Forest hydrological studies to improve water management in marine lowlands in Palembang, Indonesia

Abstract Marine lowlands are a challenging environment for forestry plantation in Indonesia, due to poor drainage, low soil pH and frequent flooding (caused by the almost completely flat area). In the beginning of 2017, OKI pulp and paper mill Ltd (machinery from Finland) initiated its production in the Palembang region in south-west Sumatra (Indonesia), where the wood for pulp is also produced. The area meant to provide wood to the mill will not be sufficient if the land and forest production deteriorates due to the observed potential problems with marine clays, such as land subsidence, floods and acidity. To meet the demand for wood, Sinar Mas forestry Ltd in the Palembang region has initiated a study to improve water and land management in order to maintain long term forest productivity. This doctoral thesis aims to study the hydrology and water management of the Eucalyptus pellita forest in these lowland areas. The first study focused on the water requirements of Eucalyptus pellita during initial growth (meso scale). The results showed that the average Kc value for E. pellita at age 40–142 days is 0.79, which exceeds that reported for E. grandis. Thus, the recommended irrigation requirement varies depending on precipitation, from 70 mL/plant/day with no rainfall to zero when there is precipitation of >30 mm/day. The second study was carried out to explore the functioning of the existing drainage system adjacent to a flooding river (catchment scale of water management). The study shows how the river capacity controls drainage. The second study showed the tidal affects in the river and the adjacent drainage area with Acacia plantations. Cleaning of the river had a significant effect on each river monitoring station and increased the discharge and velocity by more than 5 times and reduced the water level by more than 40%. The third study looked at the effect of the water table on growth of E. pellita (field scale). The results of third study showed that the best tree growth over a 12-month period was in WT 40–80 cm with mortality around 10%. With WT 0–40 cm, the mortality was 50% due to 2 months of flooding when the trees were 2 months old. With a shallow WT range of 0–40 cm, the trees had the shortest root depth (about 22 cm). This thesis provides practical information to support sustainable forest management in Indonesian lowlands, while also considering local communities. The framework presented here could be used by operation teams in order to ensure wood for the regional pulp and paper industry in Indonesia.Tiivistelmä Alavat alueet Indonesiassa ovat haastavia metsätaloudelle rannkion tulvariskien ja savimaiden alhaisen maaperän pH:n vuoksi. Vuoden 2017 alussa OKI sellu- ja paperitehdas Oy käynnisti tuotantonsa Palembangin alueella Sumatralla (Indonesia). Metsätalouteen varattu alue ei tule riittämään, jos maan ja metsän tuotanto heikkenee havaittujen kuivatus ja puunkasvatuksen liittyvien ongelmien vuoksi, jotka liittyvät maanpinnan laskuun, toistuviin tulviin ja maaperän happamuuteen. Vastatakseen puun kysyntään Palembangin alueella sijaitseva Sinar Mas Forestry Ltd on käynnistänyt tutkimuksen vesi- ja maankäytön parantamiseksi metsän pitkän aikavälin tuottavuuden ylläpitämiseksi. Tähän liittyen, tämän väitöskirja tavoitteena oli Palembangin alavien savialueiden hydrologian ja vesitalouden tutkiminen. Ensimmäisessä osa-tutkimuksessa tutkittiin Eucalyptus pellitan veden tarvetta kasvatuksen alkuvaiheessa. Toisessa osatutkimuksessa selvitettiin tulvivan rannikkojoen vaikutusta ojitettujen savimaiden hydrologiaan ja kuivatukseen. Tutkimus osoitti, että joen puhdistaminen kasvillisuudesta lisäsi virtausta ja virtausnopeutta paikoin viisinkertaisesti ja vedenpintaa noin 40%. Kolmannessa tutkimuksessa tarkasteltiin Eukalyptus pellita-puun kasvua kenttämittakaavassa erilaisilla kuivatusolosuhteilla (kuivavara). Tutkimuksen tulokset osoittivat, että paras puun kasvu 12 kuukauteen asti saavutettiin on pohjaveden tasoilla 40–80 cm, jolloin kuolleisuus oli noin 10 %. Pohjaveden tasoilla 0–40 cm, tulvakuolleisuus oli 50 % noin 2 kuukauden ikäisillä puilla. Matalalla pohjaveden tasoilla (0–40 cm) puiden juurisyvyys oli vain 22 cm. Väitöstyö tuo käytännöllisiä ja kestäviä ratkaisuja metsätalouteen huomioiden paikallisen puun tuotannon ja lähialueen yhdyskunnat. Tässä esitettyä viitekehystä voidaan käyttää myös laajemmin edistämään metsän kasvua vastaavissa olosuhteissa

