PENGARUH BERBAGAI DOSIS KOMPOS SAMPAH KOTA TERHADAP PERTUMBUHAN DAN HASIL TANAMAN JAHE GAJAH (Zingiber officinale var. officinale) PADA SISTEM PENANAMAN BAG CULTURE

Penggunaan bahan organik kompos sampah kota merupakan salah satu alternatif yang cukup prospektif untuk keberhasilan budidaya tanaman jahe pada sistem penanaman bag culture. Penelitian ini bertujuan untuk mengetahui pengaruh berbagai dosis kompos sampah kota terhadap pertumbuhan dan hasil tanaman jahe gajah pada sistem penanaman bag culture. Penelitian dilaksanakan pada bulan April 2020 sampai Agustus 2020 di Balai Gadang, Kecamatan Koto Tangah, Padang, Sumatera Barat, menggunakan tanah Ultisol. Metode penelitian ini berbentuk percobaan lapangan menggunakan Rancangan Acak Lengkap (RAL) dengan 5 taraf perlakuan dan 3 ulangan sehingga terdapat 15 satuan percobaan, dalam setiap satuan percobaan terdiri dari 3 tanaman sehingga secara keseluruhan terdapat 45 tanaman. Perlakuan yang digunakan adalah dosis kompos sampah kota 0 ton/ha, 5 ton/ha, 10 ton/ha, 15 ton/ha, 20 ton/ha. Variabel pengamatannya adalah tinngi tanaman, jumlah daun, jumlah batang semu, analisis kandungan klorofil, bobot rimpang per rumpun. Data dianalisis secara statistik dengan uji F taraf 5% dan jika F hitung lebih besar dari F tabel 5% maka dilanjutkan dengan uji Duncan’s New Multiple Range Test (DNMRT) 5%. Hasil penelitian menunjukkan bahwa adanya pengaruh pemberian dosis kompos sampah kota terhadap pertumbuhan dan hasil tanaman jahe gajah, pemberian dosis 20 ton/ha menunjukkan hasil yang terbaik dibandingkan dosis lainnya

Carbon and energy exchange of semi-arid ecosystems with heterogeneous canopy structure

Carbon and energy fluxes were measured with the eddy covariance technique above two semi-arid ecosystems, ponderosa pine and juniper/sagebrush, located in central Oregon. The two ecosystems have low LAI and a very open canopy structure. The energy closure was ~70-80% at both ecosystems, equivalent to an imbalance of 150-250 W m⁻² on cloudless summer days, when net radiation (R[subscript n]) was ~600-700 W m⁻². The lack of closure cannot be explained by the uncertainty of an estimate of available energy due to a single R[subscript n] sensor location. At the more open juniper/sagebrush ecosystem, a numerical model showed that spatial variation in R[subscript n], even for large differences in surface radiation temperature and reflection coefficient between ecosystem components (soil and vegetation), is less than 10% of measured R[subscript n]. The uncertainty in R[subscript n] at the two-layered ponderosa pine ecosystem with patches of young and old-growth trees is expected to be smaller than at the juniper ecosystem. Net carbon exchange (NEE) at the pine site strongly depends on environmental factors effecting carbon assimilation (A[subscript c]) and ecosystem respiration (R[subscript e]). A more detailed analysis of the carbon budget showed a strong negative response of carbon uptake to large vapor pressure deficits (VPD), whereas water vapor exchange (LE) was less affected. At large VPD the vegetation maintains a sustainable water flow through the soil-plant system by stomatal control of transpiration. The stomatal closure leads to limitation in A[subscript c], but LE is subject to a positive feedback from higher evaporative demand. Annual NEE of the ponderosa pine forest (200-300 gC m⁻²) was in the mid-range of reported NEE of temperate forest ecosystems, though, unusually, much of the annual carbon gain occurred during the fall through spring, because the relatively mild winters allowed carbon assimilation to occur and R[subscript e] rates were low. The information gathered at our ponderosa pine site during two years with contrasting climate suggests that the carbon uptake of the ponderosa pine ecosystem will be more sensitive to global climate change than the water vapor exchange

E-Commerce untuk Mendukung Business To Business Menggunakan Dynamic Dbmss: Studi Kasus pada Perusahaan Dagang Cross Tech

