A aplicação localizada de monoamônio fosfato favorece a disponibilidade de p no solo e sua absorção

O objetivo do presente trabalho foi avaliar a absorção de fósforo pelas plântulas de milho em função da aplicação localizada de fosfatos de cálcio e de amônio, em dois solos catarinenses. O trabalho foi realizado em 2011, com amostra de um Cambissolo Húmico (CH) e um Nitossolo Vermelho (NV). Os tratamentos consistiram da aplicação de superfosfato triplo (SFT), superfosfato simples (SS), diamônio fosfato (DAP) e monoamônio fosfato (MAP), além de uma testemunha sem a adição de P. Em todos os tratamentos com P adicionou-se 200 mg kg-1 de P e 100 mg kg-1 de K, na forma de KCl; a quantidade de N adicionada pelo DAP (160 mg kg-1) foi ajustada nos demais tratamentos pela adição de CaNO3. A produção de massa seca da parte aérea (MSPA) foi maior nos tratamentos com SFT, SS e MAP, nas quais os incrementos foram respectivamente 71, 67 e 62% maiores que a testemunha; enquanto com o DAP foi de 38%. Os teores de P na parte aérea e nas raízes foram maiores no solo tratado com MAP. O SFT, MAP e DAP aumentaram as concentrações de P no solo, cuja média foi 93% superior a testemunha. A disponibilidade de P no solo e sua absorção são aumentadas pela aplicação localizada de MAP; por outro lado, a aplicação localizada de DAP inibe o crescimento de raízes

Edaphic fauna affects soybean productivity under no-till system

This study aimed to evaluate the relationship of edaphic fauna under a no-tillage system with different levels of soybean productivity [High (NTH), Medium (NTM) and Low (NTL)] in the west of Santa Catarina (Brazil), identifying which chemical and physical variables most affect them, and the best indicators that can be used. Native forest (NF) areas were used as a reference. A total of 207 samples of soil fauna were collected by soil monolith and pitfall trap methods over two years of evaluation in four municipalities. Based on edaphic fauna data, Shannon-Wiener (H’), Pielou (J), Dominance (D), Margalef and Fisher Alpha (α) indices were generated, in addition to the average richness and abundance. Data from NTs were submitted to analysis of variance and compared by Tukey’s test (p > 0.05). The NF was used as a reference and compared with the agriculture system by Dunnett test (p > 0.05), and regressions between soybean productivity and diversity indices. The H’, Margalef, α indices, and average richness for soil fauna sampled by soil monoliths followed the productivity gradient NTH > NTM > NTL, showing a positive correlation with the increase of soybean productivity. NTH has a diversity index similar to that of NF. Soybean productivity is affected by the richness and diversity of edaphic fauna, but abundance was not sensitive in predicting treatments under no-tillage; Fisher’s alpha index was more sensitive in treatment separation with soil monoliths. The environmental variables aluminum, organic matter, phosphorus, potassium and penetration resistance affect the fauna edaphic

Soil spiders (Arachnida: Araneae) in native and reforested Araucaria forests

Spiders are part of the soil biodiversity, considered fundamental to the food chain hierarchy, directly and indirectly influencing several services in agricultural and forest ecosystems. The present study aimed to evaluate the biodiversity of soil spider families and identify which soil properties influence their presence, as well as proposing families as potential bioindicators. Native forest (NF) and reforested sites (RF) with Araucaria angustifolia (Bertol.) Kuntze were evaluated in three regions of the state São Paulo, both in the winter and summer. Fifteen soil samples were collected from each forest to evaluate the biological (spiders and microbiological), chemical and physical soil properties, in addition to properties of the litter (dry matter and C, N and S contents). For soil spiders, two sampling methods were used: pitfall traps and soil monoliths. In total, 591 individuals were collected, and distributed in 30 families, of which 306 individuals (22 families) came from pitfall traps and 285 individuals (26 families) from monoliths. Only samples obtained by the monolith method revealed seasonal differences in the mean density and richness of spiders between NF and RF. Canonical discriminant analysis showed the separation of these forests of Araucaria. Principal Component Analysis demonstrated the correlation of a number of spider families with certain soil properties (organic carbon, basal respiration, metabolic quotient, litter carbon, total porosity, bulk density and soil moisture). We identified 10 families (Anapidae, Corinnidae, Dipluridae, Hahniidae, Linyphiidae, Lycosidae, Nemesiidae, Palpimanidae, Salticidae, Scytodidae) that contributed most to separating native forest from the replanted forest, indicating the possibility of the spiders being used as bioindicators

