Water requirements and crop coefficients of edible, spicy and medicinal herbs and vegetables; a review aimed at supporting plant and water management

Abstract

AbstractTraditional edible, spicy and medicinal herbs rarely are included in studies on water requirements, evapotranspiration and crop coefficients (Kc) of vegetable crops. While the latter refer to large markets and are used worldwide, the former has small and specialized markets. They are very rarely grown in large farms but rather in small farming systems, or just harvested in the wild, and related evapotranspiration (ET) studies are less frequently considered in main journals focused on water management in agriculture. However, there is abundant bibliography covering traditional edible, spicy and medicinal herbs. Following the partition adopted in recently published articles on Kc values, such crops are grouped according to the main part of the plant purposefully harvested: roots, rhizomes and tubers; leaves and flowers; fruits, pods and seeds. Since we focused on Kc and not on the products, and because many crops have simultaneously two usages such as spicy and medicinal, main uses are presented to characterize the crop. Interestingly, the reviewed crop coefficients have values quite similar to those of the more common and popular vegetable crops. The single crop coefficients reviewed, and referring to the initial, mid-season and end-season periods, are tabulated according to the referred groups. In addition, aiming at their use in water management and modelling, crop heights, root depths, fractions of ground cover and fractions of soil water extraction without stress are also tabulated. In conclusion, this review aimed at successfully provide Kc values to be used for computing crop evapotranspiration for irrigation scheduling and crop water management of the referred herbs and vegetables.