Gabriel Barth

Alterações químicas do solo e resposta do milho à calagem e aplicação de gesso

Root growth and crop yield can be affected by chemical modifications of the soil profile owing to lime and gypsum applications. A field trial was carried out on a dystrophic Clay Rhodic Hapludox in Ponta Grossa, Parana State, Brazil, aiming to evaluate the changes in the chemical soil properties and corn response to lime and gypsum applications at the installation of a no-tillage system. A randomized complete block design was used, with three replications, in a split-plot experiment. The main plots received dolomitic limestone treatments (no lime; 4.5 t ha-1 of lime applied on the surface supplying the total demand; 1/3 of the total demand applied on the surface during three years; total demand incorporated into the soil) and the subplots received gypsum rates (0, 3, 6, and 9 t ha-1). The treatments with lime were applied in July 1998 and the rates of gypsum in October 1998. Corn was evaluated in the agricultural year of 2001/02. The applied surface liming, at full or split rates, provided a more accentuated soil acidity correction in the superficial layer (0-0.05 m), and there was a stronger reaction in the 0.05-0.10 and 0.10-0.20 m layers, when lime was incorporated into the soil. Gypsum improved the subsoil, increasing the concentrations of Ca and S-SO42-, raised N, K, and Ca concentrations in the corn leaves, while it reduced the Mg concentration in soil and corn leaves. Liming and gypsum treatments did not affect the corn root growth. Liming (whether surface applied, at full or split rates, or incorporated into the soil) and gypsum increased the corn yield, due to an increase in the Ca soil saturation of the superficial layers. The application of gypsum associated to liming was an effective strategy to maximize grain yields.

Lime and gypsum application on the wheat crop

Root growth and crop yield can be affected by chemical modifications of the soil profile owing to lime and gypsum applications. A field trial was carried out on a dystrophic Clayey Rhodic Hapludox at Ponta Grossa, PR, Brazil, aiming to evaluate lime (without or with incorporation into the soil) and gypsum effects on root growth, mineral nutrition and grain yield of wheat (cv. OR 1). A randomized complete block design was used, with three replications, in a split-plot experiment. Treatments with dolomitic limestone (without lime and 4.5 t ha-1 of lime applied on the surface, in total rate and 1/3 of the requirement per year during 3 years, or incorporated into the soil) were applied in July 1998 (main plots) and the rates of gypsum (0, 3, 6 and 9 t ha-1) in October 1998 (subplots). Wheat was evaluated in the 2000 winter season. In conditions of water deficit absence, there was no limitation in root growth in depth, for exchangeable Ca of 6 mmolc dm-3. Lime incorporation of lime increased the Mg concentration in the leaves, but wheat yield was not influenced by the correction of soil acidity through liming treatments. Gypsum increased the concentrations of Ca and S in wheat leaves, with significant effects on grain yield. The critical level of S-SO42- in the 0-20 cm soil layer, extracted by ammonium acetate 0.5 mol L-1 in acetic acid 0.25 mol L-1, was 25.8 mg dm-3.

Surface application of lime ameliorates subsoil acidity and improves root growth and yield of wheat in an acid soil under no-till system

A calagem na superficie do solo em plantio direto ocasiona modificacoes quimicas no perfil que podem influenciar o crescimento do sistema radicular e a producao de graos das culturas. O crescimento de raizes e a producao de trigo (Triticum aestivum L. cv. CD 104, moderadamente sensivel ao Al), foram estudados cerca de 10 anos apos a aplicacao superficial de calcario (0, 2, 4 e 6 Mg ha-1) e tres anos da reaplicacao de calcario na superficie (0 e 3 Mg ha-1), em um Latossolo Vermelho distrofico textura media, manejado durante longo periodo no sistema plantio direto, em Ponta Grossa (PR). A acidez do solo limitou drasticamente o crescimento radicular e a producao de trigo, provavelmente por causa de prolongada falta de agua ocorrida durante a fase de desenvolvimento vegetativo da cultura. A calagem na superficie ocasionou aumento de ate 66% no crescimento radicular (0-60 cm) e de ate 140% na producao de trigo. A densidade de raizes e a producao de trigo correlacionaram-se positivamente com o pH e o teor de Ca2+ trocavel, e negativamente com o teor de Al3+ trocavel e a saturacao por Al3+, nas camadas superficiais e do subsolo.

