Alley-cropping system increases vegetation heterogeneity and moderates extreme microclimates in oil palm plantations

Abstract

Forest conversion to oil palm plantation is causing a major loss of biodiversity in Southeast Asia and other tropical regions. Oil palm plantations have less biodiversity because of their simplified vegetation, human disturbances, and extreme microclimate conditions. Alleycropping system incorporates a secondary crop in the alleys between the main crops. In some cases alley-cropping can result in a greater vegetation structural complexity, thus potentially providing agricultural and ecological benefits, including: buffering against weather extremes, reduction in soil erosion, increased biodiversity, and increased nutrient and water-use efficiency. In this study, we compared vegetation structure (height and cover of vegetation), microclimate (air temperature, relative humidity, light intensity and wind speed), and soil conditions (soil surface temperature, soil pH and soil moisture) across a range of alley-cropping systems and two ages of monoculture oil palm. We found that alley-cropping system had varied structural complexity across different crops when compared to oil palm monoculture system. Careful selection of crops was essential, with black pepper and cacao having the largest impact on improving vegetation heterogeneity and microclimate regulation when incorporated into an alley-cropping system. In particular, we found that systems intercropped with black pepper had air and soil surface temperatures up to 1.3 °C and 2.1 °C cooler than those in oil palm monoculture. In contrast, systems intercropped with bactris and bamboo had increased air temperatures. Our findings show that some alley-cropping systems have great potential as a climate-smart practice in sustainable oil palm agriculture. This study also shows that careful selection of crops is important in the planning and management of future alley-cropping system to optimise the ecosystem benefits that can be gained from this management system.

Land use conversion from peat swamp forest to oil palm agriculture greatly modifies microclimate and soil conditions

“…From the observation at these smallholding and large scale plantations, differences of the vegetation structure created from different planting designs and management between both plantations, greatly influence light penetration underneath tree canopies, thus affecting the microclimate and soil characteristics. Similarly, Ashraf et al (2019) also highlighted that the alley-cropping system used in oil palm polyculture plantation improved the vegetation heterogeneity and microclimate regulation, however, it is also especially important to carefully selecting the crops when incorporating them with the oil palm trees as the selected crop characteristics and surrounding vegetation structural characteristics may influence the microclimate and soil conditions of an area. This emphasizes that polyculture agricultural systems used in smallholdings may serve as an alternative to sustainable agricultural practice and consequently contribute to overcoming global warming and biodiversity conservation challenges.…”

“…Age stand may also contribute to the differences between the findings in the smallholdings and large scale plantations. For example, Ashraf et al (2019) found that the monoculture oil palm plantation of different ages had different effects on microclimate conditions where a 15-year old oil palm showed lower solar radiation interception below canopy and higher relative humidity due to a more closed structure compared to a younger oil palm stand (7 year old).…”

Canopy Microclimate Modification with Reflective Mulches Under Oil Palm and Its Role to Soybean Growth

“…Luas lahan perkebunan kelapa sawit di Indonesia pada tahun 2015 telah mencapai 11.6 juta ha (Kementan, 2016). Pemanfaatan lahan di bawah tegakan tanaman utama seperti di bawah perkebunan kelapa sawit terkendala oleh suhu udara yang rendah (Ashraf et al, 2019), ancaman kekeringan (Corley et al, 2018), tanah masam (Dhandapani et al, 2019), dan gangguan dari organisme pengganggu tanaman (Sopandie and Trikoesoemaningtyas, 2011). Lahan di bawah tegakan perkebunan kelapa sawit dikategorikan sebagai lahan marjinal karena faktor-faktor pembatas untuk pemanfaatannya.…”

Intercropping of Rice and Water Mimosa (Neptunia oleracea Lour.): A Novel Model to Control Pests and Diseases and Improve Yield and Grain Quality while Reducing N Fertilizer Application

“…The influence of structural diversity of plants on microclimatic parameters has become increasingly clear [11]. In the intercropping system, the aboveground and belowground microclimates were changed through horizontal and vertical plant growth [12].…”