Caractérisation expérimentale de l'interaction sol-géotextile sous chargement dynamique de type impact

[Departement_IRSTEA]Eaux [TR1_IRSTEA]RIVAGEInternational audienceAn original pull-out test apparatus has been developed to study the behaviour of soilgeosynthetic interface under dynamic load of impact type (rapid pull-out). The development of the device and the experimental procedure are first presented, then results of a feasibility campaign are analysed. In this campaign, only one type of soil and geotextile were used, under constant confinement, and several pull-out energies were applied. The repeatability of the test is first addressed, and appears to be very satisfactory. The tests performed under several pull-out energies showed similar trends. In particular, after a peak of pull-out force, a force plateau has been observed for all tests, taking place as the maximum pullout velocity is reached. A soil-geotextile interaction model cannot be extrapolated yet, but the first experimental results are very encouraging in going this way

Caractérisation expérimentale de l'interaction sol-géotextile sous chargement dynamique de type impact

International audienceAn original pull-out test apparatus has been developed to study the behaviour of soilgeosynthetic interface under dynamic load of impact type (rapid pull-out). The development of the device and the experimental procedure are first presented, then results of a feasibility campaign are analysed. In this campaign, only one type of soil and geotextile were used, under constant confinement, and several pull-out energies were applied. The repeatability of the test is first addressed, and appears to be very satisfactory. The tests performed under several pull-out energies showed similar trends. In particular, after a peak of pull-out force, a force plateau has been observed for all tests, taking place as the maximum pullout velocity is reached. A soil-geotextile interaction model cannot be extrapolated yet, but the first experimental results are very encouraging in going this way

Dispositif d'essai d'extraction rapide de géotextile

International audiencePull-out test is commonly used to investigate the pull-out behavior of geotextile reinforcement embedded in soil. It is also used by different authors to propose interface friction angles values. Unfortunately these works mainly deal with cyclic loadings with reference to seismic action, which are believed to be different to the load exposed to reinforced earthworks due to lateral impacts. Therefore an original rapid pull-out test apparatus is proposed in this study. This article assess the proposed test method in addressing the rapid pull-out response of a geotextile embedded in soil. The testing apparatus allows investigating shear velocities within the range of 0.1 to 1.2 m/s. This test method seems promising in addressing the response of soil-geotextile interfaces under dynamic loadings. Nevertheless, improvements concerning the testing apparatus are still required. The loading system could be modified to avoid oscillations and specific equipment should be added to increase the normal stress

Democracia, paz y desarrollo en el ámbito local urbano

"Desde este punto de vista, los temas que se abordaron en el Taller fueron: Democracia, partidos y régimen político, a cargo de Jaime de Althaus, analista del diario Expreso y Romeo Grompone, investigador del IEP; violencia y pacificación, con la participación de Isabel Coral, directora de CEPRODEP y Carlos Iván Degregori, director del IEP; y posibles salidas y acuerdo nacional, con la presentación de Michel Azcueta, regidor de la Municipalidad de Lima y ex-alcalde de Villa El Salvador y de Julio Cotler, investigador del IEP".― Página

Irrigation requirement for Eucalyptus pellita during initial growth

Abstract The growth of Eucalyptus pellita in forestry plantations requires attention to water requirements, especially in the initial growth phase from seedling to field-ready plant. In this study, actual evapotranspiration (ETa), crop coefficient (Kc), and the irrigation requirement of E. pellita were assessed during the nursery growth phase (day 40–142). The experimental set-up included lysimeters with different treatments in terms of plants, drainage, and soil conditions. Plant growth and water balance were monitored during June September 2018 in an open nursery area in Riau, Indonesia. ETa was determined by the water balance lysimeter method and potential (reference) evapotranspiration (ETo) was extracted based on the Penman-Monteith method (FAO/56). The results showed that the average Kc value for E. pellita at age 40–142 days is 0.79, which exceeds that reported for E. grandis. The recommended irrigation requirement varies depending on precipitation, from 70 mL/plant/day with no rainfall to zero at precipitation of >30 mm/day. This is the first study to assess water use in E. pellita growing in pots during the nursery phase, which provides guidance on irrigation requirements during their initial growth phase