Agroforestry is often seen as a sustainable land-use system for agricultural production providing ecosystem services. Intercropping with food crops leads to equal or higher productivity than monoculture and results in food production for industry and subsistence. Low rubber price and low labor productivity in smallholdings have led to a dramatic conversion of rubber plantations to more profitable crops. The literature analysis performed in this paper aimed at better understanding the ins and outs that could make rubber-based agroforestry more attractive for farmers. A comprehensive search of references was conducted in March 2023 using several international databases and search engines. A Zotero library was set up consisting of 415 scientific references. Each reference was carefully read and tagged in several categories: cropping system, country, main tree species, intercrop type, intercrop product, level of product use, discipline of the study, research topic, and intercrop species. Of the 232 journal articles, 141 studies were carried out on rubber agroforestry. Since 2011, the number of studies per year has increased. Studies on rubber-based agroforestry systems are performed in most rubber-producing countries, in particular in Indonesia, Thailand, China, and Brazil. These studies focus more or less equally on perennials (forest species and fruit trees), annual intercrops, and mixed plantations. Of the 47 annual crops associated with rubber in the literature, 20 studies dealt with rice, maize, banana, and cassava. Agronomy is the main discipline in the literature followed by socio-economy and then ecology. Only four papers are devoted to plant physiology and breeding. The Discussion Section has attempted to analyze the evolution of rubber agroforestry research, progress in the selection of food crop varieties adapted to agroforestry systems, and to draw some recommendations for rubber-based agroforestry systems associated with food crops.

Agroforestry is often seen as a sustainable land-use system for agricultural production providing ecosystem services. Intercropping with food crops leads to equal or higher productivity than monoculture and results in food production for industry and subsistence. Low rubber price and low labor productivity in smallholdings have led to a dramatic conversion of rubber plantations to more profitable crops. The literature analysis performed in this paper aimed at better understanding the ins and outs that could make rubber-based agroforestry more attractive for farmers. A library was set-up consisting of 415 scientific references. Of the 232 journal articles, 141 studies were carried out on rubber agroforestry. Since 2011, the number of studies per year has increased. Studies on rubber-based agroforestry systems are performed in most rubber producing countries, in particular in Indonesia, Thailand, China and Brazil. These studies focus more or less equally on perennials (forest species and fruit trees), annual intercrops and mixed plantations. Of the 47 annual crops associated with rubber in the literature, 20 studies dealt with rice, maize, banana and cassava. Agronomy is the main discipline in the literature followed by socio-economy and then ecology. Only 4 papers are devoted to plant physiology and breeding. The discussion section has attempted to analyze the evolution of rubber agroforestry research, progress in the selection of food crop varieties adapted to agroforestry systems, and to draw some recommendations for rubber-based agroforestry systems associated with food crops.

Minat dalam berkebun karet saat ini cukup tinggi karena hasil lateks yang memiliki harga jual yang tinggi. Kondisi ini mendorong suatu upaya untuk menyediakan bahan tanam yang berkualitas. Bahan tanam yang umum digunakan berasal dari stum mata tidur atau bibit polibag dengan beberapa kelemahan. Teknik penyediaan bahan tanam dengan root trainer merupakan suatu alternatif dalam penyediaan bahan tanam, yang diharapkan mampu meminimalkan efek negatif pertumbuhan dan perkembangan bibit di lapangan. Keuntungan menggunakan root trainer nampak dari segi keragaan tanaman maupun finansial. Akar lateral yang terbentuk dari bibit yang berasal dari root trainer lebih banyak dan memberikan pertumbuhan yang baik di lapangan karena penyerapan unsur hara untuk metabolisme dalam tanaman lebih optimal. Disamping itu, root trainer dapat menghemat tenaga kerja, dapat digunakan berulang kali, dan biaya rendah pada proses transportasi dan distribusi.

