Examinando por Materia "Rubber"

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Conversion of lowland tropical forests to tree cash crop plantations loses up to one-half of stored soil organic carbon
(Stanford University, 2015-08-11) Van Straaten, Oliver; Corre, Marife D.; Wolf, Katrin; Tchienkoua, Martin; Cuellar Bautista, José Eloy; Matthews, Robin; Veldkamp, Edzo
Tropical deforestation for the establishment of tree cash crop plantations causes significant alterations to soil organic carbon (SOC) dynamics. Despite this recognition, the current Intergovernmental Panel on Climate Change (IPCC) tier 1 method has a SOC change factor of 1 (no SOC loss) for conversion of forests to perennial tree crops, because of scarcity of SOC data. In this pantropic study, conducted in active deforestation regions of Indonesia, Cameroon, and Peru, we quantified the impact of forest conversion to oil palm (Elaeis guineensis), rubber (Hevea brasiliensis), and cacao (Theobroma cacao) agroforestry plantations on SOC stocks within 3-m depth in deeply weathered mineral soils. We also investigated the underlying biophysical controls regulating SOC stock changes. Using a space-for-time substitution approach, we compared SOC stocks from paired forests (n = 32) and adjacent plantations (n = 54). Our study showed that deforestation for tree plantations decreased SOC stocks by up to 50%. The key variable that predicted SOC changes across plantations was the amount of SOC present in the forest before conversion—the higher the initial SOC, the higher the loss. Decreases in SOC stocks were most pronounced in the topsoil, although older plantations showed considerable SOC losses below 1-m depth. Our results suggest that (i) the IPCC tier 1 method should be revised from its current SOC change factor of 1 to 0.6 ± 0.1 for oil palm and cacao agroforestry plantations and 0.8 ± 0.3 for rubber plantations in the humid tropics; and (ii) land use management policies should protect natural forests on carbon-rich mineral soils to minimize SOC losses.
Evaluación del prendimiento y desarrollo de clones de caucho (Hevea brasiliensis) propagados por injerto en la selva peruana
(Universidad Autónoma de Yucatán, 2024-07-15) Navarro, Jorge M.; Alva Arévalo, Alberto; Lozano, Andi; Alva Arévalo, Celso Misael; García Gonzales, Patricia; Gaona Jimenez, Nery; Baselly Villanueva, Juan Rodrigo; Saavedra Ramírez, Jorge; Vallejos Torres, Geomar
The latex yield in Hevea brasiliensis trees is highly variable; Therefore, it is important to propagate commercial clones of this species by grafting in order to standardize or improve latex yields and therefore improve the economic income of producers in this part of the Amazon region. Objective. To evaluate the attachment and development of rubber clones propagated by grafting in the Peruvian jungle. Methodology. Nine-month-old patterns installed in the field were used. These were grafted with budding rods from the commercial clones TR-1, FX-3864, RRIM-600, IAN-873 and MDF-180. A completely randomized block design was used with five treatments and three blocks with 15 experimental units; each containing 30 repetitions. The data obtained were subjected to analysis of variance and Tukey's multiple range test (p<0.05) and the Kruskal Wallis test. Results. The best results in attachment and number of shoots were obtained in grafts with clone MDF-180 with values of 73.33 % and 7.83 shoots respectively; Regarding days to the appearance of the shoot and length, clone TR-1 presented it with 36.63 days and 27.47 cm; The largest leaf area was presented by the graft with clone IAN-873 with 55.46 cm2, while the highest chlorophyll content was obtained in grafts with clone RRIM-600 with 47.18 SPAD. Implications. More studies are required to establish the quality and adaptability of rubber clones propagated by grafting in different site conditions and establish patterns of tree productivity in a short time; Likewise, it is desired to evaluate the quality and quantity of latex produced by these clones. Conclusions. These results indicate the feasibility of propagating Hevea brasiliensis through shoot grafting in the field, which opens great possibilities for propagating rubber trees with better commercial characteristics, particularly with greater latex production.