Carbono, nitrogênio e fósforo em latossolo após aplicação de lodo de esgoto por dezoito anos consecutivos
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Data
2016-07-28
Autores
Delarica, Denise de Lima Dias [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O uso do lodo de esgoto (LE) em áreas agrícolas apresenta-se como uma das práticas mais sustentáveis para manejo e disposição final do resíduo, pois contempla o potencial deste em atuar como condicionador do solo e promover ação fertilizante. O objetivo deste estudo foi avaliar o efeito da aplicação de doses crescentes de LE por dezoito anos consecutivos no teor de carbono das substâncias húmicas e de carboidratos, na concentração de nitrogênio (N) e fósforo (P) de um Latossolo Vermelho distrófico (LVd), até a profundidade 0,60 m. Em plantas de milho cultivadas no LVd objetivou-se avaliar à disponibilidade de N e P a produção de matéria seca e a produtividade. O experimento foi instalado em condições de campo em Jaboticabal, SP com delineamento experimental em blocos casualizados com 4 tratamentos e 5 repetições. Os tratamentos para o décimo oitavo ano de experimentação foram: T0= controle (fertilização mineral, sem aplicação de LE), T5 = 5 Mg ha-1 LE, T10= 10 Mg ha-1 LE e T20= 20 Mg ha-1 LE, todos base seca. Os teores de carboidratos totais e solúveis no LVd variaram tanto em função das doses de LE adicionadas ao solo, quanto em virtude do aumento da profundidade de amostragem. Na camada superficial todas as doses de LE proporcionaram incremento do teor de carboidratos totais no solo, porém, em função do aumento da profundidade notou-se queda nesses teores. Em função da aplicação do LE, os tratamentos que o receberam apresentaram maiores concentrações de C nas frações ácido húmico e fúlvico. A concentração de N-total apresentou decréscimo por efeito do aumento da profundidade do solo, e acréscimo em função do incremento das doses de LE. Os teores de amônio e nitrato elevaram-se com o aumento da profundidade e em função das maiores doses do resíduo, caracterizando um alerta quanto a possível contaminação de águas subterrâneas. Quanto maior a dose de LE, maior o teor disponível de P no solo, em função da profundidade e do tipo de fonte de P a disponibilidade do mesmo foi reduzida, estando na camada 0,40-0,60 m e no tratamento que recebeu fertilização mineral o menor teor do nutriente. O teor de N e P absorvido por plantas encontraram-se dentro da faixa adequada para a cultura do milho. Doses de LE de até 20 Mg ha-1 aplicadas por dezoito anos consecutivos no solo garantiram produtividade de grãos e produção de matéria seca adequadas, já que proporcionaram valores semelhantes ao encontrado no tratamento que recebeu fertilização mineral.
The use of sewage sludge (SS) in agricultural areas is presented as one of the most sustainable practices for management and final disposal of the waste as it contemplates the potential for this to act as soil conditioner, fertilizer promoting action. The objective of this study was to evaluate the effect of application of increasing doses of LE for eighteen consecutive years on the carbon content of humic and carbohydrate substances, the concentration of nitrogen (N) and phosphorus (P) of an Oxisol (LVd) to a depth 0.60 m. In corn plants grown in LVd aimed to evaluate the availability of N and P to dry matter production and productivity. The experiment was conducted under field conditions in Jaboticabal, SP with a randomized block design with 4 treatments and 5 repetitions. Treatments for the eighteenth year of experimentation were: T0 = control (mineral fertilization, without applying SS), T5 = 5 Mg ha-1 SS, T10 = 10 Mg ha-1 SS and T20 = 20 Mg ha-1 SS all on a dry basis. Levels of total and soluble carbohydrates in LVd varied both in terms of doses SS added to the soil, as a result of increased sampling depth. The surface layer all SS doses provided increased the total carbohydrate content in the soil, however, due to the increasing depth was noted decrease in these levels. Depending on the application of the SS, the treatments that received showed higher concentrations of C in fractions humic and fulvic acid. The total N concentration showed a decrease effect of increasing soil depth, and increase due to the increase of SS doses. Ammonium and nitrate levels were elevated with increasing depth, and due to higher doses than residue featuring an alert for possible contamination of groundwater. The higher dose of SS, the greater the available P in soil, depending on the depth and type P source its availability was reduced, 0.40-0.60 m layer being in me received fertilization treatment the lowest level of mineral nutrient. The N content and P uptake by plants were within the range for the corn crop. SS doses up to 20 Mg-1 eighteen consecutive years in soil productivity ensured adequate grain and dry matter production, as provided similar values to those found in treatments with mineral fertilizers.
The use of sewage sludge (SS) in agricultural areas is presented as one of the most sustainable practices for management and final disposal of the waste as it contemplates the potential for this to act as soil conditioner, fertilizer promoting action. The objective of this study was to evaluate the effect of application of increasing doses of LE for eighteen consecutive years on the carbon content of humic and carbohydrate substances, the concentration of nitrogen (N) and phosphorus (P) of an Oxisol (LVd) to a depth 0.60 m. In corn plants grown in LVd aimed to evaluate the availability of N and P to dry matter production and productivity. The experiment was conducted under field conditions in Jaboticabal, SP with a randomized block design with 4 treatments and 5 repetitions. Treatments for the eighteenth year of experimentation were: T0 = control (mineral fertilization, without applying SS), T5 = 5 Mg ha-1 SS, T10 = 10 Mg ha-1 SS and T20 = 20 Mg ha-1 SS all on a dry basis. Levels of total and soluble carbohydrates in LVd varied both in terms of doses SS added to the soil, as a result of increased sampling depth. The surface layer all SS doses provided increased the total carbohydrate content in the soil, however, due to the increasing depth was noted decrease in these levels. Depending on the application of the SS, the treatments that received showed higher concentrations of C in fractions humic and fulvic acid. The total N concentration showed a decrease effect of increasing soil depth, and increase due to the increase of SS doses. Ammonium and nitrate levels were elevated with increasing depth, and due to higher doses than residue featuring an alert for possible contamination of groundwater. The higher dose of SS, the greater the available P in soil, depending on the depth and type P source its availability was reduced, 0.40-0.60 m layer being in me received fertilization treatment the lowest level of mineral nutrient. The N content and P uptake by plants were within the range for the corn crop. SS doses up to 20 Mg-1 eighteen consecutive years in soil productivity ensured adequate grain and dry matter production, as provided similar values to those found in treatments with mineral fertilizers.
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Palavras-chave
Nitrato, Amônio, Carboidratos, Matéria orgânica, Substâncias húmicas, Sustentabilidade agrícola nutrição de plantas, Sustainability in agriculture, Nitrate, Ammonium, Soil carbohydrates, Organic matter and plant nutrition