Soil Base Saturation Research Articles

Agronomic performance and water‐use efficiency of F3 soybean populations grown under contrasting base saturation

AbstractMost of the Brazilian soils, especially in Cerrado biome, have high acidity and toxic aluminium, making the application of limestone an indispensable technique to obtain high yield in soybean crop. The hypothesis of this study was that contrasting base saturation provides changes in water‐use efficiency (WUE) and agronomic traits of soybean populations. Thus, we evaluated the WUE and agronomic performance of F3 soybean populations under different base saturation levels. Each experiment was conducted in a randomized complete blocks design with three replicates and 10 F3 populations (P1, P2, P3, P4, P5, P6, P7, P8, P9 and P10) for two crop seasons. Segregating populations were obtained by bulk method. In the first experiment, F3 populations were evaluated without correction of base saturation (V = 30%), while in the second experiment, limestone was applied three months before sowing to increase base saturation to 60%. The traits evaluated were as follows: calcium, magnesium and potassium contents, water‐use efficiency (WUE), plant height, first pod height, main stem diameter and grain yield. Our findings indicate that WUE and agronomic performance of F3 soybean populations depends on the saturation condition. We identified the P4 and P9 populations as the most promising for use in breeding programmes aiming at higher tolerance to abiotic stress caused by low base saturation in soil.

Combined effects of soil fertility and vegetation structure on early decomposition of organic matter in a tropical riparian zone

Monitoring forests undergoing restoration is important to evaluate not only the development of trees, but also the recovery of ecosystem functions. The decomposition of the organic matter is an important ecological process, and nutrient cycling in ecosystems is a good indicator of forest ecosystem functions because it responds to physical, chemical, and biological characteristics of the vegetation and the soil. We hypothesized that both soil fertility and vegetation structure have direct and positive effects on decomposition processes. We used the Tea Bag Index (Keuskamp et al., 2013) to evaluate early decomposition of the organic matter in three land use categories, pasture, riparian forest undergoing restoration, and riparian forest remnant. Each category extended along a gradient of soil nutrients, enabling to jointly evaluate the effects of soil nutrients and vegetation structure on the decomposition process, using structural equations models to also describe the covariance between soil nutrients and vegetation. The decomposition rates (k) were negatively related to vegetation development, possibly due to less light in the forest floor, and less activity of the decomposer community. On the other hand, soil fertility had direct positive effects on k, possibly with higher microbial activity due to higher nutrient availability. The stabilization factor (S) was not influenced by soil nutrients or vegetation structure. However, in the riparian forest remnant plots, S increased with soil base saturation, indicating an interaction between the effects of soil fertility and land use category. Therefore, the decomposition process in this system responded to soil fertility and vegetation structure, but the magnitude of these effects varied with land use. The monitoring of this ecosystem function to evaluate ecosystem recovery should include simultaneously both soil and vegetation variables.

Variations of soil physicochemical properties and vegetation cover under different altitudinal gradient, western Hyrcanean forest, north of Iran

This study was done to quantify the amount of soil organic matter and to evaluate physicochemical properties and vegetation cover changes along the altitudinal gradient. Nine altitudinal transects were selected from 100 m a.s.l. to 1 700 m a.s.l. Then, 160 circular plots of 1 000 m2 area with a distance of 150 m from each other were studied. Soil texture, bulk density, particle density, soil base saturation, phosphorus and potassium values did not indicate any specific variation pattern. Whereas pH decreased powerfully, the highest and the lowest value of pH was measured at 100 m a.s.l. and 1 700 m a.s.l., respectively. Soil organic carbon content increased significantly with increasing altitude (P ≤ 0.01). Density of trees decreased dramatically from 100 to 900 m a.s.l., whereas this trend was ascending from 1 100 to 1 700 m a.s.l. Density of shrub species increased with increasing altitude along the gradient and the highest value was revealed at 1 300 m a.s.l. The highest percentage of herbaceous species cover was found at a lower altitude and a decreasing trend was found along the altitudinal gradient.