Correção da acidez do solo, crescimento radicular e nutrição do milho de acordo com a calagem na superfície em sistema plantio direto

Os efeitos das alteracoes quimicas do solo, decorrentes da calagem na superficie, em sistema plantio direto, no crescimento radicular e na nutricao do milho nao sao muito conhecidos. Com o objetivo de estudar a correcao da acidez do solo, o crescimento de raizes de milho (hibrido AG 9090), a nutricao da planta e seus reflexos sobre a producao de graos, considerando a aplicacao superficial de calcario no sistema plantio direto, foi realizado um experimento em um Latossolo Vermelho distrofico textura media, em Ponta Grossa (PR). O delineamento experimental empregado foi o de blocos ao acaso em parcelas subdivididas, com tres repeticoes. As parcelas receberam quatro doses de calcario dolomitico na superficie (0, 2, 4 e 6 t ha-1), em julho de 1993, e, nas subparcelas, foram reaplicadas duas doses de calcario dolomitico na superficie (0 e 3 t ha-1), em junho de 2000. A calagem, apos 92 meses, aumentou o pH, o Ca trocavel e a saturacao por bases e reduziu o Al trocavel do solo, ate a profundidade de 0,60 m. A reaplicacao de calcario, apos nove meses, proporcionou aumento no pH, Ca trocavel e saturacao por bases e reducao no Al trocavel do solo, ate a profundidade de 0,20 m. A reacao do calcario reaplicado na superficie foi mais rapida em condicoes de maior acidez do solo. Nao houve limitacao do crescimento radicular e da producao de milho para concentracao de 10 mmolc dm-3 de Al trocavel, na ausencia de deficit hidrico em solo com alto teor de materia orgânica, mas a calagem na superficie melhorou a distribuicao relativa de raizes na presenca de solo compactado. O calcario dolomitico aplicado na superficie em plantio direto proporcionou reducao no teor de K no tecido foliar do milho, sem alterar a producao de graos.

Soil acidity, liming and soybean performance under no-till

Os efeitos das alteracoes quimicas do solo ocasionadas pela aplicacao superficial de calcario no crescimento radicular, na nutricao mineral e na producao de graos de soja cultivada em sistema plantio direto sao pouco conhecidos e foram estudados no presente trabalho. O experimento foi realizado em um Latossolo Vermelho distrofico textura media, em Ponta Grossa (PR). O delineamento experimental empregado foi o de blocos completos ao acaso em parcelas subdivididas, com tres repeticoes. As parcelas receberam quatro doses de calcario dolomitico na superficie (0, 2, 4 e 6 Mg ha-1), em julho de 1993, e, nas subparcelas, foram reaplicadas duas doses de calcario dolomitico na superficie (0 e 3 Mg ha-1), em junho de 2000. A calagem, apos nove anos, aumentou o pH e o Ca2+ trocavel e reduziu o Al3+ trocavel e a saturacao por aluminio do solo, ate a profundidade de 60 cm. A reaplicacao de calcario, apos dois anos, tambem proporcionou melhoria nas condicoes de acidez do solo ate a profundidade de 60 cm. O comprimento total de raizes de soja por unidade de area superficial de solo (0-60 cm) foi reduzido com a calagem na superficie em plantio direto. A reducao de Al3+ trocavel no solo com a calagem nao alterou as concentracoes de Al nas raizes e nas folhas de soja. O calcario dolomitico aplicado na superficie em plantio direto aumentou as concentracoes de Ca e Mg e reduziu o teor de Mn nas raizes e nas folhas de soja. A producao de graos de soja nao foi influenciada pela calagem na superficie por causa da baixa toxicidade do Al e ainda porque o crescimento radicular foi estimulado por condicoes de stress de acidez do solo no sistema plantio direto.

