Zonal Soil Type Determines Soil Microbial Responses to Maize Cropping and Fertilization.

Soil types heavily influence ecological dynamics. It remains controversial to what extent soil types shape microbial responses to land management changes, largely due to lack of in-depth comparison across various soil types. Here, we collected samples from three major zonal soil types spanning from cold temperate to subtropical climate zones. We examined bacterial and fungal community structures, as well as microbial functional genes. Different soil types had distinct microbial biomass levels and community compositions. Five years of maize cropping (growing corn or maize) changed the bacterial community composition of the Ultisol soil type and the fungal composition of the Mollisol soil type but had little effect on the microbial composition of the Inceptisol soil type. Meanwhile, 5 years of fertilization resulted in soil acidification. Microbial compositions of the Mollisol and Ultisol, but not the Inceptisol, were changed and correlated (P < 0.05) with soil pH. These results demonstrated the critical role of soil type in determining microbial responses to land management changes. We also found that soil nitrification potentials correlated with the total abundance of nitrifiers and that soil heterotrophic respiration correlated with the total abundance of carbon degradation genes, suggesting that changes in microbial community structure had altered ecosystem processes. IMPORTANCE Microbial communities are essential drivers of soil functional processes such as nitrification and heterotrophic respiration. Although there is initial evidence revealing the importance of soil type in shaping microbial communities, there has been no in-depth, comprehensive survey to robustly establish it as a major determinant of microbial community composition, functional gene structure, or ecosystem functioning. We examined bacterial and fungal community structures using Illumina sequencing, microbial functional genes using GeoChip, microbial biomass using phospholipid fatty acid analysis, as well as functional processes of soil nitrification potential and CO2 efflux. We demonstrated the critical role of soil type in determining microbial responses to land use changes at the continental level. Our findings underscore the inherent difficulty in generalizing ecosystem responses across landscapes and suggest that assessments of community feedback must take soil types into consideration. Author Video: An author video summary of this article is available

Pattern and process in Amazon tree turnover, 1976-2001

Previous work has shown that tree turnover, tree biomass and large liana densities have increased in mature tropical forest plots in the late twentieth century. These results point to a concerted shift in forest ecological processes that may already be having significant impacts on terrestrial carbon stocks, fluxes and biodiversity. However, the findings have proved controversial, partly because a rather limited number of permanent plots have been monitored for rather short periods. The aim of this paper is to characterize regional-scale patterns of 'tree turnover' (the rate with which trees die and recruit into a population) by using improved datasets now available for Amazonia that span the past 25 years. Specifically, we assess whether concerted changes in turnover are occurring, and if so whether they are general throughout the Amazon or restricted to one region or environmental zone. In addition, we ask whether they are driven by changes in recruitment, mortality or both. We find that: (i) trees 10 cm or more in diameter recruit and die twice as fast on the richer soils of southern and western Amazonia than on the poorer soils of eastern and central Amazonia; (ii) turnover rates have increased throughout Amazonia over the past two decades; (iii) mortality and recruitment rates have both increased significantly in every region and environmental zone, with the exception of mortality in eastern Amazonia; (iv) recruitment rates have consistently exceeded mortality rates; (v) absolute increases in recruitment and mortality rates are greatest in western Amazonian sites; and (vi) mortality appears to be lagging recruitment at regional scales. These spatial patterns and temporal trends are not caused by obvious artefacts in the data or the analyses. The trends cannot be directly driven by a mortality driver (such as increased drought or fragmentation-related death) because the biomass in these forests has simultaneously increased. Our findings therefore indicate that long-acting and widespread environmental changes are stimulating the growth and productivity of Amazon forests

IDENTIFIKASI SIFAT FISIK TANAH INCEPTISOL PADA PENGGUNAAAN LAHAN (LAND USED) DI SEKITAR KAWASAN KAMPUS BINA WIDYA UNIVERSITAS RIAU

Tanah adalah perubahan mineral dan bahan organik yang dipengaruhi oleh bahan induk, iklim, topografi, waktu, dan vegetasi yang dapat dibedakan dari ciri-ciri bahan induk asalnya secara sifat fisik tanah dan memiliki beberapa jenis tanah seperti jenis tanah Inceptisol adalah tanah Inceptisol. Tanah Inceptisol merupakan salah satu jenis tanah pada lahan kering yang luasnya 2.600.000 ha di Provinsi Riau dan salah satu penggunaan lahan tanah Inceptisol berada di Riau yaitu di kampus Universitas Riau. Penelitian ini bertujuan untuk mengetahui karakterisasi sifat fisika tanah inceptisol pada penggunaan lahan di Kampus Bina Widya Universitas Riau. metode yang digunakan survei dan observasi dengan  Analisis data dilakukan dengan analisis analisis kuantitatif. Hasil penelitian ini menunjukkan bahwa penggunaan lahan Inceptisol di Universitas Riau memberikan pengaruh terhadap perubahan sifat fisik tanah terutama pada penggunaan lahan akasia dan Arboretum memberikan peningkatan terhadap kadar air, C-organik, warna tanah, dan porositas. Selain itu penggunaan lahan rumput, ekaliptus memberikan pengaruh terhadap peningkatan total ruang pori, permeabilitas, laju infiltrasi. Tekstur tanah pada berbagai penggunaan lahan memiliki tekstur tanah yang hampir sama yaitu kandungan fraksi pasir yang lebih tinggi

Parallel functional and stoichiometric trait shifts in South American and African forest communities with elevation

