soil displace-ment ratio between the method by simultaneous equations of three unknowns and conditional inequa-lity was 0.5% at the most except one case. Therefore, we think that validity of the both methods was proved.
6) Synthesizing the various experiment results of this parper, the electrical conductivity method used the mixture soil of KCI is effective as method to estimate the displacement ratio of soil tilled by rotary tillage.