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Cobertura herbácea da entrelinha do olival, controle da erosão e propriedades físicas do solo: efeitos da espécie da flora espontânea e semeada
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Abstract(s)
A erosão hídrica constitui um dos principais fatores de degradação dos solos agrícolas em regiões mediterrâneas, onde a combinação entre elevada pluviosidade concentrada, declives acentuados e manejo inadequado potencializa a perda de solo e nutrientes. Nos olivais tradicionais do Nordeste de Portugal, a prática frequente de mobilização do solo, visando o controle de plantas espontâneas, tem agravado o processo erosivo e comprometido a sustentabilidade produtiva e ambiental desses sistemas. Diante desse cenário, o presente trabalho teve como objetivo avaliar o efeito de diferentes espécies e densidades de plantas de cobertura sobre os processos erosivos e as propriedades físicas e hidráulicas do solo, sob condições controladas de chuva simulada. Foram conduzidos dois ensaios experimentais em lisímetros, utilizando espécies de cobertura com distintos hábitos radiculares (Lolium multiflorum, Calendula officinalis, Ornithopus compressus, Brachypodium distachyon, Trifolium subterraneum, Centaurea cyanus e Silene gallica), além de um tratamento controle sem vegetação. As variáveis analisadas incluíram escoamento superficial, perda de solo, salpicamento, densidade aparente, porosidade total, macro e microporosidade, condutividade hidráulica (inicial e final), capacidade de campo (CC) e capacidade máxima de água (CMA).
Os resultados demonstraram que a presença de cobertura vegetal reduziu significativamente o escoamento e a perda de solo, evidenciando forte correlação inversa entre a porcentagem de cobertura e a Erosividade (R² > 0,90). As plantas de cobertura também promoveram melhorias estruturais expressivas, reduzindo a densidade aparente e aumentando a conectividade do sistema poroso. Observou-se que a macroporosidade e a condutividade hidráulica foram fortemente influenciadas pela atividade radicular, sendo que os tratamentos com maior emergência e densidade de plantas apresentaram condutividade mais elevada, mesmo quando o volume total de macroporos era inferior, o que indica que a continuidade e funcionalidade dos poros são mais determinantes que seu volume absoluto. De forma geral, os ensaios revelaram que o uso de plantas de cobertura contribui para a melhoria da estrutura e da funcionalidade hidráulica do solo, reduzindo a vulnerabilidade à erosão e promovendo maior eficiência no uso da água. Além dos benefícios ambientais, a adoção dessas práticas apresenta viabilidade econômica e relevância social, pois alia a conservação dos recursos naturais ao fortalecimento da sustentabilidade da olivicultura transmontana. Os resultados obtidos reforçam que a cobertura vegetal, quando adequadamente manejada, representa uma ferramenta eficaz e ecologicamente responsável para o controle da erosão e a recuperação da qualidade física dos solos mediterrâneos.
Water erosion is one of the main factors of soil degradation in Mediterranean agricultural regions, where the combination of intense and concentrated rainfall, steep slopes, and inadequate management practices increases soil and nutrient losses. In traditional olive groves of Northeast Portugal, frequent soil tillage aimed at controlling spontaneous vegetation has intensified erosion processes, compromising both the productive and environmental sustainability of these systems. In this context, the present study aimed to evaluate the effects of different cover crop species and sowing densities on soil erosion and on the physical and hydraulic properties of the soil, under controlled simulated rainfall conditions. Two experimental trials were carried out in erosion trays using cover crop species with contrasting root systems (Lolium multiflorum, Calendula officinalis, Ornithopus compressus, Brachypodium distachyon, Trifolium subterraneum, Centaurea cyanus and Silene gallica), as well as a bare soil control. The variables analyzed included surface runoff, soil loss, splash detachment, bulk density, total, macro- and microporosity, hydraulic conductivity (initial and final), field capacity (FC), and maximum water capacity (MWC). Results showed that the presence of vegetation significantly reduced both runoff and soil loss, revealing a strong negative correlation between soil cover percentage and erosion intensity (R² > 0.90). Cover crops also promoted structural improvements, decreasing bulk density and enhancing pore system connectivity. It was observed that macroporosity and hydraulic conductivity were strongly influenced by root activity, as treatments with higher plant emergence and density exhibited greater conductivity even when total macroporosity was lower, indicating that pore continuity and functionality are more decisive than total pore volume. Overall, the experiments demonstrated that the use of cover crops effectively improves soil structure and hydraulic functionality, reducing vulnerability to erosion and enhancing water use efficiency. Beyond environmental benefits, adopting such practices offers economic feasibility and social relevance, as it combines natural resource conservation with the long-term sustainability of the Trás-os-Montes olive groves. The results highlight that cover crops, when properly managed, are an efficient and ecologically responsible tool for erosion control and for restoring the physical quality of Mediterranean soils.
Water erosion is one of the main factors of soil degradation in Mediterranean agricultural regions, where the combination of intense and concentrated rainfall, steep slopes, and inadequate management practices increases soil and nutrient losses. In traditional olive groves of Northeast Portugal, frequent soil tillage aimed at controlling spontaneous vegetation has intensified erosion processes, compromising both the productive and environmental sustainability of these systems. In this context, the present study aimed to evaluate the effects of different cover crop species and sowing densities on soil erosion and on the physical and hydraulic properties of the soil, under controlled simulated rainfall conditions. Two experimental trials were carried out in erosion trays using cover crop species with contrasting root systems (Lolium multiflorum, Calendula officinalis, Ornithopus compressus, Brachypodium distachyon, Trifolium subterraneum, Centaurea cyanus and Silene gallica), as well as a bare soil control. The variables analyzed included surface runoff, soil loss, splash detachment, bulk density, total, macro- and microporosity, hydraulic conductivity (initial and final), field capacity (FC), and maximum water capacity (MWC). Results showed that the presence of vegetation significantly reduced both runoff and soil loss, revealing a strong negative correlation between soil cover percentage and erosion intensity (R² > 0.90). Cover crops also promoted structural improvements, decreasing bulk density and enhancing pore system connectivity. It was observed that macroporosity and hydraulic conductivity were strongly influenced by root activity, as treatments with higher plant emergence and density exhibited greater conductivity even when total macroporosity was lower, indicating that pore continuity and functionality are more decisive than total pore volume. Overall, the experiments demonstrated that the use of cover crops effectively improves soil structure and hydraulic functionality, reducing vulnerability to erosion and enhancing water use efficiency. Beyond environmental benefits, adopting such practices offers economic feasibility and social relevance, as it combines natural resource conservation with the long-term sustainability of the Trás-os-Montes olive groves. The results highlight that cover crops, when properly managed, are an efficient and ecologically responsible tool for erosion control and for restoring the physical quality of Mediterranean soils.
Description
Keywords
Erosão hídrica Plantas de cobertura Propriedades físicas do solo Condutividade hidráulica Conservação do solo Olival mediterrâneo