The use of agrochemicals is expected to increase with the global expansion of oil palm plantations. In line with environmentally sustainable palm oil certification, targeted grazing can minimize the dependency on herbicides for controlling weeds in plantations. Here, we show for the first time that targeted grazing would control weeds and improve biodiversity of desired animal species. We sampled birds at 45 oil palm plantations in Peninsular Malaysia that were systematically grazed, non-systematically grazed, or herbicidecontrolled plantations without cattle grazing. We found that bird species richness increased with size of grazing area, but decreased with number of cattle. Bird abundance was higher in the systematic grazing system, but negatively related to number of cattle. These factors explained 18.41 and 25.34% of the observed variations in bird species richness and abundance, respectively. Our findings suggest that targeted cattle grazing can be instrumental for transforming conventional oil palm agriculture into more biodiversity-friendly agroecosystems. Targeted grazing is likely to be practical under field conditions in major palm oil producing countries. In addition, the use of targeted grazing as a biological control method for weeds would be welcomed by palm oil consumers and encouraged by sustainable palm oil certification bodies such as the Roundtable on Sustainable Palm Oil (RSPO).

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Herbage dry matter (DM) production, botanical composition and nutritive value were compared over 2 years under irrigation and dairy cow grazing for simple two-species grass (perennial ryegrass or tall fescue)- white clover pastures and diverse pastures where herbs (chicory and plantain), legumes (red clover and lucerne) and prairie grass were added to the simple mixtures. Averaged over 2 years, annual herbage DM production was 1.62 t DM/ha greater in diverse (16.77 t DM/ ha) than simple (15.15 t DM/ha) pastures, primarily reflecting greater DM production in summer. Diverse pastures had lower metabolisable energy (ME) (12.0 vs 12.2 MJ ME/kg DM) and neutral detergent fibre (301 vs 368 g/kg DM) content than simple pastures, although the total ME produced per year was greater in diverse than simple pastures (202 vs 185 GJ ME/ha). Ryegrassbased pastures had higher annual DM production than tall fescue-based pastures in the first but not second year. The results indicate that including additional legumes and herbs with simple grass-white clover pastures may increase total DM and ME production of dairy pastures under irrigation. Keywords: Lolium perenne L., Festuca arundinacea, herbs, legumes, pasture mixtures, diversity, nutritive value

The largest contributor to nitrogen (N) leaching from ryegrass-clover pasture based dairy farms is the surplus feed N excreted as urinary N (UN) onto pastures. Pastures consisting of mixtures of ryegrass, herbs and legumes (diverse pastures) have shown potential to yield similar DM, but with a lower N content and a higher water soluble carbohydrate : crude protein ratio compared with standard ryegrass–clover pastures. These diverse pastures have shown the potential to lower the UN excreted by dairy cows in short-term, late-lactation studies. This modelling study was designed to scale the results from component studies up to farm and over a full season to evaluate the potential of diverse pastures to become a suitable strategy for reducing N leaching on New Zealand dairy farms. The Molly cow model was tested against observed data from one indoor and one outdoor study where feeding diverse pasture resulted in UN (N excreted in urine g/day) reductions of 50% and 17%, respectively. The model predicted UN reductions of 23% and 17%. Farm-scale model scenarios, where 20% or 50% of the farm was sown with diverse pastures, resulted in 2% and 6% reductions in UN deposited onto paddocks. This reduction was smaller than expected with some system interactions related to seasonal feed supply, diet composition and total N intake being likely to play a role. The reduction in UN onto paddocks, together with a dilution effect from larger urine volumes per cow per day as a result of lower DM% of diverse pastures, resulted in N leaching reductions of 11% and 19% for the two scenarios, respectively. This potential to reduce N leaching needs to be evaluated further in the context of farm profitability when other aspects of diverse pastures such as yield, persistency, drought resistance and ability to extract N from the soil becomes part of the farm-system analysis.

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In human‐modified landscapes, important ecological functions such as predation are negatively affected by anthropogenic activities, including the use of pesticides and habitat degradation. Predation of insect pests is an indicator of healthy ecosystem functioning, which provides important ecosystem services, especially for agricultural systems. In this study, we compare predation attempts from arthropods, mammals, and birds on artificial caterpillars in the understory, between three tropical agricultural land‐use types: oil palm plantations, rubber tree plantations, and fruit orchards. We collected a range of local and landscape‐scale data including undergrowth vegetation structure; elevation; proximity to forest; and canopy cover in order to understand how environmental variables can affect predation. In all three land‐use types, our results showed that arthropods and mammals were important predators of artificial caterpillars and there was little predation by birds. We did not find any effect of the environmental variables on predation. There was an interactive effect between land‐use type and predator type. Predation by mammals was considerably higher in fruit orchards and rubber tree than in oil palm plantations, likely due to their ability to support higher abundances of insectivorous mammals. In order to maintain or enhance natural pest control in these common tropical agricultural land‐use types, management practices that benefit insectivorous animals should be introduced, such as the reduction of pesticides, improvement of understory vegetation, and local and landscape heterogeneity.

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