Content characteristics of mineral elements and its correlation with soil nutrients and effective components in Chrysanthemum morifolium from different producing areas in Macheng / 中国中药杂志

In this study, 24 copies of samples of Chrysanthemum morifolium and soil from two main production towns in Macheng city were collected, and the contents of 13 mineral elements, 5 effective components and 14 soil nutrient factors in Ch. morifolium were determined. The enrichment characteristics of available soil nutrients by mineral elements were analyzed and the dominant factors affecting the effective components of Ch. morifolium were screened. The results showed that the content of mineral elements and soil nutrients and effective components are very different, and variation of soil fertility was much greater than that of inorganic elements in chrysanthemum plants. In general, the level of element content in Ch. morifolium from different producing areas is K>N>P>Mg>Ca>Fe>Mn>Zn>Cu>Ni>Cr>Pb>Cd. The content of K, N and Mg is higher than that of common crops, and the content of Cu, Cd and Pb in Ch. morifolium from various producing areas does not exceed the relevant standards. The N, P and K enrichment capacity in soil was stronger than that of other elements, and the Ca enrichment ability was the worst. The content of AvCu in the soil was positively correlated with the contents of N, Mg, K, Fe and Cu elements in Ch. morifolium. The contents of chlorogenic acid, luteolin, 3,5-O-dicaffeoylquinic acid reached the pharmacopoeia standard. The percentage of chlorogenic acid and 3,5-O-dicaffeoylquinic acid in Ch. morifolium that from Huangtugang town in the active components were generally higher than that from Futianhe town, and the diffe-rences of luteolin contents in the two producing areas were relatively small. The correlation and regression analysis showed that the contents of Cu, Zn and Cr in Ch. morifolium were positively correlated with the active components, while the contents of Fe, Mn and Ni were negatively correlated with the contents of AvP, AvK, TK, AvMn and AvCu in soil. In general, Zn and Ca fertilizer should be added to the ecological planting of Ch. morifolium, K fertilizer should be added, and N and P fertilizer should be applied appropriately.

Effect of Different Arbuscular Mycorrhizal Fungi Combinations and Inoculation Periods on Rhizosphere Soil Physicochemical Properties and Microbial Quantity of Paris polyphylla var. yunnanensis Seedlings / 中国实验方剂学杂志

Objective:To study the effects of different arbuscular mycorrhizal （AM） fungi combinations on rhizosphere soil physicochemical properties and microbial quantity in the seedlings of Paris polyphylla var. yunnanensis at different inoculation periods，so as to lay a foundation for cultivating high-quality P. polyphylla var. yunnanensis. Method:The spore density，infection rate，nutrient and enzyme activity in the soil around the roots of P. polyphylla var. yunnanensis seedlings under different AM fungi combinations and different inoculation periods were analyzed by the greenhouse pot inoculation trials and soil agrochemical analysis methods. Result:The infection rate of different AM fungi treatment groups was more than 80% in different inoculation periods，and the spore density was higher than control （CK） group in some periods. It reflected that the relationship between AM fungi and roots of Paris polyphylla seedlings was favorable. The content of nitrogen in the soil decreased，but the content of available P，available K and soil pH increased. The soil nutrients in the cultivar one-year seedlings and wild seedlings were higher. The total number of soil microorganisms showed that bacteria>actinomycetes>fungi. The cultivar two-year seedlings with AM fungi combinations of S3，S5 and S8 had better soil structure and higher biomass carbon content. The growth rates of phosphatase and protease activity were higher in the soil，but catalase activity was lowest. In the treatment groups S2，S3，S4，S5 and S6，the soil enzyme activities of the wild seedlings and one-year-old seedlings were best. Conclusion:Different AM fungal treatment groups and different inoculation periods had certain effects on rhizosphere soil physicochemical properties and microbial quantity in the seedlings of P. polyphylla var. yunnanensis， which provided a technical basis for the cultivation of P. polyphylla var. yunnanensis.

