Antonio Carlos Vargas Motta

Tillage intensity effects on chemical indicators of soil quality in two coastal plain soils

Few experiments in the coastal plain region of the southeastern United States have reported the effect of long-term tillage and tillage intensity on chemical soil quality indicators. The purpose of this study was to determine the 17-year influence of four tillage systems on chemical soil quality indicators in a Benndale fine sandy loam (coarse-loamy, siliceous, semiactive, thermic, Typic Paleudults) and a Lucedale very fine sandy loam (fine-loamy, siliceous, subactive, thermic, Rhodic Paleudults) in the coastal plain region of Alabama. Tillage systems were no-tillage, disk, moldboard plow, and chisel plow under varied double-cropping in a randomized complete block design with four replications. Soil pH, sum of extractable bases, soil organic carbon (SOC), and soil nitrogen (N), phosphorus (P), calcium (Ca), magnesium (Mg), potassium (K), zinc (Zn), manganese (Mn), copper (Cu), and iron (Fe) were determined on soil samples collected at depths of 0–2.5, 2.5–7.5, 7.5–15.0, 15.0–22.5, and 22.5–30 cm. Soil carbon (C) accumulation occurred primarily in the top 2.5 cm, varied by soil type, and was inversely proportional to tillage intensity. The coarse textured Benndale soil averaged 27.6, 13.1, 12.7, and 10.4 g C kg− 1 soil with no-tillage, disk, chisel, and moldboard plow management, respectively, in the top 2.5 cm. The finer textured Lucedale soil averaged 16.7, 10.0, 9.8, and 6.9 g C kg− 1 soil, for the same treatments and depth, respectively. Surface applications of lime maintained soil pH at an acceptable level within the plow layer on both soil types and all tillage systems. Extractable P was higher with no-tillage than moldboard plowing to the 22.5 cm depth on the Lucedale soil. On the Benndale soil, P tended to accumulate at the 15 to 22.5 cm depth with tillage systems other than moldboard plowing, and no-tillage had the most extractable P at these depths. Soil C and pH combined proved effective as continuous pedotransfer functions, predicting 73% and 86% of the variation in sum of extractable bases for the Benndale and Lucedale soils, respectively. As determined from chemical indicators of soil quality, adoption of conservation tillage with doublecropping is a sustainable practice for these soils.

Conservation Tillage, Rotations, and Cover Crop Affecting Soil Quality in the Tennessee Valley: Particulate Organic Matter, Organic Matter, and Microbial Biomass

Abstract The impact of conservation tillage, crop rotation, and cover cropping on soil‐quality indicators was evaluated in a long‐term experiment for cotton. Compared to conventional‐tillage cotton, other treatments had 3.4 to 7.7 Mg ha−1 more carbon (C) over all soil depths. The particulate organic matter C (POMc) accounts for 29 to 48 and 16 to 22% of soil organic C (SOC) for the 0‐ to 3‐and 3‐ to 6‐cm depths, respectively. Tillage had a strongth influence on POMc within the 0‐ to 3‐cm depth, but cropping intensity and cover crop did not affect POMc. A large stratification for microbial biomass was observed varing from 221 to 434 and 63 to 110 mg kg−1 within depth of 0–3 and 12–24 cm respectively. The microbial biomass is a more sensitive indicator (compared to SOC) of management impacts, showing clear effect of tillage, rotation, and cropping intensity. The no‐tillage cotton double‐cropped wheat/soybean system that combined high cropping intensity and crop rotation provided the best soil quality.

Efeitos em longo prazo da aplicação de gesso e calcário no sistema de plantio direto

Os efeitos da calagem e da gessagem sao amplamente conhecidos na literatura, mas a sua magnitude em relacao aos efeitos no perfil do solo e dependente do tempo apos a aplicacao desses insumos. Dessa maneira, o objetivo deste trabalho foi avaliar em longo prazo a aplicacao conjunta de gesso e calcario nos atributos quimicos de um solo em rotacao de culturas, no sistema de plantio direto. O experimento foi conduzido em uma propriedade rural no municipio de Jaguariaiva, PR, em um Latossolo Vermelho-Amarelo distrofico tipico, de textura areia franca, durante os anos de 2002 a 2008. O experimento foi conduzido em blocos ao acaso sob esquema fatorial com 10 tratamentos, sendo cinco doses de gesso agricola (0; 1,5; 3,0; 6,0; e 12,0 Mg ha-1) e duas doses de calcario (0 e 3,42 Mg ha-1), com tres repeticoes. Foram avaliadas no decorrer dos 72 meses as especies aveia-preta-comum (2004, 2006 e 2007), milho (2005/2006), trigo (2003) e soja (2003/2004, 2004/2005, 2006/2007 e 2007/2008). Realizaram-se amostragem e analise de solo nos anos de 2005 e 2008 ate 100 cm de profundidade e de tecido foliar da soja, na safra de 2007/2008. A aplicacao de calcario corrigiu o pH, aumentou a concentracao de Ca e Mg e diminuiu o Al, nas camadas superficiais do solo. O gesso proporcionou incremento no pH e nas concentracoes de Ca e S em profundidade, lixiviou Mg e nao lixiviou o K. A calagem elevou a produtividade do milho, da soja (uma das quatro safras avaliadas) e da aveia- preta. O gesso favoreceu a produtividade do milho e do trigo e a da soja, somente quando houve deficiencia hidrica. Quando, no entanto, nao houve deficiencia hidrica, altas doses de gesso prejudicaram a produtividade de graos de soja por inducao de deficiencia de Mg.

