SOIL FERTILITY AND ESSENTIAL OIL PRODUCTION IN CITRONELLA CULTIVATION IRRIGATED WITH DAIRY CATTLE WASTEWATER (DCW)

Abstract

Background. Due to the negative impacts caused by the inadequate disposal of dairy cattle wastewater (DCW), alternatives are needed to reduce the environmental impact. Objective. The aim of this study was to evaluate the effects of applying DCW via fertigation on the physical and chemical characteristics of the soil and on the production of citronella essential oil (Cymbopogon nardus (L.) Rendle). Methodology. Nitrogen (N) was adopted as a reference element and DCW equivalent amount to be applied so as to replace this element was calculated. Doses equivalent to 100%, 200%, 300% and 400% of the recommended N concentration were applied. After six months of cultivation, the availability of nutrients for the soil and its relationship to the production of essential oil were evaluated. Results. The results showed that DCW supply for citronella cultivation was effective and, in most parameters, equivalent to the treatment with mineral fertilization. Besides, there was no significant difference between the treatments, regarding the quantity and quality of essential oil production. Implications: DCW does not increase the yield of essential oil, but it is an excellent alternative for the supply of nutrients in degraded soils. Conclusions. Therefore, DCW use for fertigation of citronella cultivation is a valid alternative, helping to mitigate the impacts related to its disposal. However, new studies with a longer evaluation period and other types of soil are suggested.