Multi-country evidence that crop diversification promotes ecological intensification of agriculture

Abstract

Global food security requires increased crop productivity to meet escalating demand(1-3). Current food production systems are heavily dependent on synthetic inputs that threaten the environment and human well-being(2,4,5). Biodiversity, for instance, is key to the provision of ecosystem services such as pest control(6,7), but is eroded in conventional agricultural systems. Yet the conservation and reinstatement of biodiversity is challenging(5,8,9), and it remains unclear whether the promotion of biodiversity can reduce reliance on inputs without penalizing yields on a regional scale. Here we present results from multi-site field studies replicated in Thailand, China and Vietnam over a period of four years, in which we grew nectar-producing plants around rice fields, and monitored levels of pest infestation, insecticide use and yields. Compiling the data from all sites, we report that this inexpensive intervention significantly reduced populations of two key pests, reduced insecticide applications by 70%, increased grain yields by 5% and delivered an economic advantage of 7.5%. Additional field studies showed that predators and parasitoids of the main rice pests, together with detritivores, were more abundant in the presence of nectar-producing plants. We conclude that a simple diversification approach, in this case the growth of nectar-producing plants, can contribute to the ecological intensification of agricultural systems.

Edge-biased distributions of insects. A review

“…In addition, better understanding of edge-biased distributions may be used to optimize deployments of anti-insect nets in the orchard industry (Castellano et al 2008). Finally, there is a growing body of literature on the potential use of banker plant systems (Zheng et al 2017;Gurr et al 2004Gurr et al , 2012Gurr et al , 2015Gurr et al , 2016Lu et al 2015;Zehnder et al 2007;Hossain et al 2002). In these agricultural systems, the agroecological landscape is manipulated through integration of special plants along crop banks.…”

Integrated pest management for sustainable rice cultivation: a holistic approach

“…For this reason, it is strongly advised not to spray rice fields with insecticides during the first 40 days after transplanting (Kenmore et al, 1984). The success of this heuristic has been borne out by several studies, and most recently by a convincing study from China (Gurr et al, 2016).…”

“…Therefore, several strategies have been devised to restore natural enemies, increase their efficiency and also improve the resilience of rice ecosystems against perturbations -including resilience against climate change (Gurr, 2009;Gurr et al, 2016;Westphal et al, 2015;Horgan et al, 2016d). For example, in a comprehensive study, Kiritani (1999) indicated that most predators and parasitoids in Japanese rice fields were likely to increase the number of generations they achieved by 2 or 3 under average mean monthly temperature increases of 2°C, whereas most rice pests would only increase their generations by one.…”

“…Strategies that create adequate habitat for natural enemies can be included under the broad title of 'agro-ecology'; however, recently the terms 'ecological intensification' (Gurr et al, 2016) and 'ecological engineering' (Gurr, 2009;Horgan et al, 2016d) have gained prominence. Ecological intensification implies increasing the per unit production of farms through the application of ecological principles while at the same time 'sparing' natural areas for biodiversity conservation.…”

“…Ecological intensification implies increasing the per unit production of farms through the application of ecological principles while at the same time 'sparing' natural areas for biodiversity conservation. Though the concept is often used in terms of simple intensification practices, ecological intensification is more correctly associated with diversification of crop production in time and space (Bommarco et al, 2013;Gurr et al, 2016). Unfortunately, evidence suggests that intensifying agricultural lands for food and fibre production is unlikely to lead to sparing of natural areas, particularly in developing Figure 7 Ecological engineering: Luffa (Luffa spp.…”