Effects of Liming on the Growth and Nutritional Status of Crambe (Crambe abyssinica Hochst)

Crambe cultivation has expanded in Brazil. The species is a promising alternative for biodiesel production since its seed contain great amounts of oil. Nevertheless, only few studies have focused on the growth and nutritional requirements of crambe cultivated in acidic soils. Thus, this study aimed to evaluate the effects of liming on the growth and nutrient accumulation of crambe cultivated in a Yellow Latosol of medium texture. The experiment was carried out using a randomized complete block design. The treatments consisted of different soil base saturation levels (0%, 20%, 40%, 60% and 80%) with five replications. Plant height, leaf length, leaf width and the number of seeds were evaluated 90 days after planting. The plant material was separated into leaves, stem, seeds and roots, which were oven dried at 70 ºC until constant weight. Analysis of variance was performed, followed by data regression when significant at 5% probability level by the F test. Crambe responded positively to liming in the soil under study at a base saturation of 56.95% as a function of the biometric variables. The increase in the base saturation of the soil to up to 60% promoted a drastic reduction in plant growth and, therefore, in the final grain yield. The decreasing order of the leaf nutritional content at 56.95% base saturation was: N>Ca>K>Mg>S>P>Fe>B>Mn>Zn> Cu.

Tree communities and soil properties influence fungal community assembly in neotropical forests

AbstractThe influence exerted by tree communities, topography, and soil chemistry on the assembly of macrofungal communities remains poorly understood, especially in highly diverse tropical forests. Here, we used a large dataset that combines inventories of macrofungal Basidiomycetes fruiting bodies, tree species composition, and measurements for 16 soil physicochemical parameters, collected in 34 plots located in four sites of lowland rain forests in French Guiana. Plots were established on three different topographical conditions: hilltop, slope, and seasonally flooded soils. We found hyperdiverse Basidiomycetes communities, mainly comprising members of Agaricales and Polyporales. Phosphorus, clay contents, and base saturation in soils strongly varied across plots and shaped the richness and composition of tree communities. The latter composition explained 23% of the variation in the composition of macrofungal communities, probably through high heterogeneity of the litter chemistry and selective effects of biotic interactions. The high local heterogeneity of habitats influenced the distribution of both macrofungi and trees, as a result of diversed local soil hydromorphic conditions associated with contrasting soil chemistry. This first regional study across habitats of French Guiana forests revealed new niches for macrofungi, such as ectomycorrhizal ones, and illustrates how macrofungi inventories are still paramount to can be to understand the processes at work in the tropics.Abstract in Spanish is available with online material.

Yield index of crops grown under no-tillage after superficial application of micronized liming materials (MLM) on the soil

The development of strategies for the control of soil acidity in production systems using micronized liming material (MLM) could be a strategy in areas under no-till (NT) to produce high crops yield. The micronized liming material (MLM) have faster reaction on the soil surface even without incorporation to the soil. The experimental design used was completely randomized blocks in split-plot with four replications in a Typic Distrudept under NT treated with MLM. In the main plots the dolomitic limestone (DL) and MLM (granulated micronized calcite (GMC); granulated micronized dolomite (GMD) and carbonated suspension (CS) were studied. In the subplots, four doses of liming materials aiming were assigned to increase soil base saturation (BS) to 50, 70 and 90 %, besides of control treatment. We measured the relative yield (RY), relative yield change (RYC) and production efficiency (PE) of wheat, soybean, black oat and maize during four consecutive years (2012 to 2016). The MLM presented major RY and PE along experimental period than DL. Besides, the major RYC of MLM refers to lower responsiveness, major residual effect as well as major or maintenance crops yield. Better results were found in the BS dose aiming to 61 % for all the liming materials studied for PE, showing that it is the adequate BS for control of acidity in Typic Distrudept.