The purpose of this study is to develop an e-commerce that can distribute any information about the products of PD Cross Tech. The e-commerce is supported by dynamic DBMS and can be connected via database reseller server so that it can do information sharing. The distribution is performed using the Distributed Relational Database Management System (DRDBMS), supported by the File Transfer Protocol and Virtual Private Network. In other words the e-Commerce supports multiplatform database. Research methodologies used are analytical methods, design methods, and literature study. Results showed that PD Cross Tech needs a new e-Commerce that supports multiplatform database. With this e-Commerce, it is expected that similar computer equipment needs for many organization in Indonesia can be designed in the same way

Uncertainties in the land-use flux resulting from land-use change reconstructions and gross land transitions

Land-use and land-cover (LUC) changes are a key uncertainty when attributing changes in measured atmospheric CO2 concentration to its sinks and sources and must also be much better understood to determine the possibilities for land-based climate change mitigation, especially in the light of human demand on other land-based resources. On the spatial scale typically used in terrestrial ecosystem models (0.5 or 1°) changes in LUC over time periods of a few years or more can include bidirectional changes on the sub-grid level, such as the parallel expansion and abandonment of agricultural land (e.g. in shifting cultivation) or cropland–grassland conversion (and vice versa). These complex changes between classes within a grid cell have often been neglected in previous studies, and only net changes of land between natural vegetation cover, cropland and pastures accounted for, mainly because of a lack of reliable high-resolution historical information on gross land transitions, in combination with technical limitations within the models themselves. In the present study we applied a state-of-the-art dynamic global vegetation model with a detailed representation of croplands and carbon–nitrogen dynamics to quantify the uncertainty in terrestrial ecosystem carbon stocks and fluxes arising from the choice between net and gross representations of LUC. We used three frequently applied global, one recent global and one recent European LUC datasets, two of which resolve gross land transitions, either in Europe or in certain tropical regions. When considering only net changes, land-use-transition uncertainties (expressed as 1 standard deviation around decadal means of four models) in global carbon emissions from LUC (ELUC) are ±0.19, ±0.66 and ±0.47 Pg C a−1 in the 1980s, 1990s and 2000s, respectively, or between 14 and 39 % of mean ELUC. Carbon stocks at the end of the 20th century vary by ±11 Pg C for vegetation and ±37 Pg C for soil C due to the choice of LUC reconstruction, i.e. around 3 % of the respective C pools. Accounting for sub-grid (gross) land conversions significantly increased the effect of LUC on global and European carbon stocks and fluxes, most noticeably enhancing global cumulative ELUC by 33 Pg C (1750–2014) and entailing a significant reduction in carbon stored in vegetation, although the effect on soil C stocks was limited. Simulations demonstrated that assessments of historical carbon stocks and fluxes are highly uncertain due to the choice of LUC reconstruction and that the consideration of different contrasting LUC reconstructions is needed to account for this uncertainty. The analysis of gross, in addition to net, land-use changes showed that the full complexity of gross land-use changes is required in order to accurately predict the magnitude of LUC change emissions. This introduces technical challenges to process-based models and relies on extensive information regarding historical land-use transitions

Climatic versus biotic constraints on carbon and water fluxes in seasonally drought-affected ponderosa pine ecosystems

We investigated the relative importance of climatic versus biotic controls on gross primary production (GPP) and water vapor fluxes in seasonally drought-affected ponderosa pine forests. The study was conducted in young (YS), mature (MS), and old stands (OS) over 4 years at the AmeriFlux Metolius sites. Model simulations showed that interannual variation of GPP did not follow the same trends as precipitation, and effects of climatic variation were smallest at the OS (50%), and intermediate at the YS (<20%). In the young, developing stand, interannual variation in leaf area has larger effects on fluxes than climate, although leaf area is a function of climate in that climate can interact with age-related shifts in carbon allocation and affect whole-tree hydraulic conductance. Older forests, with well-established root systems, appear to be better buffered from effects of seasonal drought and interannual climatic variation. Interannual variation of net ecosystem exchange (NEE) was also lowest at the OS, where NEE is controlled more by interannual variation of ecosystem respiration, 70% of which is from soil, than by the variation of GPP, whereas variation in GPP is the primary reason for interannual changes in NEE at the YS and MS. Across spatially heterogeneous landscapes with high frequency of younger stands resulting from natural and anthropogenic disturbances, interannual climatic variation and change in leaf area are likely to result in large interannual variation in GPP and NEE