Effect of Different Arbuscular Mycorrhizal Fungi on Soil Nutrients in Rhizosphere Soil of Paris polyphylla var. yunnanensis Seedlings / 中国实验方剂学杂志

Objective:To clarify the effect of the arbuscular mycorrhizal （AM） fungi on the rhizosphere soil nutrient content，AM fungi infection rate and total rhizome saponins content of Paris polyphylla var. yunnanensis under symbiosis culture. Method:The changes in the root AM fungi infection rate，rhizosphere soil nutrient content，total rhizome saponins content of P. polyphylla var. yunnanensis and the relationship of the rhizosphere soil factors，the infection rate and the total rhizome saponins content after AM fungi inoculation were analyzed by the method of combining room temperature pot inoculation and data analysis. Result:As compared with the CK group，the root AM fungi infection rate of the AM inoculation group was significantly enhanced （P<0.05），the content of easily extractable glomalin，total glomalin，and total nitrogen increased significantly，while available potassium content and pH significantly decreased. After inoculation with AM fungi，the contents of total phosphorus，available phosphorus，available nitrogen，ammonium nitrogen，nitrate nitrogen，available potassium，and organic matter in the rhizosphere soil of P. polyphylla var. yunnanensis showed significant differences as compared with the CK group. The soil nutrient status was improved，and the total saponin content in the rhizome of P. polyphylla var. yunnanensis was increased. Conclusion:Inoculation with AM fungi can improve the rhizosphere soil nutrient status of P. polyphylla var. yunnanensis，promote the nutrient transformation in the rhizosphere soil，promote the growth of P. polyphylla var. yunnanensis，and improve the quality of medicinal herbs.

Variation Pattern of Rhizospheric Soil Nutrient for Fritillaria taipaiensis / 中国实验方剂学杂志

Objective: To study the variation patterns of rhizospheric soil nutrient and the content of nutrient elements for Fritillaria taipaiensis,in order to provide the theoretical base for the soil improvement and balanced fertilization during the artificial cultivation. Method: Totally 14 samples of rhizospheric soil of Fritillaria taipaiensis from different origins and years were taken as the research objects. Total N,available N,total P,available P,total K,available K,organic matter,pH and 7 nutrient element contents (Ca,Mg,Na,Mn,Zn,Cu and Ni) were analyzed by the soil agrochemical analysis method combined with the atomic absorption spectrophotometry. SPSS 22.0 software was applied for data multiple comparison and correlation analysis. Result: The all results showed significant differences (PF. taipaiensis. The content of total N,available N,total P,available P and organic matter of rhizospheric soil collected from cultivated varieties decreased with the increase of years,and the content of total K,available K and pH decreased first and then increased. However,the soil physical and chemical properties of wild varieties had no obvious change with the increase of years. The content of Ca,Mg,Na and Cu of soil from cultivated varieties decreased with the increase of years,while the content of Mn decreased first and then increased. And Zn and Ni showed no significant change with the increase of years. Compared with cultivated varieties,the content of Ca,Mg,Na,Mn and Cu increased first and then decreased. The content of Zn and Ni showed no obvious change. In general,the rhizospheric soil nutrient and the content of nutrient elements for wild F. taipaiensis were superior to those of cultivated varieties. Conclusion: The third year is the turning point of F. taipaiensis growth. The rhizospheric soil nutrient and the content of nutrient elements decreased obviously after three years. Attention shall be given to the balanced fertilization,the improvement of soil quality and the prevention of the cropping during cultivation of F. taipaiensis.

Understory host plant and insect gall diversity changes across topographic habitats differing in nutrient and water stress in the Brazilian Amazon rainforest / Riqueza de insetos galhadores associados a habitats de sub-bosque com diferentes topografias e níveis de estresse hídrico e nutricional em uma floresta da Amazônia Central, Brasil

ABSTRACT Topographic gradients in terra firme forests are associated with pronounced changes in soil texture, soil nutrients and distance to the water-table, thereby creating different hydric and nutritional conditions for plants and their associated herbivore community. The aim of this study was to investigate galling species and host plant richness and gall species composition across topographic habitats differing in nutrient and water stress in the Brazilian Amazon rainforest. Nineteen 250 x 3 m plots were randomly sampled in the valley, slope, plateau-slope transition, and plateau habitats in terra firme forests. All individual dicotyledonous plants 1 to 3 meters high were examined for the presence of insect galls. Galling species and host plant richness differed significantly among the studied habitats and were higher in slope habitats (drier habitats), as expected. More humid areas (valleys) showed the lowest richness of galling species, and a lower number of understory host plants. PERMANOVA and PERMDISP results demonstrated that the gall species composition differed significantly in the valley, slope, plateau-slope transition, and plateau areas. However, these structural differences in species composition could be due to unequal dispersion of variability among forest habitats. Our data suggested that spatial heterogeneity, such as a mosaic of local water status and nutrient availability resulting from the topographic conditions, can affect host plants and their associated galling insects.