Palm Oil Mill Efluent - Zeolite Mixture Improves Acid and Base Cations in Acid Sulfate Soil

Acid sulfate soil contains high acid cations. Palm oil mill effluent (POME) mixed with zeolite can increase pH of acid sulfate soil. Base cations (Ca, K and Mg) on zeolite are exchangeable with H+ and Al3+ ions in acid sulfate soil. The aim of this study was to investigate the effects of application of POME-zeolite mixture on acid cations of acid sulfate soil. The study was arranged in a Completely Randomized Design, with 9 treatments of POME applied on 10 kg of acid sulfate soil. Acid sulfate soil was put into 45cm x 40cm polybag. POME plus zeolite powder (60 mesh, type clinoptilolite) was applied on soil by watering evenly and incubated for 4 weeks at room temperature. The results showed that the content of acid cations of exchangeable-Al and exchangeable-H decreased by 71.21% and 27.71%, respectively after application of POME -zeolite. The application of POME without zeolite decreased the content of exchangeable-Al and exchangeable-H by 46.54% and 42.75%, respectively. Aluminium saturation has decreased after POME-zeolite application from 42.68% (high) to 8.52% (very low). Base saturation increased after application of POME-zeolite application from 17.64% (very low) to 34.88% (low). Application of palm oil mill effluent-zeolite mixture decreased acid cations in acid sulfate soil. Base saturation correlates positively to pH and cation exchange capacity and negatively correlates to Al saturation. The main factors controlling the increase of pH, base saturation and cation exchange capacity of acid sulfate soil after POME-zeolite application were the decrease of exchangeable-H, followed by exchangeable-Al and total-Fe.

Changes in Soil Properties and Crop Yield as a Function of Early Desiccation of Pastures

The aim of this study was to evaluate the early desiccation of pasture on soil biological and chemical properties, and yield of soybean (Glycine max) and maize (Zea mays). The experiment was carried out in a Dystroferric Red Argisol. The experimental area was occupied with Urochloa brizantha (cv Marandu) for 5 years before this experiment. The experiment was designed with five treatments, consisting of different periods from desiccation of pastures (15, 30, 60, 120, and 150 days before soybean). Soybean and maize were grown in two consecutive years and soil samples were collected at the beginning and end of each crop for analysis of biological (microbial biomass C and N, microbial quotient, soil respiration, metabolic quotient (qCO2), dehydrogenase and phosphatase) and chemical (pH, soil organic matter, P, K, H + Al and base saturation) properties. The earliest desiccation of pastures (150 days) increased soil microbial biomass C (136 mg kg− 1) and N (16 mg kg− 1), while decreased soil respiration (1.4 mg C-CO2 kg− 1 h− 1) during the first year of soybean and maize. Soil pH (6.4), K content (74.3 mg kg−1) and base saturation (37.2%) also increased with the earliest period of desiccation. During the second year of soybean and maize, the differences in soil biological properties were lower than the first year. The early desiccation of pastures contributed for increasing crop yield. The early desiccation of pastures influences positively the soil properties and crop yield, being a suitable practice for improving soil quality and yield.

Acidity Control After Surface Application of Micronized Liming Material in a Typic Distrudept Under No-Tillage

Abstract The objected to evaluate the pH and soil base saturation (V) values, during 45 months after, surface application and without incorporation of the liming materials in deeper layers of soil. The experimental design was completely randomized blocks in split-plot with four replications. In the plots were studied the dolomitic limestone (DL) and micronized liming materials (MLM) - granulated micronized calcite (GMC) and dolomite (GMD), and carbonated suspension (CS). In the subplots were studied doses of all the liming materials aiming to increase V to 50, 70 and 90% besides of control treatment. We measured the pH and V values in 0-5, 5-10, 10-20, 20-40 and 40-60 cm soil layers over time (5, 15, 28, 37 and 45 months). The MLM were more efficient to increase and maintain the pH and V, over time, than DL. The doses of MLM aiming V to 50-70% increasing the pH and V of Typic Distrudept. Despite the MLM are more fineness than DL, the effectiveness for soil acidity control in subsoil were inefficient, because theses pH and V increases/maintains occurred just in 0-5 cm layer. However, the MLM present lower gap between the V estimated and obtained, in the 0-5 cm layer, than DL.

