Modeling of climate parameters with planting area and pest attacked area on shallots for the development of early warning systems and horticultural cropping schedules

Abstract

One way to mitigate the decrease in shallot production during the off-season is preparing an early warning system and the management of crops planting. This system needs a mathematical model to assist in decision-making. This paper presents a modeling of the relationship between rainfall and planting area and pest attacked area of shallot. The results of the modeling analysis between rainfall and planted area illustrate that an increase of rainfall up to 137.5 mm/month in the lowland area at Brebes, or up to 247.0 mm/month in rainfed or upland area at Garut, is correlated with an increase in the planting area, however then above that rainfall intensity, an increase of rainfall is correlated with a decrease in the planting area. Regression analysis between the Spodoptera exigua attacked the area of the shallot and climate variables illustrates that the attacked area of the shallot decreases if there is an increase in the minimum temperature up to 25.5 °C. Conversely, an increase in the S. exigua attack area of shallot occurs if there is an increase in the duration of solar irradiation of up to 8 hours/day or an increase in a means air humidity of up to 77%. Regression analysis between the Trotol attack area and climate variables illustrates that the Trotol attack area decreases if there is an increase in the average wind speed of up to 5.7 knots. Conversely, an increase in the attacked area of Trotol occurs if there is an increase in rainfall of up to 205 mm/month or an increase in a means air temperature of up to 29.0 °C. This illustrates that climate conditions that are sunny, cool, dry, and calm can reduce the area of attack by S. exigua and Trotol. The threshold values obtained through the above analysis are then used in decision support in the EWS SIPANTARA, namely the Early Warning System and Planting Schedules Management for Horticulture.