O manejo agroecológico do solo: o efeito do mulch e da adubação verde na qualidade do solo
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Data
2020-10-22
Autores
Pestana, Caio Eduardo [UNIFESP]
Orientadores
Montero, Leda Lorenzo [UNIFESP]
Tipo
Trabalho de conclusão de curso de graduação
Título da Revista
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Resumo
O atual panorama de degradação de solo é preocupante, a maior parte dos solos produtivos sofre
erosão em nível global. As perdas de solo produtivo são um dos fatores de degradação mais
sérios da atualidade, pois ameaçam a capacidade de produzir alimentos para a humanidade em
um futuro próximo. O manejo agroecológico do solo tem potencial para reverter essa situação,
promovendo a saúde produtiva do solo ao protegê-lo contra a erosão e recuperar os processos
responsáveis pela manutenção da sua fertilidade. Assim, este trabalho estudou os efeitos do
primeiro ano de manejo agroecológico do solo sobre a qualidade do mesmo. Foram avaliados
os efeitos do uso permanente de cobertura vegetal morta (mulch) combinado com um ciclo de
adubação verde, sobre as propriedades químicas e físicas do solo em um sistema agroflorestal
experimental (SAF). Realizou-se a descrição morfológica do solo, análises químicas (pH- H2O
e KCl, Na+
, K+
, Ca2+, Mg2+, Al3+, Al3+ + H+
) e físicas (densidade do solo, densidade das
partículas e porosidade) das parcelas antes (t0) e depois de um ano (t1) do manejo. Observouse a formação de um novo horizonte biogênico e alterações significativas nas propriedades
químicas (todos p<0,05). Houve aumento médio de pH de 0,5 unidades em ambos os horizontes
A1 e A2, redução de Na+
, de 0,4 mmolc kg-1
(no A1) e 0,3 mmolc kg-1
(no A2) e de K+
de 3,2
mmolc kg-1
(no A1) e 1,9 mmolc kg-1
(no A2). Além da redução da saturação em alumínio em
5% e 10% nos horizontes A1 e A2 respectivamente e do aumento da saturação de bases de 40%
para 50% no A1. As propriedades físicas não mudaram significativamente. Os resultados
apontam a melhoria da qualidade do solo com o manejo agroecológico. A diminuição da acidez
do solo pode estar relacionada à liberação de bases no processo de decomposição e/ou à
complexação do Al3+ trocável presente no solo. A redução da concentração de K+
no solo pode
estar relacionada com a lixiviação deste nutriente. As perdas de Na+
e K+
poderiam ser
minimizadas realizando o plantio das espécies produtivas concomitantemente com a adubação
verde. Conclui-se que o manejo do solo com o aporte do mulch e um ciclo de adubação verde
contribui para a melhoria da qualidade do solo, estimulando a atividade biológica, reduzindo a
acidez e alterando a ciclagem de nutrientes.
Soil degradation is currently a worrying panorama; globally, most of productive soils suffers erosion. Losses of productive soil are one of the most serious degradation factors today, as they threaten the ability to produce food for humanity in a near future. Agroecological soil management has the potential to reverse this situation, promoting productive soil health by protecting it against erosion and recovering the processes that are responsible for maintaining its fertility. This work aimed to study the effects of soil agroecological management on soil quality. We evaluated the effects of the combined use of mulch with green manure for one year on the soil chemical and physical properties in an experimental agroforestry system (SAF). Soil morphological description, chemical (pH- H2O and KCl, Na+ , K+ , Ca2+, Mg2+, Al3+, Al3+ + H+ ) and physical properties (soil density, particle density and porosity) we determined before (t0) and after one year (t1) of mulch application and green manure. We observed the formation of a new biogenic soil horizon and significant changes in chemical properties (all p <0.05). There was an average increase of pH of 0.5 units in both horizons A1 and A2, reduction of Na+ , 0.4 mmolc kg-1 (A1) and 0.3 mmolc kg-1 (A2) and K+ of 3.2 mmolc kg-1 (A1) and 1.9 mmolc kg-1 (A2). In addition to reducing aluminum saturation by 5% and 10% in horizons A1 and A2 respectively and increasing base saturation from 40% to 50% in A1. Physical properties have not changed significantly. The results shown an improvement in soil quality with agroecological management. The decrease in soil acidity may be related to the release of bases in the decomposition process and / or to the complexation of exchangeable Al3+ present in the soil. The reduction in the concentration of K+ in the soil may be related to the leaching of this nutrient. Losses of Na+ and K+ could be minimized by planting productive species together with green manure. We concluded that soil management with mulch and one green manure cycle contributes to the improvement of soil quality, stimulating biological activity, reducing acidity and altering nutrient cycling.
Soil degradation is currently a worrying panorama; globally, most of productive soils suffers erosion. Losses of productive soil are one of the most serious degradation factors today, as they threaten the ability to produce food for humanity in a near future. Agroecological soil management has the potential to reverse this situation, promoting productive soil health by protecting it against erosion and recovering the processes that are responsible for maintaining its fertility. This work aimed to study the effects of soil agroecological management on soil quality. We evaluated the effects of the combined use of mulch with green manure for one year on the soil chemical and physical properties in an experimental agroforestry system (SAF). Soil morphological description, chemical (pH- H2O and KCl, Na+ , K+ , Ca2+, Mg2+, Al3+, Al3+ + H+ ) and physical properties (soil density, particle density and porosity) we determined before (t0) and after one year (t1) of mulch application and green manure. We observed the formation of a new biogenic soil horizon and significant changes in chemical properties (all p <0.05). There was an average increase of pH of 0.5 units in both horizons A1 and A2, reduction of Na+ , 0.4 mmolc kg-1 (A1) and 0.3 mmolc kg-1 (A2) and K+ of 3.2 mmolc kg-1 (A1) and 1.9 mmolc kg-1 (A2). In addition to reducing aluminum saturation by 5% and 10% in horizons A1 and A2 respectively and increasing base saturation from 40% to 50% in A1. Physical properties have not changed significantly. The results shown an improvement in soil quality with agroecological management. The decrease in soil acidity may be related to the release of bases in the decomposition process and / or to the complexation of exchangeable Al3+ present in the soil. The reduction in the concentration of K+ in the soil may be related to the leaching of this nutrient. Losses of Na+ and K+ could be minimized by planting productive species together with green manure. We concluded that soil management with mulch and one green manure cycle contributes to the improvement of soil quality, stimulating biological activity, reducing acidity and altering nutrient cycling.