Extended use of poultry manure as a nutrient source for flood-irrigated rice crop

Abstract: The objective of this work was to evaluate changes in the soil chemical properties, nitrogen use efficiency, and grain yield of flood-irrigated rice fields after the addition of poultry manure during five years. Trials were carried out in a randomized complete block design, with three replicates. The treatments were: chemical fertilizers, N-P2O5-K2O; control, no fertilizers; and poultry manure doses, 2.5, 5.0, and 10.0 Mg ha-1. Poultry manure increased soil pH, base saturation, and phosphorus, potassium, calcium, and zinc contents more than the chemical fertilizers. Adding poultry manure to the soil increased N ammonification (35 mg kg-1 NH4 +-N) from the first to the fourth week after rice was sown. The exclusive use of poultry manure was not sufficient to provide adequate nutrition to rice plants after the decrease in NH4 +-N content in the soil. The cumulative N uptake by plants and rice yield were lower with poultry manure application than with the chemical fertilizers. Adding poultry manure to flood-irrigated rice fields for five years alters soil chemical properties, improves fertility, does not favor nitrogen use efficiency by rice plants, and promotes a lower grain yield than the chemical fertilizers.

Acidity Control Utilizing Different Soil Management Methods in Italian Ryegrass and Silage Maize Production Systems

Abstract This study examined the effects of liming on soil acidity and base saturation (V) in Italian ryegrass (ryegrass) and silage maize production systems over the medium-term. A split-plot design with four replications was employed on Humic Hapludox. The plots consisted of four soil management methods: conventional tillage (CT), minimum tillage (MT), no-tillage (NT) and chiselled NT (CNT). Within the split plots, ryegrass was used as cover crop (CC), silage (S), and integrated crop-livestock (ICL) system. Following ryegrass phytomass the maize was sowed. Once the maize had been cut with a silage machine, soil samples were collected from the layers 0-5, 5-10, 10-15, 15-20 and 20-30 cm at 24 and 60 months after liming. The attributes pH, H+Al, exchangeable aluminium (Al3+), and V were evaluated. The highest pH and V values were observed in the 0-5 cm layer in NT. The CNT did not result in improvement of acidity conditions or V. The ryegrass as S and ICL decreased soil acidity from 10 cm layer. NT combined with ICL provided soil acidity improvements 60 months after liming. Therefore, the exploration of winter with Italian ryegrass may elicit greater benefits in deep soil layers than cover crops.

Soil chemical attributes in coffee growing with different agronomic techniques

The objective was to evaluate the effects on soil chemical attributes in a coffee growing area, according to different agronomic techniques used and their associations. The experiment was conducted in the field, in an experimental area at the Department of Agriculture - DAG, in Lavras - MG, from January 2016 to October 2018. Coffee was planted in January 2016, with Mundo Novo IAC 379-19 coffee seedlings, with a spacing of 3.6 m between rows and 0.75 m between plants in the planting row. The factors under study were arranged in a 3x2x5 factorial scheme, making a total of 30 treatments. In the plots, three soil managements were randomized (soil cover with polyethylene film, soil cover with brachiaria grass and conventional management of spontaneous vegetation). In the subplots, two types of fertilizers used in the fertilization of coffee trees were tested (conventional and increased-efficiency fertilizer). In the sub-subplots, four soil conditioners were tested (coffee husk, phosphogypsum, water retention polymer, organic compost), and the control without conditioner. Aimed to evaluate soil chemical attributes in coffee growing with different agronomic techniques through the evaluation of: soil pH, phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), aluminum saturation (m) and base saturation (V%), by soil analysis carried out in October 2018 and leaf analysis in December 2018. It is noteworthy that the chemical attributes of the leaf were used only for principal component analysis through multivariate analysis. The use of fertilization (with conventional fertilizers or those with increased efficiency), combined with the application of organic compost or coffee husk, provide increased soil pH, as well as the use of ecological management of brachiaria grass. The use of organic compost as a soil conditioner increases phosphorus availability in the soil. Coffee husk, as a soil conditioner, is an efficient potassium source for the coffee crop. The use of organic compost and phosphogypsum increases the calcium and magnesium contents in the soil. The use of organic compost and coffee husk was efficient in increasing the base saturation (V%) grown with coffee. The use of organic compost, coffee husk and phosphogypsum reduced aluminum saturation in the soil. Treatments associated with the use of organic compost improve calcium, phosphorus and magnesium levels, increase pH and base saturation, besides decreasing aluminum saturation. Key words: Coffea arabica; soil managements; fertilizers; soil conditioners.