This study was conducted to evaluate the effects of ethephon stimulation and fertilization on latex production and physiological latex in different clones. This study was conducted in the experimental field of the Indonesian Rubber Research Institute in South Sumatra. The experiment was laid out in a randomized complete block design with three replications. The main block is the rubber clones, and the subblocks are fertilization rate and ethephon stimulation. The rubber clones for this research were GT 1, BPM 24, PB 260, and IRR 112. The different fertilization rates used in the experiment were control (no fertilizer), 50% recommended rate (50 RR), 100% recommended rate (100 RR), and 150% recommended rate (150 RR). Ethephon stimulation was applied every two months during the observation period with a rate of S/2 d3 ET2.5% 6/y. The observed parameters included: latex yield, physiological latex (sucrose, inorganic phosphorus, and thiol), and tapping panel dryness. Results showed that rubber yields, such as latex production and dry rubber content, increased by 10%–16% with fertilization and ethephon stimulation. Latex characteristics, including thiol, inorganic phosphate, and sucrose, remained within their optimal ranges, with thiol levels increasing from 0.11 to 0.29 mM, inorganic phosphate from 7.29 to 1.58 mM, and sucrose from 0.42 to 7.12 mM upon fertilization.

Parameter fisiologis lateks dipengaruhi oleh fluktuasi status air tanaman sedangkan status air tanaman dipengaruhi oleh kadar air tanah. Penelitian ini bertujuan untuk mengetahui pengaruh kadar air tanah terhadap beberapa parameter fisiologis lateks agar dapat menjadi bahan pertimbangan untuk aplikasi stimulan lateks. Penelitian ini dilaksanakan pada September 2018 hingga Agustus 2019 di Kebun Percobaan dan Produksi, Pusat Penelitian Karet, Sumatera Selatan, dengan menggunakan klon PB 260 dan IRR 112. Sampel terdiri dari 30 pohon per klon. Tanah di daerah penelitian diklasifikasikan sebagai ultisol yang miskin nutrisi dan memiliki drainase sedang. Hasil penelitian menunjukkan bahwa kadar air tanah memiliki korelasi positif dengan sukrosa dan fosfat organik. Sebaliknya kadar air tanah memiliki korelasi negatif dengan thiol. Perbedaan karakter fisiologis antar klon menunjukkan bahwa respons terhadap dinamika air tanah dipengaruhi oleh efisiensi metabolisme masing-masing klon.

Soil is a critical factor in determining fertilizer efficiency. Rubber tree requires a stable environment to achieve optimal growth and production. The research aimed to evaluate how fertilization and ethephon stimulation affected the nutrient dynamics of rubber in various clones. The Indonesian Rubber Research Institute experimental field in South Sumatra served as the site for the research. Three replications of the experiment were set up using a split-plot design with three factors. The rubber clones were the primary plot, with ethephon stimulation and fertilization rate as subplots. The rubber clones used in this research, namely GT 1, BPM 24, PB 260, and IRR 112, were planted in 2011 (8 years) with a 6 x 3 m planting spacing on the existing rubber plantation. Several rates of fertilization were used in the experiment: 50% recommended rate (50 RR), 100% recommended rate (100 RR), 150% recommended rate (150 RR), and control (no fertilizer). During the observation period, ethephon stimulation was administered at a rate of S/2 d3 ET2.5% 6/y (half spiral cut, tapped downward every 3 days with ethephon stimulation of 2.5% active ingredient and application of 1 g per tree on groove, six times per year at monthly intervals) every two months. Observation parameters were soil nutrient analysis (soil pH, cation exchange capacity (CEC), C-Organic, total nitrogen, available phosphorus, and exchangeable bases (K, Ca, Mg), and leaf nutrient analysis (N, P, K). Results showed that soil properties were improved by fertilization after a year of treatment. Organic-C, CEC, total nitrogen, available phosphorus, and exchangeable cation increased across rubber clones. Tissue analysis in leaves and nutrient content also showed significant differences between fertilization and stimulation treatments in all clones. Further research is required on which chemical fertilizers with biological fertilizers can induce low nutrient availability in poor soil conditions. Keywords: rubber clones; ethephon stimulation; fertilizer rate; nutrient dynamics; soil properties