RESUMO As variações topográficas encontradas nas florestas de terra firme são acompanhadas por fortes mudanças no conteúdo de argila e concentração de nutrientes do solo, criando, portanto, diferentes condições hídricas e nutricionais para plantas e as comunidades de herbívoros associadas. O objetivo do presente estudo foi avaliar a riqueza e composição de espécies de insetos galhadores e suas plantas hospedeiras ao longo de um gradiente topográfico com habitats que diferem quanto ao estresse hídrico e nutricional. Dezenove parcelas de 250 x 3 m foram estabelecidos aleatoriamente em habitats de vertente, platô, transição platô-vertente e baixio, claramente distintos em áreas de terra firme. Todas as dicotiledôneas com 1 a 3 metros de altura foram examinadas quanto à presença de galhas de insetos. As galhas encontradas foram coletadas e insetos galhadores foram classificados em morfoespécies. A riqueza de galhadores e de plantas hospedeiras diferiram significativamente entre os habitats estudados, e como esperado, foi maior no habitat de vertente. As áreas mais úmidas (baixios) apresentaram menor riqueza de plantas hospedeiras no sub-bosque e, conseqüentemente, um número menor de espécies de galhadores. Os resultados das análises de PERMANOVA e PERMDISP demonstraram que a composição da espécie de insetos galhadores variou significativamente entre as áreas de floresta de terra firme. No entanto, essas diferenças estruturais na composição das espécies podem ser devidas à dispersão desigual da variabilidade entre os habitats. Nossos dados sugerem que a heterogeneidade espacial, tal como o mosaico de status hídrico e nutricional do solo associado às condições topográficas, pode afetar plantas hospedeiras e insetos galhadores associados.

A survey on ecological environment of wild Adiantum reniforme var. sinense in Three Gorges Reservoir region / 中国中药杂志

The study aims at investigating the ecological environment Adiantum reniforme var. sinense of in Three Gorges Reservoir region, and providing a reference basis for the protection of resources and artificial cultivation of A. reniforme var. sinense. By using the method of investigation, field survey and experimental analysis, the vegetation, natural geographical environment, climate, soil nutrients of A. reniforme var. sinense were studied and analyzed. The survey found that A. reniforme var. sinense distribution area reduced fast in Three Gorges region, a lot of distribution has diminished and vanished due to excessive digging, currently only in 3 towns of Wanzhou there exist 4 wild distribution areas. The growth of A. reniforme var. sinense needs an environment with low altitude, steep slope and thin soil, northeast slope, canopy height and warm and humid climate characteristics, and the soil in distribution has the characteristics of high organic matter, available nitrogen, available potassium, and low available phosphorus content.

Development of transgenic pigeonpea (Cajanus cajan. L Millsp) overexpressing citrate synthase gene for high phosphorus uptake.

Plants have developed several adaptive strategies to enhance the availability and uptake of phosphorus (P) from the soil under conditions of P deficiency. Exudation of organic acids like citrate is one of the important strategies. In this study, we developed transgenic pigeonpea (Cajanus cajan) over-expressing Dacus carota citrate synthase (DcCs) gene to increase the synthesis and exudation of citrate. Transgenic plants were generated through agro bacterium mediated in-planta transformation technique. Integration and expression of the transgene was confirmed by genomic Southern and RT-PCR analysis. We observed that the transgenic lines had more tissue P and chlorophyll content, and also citrate synthase content higher in the roots. Further, transgenic lines had more vigorous root system both under P sufficient and deficient conditions with more lateral roots and root hairs under P deficient conditions. We conclude that the transgenic pigeonpea plants have the capacity to acquire more P under P deficient conditions.

Correlation of Active Ingredients in the Roots of Paridis rhizoma Genus Plants with Mycorrhizal Infection Rate and Soil Nutrients / 中国药房