Soil physico-hydrical properties resulting from the management in Integrated Production Systems

Anthropic action, such as the soil use and management systems, promote changes in the soil structure. These changes might hamper the development of plants in soil management practices that involve its mobilization, and the negative effects might be increased due to intensive use. The aim of this study was to evaluate the physico-hydrical properties of a Haplohumox in integrated production systems under different soil managements. The soil superficial (0.0-0.10 m) and sub-superficial (0.10-0.20 m) layers were evaluated in the different systems: conventional tillage (CT), minimum tillage (MT), no-tillage (NT) and chiseled no-tillage (CNT), taking into consideration the annual ryegrass cropped for different uses [cover crop (C), grazing (G) and silage (S)] during the winter. Soil bulk density (Db), total porosity (TP), macro (Ma) and microporosity (Mi), water retention curves (SWRC) and water retention due to pore size (r) were determined. The annual ryegrass used as C produced lower Db and Mi and higher TP and Ma in CT, MT and CNT systems. No difference was verified between G and S in any of the management systems or soil layers. The superficial layer SWRC presented similar behavior regarding CT, MT and CNT. Under NT, C resulted in higher water retention. However, G and S provided higher water retention due to the pore size in this system.

Optimizing Nitrogen Use Efficiency for No-Till Corn Production by Improving Root Growth and Capturing NO3-N in Subsoil

Abstract Subsoil acidity restricts root growth and reduces crop yields in many parts of the world. More than half of the fertilizer nitrogen (N) applied in crop production is currently lost to the environment. This study aimed to investigate the effect of gypsum application on the efficiency of N fertilizer in no-till corn ( Zea mays L.) production in southern Brazil. A field experiment examined the effects of surface-applied gypsum (0, 5, 10, and 15 Mg ha −1 ) and top-dressed ammonium nitrate (NH 4 NO 3 ) (60, 120, and 180 kg N ha −1 ) on corn root length, N uptake, and grain yield. A greenhouse experiment was conducted using undisturbed soil columns collected from the field experiment site to evaluate NO 3 -N leaching, N uptake, and root length with surface-applied gypsum (0 and 10 Mg ha −1 ) and top-dressed NH 4 NO 3 (0 and 180 kg N ha −1 ). Amelioration of subsoil acidity due to gypsum application increased corn root growth, N uptake, grain yield, and N use efficiency. Applying gypsum to the soil surface increased corn grain yield by 19%–38% and partial factor productivity of N (PFP N ) by 27%–38%, depending on the N application rate. Results of the undisturbed soil column greenhouse experiment showed that improvement of N use efficiency by gypsum application was due to the higher N uptake from NO 3 -N in the subsoil as a result of increased corn root length. Our results suggest that ameliorating subsoil acidity with gypsum in a no-till corn system could increase N use efficiency, improve grain yield, and reduce environmental risks due to NO 3 -N leaching.

Silage maize quality in different uses of Italian ryegrass and soil management methods after liming

ABSTRACT The effects of lime application with multiple soil management methods and uses on dry matter (DM) yield and crude protein (CP) content of Silage maize cropping in succession with Italian ryegrass (ryegrass) from 2009 to 2014 in a southern Brazilian Oxisol were studied. The experimental design was completely randomized block in split-plot with four replications. The main plot treatments were the four soil management methods: conventional tillage (CT), minimum tillage (MT), no-tillage (NT) and chiseled no-tillage (CNT). The sub-plots treatments were the three uses of Italian ryegrass (ryegrass): cover crop (CC), silage (S), and grazing dairy heifers as part of integrated crop-livestock system (ICL). In all the years, the maize was sown approximately 30 days after the ryegrass desiccation with herbicide. In the medium-term (5 yrs.) after liming, soil management methods did not change DM yield and CP content in silage maize. The use of ryegrass for S and ICL did not change DM yield, but notably maintained or increased CP content in silage maize after liming. The use of ryegrass only as CC provided less measurable benefits than the combined production system of silage maize with ryegrass.