Fauna edáfica e suas relações com atributos químicos, físicos e microbiológicos em Floresta de Araucária

The permanent plant cover of the soil, in Araucaria forests, contributes to the conservation of the soil biodiversity. The aim of this study was to evaluate the potential of the soil fauna in discriminating native and reforested Araucaria forests. Native (NF) and reforested (RF) Araucaria angustifolia forests were evaluated in three regions of the state of São Paulo, representing three true replicates. In each area, fifteen soil samples were collected for the evaluation of the physical, chemical, and microbiological attributes and at the same points, the fauna was collected, using pitfall traps. The soil fauna was influenced by seasonality, presenting greater abundance of individuals in the summer. Collembola, Formicidae and Coleoptera groups were the most abundant ones, independently of the sampling season and the forest type. The Principal Component Analysis (PCA) and Canonical Discriminant Analysis (CDA) clearly differentiated native or reforested Araucaria areas. In PCA, Hemiptera, Collembola and Diplopoda were associated with RF in the winter, mainly due to the higher litter dry mass values. In NF, Orthoptera, Hymenoptera, Araneae and Coleoptera groups were explained by the higher quality of soil and litter, which was associated with NF. In summer, the groups Hemiptera, Orthoptera, Araneae, Coleoptera and Collembola, associated with NF, were explained by the higher values of microbial biomass carbon, Ca, P, organic carbon, macroporosity and dehydrogenase activity. In the CDA, the abundance of taxonomic groups was the most important attribute of the soil fauna for the discrimination of the forests. Likewise, soil moisture, soil P content, total porosity, and sulfur content of the surface litter contributed to discrimination between forests. There was some similarity between areas regarding certain groups of soil fauna, which we suggest being a result of the stability reached by the reforested areas, rendering them somewhat similar to the native ones.A permanente cobertura vegetal do solo, em Florestas de Araucária, contribui na conservação de sua biodiversidade edáfica. O objetivo deste trabalho foi avaliar o potencial da fauna edáfica e das variáveis ambientais explicativas (físico-químicas e microbiológicas do solo) na discriminação de florestas com araucária nativa e reflorestada. Avaliaram-se florestas com Araucaria angustifolia nativa (NF) e reflorestada (RF) em três regiões distintas no estado de São Paulo, representando três repetições. Em cada área, 15 amostras de solo foram coletadas para avaliação dos atributos físicos, químicos e microbiológicos e, nos mesmos pontos, procedeu-se às coletas da fauna utilizando-se o método de armadilhas de queda (Pitfall traps). A fauna do solo foi influenciada pela sazonalidade, apresentando maior abundância de indivíduos no verão. Os grupos Collembola, Formicidae e Coleoptera foram os mais abundantes, independentemente da época de amostragem e tipo de floresta. A Análise de Componentes Principais (ACP) e Análise Canônica Discriminante (ACD) claramente diferenciaram as áreas de araucárias. Na ACP, Hemiptera, Collembola e Diplopoda ficaram associados à RF no inverno, principalmente pelos maiores valores de matéria seca da serapilheira. Já em NF, foram os grupos Orthoptera, Hymenoptera, Araneae e Coleoptera, explicados pela melhor qualidade do solo e da serapilheira. No verão, ficaram associados à NF, os grupos Formicidae, Hemiptera, Orthoptera, Araneae, Coleoptera e Collembola, explicados pelos maiores valores de CBM, Ca, P, C-org, macroporosidade e atividade de desidrogenase. Na ACD, a abundância de grupos taxonômicos foi o atributo da fauna edáfica mais importante para a discriminação das florestas. Da mesma forma, a umidade do solo, teor de P no solo, porosidade total e teor de S na serapilheira contribuíram na discriminação das florestas. A semelhança entre as áreas, em relação aos grupos da fauna edáfica, indica que está ocorrendo uma estabilidade das áreas reflorestadas comparável às nativas

Impact of Revegetation on Ecological Restoration of a Constructed Soil in a Coal Mining in Southern Brazil

