PermVeg: A Model to Design Crop Sequences for Permanent Vegetable Production Systems in the Red River Delta, Vietnam

Abstract

The constraints in current vegetable production systems in the Red River Delta, Vietnam, in which vegetables are rotated with flooded rice, called for the design of alternative systems of permanent vegetable production. The practical model, PermVeg, was developed to generate vegetable crop sequences for permanent vegetable production, as based on a set of rules and restrictions. Permanent vegetable production systems were designed based on the following five scenarios: (i) increased profit, (ii) reduced labour requirement, (iii) decreased costs of pesticide use, (iv) improved crop biodiversity and (v) selected crops with low‐perishable products. PermVeg showed that theoretically all selected crop sequences in the different alternative systems increased farmers' income compared to the traditional system. The system with the highest profitability increased profit per hectare per day by a factor of three as compared to the traditional system. Labour requirement in days per hectare per day in a crop sequence also increased in all systems. Except for the system with low costs of pesticide use, permanent vegetable production systems had higher pesticide costs than the traditional, vegetable – flooded rice crop sequence. Given the model outcomes, permanent vegetable production systems can be an option to improve farmers' income, to provide labour opportunities, and, in the case of the high crop biodiversity system, to contribute to the development of sustainable production systems. The PermVeg model can act as a practical tool to rapidly explore crop sequence options and to help farmers' decision‐making.

Intensification of an irrigated rice system in Senegal: Crop rotations, climate risks, sowing dates and varietal adaptation options

“…The option of growing for example 5 crops in 2 years (e.g. see Huong et al (2014)) was not considered because of the increased chance that one of these 5 crops would be a rice crop exposed to severe cold sterility in the cold dry season.…”

“…Compared to models like APSIM and DSSAT (Holzworth et al, 2014;Jones et al, 2003;Keating et al, 2003) (Holzworth et al, 2014;Jones et al, 2003), our model allows for systematic comparison of large numbers of crop rotations, including associated climatic risks. Compared to specialised models for comparing crop rotations (Dogliotti et al, 2003;Huong et al, 2014) our analysis adds a more mechanistic simulation of climatic risks and effects of varietal differences.…”

“…Such carryover effects are less common in continuous irrigated rice systems (Dobermann et al, 2000) in comparison with more vulnerable vegetable systems. In systems where carry-over effects of build-up of pests and diseases play an important role it is better to use models that can simulate these effects, such as ROTAT and PermVeg Dogliotti et al (2003); (Huong et al, 2014;Van Den Berg and Rossing, 2005;Van Den Berg et al, 2006).…”

“…There have been no ideotyping studies in which trait optimisation has been conducted in the crop rotation context. A few models have been proposed for comparing crop rotations (Dogliotti et al, 2003;Huong et al, 2014) but with these it is difficult to simulate in detail climatic risks and effects of varietal differences. With other models such as APSIM and DSSAT crop rotations can be simulated and climatic risks quantified (Jones et al, 2003;Keating et al, 2003) (Holzworth et al, 2014;Jones et al, 2003), but these models do not allow for easily generating and comparing very large numbers of cropping calendar options and varietal traits.…”

Performance of Permanent Vegetable Production Systems Designed with the PermVeg Model for the Red River Delta, Vietnam

“…The disadvantages of the present vegetable production systems called for the development of innovative permanent vegetable production systems for the RRD [10]. Innovative production systems can be designed by using models.…”