OBJECTIVE:To investigate the correlation of total saponins and total polysaccharides content in the roots of Pari-dis rhizoma genus plants with Arbuscular mycorrhizal fungi(AMF)infection rate and rhizosphere soil nutrients. METHODS:Tak-ing 16 pieces of Paridis rhizoma herbs and rhizosphere soil in Three Gorges Reservoir Area as the research object,mycorrhizal in-fection rate and infection intensity,the contents of total saponins and total polysaccharides in roots and stem,and rhizosphere soil nutrient contents were all determined. SPSS18.0 software was adopted for data multiple comparison and correlation analysis. RE-SULTS:Paridis rhizoma genus plants roots in Three Gorges Reservoir Area could form a good symbiotic relationship with AMF. In-fection rate ranged from 85.19% to 99.80%,and infection intensity ranged from 16.55% to 72.27%. Paridis rhizoma from differ-ent origins and varieties had significant difference in the contents of total saponins and total polysaccharides (P<0.05). Soil pH was moderate,the average content of total nitrogen was in insufficient level,the average concentration of the remaining nutrients belonged to middle levels or above. Correlation analysis showed that the mycorrhizal infection rate and infection intensity of Paridis rhizoma were not significantly correlated with its quality. The total saponins were significantly negatively correlated with organic matter and available nitrogen. The total saponins and total polysaccharides were positively correlated with available phosphorus,po-tassium and pH value,but they were not significantly correlated with the other soil nutrients. CONCLUSIONS:Paridis rhizoma is selective to different soil nutrients. Rich soil available phosphorus and potassium supply are in favor of the synthesis and accumula-tion of total saponins and total polysaccharides in Paridis rhizoma roots.

Recuperación de tres coberturas forestales de altura media en Costa Rica: análisis de los oligoquetos, el mantillo y suelo / Recovery of three tropical forest covers from mid-elevation sites in Costa Rica: oligochaetes, litter and soil analysis

In Costa Rica, the region of Río Macho is a highly fragmented landscape with imminent risk of landslides. This area, which provides important environmental services, has been partially recovered to its original forest through intentional reforestation with exotic species or natural regeneration after abandonment. The aim of this study was to evaluate the bioindicator potential of oligochaete presence as well as some litter and soil characteristics. The ecosystem recovery of the two common restoration modes was measured within three different forest covers. For this, some substrate characteristics were analyzed and compared in a 50 years old secondary forest, a 13 years tacotal, and a 35 years cypress (Cupressus lusitanica) plantation. The three sites studied differed in density, biomass and average mass of oligochaetes, and in some litter (depth, nitrogen, phosphorus and C/N ratio of litter), and soil variables (soil water content (CA), pH, phosphorus, cation exchange capacity, and magnesium). The forest registered the lowest density of earthworms and soil pH, and the highest soil CA and phosphorus. CA was inversely related to the oligochaete density across sites. Besides, there were positive correlations between C/N and C/P ratios from the litter and soil pH, and inverse correlations of litter depth, litter N and P concentrations with soil P. Discriminant Analysis (AD) performed with all soil and litter variables, produced a sharp classification of the three forest cover types. AD suggests that site differences were mostly determined by soil CA and litter nitrogen concentration. Considering all the evaluated parameters, our results suggest in the first place, that oligochaetes are sensitive to changes in some soil and litter characteristics. Secondly, aside from the striking oligochaete differences between the old secondary forest and the other two sites, some soil and litter traits resulted good indicators of the present recovery of the three forest covers. In addition, comparing soil nutrients content (organic carbon, nitrogen, calcium, potassium and sulfur) among the three sites, our findings indicate that the cypress plantation had reached soil nutrient conditions similar to the old secondary forest, presumably by the accumulation of nutrients, as a result of low nutrient recirculation. In conclusion, ecosystem level studies throughout simple evaluation criteria (soils, oligochaetes and ground litter) can be used as rapid indicators of the state of some of the many and complex forest ecosystem compartments.

La región Río Macho, un paisaje altamente fragmentado con riesgos inminentes de derrumbes e importantes servicios ambientales, ha sufrido una recuperación parcial de su vocación forestal por reforestación con especies exóticas y regeneración natural. Hemos comparado algunos rasgos del sustrato mediante la combinación del potencial bioindicador de los oligoquetos, rasgos del mantillo y características fisicoquímicos del suelo en tres sitios (bosque secundario viejo, tacotal y plantación Cupressus lusitanica). El bosque presentó la menor densidad de oligoquetos, el menor pH y el mayor contenido de humedad (CA) y fósforo del suelo. Hubo una correlación positiva entre los cocientes de C/N y C/P del mantillo y el pH del suelo, y negativa entre la profundidad, nitrógeno, fósforo del mantillo y fósforo del suelo. Los resultados sugieren que los oligoquetos son sensibles a cambios de los rasgos antes mencionados, que algunos de estos rasgos pueden ser buenos indicadores de la condición actual de regeneración de las coberturas estudiadas, y las coberturas han alcanzado concentraciones de varios nutrientes similares al bosque secundario viejo. Estos estudios a nivel ecosistémico a través de la evaluación de criterios sencillos pueden ayudarnos a inferir rápidamente el estado de algunos de los muchos y complejos compartimentos de los ecosistemas.