The main problems in the constructed soils are the generation of acid mine drainage promoted by the presence of coal debris in the overburden layer and the compaction of the topsoil promoted by the machine traffic when the material used in the overburden cover is more clayey. This book chapter aimed to show an overview of the impact of more than a decade of revegetation with different perennial grasses on the chemical, physical, and biological quality of constructed soil after coal mining. The study was carried out in a coal mining area, located in southern Brazil. The soil was constructed in early 2003 and the perennial grasses, Hemarthria altissima; Paspalum notatum cv. Pensacola; Cynodon dactylon cv Tifton; and Urochloa brizantha; were implanted in November/December 2003. In 11.5, 17.6 and 18 years of revegetation soil samples were collected and the chemical, physical, and biological attributes were determined. Our results show that liming is an important practice in the restoration of these strongly anthropized soils because this positively impacts the plants’ development, facilitating the roots system expansion. Biological attributes such as soil fauna and the microorganism’s population are the attributes that possibly takes longer to establish itself in these areas

Globally invariant metabolism but density-diversity mismatch in springtails.

Soil life supports the functioning and biodiversity of terrestrial ecosystems. Springtails (Collembola) are among the most abundant soil arthropods regulating soil fertility and flow of energy through above- and belowground food webs. However, the global distribution of springtail diversity and density, and how these relate to energy fluxes remains unknown. Here, using a global dataset representing 2470 sites, we estimate the total soil springtail biomass at 27.5 megatons carbon, which is threefold higher than wild terrestrial vertebrates, and record peak densities up to 2 million individuals per square meter in the tundra. Despite a 20-fold biomass difference between the tundra and the tropics, springtail energy use (community metabolism) remains similar across the latitudinal gradient, owing to the changes in temperature with latitude. Neither springtail density nor community metabolism is predicted by local species richness, which is high in the tropics, but comparably high in some temperate forests and even tundra. Changes in springtail activity may emerge from latitudinal gradients in temperature, predation and resource limitation in soil communities. Contrasting relationships of biomass, diversity and activity of springtail communities with temperature suggest that climate warming will alter fundamental soil biodiversity metrics in different directions, potentially restructuring terrestrial food webs and affecting soil functioning

A aplicação localizada de monoamônio fosfato favorece a disponibilidade de P no solo e sua absorção

The objective of this study was to evaluate the phorphorus absorption by corn seedlings according to the localized application of calcium and ammonium phosphates. The study was conducted in 2011, with samples of Inceptisol (CH) and Udox (NV). The treatments consisted on the application of triple superphosphate (TSP), simple superphosphate (SS) and diammonium phosphate (DAP) and monoammonium phosphate (MAP), beside a control without the addition of P. In all treatments with P, were added 200 mg kg-1 of P and 100 mg kg-1 of K as KCl; the amount of N added by DAP (160 mg kg-1) was adjusted in all treatments by adding CaNO3. Dry matter production of the aerial part (MSPA) was higher in treatments with STF, SS and MAP, in which were respectively 71, 67, 62% higher than the control; while with the DAP was 38%. The phosporus content in the shoots and roots were higher in the soil treated with MAP. The TSP, MAP, and DAP increased P concentrations in the soil, an average 93% higher than the control. The availability of P in the soil and its absorption in increased by localized application of MAP; however, localized application of DAP, inhibits the growth of roots.O objetivo do presente trabalho foi avaliar a absorção de fósforo pelas plântulas de milho em função da aplicação localizada de fosfatos de cálcio e de amônio. O trabalho foi realizado em 2011, com amostra de um Cambissolo Húmico (CH) e um Nitossolo Vermelho (NV). Os tratamentos consistiram da aplicação de superfosfato triplo (SFT), superfosfato simples (SS), diamônio fosfato (DAP) e monoamônio fosfato (MAP), além de uma testemunha sem a adição de P. Em todos os tratamentos com P adicionou-se 200 mg kg-1 de P e 100 mg kg-1 de K, na forma de KCl; a quantidade de N adicionada pelo DAP (160 mg kg-1) foi ajustada nos demais tratamentos pela adição de CaNO3. A produção de massa seca da parte aérea (MSPA) foi maior nos tratamentos com SFT, SS e MAP, nas quais os incrementos foram respectivamente 71, 67 e 62% maiores que a testemunha; enquanto com o DAP foi de 38%. Os teores de P na parte aérea e nas raízes foram maiores no solo tratado com MAP. O SFT, MAP e DAP aumentaram as concentrações de P no solo, cuja média foi 93% superior a testemunha. A disponibilidade de P no solo e sua absorção são aumentadas pela aplicação localizada de MAP; por outro lado, a aplicação localizada de DAP inibe o crescimento de raízes