Abstract: A long-term study on the effects of different crop rotations on microbial biomass, Dehydrogenase Activity (DHA) and chemical soil properties is reported. The experiment was established in 2000 at the Technical Center of Organic Agriculture Station located in Sousse, Tunisia. The 10 cropping systems (8 organic plots and 2 conventional plots as control) were compared. Differences in microbial biomass Carbon (C) and Nitrogen (N), dehydrogenase activity, available phosphorus, soil bases, Electrical Conductivity (EC) and pH appeared to be related in parts to inputs but perhaps also to differing efficiency of crop rotations at soil fertility maintenance. Overall, the finding indicates that soils in the organic systems had higher microbial biomass, DHA, soil bases, EC and available phosphorus than soils in conventional systems. Organic green house plot, characterized by the most diversified crops (19 crops in 10 years), had the highest levels of microbial biomass C and N, dehydrogenase activity, available phosphorus, exchangeable K and Na and EC. pH was the highest in an organic open field plot which included a combination of crops (perennial, vegetable and field crops) with different deep rooting.
Nadia Elabed, Hanem Grissa, Najla Mousratiand and Mohamed Ben Kheder, 2014. Effect of Different Organic Crop Rotations on Soil Chemical and Biochemical Properties. Agricultural Journal, 9: 51-55.