Change of some soil properties since conversion from conventional to organic farming

Abstract

The transition from conventional to organic agriculture need 12-36 months to offer the benefit in the reduction to nutrients and chemical that can be toxic in excessive amount. Therefore, the objective of this research was to quantify the time required for such changes and which soil properties was most affected. Such a transition was monitored for 12 months from June 2016 to July 2017.  Soil samples were collected from selected crop and field, including vegetables (2 field), annual crops (2 fields), and longan (1 field).  The selected field were managed differently in fertilizer type and application amount. Soil samples were collected from the 0-20 and 40-60 cm. depths in vegetable and annual crop fields, and from 0-20 and 80-100 cm in longan field.  Samples were taken from all field, 0, 2, 4, 6, 8, and 12 months.  The soil samples were analyzed for selected soil properties and content of plant nutrients. The result showed that the content of plant nutrients (Total N, P, K, Ca, Mg Mn, Fe, Zn and Cu) was significantly decreased after 12 months (P<0.01) under organic management, whereas soil pH and organic matter were slightly changed. The decrease of plant nutrients after 12 months was significantly correlated (P<0.01) with soil pH and %Clay, this result indicates that the selected soil properties are the important factors that can lead to the decreased level of plant nutrients in soil during the conversion from conventional to organic agricultural management.  Therefore, these factors should be considered in such conversion.