The Amazon and Congo basins are the two largest continuous blocks of tropical forest with a central role for global biogeochemical cycles and ecology. However, both biomes differ in structure and species richness and composition. Understanding future directions of the response of both biomes to environmental change is paramount. We used one elevational gradient on both continents to investigate functional and stoichiometric trait shifts of tropical forest in South America and Africa. We measured community-weighted functional canopy traits and canopy and topsoil delta N-15 signatures. We found that the functional forest composition response along both transects was parallel, with a shift towards more nitrogen-conservative species at higher elevations. Moreover, canopy and topsoil delta N-15 signals decreased with increasing altitude, suggesting a more conservative N cycle at higher elevations. This cross-continental study provides empirical indications that both South American and African tropical forest show a parallel response with altitude, driven by nitrogen availability along the elevational gradients, which in turn induces a shift in the functional forest composition. More standardized research, and more research on other elevational gradients is needed to confirm our observations

HASIL TANAMAN SELADA (Lactuca sativa L.) PADA KOMPOSISI MEDIUM BERBEDA YANG DIPUPUK DENGAN UREA DALAM SISTEM BUDIDAYA TERAPUNG LAHAN RAWA GAMBUT

The cultivation of lettuce floating system peat swamps with different media compositions given with urea has never been studied. The aim of this study was to determine the interaction between medium composition and the dose of urea which produces best lettuce (Lactuca sativa L.) growth and yield on peat swamp floating cultivation. The research used 4×4 factorial in completely randomized design with two factors. First factor was type of medium composition consists of four levels, 70% peat:5% Inceptisol:20% chicken manure fertilizer:5% OPEFB ash; 60% peat:15% Inceptisol:20% chicken manure fertilizer:5% OPEFB ash; 50% peat:25% Inceptisol:20% chicken manure fertilizer:5% OPEFB ash); 40% peat:35% Inceptisol:20% chicken manure fertilizer:5% OPEFB ash. The second factor was urea dose consists of fout levels, without urea), 2 g per polybag; 4 g per polybag, 6 g per polybag. The results showed that the interaction between the medium composition and the dose of urea had an effect on the yield of lettuce. The composition of 50% peat:25% Inceptisol:20% chicken manure fertilizer:5% OPEFB ash medium produced the best lettuce growth when fertilized with a dose of 2 g per polybag urea.

Perubahan Beberapa Sifat Kimia Tanah, Serapan P Dan Pertumbuhan Tanaman Jagung Pada Tanah Inceptisol Kwala Bekala Akibat Pemberian Pupuk Kandang Ayam Dan Beberapa Sumber P

Tanah Inceptisol memiliki kandungan bahan organik yang rendah dan pH yang rendah.Kandungan bahan organik rendah dengan ratio C/N tergolong rendah dan kandungan P potensial rendah.Penelitian ini dilaksanakan di Rumah Kasa Fakultas Pertanian Universitas Sumatera Utara, Medan.Pada bulan Agustus tahun 2015 sampai dengan selesai.Rancangan yang digunakan adalah rancangan acak kelompok (RAK) faktorial terdiri dari 2 faktor. Faktor I adalah pupuk kandang ayam dengan 4 taraf yaitu: tanpa aplikasi pupuk kandang ayam, 40 g/polibag, 80 g/polibag, dan 120 g/polibag. Faktor II adalah beberapa sumber Pyang terdiri dari: tanpa aplikasi pupuk P, pupuk SP-36, dan pupuk TSP. Hasil penelitian menunjukkan pemberian pupuk kandang ayam dapat merubah beberapa sifat kimia tanah, serapan P dan produksi tanaman jagung pada Tanah Inceptisol Kwala Bekala. Pemberian beberapa sumber P dapat merubah beberapa sifat kimia tanah, serapan P dan pertumbuhan tanaman jagung pada Tanah Inceptisol Kwala Bekala. Interaksi antara pupuk kandang ayam dan beberapa sumber P dapat merubah beberapa sifat kimia tanah, serapan P dan produksi tanaman jagung pada Tanah Inceptisol Kwala Bekala

Pengujian Media Tanam Kompos Dan Residu Sampah Rumah Tangga Terhadap Basa Tukar, Ktk, Kb Dan Produksi Tanaman Sawi (Brassica Juncea L. Czern) Di Lahan Pekarangan Kec. Sunggal

The Study to evaluate the effect compost of household waste as growing media and the residual ofhousehold waste pit on the availability of KTK, KB and the production of mustard (Brassica junceaL. Czern) corp in yard. This research was conducted in the compost yard in Desa Sei SemayangKecamatan Sunggal Kabupaten Deli Serdang and in the laboratory of Agricultural Faculty ofUniversity of North Sumatra. The design of this research were non-factorial random design which isconsisting of 9 treatments with 3 replications. The treatment are M1 (100% soil), M2 (75% soil +25% compost), M3 (50% soil + 50% compost), M4 (25% soil + 75% compost), M5 (75% soil +25% residues of the household waste pit), M6 (50% soil + 50% residues of the household wastepit), M7 (25% soil + 75% residues of the household waste pit), M8 (50% compost+ 50% residues ofthe household waste pit), M9 (100% residues of the household waste pit). The result is that researchas household waste compost and residues of the household waste pit and the combination of both,very significantly increased the K-dd, Base Saturation of the soil as well as the production of thewet weight mustard plant and not significant to Ca, Mg and Na contensts