Esterco líquido de bovinos leiteiros combinado com adubação mineral sobre atributos químicos de um Latossolo Bruno

This study aimed to evaluate the influence of fertilization doses of liquid dairy manure combined with mineral fertilizer on the chemical properties of a Brown Oxisol, in no-tillage system and winter and summer crop rotation (sorghum/black-oat/corn/ryegrass/corn/ryegrass), for silage production, in the layers 0-5, 5-10, 10-30, 30-50 and 50-80 cm. The treatments were distributed in three randomized blocks, divided in 12 plots per block, in a 3 x 4 factorial arrangement, with three mineral fertilizer levels (0, 50 and 100 % of the dose recommended for the crops) and four organic fertilizer levels (0, 30, 60 and 90 m3 ha-1 year-1). The liquid dairy manure increased the pH linearly in the 0-5 cm layer and quadratic in the 30-50 cm layer. The mineral fertilization reduced the pH values linearly in the 0-5 and 5-10 cm layers, with quadratic effect at 50-80 cm. The potential acidity decreased in 5-10 cm, with quadratic pattern at 10-30 cm. The exchangeable Ca2+ increased in the 0-5 cm layer with manure, but no effect of mineral fertilization on this attribute was verified. An increase in exchangeable Mg2+ levels was observed in the manure treatments to a depth of 30 cm; under mineral fertilizer, increases were observed from 30 cm downwards. There was a linear increase of base saturation through manure doses, down to a depth of 10 cm, and the mineral fertilization decreased base saturation at 5-10 cm, with a quadratic effect at 50-80 cm.

Land reclamation recovery with the sewage sludge use

Obras de infra-estrutura proximas aos grandes centros levam ao surgimento de areas degradadas por decapamento que podem ser reintegradas a paisagem atraves dos processos de recuperacao com o uso do lodo de esgoto. Estabeleceu-se um experimento com cinco tratamentos [testemunha, tres doses de lodo alcalinizado (60, 120, 240Mgha-1 em base seca) e corretivo mais adubo mineral], para avaliar a recuperacao imediata de uma area de emprestimo. A aplicacao de lodo de esgoto alcalinizado atuou como corretivo da acidez, proporcionou aumento no teor de materia orgânica (21 para 43,5g dm-3) e P disponivel (4,4 para 156mg dm-3) e total, se mostrando superior ao mineral mais calagem. Mesmo com uso da maior dose, nao foi observado acrescimos nos teores de 32 metais analisados, dado a baixa concentracao de metais no lodo. Os resultados obtidos indicam que e possivel o uso de doses elevadas de lodo de esgoto na recuperacao de areas degradadas.

Avaliação de atrativos alimentares utilizados no monitoramento de mosca-das-frutas em pessegueiro na lapa- PR

Fruit flies of Anastrepha genus are a key pest in peach trees in Parana. Food attractants were tested to determine their efficiency in monitoring fruit flies captured in McPhail fly traps. The experiment was conducted over a period of three years. In 2002 the following attractors were tested: Maguari® brand grape juice, BioAnastrepha® brand hydrolyzed enzymatic protein and Chemin Agrin® vinegar. Over the next two years, the vinegar was replaced by Torula® hydrolyzed protein compound. Protein-based attractants were the most efficient in trapping Anastrepha spp. and captured flies earlier comparing to grape juice. According to the results, the use of protein-based attractants for monitoring Anastrepha spp in the Lapa peach trees was recommended.

