Rodent damage to rice crops is not affected by the water-saving technique, alternate wetting and drying

Abstract

Rice farmers in Southeast Asia are hesitant to adopt the water-saving technology, Alternate Wetting and Drying (AWD), for fear the practice will lead to increased rodent pest activity, consequently exacerbating yield loss.We examined the effects of AWD on the population dynamics, habitat use and damage levels inflicted on rice crops by the most important rodent pest of rice in Indonesia and the Philippines, Rattus argentiventer, and R. tanezumi, respectively. Rice crop damage levels were not affected by the water management scheme employed. Rodent activity in rice fields was not influenced by water level. Both species tended to use the rice paddies over bunds regardless of water level, indicating that something other than water affects their habitat use, and we argue it is likely that the perceived risk of predation is the primary factor driving habitat use. Activity levels and damage inflicted by rodent pests on rice are, therefore, not correlated. AWD had no effect on breeding and population dynamics of these species.Breeding of R. argentiventer is tied to the growth stages of rice whilst available resource dictates breeding by R. tanezumi. Our findings clearly indicate that rice farmers in both Indonesia and the Philippines have no cause to reject AWD based on concerns that AWD would exacerbate crop losses by rodents. Given AWD is being promoted as a climate-smart technology for rice production in Asia and Africa, we strongly recommend its adoption without concerns that it would aggravate rodent pest impacts in lowland irrigated rice cropping systems.

Risk characteristics, government subsidies and farmers' willingness to adopt water‐saving irrigation techniques*

“…In this paper, hypothesis 1 is verified. The result is in line with Lorica et al (2020). This means that risk-tolerant farmers have a lower willingness to adopt water-saving irrigation techniques, while risk-averse or risk-neutral farmers have a higher willingness to adopt water-saving irrigation techniques, and actively adopt water-saving irrigation technology to deal with the risks to agricultural production.…”

Rodent management and cereal production in Asia: Balancing food security and conservation

“…Results of a study, which examined the effects of AWD on the population dynamics, habitat use, and damage levels inflicted on rice crops by Rattus argentiventer in Indonesia, and R. tanezumi in the Philippines, demonstrate that damage levels on standing rice crop were not affected by the water management scheme used, as shown by replicated damage assessments done on AWD and control fields. Rodent activity and movement, examined using spool‐and‐line tracking, also was not influenced by water level 53 . AWD also had no significant effect on the breeding performance and population dynamics of these species.…”

Optimizing the capture of neophobic rice field rats in lowland Asian rice ecosystems

“…Trapping of rodents was conducted over two rice cropping seasons: the dry season in 2016 and in 2017. Trapping was limited to the dry season as this was concurrent with an investigation the effect of intermittent irrigation on rodent pest ecology (see Lorica, et al 28 …”

“…Trapping of rodents was conducted over two rice cropping seasons: the dry season in 2016 and in 2017. Trapping was limited to the dry season as this was concurrent with an investigation the effect of intermittent irrigation on rodent pest ecology (see Lorica, et al 28 ). Traps were set for four nights during the following four stages of the rice crop: maximum tillering, panicle initiation/booting, flowering, and ripening.…”