Soil quality in two coffee crop systems in the Amazon biome

ABSTRACT The form of occupation of the state of Rondônia, Brazil, favored the extensive agriculture, which resulted in a fast deforestation. The removal of forests and inadequate soil management and use, combined with a hot and wet climate, affected the soil chemical, physical, and biological attributes. In search for less impacting and alternatives that promote greater soil conservation for coffee production in the North region of Brazil, the objective of this work was to evaluate the effects of two coffee crop systems on the soil chemical and microbiological attributes. The treatments consisted of a shaded coffee crop (SCC) and a full-sun coffee crop (FCC). A completely randomized design was used, with four clusters per treatment and seven sampling points per cluster, which constituted a replication, totaling 28 replications per treatment. The data were collected in April 2018, in a rural property in the municipality of Cacoal, state of Rondônia, Brazil (11º21’50’’S, 61º20’10’’W, and altitude of 238 m). The soil organic matter, pH, P, K, Ca, Mg, Al, H+Al, base saturation, and basal respiration were determined. The soil under SCC had higher Ca content, pH, and base saturation, and lower potential acidity (H+Al) and Al content than that under FCC. The litterfall on the soil under FCC presented higher N and Mg contents. The soil basal respiration increased in the first 5 cm depth in the treatment with SCC.

LAND SUITABILITY EVALUATION FOR A NUMBER OF ANNUAL CROPS IN THE TIWORO RIVER WATERSHED, MUNA, SOUTHEAST SULAWESI

The Tiworo River Watershed, which covers a total area of 29,047.82 ha, has been a resource for agricultural development for the local people of Muna, Indonesia. The information regarding the land suitability for annual crops in this watershed was, however, still very limited. A survey-based study was, therefore, conducted to evaluate the land suitability in the watershed for six annual crops (i.e. paddy-rice, corn, peanut, soybean, cassava, and tomato). The evaluation was based on Djaenuddin’s criteria, that was by matching the respective crop growth requirements against soil characteristics (e.g. soil pH, organic-C content, total-N, P2O5, K2O, CEC, base saturation, soil texture and drainage, rock outcrops, effective soil depth, and slope) and climate (e.g. rainfall, and air temperature and humidity). Soil characteristics were collected from 87 land units. A ten-year climate data series was gathered from the Betoambari weather station. The results of the evaluation showed that the land in the watershed fell into class S3 (marginally suitable) and class N (not suitable) for all the six crops evaluated, and no land units belonged to S1 (highly suitable) and S2 (moderately suitable). The main limiting factors found were low water and nutrient availability, and high erosion hazard.

Chemical and physical attributes of an Ultisol under sustainable agricultural production systems

This study aimed to evaluate the effect of four production systems: agrosilvopastoral; pasture; agropastoral and notillage, all compared to a native forest area (Cerrado), on the chemical and physical attributes of an Ultisol. Physical and chemical analyzes of the soil were performed, in the layers of 0.00-0.05, 0.05-0.10, 0.10-0.20, 0.20-0.40 and 0.40-1.00 m. Regarding the physical analysis, samples of up to 0.40 m were used. We verified that the soil under the Cerrado biome displayed higher organic matter content, aggregates larger than 2 mm percentage and weighted mean diameter in the layer of 0.05-0.10 m. The pasture system showed higher pH and soil base saturation, and higher Ca and Mg contents in the 0.10-0.20 and 0.40-1.00 m layers. All systems provided an increase in soil organic matter content. The highest contents of P, K, Ca and Mg were observed in the surface layer for all systems. Agropastoral system disaggregated the soil in the 0.05-0.10 m layer. No-tillage resulted in similar soil porosity values along the soil profile. Urochloa brizantha cv. Marandu usage as pasture contributed to improving soil chemical and physical fertility.