Produção, teor foliar e qualidade de frutos do pessegueiro 'Chimarrita' em função da adubação nitrogenada, na região da Lapa-PR

The peach (Prunus persica L. Batsch) integrated production regulates the N rates to be applied in order to obtain high yield and fruit quality without affecting plant sanity and environmental quality. However, there is a great lack of local information about N rate that it is necessary to achieve high yield for orchard at Lapa origin. So, an experiment was implanted in 5-year old commercial orchard, in the Lapa County, Parana State, Brazil where it was evaluated N rates effect over the fruit yield, leaves concentration and quality, during three years. The experimental design was a randomized block with three treatments and three replications. The treatments were three N rates (40, 80 and 160 kg of N ha-1 ano-1), using urea as N source. The reduction in nitrogen fertilization, in established orchard, diminished the yield only for the second year. There was an accumulated yield decrease of 8,4 t ha-1 during three years, comparing the smallest to largest rate. The yield was straight associated with fruit number since the fruit mass and caliber were not affected by N application. The N fertilization did not effect fruit qualitative proprieties evaluated (total soluble solids, acidity total titratable and firmness of the pulp) and them values stayed within range concentration considered normal for cultivar. Leave tissue analysis showed that only N concentration was affected by the N fertilization for the three evaluated years, but being in normal levels for all treatments. The Ca, Mg, Fe and Zn leaves concentration was below normal level established for peach..

Influence of Corn (Zea mays L.) Cultivar Development on Grain Nutrient Concentration

While corn productivity has been increased by the adoption of high-yield hybrids, there are concerns that increased grain potential may be associated with diminished grain nutrient concentration. Ten corn (Zea mays L.) cultivars representing five technological levels (landrace variety, commercial variety, and double, triple, and single cross-hybrids) were cropped on a Rhodic Ferralsol Eutric soil with high fertility in 2006 (dry year) and 2007 (normal year) in Rolândia County, Brazil. At maturity, grain was evaluated for concentrations of P, K, Ca, Mg, Fe, Mn, Zn, and Cu. In general, differences among cultivars were noted for all nutrients in both years. Concentrations of P, K, Fe, and Mn were lower in the dry year, while Ca, Mg, Cu, and Zn were higher. Soil water availability appeared to exert more influence on grain nutrient concentration than did cultivar development; nutrient removal due to grain harvest was also greatly influenced by rainfall patterns and their impact on corn productivity. Even though genetic differences were noted, which may be useful to breeding programs, long-term testing in subtropical environments will be required to clarify the interaction between genetics and climate events on grain nutrient quality and exportation.

Yield response to fertilization strategies in no-tillage soybean, corn and common bean crops

Two research fields were conducted on a Haplohumox from 1998 and to 2005. The study aimed to evaluate the strategies for starter fertilizer application on corn, soybean and common bean yield as well as the accumulation of earlier dry matter for corn in a no-tillage crop rotation system in south of Brazil. There was no increase in the yield of soybean with phosphorus and potassium application for at least seven seasons, while corn and common bean showed increased yields with phosphorus, potassium and nitrogen application. For soybean, corn and common beans in no-tillage systems with high levels of phosphorus and medium of potassium, the starter fertilizer can be applied in any of the methods evaluated and in any of the period considered. The presence or absence of potassium in the furrow, phosphorus sources and row preparation components provided similar yields to corn, soybean and common bean.

Atributos de solo e cultura espacialmente distribuídos relacionados ao rendimento do milho

Precision agriculture can increase efficiency and sustainability of grain crops in Brazil, especially in support of soil and crop management. In this study the importance of spatially-variable soil and crop attributes on the variability of grain crop yield and the use of this information to improve management decisions was examined. The study used data from the 2005/6 corn growing season of a 18 ha commercial field on a clayey Latossolo Bruno (FAO: Ferralsol). Soil (0-0.10 m layer) and crop properties were sampled at a density of two per ha. Spatially distributed crop yield was determined with a grain sensor on the harvester. Yield variability (average of 12.4 Mg ha-1, amplitude between 11.1 and 14.0 Mg ha-1) was related to the soil properties - P Mehlich, Mg2+, sum of bases and Ca:Mg, Mg:K and Mg:CEC ratios - but not with crop attributes, according to the results of a Spearman correlation matrix. Regression analysis identified a critical value of Magnesium saturation (Mg:CEC) of 0.10, and a critical Mg:K ratio of 2.3, as the most significant soil properties. Below the critical values, yields were reduced. Cluster analysis confirmed the results obtained by the two previous statistical techniques, and their combined interpretation supported the conclusion that P and Mg were the two nutrients for which spatial management is most needed. Compared to the traditional fixed-rate, whole-field application, using variable rate application would require, for the whole field, 6.6 Mg of additional lime, being 3.4 Mg calcitic lime and 3.2 Mg dolomitic lime, less P2O5 (-235 kg), and more K2O (+ 135 kg) than in the normal uniform management. However, with variable rates such inputs would be applied at adequate rates to specific parts of the field, positively affecting the yields in these parts. When management decisions are supported by appropriate statistical tools, precision agriculture is technically viable for the management of soil chemical properties, allowing for optimized dosages, with a view to an ideal economical yield.