Dinámica del ciclo del nitrógeno y fósforo en suelos / Nitrogen and phosphorus cycles dynamics in Soils

Los ciclos biogeoquímicos del fósforo (P) y del nitrógeno (N) son sistemas dinámicos que suceden a través de la biosfera, de cuyos mecanismos de transformación depende la disponibilidad de estos elementos para diferentes formas de vida. Se acepta que la diversidad y actividad de las poblaciones microbianas posee un papel crucial en la dinámica de los nutrientes y por tanto el desafío está en comprender, como responden a las condiciones ambientales. La actividad microbiana en los suelos depende tanto de la condición del recurso y como de sus propiedades químicas, físicas y biológicas. En este documento se describen conceptos que se han empleado para entender la dinámica del nitrógeno y el fósforo, con el propósito de discutir cómo las características de las diferentes fracciones orgánicas y minerales seleccionan el potencial biológico encargado del recambio de dichos elementos, panorama que actualmente se aborda a través de técnicas independientes del cultivo para estudiar las poblaciones microbianas in situ.

Biogeochemical cycle’s phosphorus (P) and nitrogen (N) are dynamic systems taking place through the biosphere, whose mechanisms of transformation depends on the availability of these elements for different forms of life. It is accepted that the diversity and activity of microbial populations plays a crucial role in nutrient dynamics and therefore the challenge is to understand how they respond to environmental conditions. Microbial activity in soils depends on both the resource condition and its chemical, physical and biological properties. Concepts described herein have been used to understand the nitrogen and phosphorus dynamics, with the aim to discuss how the characteristics of the different organic and mineral fractions select the biological potential responsible for the turnover of these elements, scenario currently addressed through cultivation-independent techniques to study microbial populations in situ.

Prosopis laevigata and Mimosa biuncifera (Leguminosae), jointly influence plant diversity and soil fertility of a Mexican semiarid ecosystem

Prosopis laevigata and Mimosa biuncifera are frequently found in arid and semiarid shrublands, but scarce information is available about their influence on plant community structure and soil fertility. We compared plant community structure, diversity and soil nutrients of three semiarid shrubland sites located in Mezquital Valley, Mexico. These sites differ in their dominant species: Site 1 (Bingu) P. laevigata, Site 2 (González) M. biuncifera, and Site 3 (Rincón) with the presence of both legumes. The results showed that the plant community with P. laevigata and M. biuncifera (Site 3) had more cover, taller plants and higher plant diversity than sites with only one legume (Site 1 and Site 2). Soil organic matter (SOM), soil organic carbon (SOC), total nitrogen (TN), phosphorus-Olsen (P) and C mineralization were higher in the soil under the canopy of both legumes than in bare soil. In contrast, soil cation concentrations were lower under the canopy of P. laevigata, but not for M. biuncifera. In addition, the density of arbuscular mycorrhizal fungi spores was higher within the soil under the canopy of M. biuncifera than in the soil under the canopy of P. laevigata. Thus, resource islands (RI) created by P. laevigata increased the amounts of SOC, TN and P when compared with the RI of M. biuncifera. This study provided evidences about the importance of species identity in order to expand the niche availability for the establishment of other plants, and highlights that P. laevigata and M. biuncifera jointly influencing plant colonization within semiarid ecosystems.

Prosopis laevigata y Mimosa biuncifera coexisten en los matorrales semiáridos; sin embargo, se desconoce su influencia sobre la diversidad de la comunidad vegetal y el suelo. Este estudio evaluó el efecto de P. laevigata y M. biuncifera sobre la estructura, diversidad vegetal y nutrimentos del suelo, en tres matorrales del Valle del Mezquital, México. Los sitios difieren en la especie dominante: Sitio 1, P. laevigata; Sitio 2, M. biuncifera y Sitio 3, ambas leguminosas. En cada sitio se recolectó suelo, tanto abajo y fuera del dosel de las leguminosas, además, se realizaron transectos para medir e identificar las plantas arbóreas y arbustivas, se calculó el índice de valor de importancia y la diversidad del matorral. Asimismo, se registró mayor riqueza y diversidad en el Sitio 3 (ICE 29 spp. y H’ 2.7), en comparación con el Sitio 1 (24 spp. y 2.4) y Sitio 2 (26 spp. y 2.1). La materia orgánica y el carbono orgánico del suelo, así como el N total, el P-Olsen y la mineralización de C fueron mayores en el suelo bajo dosel de ambas leguminosas. La abundancia de esporas de hongos micorrizógenos arbusculares fue favorecida por M. biunficera. La influencia de P. laevigata para crear islas más ricas en recursos fue mayor que en M. biunficera, lo anterior sugiere que cada leguminosa modifica de una forma diferente el microambiente, sin embargo, juntas aumentan la disponibilidad de nichos para el establecimiento de otras especies, lo queayuda a comprender el papel de P. laevigata y M. biuncifera sobre la colonización vegetal en ecosistemas semiáridos.

