Influence of land slope and soil depth on weed seedbank in palm oil plantations

Abstract

Palm oil plantations significantly contribute to economy in Indonesia, with Crude Palm Oil (CPO) exports showing a marked increase of 9.6% from 2017 to 2019. However, weeds compete with palm oil plants for light, nutrients, and space, negatively impacting the growth and yield of palm oils. This study aims to identify weed species in the seedbank at various soil depths and land slopes within an oil palm plantation in West Kalimantan. The research was conducted from January to February 2024 at Gunung Aru Estate using a Complete Randomized Block Design (CRBD). The study examined soil profiles of 0-10 cm, 10-20 cm, and 20-30 cm across flat (0-2°), wavy (2-6°), and steep (>6°) lands, resulting in 27 plots. Soil samples with the size of 0.04 m2 for each sample were collected and analysed in a greenhouse to observe weed germination. The study identified five dominant weed species: Borreria setidens, Ageratum conyzoides, Phyllanthus amarus, Eleusine indica, and Cleome rutidosperma with more weeds Boreria setidens. Results showed significant variations in weed infestation patterns across land slopes and soil depths. Flat land exhibited higher weed counts at greater soil depths (1.47 weeds), while wavy land showed increased weed numbers at shallower depths (1.87 weeds). Steep land had lower overall weed counts. Understanding the influence of land slope and soil depth on weed infestation is essential for developing effective weed management strategies in palm oil plantations.