Effect of an organic residue on herbicide field dissipation

摘要

The aim of this work was to study the effect of the application of a solid waste from olive oil production (alperujo) on the movement and persistence of the herbicide diuron [3-(3,4-dichlorophenyl)-l,l-dimethylurea]. The application of alperujo, fresh or composted, to the land has been shown to be an extremely effective contribution to increasing crop yields and to maintaining or improving soil fertility. An experimental olive grove located in Mengibar (Jaen, Spain) was divided into two plots: 1. Plot without organic amendment (blank) and 2. Plot treated with alperujo during 3 years at a rate of 17920 kg of alperujo ha~(-1). Diuron was applied to both plots at a rate of 2 kg ha~(-1)a.i. Triplicates from each plot were sampled at three depths (0-10, 10-20 and 20-30 cm), air-dried, remains of olive leaves, grass roots, and stones removed and sieved through a 5 mm mesh sieve. Diuron was extracted with methanol 1:2 weight:volume ratio, the extracts were evaporated to dryness, resuspended in 2 mL of methanol, filtered and analyzed by HPLC. Higher amounts of diuron were detected at each sampling depth in plots treated with alperujo. The increase in soil organic matter content upon amendment with alperujo slightly increased sorption, suggesting that other factors beside sorption affect diuron degradation rate in organic amended soils.