Fine-root morphological trait variation in tropical forest ecosystems: an evidence synthesis

Key functions of fine roots are often related to their morphological traits, yet little is known about the patterns and controls on fine-root morphological traits in the tropical forest biome. In this study, we consolidated data on key root morphological traits to describe patterns of root trait variation among different tropical regions and examined the relationships among root traits and climate and soil properties. We synthesized root traits (root diameter, specific root length (SRL), specific root area (SRA) and root tissue density (RTD)) from 59 site observations from nine countries in Africa, Asia, and Central and South America to determine the patterns and variation in root traits among different tropical regions. We also examined relationships among fine-root morphological traits, climate (mean annual precipitation, MAP; mean annual temperature, MAT) and soil properties (including available phosphorus (P), base saturation and clay content) using linear mixed-effects modelling. Plant fine-root morphological traits showed systematic variation among tropical regions—Africa, Asia and the Neotropics. Across the tropical biome, SRL was positively related to MAT, suggesting that in warmer tropical sites, plants tended to produce thinner roots with high SRL. Specific root length and SRA were positively related to base saturation, while soil available P explained some of the variation in SRL. This study demonstrates that soil properties, and to a lesser extent MAT, partially explain variation in key fine-root morphological traits across tropical forests. Importantly, we also identified wide variation in fine-root morphological trait values in the tropical biome that encompasses much of the variation seen worldwide. Consequently, attempts to predict tropical forest ecosystem functioning could improve significantly if regional differences in root traits are incorporated into process-based models.

PHOSPHORUS SORPTION KINETIC ON ACID UPLAND SMECTITIC SOIL AMENDED WITH CALCIUM CARBONATE AND CALCIUM SILICATE

Acid upland smectitic soil is identified by high amount of exchangeable Al due to the weathering of aluminum (Al) octahedral layer by H+ saturation and by very low phosphorus (P) status. Calcium carbonate (CaCO3) and calcium silicate (CaSiO3) were commonly used to decrease exchangeable Al and increase soil pH. Laboratory experiments were conducted with clayey smectitic Typic Paleudults from Gajrug region, West Java. The CaCO3 and CaSiO3 were added at rates to replace 0, 1.5 or 3 times of exchangeable Al. After one month of incubation, P sorption kinetic experiments were conducted. The changes in some chemical properties after one month incubation showed that both CaCO3 and CaSiO3 increased the soil pH, exchangeable Ca, and base saturation but did not increase the cation exchange capacity. The results of the experiment showed that both CaCO3 and CaSiO3 decreased the rate constant value of first order kinetic equation (k) and the P sorbed maximum (a) at given amount of added P compared to Control.The CaCO3 was better than CaSiO3 in decreasing k values and on the contrary for a values. The decrease in P maximum sorption and the rate constant of the soil amended with CaSiO3 and CaCO3 due to occupation of P sorption sites by silicates and hydroxyl ions. The CaCO3with the rate to replace 1.5 x exchangeable Al was recommended to decrease the rate constant of P sorption. However, the CaSiO3 at the rate to replace 3 x exchangeable Al was recommended to decrease the maximum P sorption.