Nutrient status in soil of Ski runs in the sub-alpine belt of Uludag mountain, Bursa, Turkey.

Large areas of land are disturbed in sensitive bio-diverse mountain environments by Ski runs. Restoration of vegetation on such disturbed mountain sites may be hampered by soil degradation but the severity and nature of the constraints is not well understood. This study was designed to compare the water holding and nutritional status of soil in three Ski runs which had different construction dates and disturbance levels, and the adjacent undisturbed site in the Abies bornmuelleriana forest community in the sub-alpine belt of Uludag Mountain (Bithynian Olympus). The values of soil parameters were depressed in proportion to the disturbance level. Water holding capacity (WHC), total nitrogen (N), organic carbon (C) and calcium (Ca2+), magnesium (Mg2+) and potassium (K+) contents (mg kg-1 dry weight) of soils in the Ski run which had the highest disturbance level were lower than that of the undisturbed adjacent sites. However, the results indicated that the soil parameters were less degraded when secondary vegetation was growing on the disturbed areas.

Effects of forest fire on soil nutrients in Turkish pine (Pinus brutia, Ten) Ecosystems.

Fire is a long-standing and poorly understood component of the Mediterranean forestlands in Turkey. Fire can alter plant composition, destroy biomass, alter soil physical and chemical properties and reduce soil nutrient pools. However, fire can also promote productivity of certain ecosystems by mineralizing soil nutrients and promoting fast growing nitrogen fixing plant species. Fire effects on soils and ecosystems in Turkey and Mediterranean regions are not well understood. This study, uses a retrospective space-for-time substitution to study soil macro-nutrient changes on sites which were burned at different times during the last 8 years. The study sites are in the Fethiye Forest Management Directorate in the western Mediterranean Sea region of Turkey. Our samples show 40% less Soil C, and cation exchange capacity (CEC) at 0-20 cm soil depth two weeks after the fire. Soil C and CEC appear to recover to pre-fire level in one year. Concentrations of Mg were significantly lower on new-burn sites, but returned to pre-fire levels in one year. Total soil N concentrations one and two years after fire were 90% higher than other sites, and total P was 9 times higher on new-burn site than averages from other sites. Some implications of these results for forest managers are discussed.

Nutrientes no solo em floresta de terra firme cortada seletivamente na Amazônia Central

Soil pH, organic matter, and concentrations of extractable-P, exchangeable K, Ca, Mg and Al were measured in selectively logged plots of upland rain forest, 80 km north of Manaus. Soil type corresponds to an acid and very clayey Oxisol, (ca. 80 % of clay). Two control plots of intact forest and two plots submitted to selective logging were studied in 1987 and 1993. Results confirmed high soil acidity, and showed highest concentrations of extractable-P, and exchangeable-K, Ca, Mg and Al in the wet season. Both control and logged plots, showed the following ranking of concentrations for soil pit analyses: Al > Ca > > Mg, in the wet season, and Al > > Mg > Ca in the dry season. There are evidences that the timber residues left from selective logging rises soil nutrient values through decay, especially during the wet season.

Foram medidos o pH, a matéria orgânica, o fósforo assimilável, o potássio, o magnésio, o cálcio e o alumínio trocáveis no solo de uma área de manejo florestal em floresta de terra firme localizada a 80 km ao norte de Manaus. O solo é um Latossolo Amarelo álico de textura muito argilosa. O experimento constou de duas parcelas controle e duas que sofreram manejo em tempos distintos (uma em 1987 e a outra em 1993). Os resultados mostraram que esses solos são muito ácidos e que os teores de fósforo assimilável, potássio, magnésio, cálcio, e alumínio trocáveis são mais altos no período chuvoso do que no período seco. Nos perfis do solo da floresta remanescente e do centro de clareira do manejo de 1987, as concentrações dos elementos estudados seguiram a ordem Al > Ca > > Mg no período chuvoso e Al > > Mg > Ca no início do período seco. Há evidências de que os resíduos de madeira deixados pela extração seletiva aumentaram a concentração de nutrientes no solo, pela sua decomposição, especialmente na estação chuvosa.