Effect of Compost on Some Physical Properties of Soil

Abstract

Compost is quite available organic substance source at farm level. Adding organic mater to soils usually results in maintaining soil productivity through improving and/or maintaining physical properties of the soils. The purposes of this sutdy were to determine rate and effect of compost on soil bulk density, size distribution of aggregates, available mosisture capacity, and crop yield as we.. field experiment was conducted on San Sai sandy sam soil at Multiple Cropping Project Station. Faculty fo Agriculture, Chiang Mai University from December, 1982 to September, 1983. Four rates of the compost incorporated into the soil were 0 , 1.5 , 3.0 , and 4.5 tons/rai. Two successive crops were grown under mulched broad bed system. First crop was garlic and the succeeding crop was sweet corn. Results showed that the incorperation rates of 3.0 and 4.5 tons/rai actually decreased bulk density of the soil while the mean weight diameter of soil aggregates was significantly increased. The latter, in turn, indicated that the bigger size of aggregates were quadratically correlated with time after the incorperation. The available moisture capacity of this soil was sharply increased right after the incorperation of the compost and decreased thereafter as a power function with time. the influernce of the compost on such physical soil properties were detected at least 6 months after the incorperation. The apolication rates of 3.0 and 4.5 tons/rai of compost also significantly increased yields of both crops.