Daddy Ruhiyat

Susanto D, Hayatudin, Setiawan A, Purnomo H, Ruhiyat D, Amirta R. 2017. Characterizing nutrient status and growth of Macaranga gigantea in tropical rainforest gaps after selective logging in East Kalimantan, Indonesia. Biodiversitas 18: 996-1003. Selective logging caused the formation of forest gaps, which stimulate the growth of the pioneer tree species. This study aims to determine the characteristic of soil nutrients status and plant growth of Macaranga gigantea in the tropical rainforest gaps after selective logging in East Kalimantan, Indonesia. We established research plots 50mx50m in natural forest production, 1 until 10 years after selective logging. The measured data of each plot is the number of trees of M. gigantea, its stem diameter, and its height, and also the soil and leaf nutrient concentration. The results showed that the soil has a pH (H2O) of 5.3 ± 0.27, cation exchange capacity of 10.6 ± 2.98 meq. 100 g-1, base saturation of 27.7 ± 10.44%, while the concentration...

The nutrients return through the forest stand litters is substantial mechanism of nutrient cycle in the forest ecosystem. The objectives of this research are to find out the litters production, the nutrient concentration of litters, and the amount of litter nutrient (N,P,K, Ca,Mg ) of  teak plantation forest at East Kalimantan, Indonesia. The 19 years old teak-dried litter weight more than 12. The litter is mainly composed by teak leaves elements, successively followed by other elements, such as; branch twig, tree skin and non-teak leaves elements. As a matter of fact, at all the litter elements, the higher nutrient concentration is Ca and otherwise P as the lowest. The amount of litter nutrient substance N, P, K, Ca and Mg in the 19 years-teak is more than 12 years. The amount of litter nutrient substance in both stand teaks are Ca as the most and P, conversely.

This study aimed to (1) determine the effect of each organic fertilizer dosage (a) the growth variables of Trembesi seedlings and (b) the quality of planting media after 120 days planted Trembesi Seedlings. This study also aimed to (2) obtain the optimum dose of organic fertilizer to be applied to the implementation of post-mining land reclamation and revegetation within the Forest Cultivation Zone. This research used various manure: Control without fertilizer; NPK synthetic fertilizer control; chicken manure, cow manure, and organic litter compost. Each of the organic fertilizer was given at doses of 125, 250, and 375 g/polybag. The test plants used were Trembesi seedlings (Samanea saman) at 4 months of age.The experimental design was prepared using Randomized Block Design (RAK) with 5 replications in each test plant group. Data analysis was completed with Fisher LSD Test and Duncan Multiple Range Test (DMRT) as well as regression analysis.The treatment of organic fertilizer dosage...

This study aims to determine the potential dynamics of carbon stocks in various land cover classes in the city of Samarinda, in the calculation of carbon stocks, land cover only devided into three (3) Class Land Cover (CLC) is a secondary forest CLC, CLC thickets and CLC shrubs. Research results show that the above ground carbon (AGC) stocks on Secondary Forest Land Cover Class average of 71.93 tonnes/ha, the land cover classes thickets of 32.34 tonnes /hectares and shrubs land cover classes of 19.66 tonnes / hectare. The carbon stocks in 2009 amounted to 2,589,929 tonnes, in 2012 there were 2,347,477 tons and in 2015 there were 2,201,005 tonnes. Estimated decrease in land-based stock carbon in the city of Samarinda during the period 2009-2015 amounted to 388,943 tonnes, or an average of 70,170 tonnes per year, or approximately 2.73%/year or the emissions in the field of land amounting to 254,538 tonnes of CO2 equivalent.

Industrial tree plantations in the tropics usually follow short rotations and intensive site management including slash and burn, and the use of heavy machinery. We attempt to quantify the implied nutrient losses (harvest export, erosion, slash and burn, leaching) in order to give plantation managers a chance to understand the significance of their planning and decisions. We used the scarce globally available information and a case study plantation in East Kalimantan, Indonesia (Acacia mangium and Eucalyptus deglupta). Adaptation involves problems and is discussed in some detail. Results are approximate only. Assuming a harvest volume of 200 m3 ha(-1), we assessed a loss of 427-680 kg ha(-1) N, 12-13 kg ha(-1) P, 178-252 kg ha(-1) Ca, 276-370 kg ha(-1) K, and 45-57 kg ha(-1) Mg per rotation. Of this overall loss, stand harvest accounted for 18-29% (N), 21-30% (P), 56-26% (K), 48-64% (Ca) and 22-37% (Mg). This means that the cumulative loss by erosion, slash and burn, and leaching exceeds that of the harvest. These losses can be influenced by management.