Recovery of degraded area of Urochloa decumbens with turkey litter fertilizer

The aimed of this study was to evaluate the effects of different dosages of turkey litter on soil’s chemical attributes and yield of the Urochloa decumbens in classified as degraded pasture. The work was performed at the municipality of Mineiros-GO between October/2011 and September/2013 in Quartzipsamment soil. The treatments consisted in applications of 0, 3, 6, 9 and 12 Mg ha-1 of turkey litter at a randomized-complete blocks design with four replications. Was evaluated the fodder’s productivity and the following soil’s chemical attributes: organic matter, hydrogenionic potential (CaCl2), phosphorus (resin), potassium, calcium, magnesium, cation exchange capacity and base saturation of soil. In general terms, the increase of turkey litter’s doses increased the grass productivity and the supply of nutrients of the soil, maintaining the balance of the soil-plant system. The dosage of 12 Mg ha-1 year-1 of turkey litter ensure higher amounts in the soil’s chemical attributes and in the productivity of dry mass of Urochloa decumbens.

Short-term forecasting of bark beetle outbreaks on two economically important conifer tree species

In recent years bark beetles have been shown to be an important risk factor in European forests. An early warning system is needed to mitigate bark beetle damage, and short-term forecasting models that assist efforts to identify attacked trees comprise an important part of such a system. The aim of this study was to develop short-term forecasting models of the probability of bark beetle outbreaks on two important conifer tree species: Norway spruce (Picea abies) and silver fir (Abies alba). For the development of the models, we used a time series of 20 years of sanitary felling because of bark beetles and relief data (altitude, slope and exposition), several soil variables, climate data (temperature and SPI), sanitary felling because of bark beetles, sanitary felling due to harmful abiotic factors, and amount of weakened trees due to bark beetles. The forecasting variable was sanitary felling because of bark beetles in the current year. The models were developed with a general linear model with binomial error distribution. For the probability of bark beetle outbreaks on silver fir, the amount of fir, soil base saturation percentage, sanitary felling of attacked fir, weakened fir, and sanitary felling because of abiotic factors increased the probability of sanitary felling because of fir bark beetles. Altitude, exposition, slope, phosphorus, soil depth, soil cation exchange capacity, SPI and temperature decreased the probability of sanitary felling because of fir bark beetles. For Norway spruce, the amount of Norway spruce, soil base saturation percentage, SPI, temperature, amount of sanitary felling in the previous year, amount of weakened trees in the previous year, and amount of sanitary felling because of abiotic factors in the previous year increased the probability of sanitary felling of Norway spruce because of bark beetles in the current year. Slope, soil cation exchange capacity, and precipitation decreased the probability of sanitary felling because of bark beetles in the current year. The performance of the bark beetle risk model for Norway spruce was very good. The performance of the model for silver fir was also good, but not on par with that for Norway spruce. Therefore, additional research on fir bark beetles is needed to further improve the risk model for bark beetle attacks on silver fir.

Uso de Rejeito de Mineração de Calcário Ornamental para a Correção de Acidez do Solo e Desenvolvimento de Plantas

In the municipality of Nova Olinda - CE, the extraction of limestone for ornamental purposes, denominated Pedra Cariri, has been causing a series of environmental impacts due to the high generation and stock of tailings in the locality. The objective of this research was to verify the efficiency of this residue as a soil acidity broker and in the development of lettuce plants. The experiment was carried out in two stages: the first consisted of the incubation of 5 dm3 of soil in pots during three months, with doses of the powder from the Pedra Cariri tailing equivalent to 0%, 50%, 100% and 200% of the recommended dose for the elevation of soil base saturation to 60%, and a dose equivalent to 100% of the recommended dose, but using commercial calcitic limestone. The second stage of the experiment consisted in the cultivation of cv Lucy Brown lettuce in pots with soil previously corrected by liming. The powder from the Pedra Cariri tailing has potential to be commercialized as an agricultural input, because it caused elevation of the pH and Ca soil contents, reduction of exchangeable acidity, potential acidity and, consequently, decrease of aluminum saturation and increase of base saturation, not differing from the action of commercial calcitic limestone. The results of analyzes of lettuce development were not significant, where lettuce did not reach its productive potential. Nevertheless, the tailings powder had no toxic effects that would impair the development of the plant.