The values of C and N were also showed in Table I. C and N contents in mangrove soils presented the
highest value. For agricultural land use, both C and N contents in field crop soils were the least and the most
values were in paddy field soils. The main reason is the characteristics of soil management which is different
in each cropping system. Usually, harvest together with land opening for field crops have been taken the
most frequencies, comparing with horticulture and paddy fields.