Mangrove forests were a typical type of tropical and subtropical forest, growing along beaches or river mouths that were affected by tides. Mangroves were often found in coastal areas that were protected from the onslaught of waves and sloping areas. Mangrove forest ecosystems had the function of absorbing carbon dioxide (CO2) from the air and storing carbon in the form of biomass. This research was conducted in September 2017. This study aimed to determine the growth, carbon stocks and biomass in mangrove forests in the area of Taman Hutan Raya Ngurah Rai (Sanur) Denpasar. Making research plots used the transect method with a size of 20 meters x 50 meters as many as 3 plots along the coast. From the measurement results, the total value of the base area in plot A was 2.37 m2 / tree, branch-free volume was 16.57 m3 / tree, biomass was 13,591 tons / plot, carbon stock was 6,795 tons / plot, the average increment was 0, 29 cm / year / tree. While the results of the measurement of the t...

Content.- 1 Forest Soils in the Humid Tropics: Characteristics and Classification.- Soils of rainforests: Characterization and major constraints of dominant forest soils in the humid tropics.- The World Reference Base for Soil Resources: An introduction with special reference to soils of tropical forest ecosystems.- Soils of the tropical forests of Leyte, Philippines 1. Weathering, soil characteristics, classification and site qualities.- Soils of the tropical forests of Leyte, Philippines 2. Impact of different land uses on status of organic matter and nutrient availability.- 2 Chemical and Hydrological Changes after Utilization.- Soil chemical changes after tropical forest disturbance and conversion: The hydrological perspective.- Hydrology of Acrisols beneath Dipterocarp forests and plantations in East Kalimantan, Indonesia.- Nutrient dynamics in intact and logged tropical rain forest in Guyana.- Logging can cause a serious lack of calcium in tropical rainforest ecosystems: An ex...

The hydrology of Haplic Acrisols on sandstone beneath old-growth and slightly logged Dipterocarp forests, and beneath Paraserianthes and Eucalyptus plantations in the lowlands of East Kalimantan was investigated to determine possible ecological constraints for forest and plantation management. The soils are characterized by 40–60 cm thick E horizons, texture silt clay, above clayey Bt horizons. Soil moisture (θ ), measured during a period of few weeks at the end of the rain season, was typically close to field capacity. Field-saturated hydraulic conductivities (K GP ) indicate that the E horizons are moderately permeable (medians of K GP 2.5–42.4 cm d−1 ), while the Bt horizons are virtually impermeable (medians of K GP < 0.17 cm d−1 ). Macropores generated by biota are likely the cause of the observed large within-plot variability of K GP in the E horizons and may provide pathways for preferential water flow. Soil water budgets constructed from measurements of precipitation (245 cm y−1 ), throughfall (210–230 cm y−1 ), using soil hydrological constraints obtained from K GP values measured in the Bt horizons, and assumed transpiration rates (90–110 cm y−1 ) suggest that 40–140 cm y−1 of the soil water is drained laterally in the E horizons. Accordingly, < 5–40 cm y−1 are available for deep seepage below 40–60 cm depth. Since lateral water flow is expected to increase with distance from the top of slopes, lower slopes receive large amounts of lateral water, depending on the slope length. It is concluded that the thickness, pore size distribution and permeability of the E horizons along with slope aspect are master variables for soil hydrology in the study area and determine site quality for forestry. Degradation of the E horizons due to compaction and erosion will increase surface flow, the frequency of flooding events and the impact of droughts on Dipterocarp forests and plantations of fast growing tree species in the lowlands of East Kalimantan. The conservation of topsoil physical and hydrological characteristics is therefore a prerequisite for sustainable forestry and landuse in this region.

Results of fine root inventories in Dipterocarp forests and plantations of Eucalyptus deglupta Bl. and Paraserianthes falcataria (L.) Niel. in East Kalimantan, Indonesia are presented. The influence of different forest land use on the amount and vertical distribution of fine roots in the soil is examined. Possible consequences for physical soil parameters related to root growth and morphology of roots are discussed. Differences in nutrient acquisition between tree species are indicated by the chemical compositon of fine roots. Fine root development and turnover in the Dipterocarp forests and the plantations is assessed by the comparison of samplings taken during dry and wet season.