Adubação nitrogenada, fosfatada e potássica na produtividade, ciclagem de nutrientes e no balanço nutricional do eucalipto
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Data
2017-12-21
Autores
Gazola, Rodolfo de Niro
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Universidade Estadual Paulista (Unesp)
Resumo
As áreas de cultivo do eucalipto têm ocupado novas regiões do Brasil, sendo que o estado do Mato Grosso do Sul lidera esta expansão. Nessas novas áreas, a condição edafoclimática é um fator limitante ao desenvolvimento dessa cultura, pois os solos do bioma Cerrado apresentam baixa fertilidade natural, com pouca disponibilidade de fósforo (P) e potássio (K), e baixo teor de matéria orgânica (M.O.), além disso, o clima é caracterizado pela presença de déficit hídrico acentuado e frequente. Portanto, a carência de nutrientes no solo aliado às condições climáticas influenciam no desenvolvimento da cultura. Neste contexto, objetivou-se avaliar a adubação nitrogenada, fosfatada e potássica dado à importância desses nutrientes na cultura do eucalipto, e a suas limitações no solo em estudo. O experimento foi conduzido na Fazenda Renascença, fundo agrícola administrado pela Cargill Agrícola S/A, localizado no município de Três Lagoas/MS, de setembro de 2011 a julho de 2017, em um NEOSSOLO QUARTZARÊNICO Órtico. Utilizou-se o delineamento em blocos casualizados com quatro tratamentos e cinco repetições. Os tratamentos foram constituídos de doses de nitrogênio (N) (0, 70, 105 e 140 kg ha-1), de P (0, 40, 70 e 100 kg ha-1 de P2O5) e de K (0, 90, 135 e 180 kg ha-1 de K2O). Cada parcela foi composta por 56 plantas, distribuídas em sete linhas de oito plantas cada, totalizando 420 m2. Nas linhas de plantio, as mudas do clone I144 (Eucalyptus urophylla) foram espaçadas em 2,5 m e nas entrelinhas em 3,0 m. Foram avaliados: a produtividade de madeira; as concentrações de nutrientes nas folhas; a produtividade de folhedos, as concentrações e a transferência de nutrientes de folhedos; a disponibilidade dos macronutrientes no solo; o balanço dos nutrientes nas folhas e no solo (relação log isométrica); a produção, concentrações de nutrientes e seu acúmulo na biomassa e a eficiência no uso dos nutrientes. A adubação nitrogenada, fosfatada e potássica aumentaram a produção de biomassa, volume de madeira e estoque de nutrientes na biomassa. As doses de N influenciaram nas concentrações de N na folha e no folhedo, nos balanços foliares de [N | P], [K | Ca, Mg] e [Ca | Mg] e na ciclagem de K e não interferiram na produtividade de folhedo, nos teores de P, K, Ca, Mg e S no solo e na eficiência da utilização dos nutrientes. As doses de P influenciaram positivamente na transferência de P e K para solo, no balanço foliares de [N | P], nos teores de P solo e não interferiram na produtividade de folhedo, nos teores de K, Ca, Mg e S no solo e na eficiência da utilização dos nutrientes. As doses de K influenciaram positivamente nas concentrações de K e negativamente nas de Mg na folha e no folhedo, na transferência de K e Mg para o solo, nos balanços foliares de [K | Ca, Mg] e [Ca | Mg] e do solo de [K, Ca, Mg | H+Al] e [K | Ca, Mg], na eficiência da utilização do N e não interferiram na produtividade de folhedo e nos teores de P, Ca, Mg e S no solo.
The areas of eucalyptus cultivation have occupied new regions of Brazil, being that the state of Mato Grosso do Sul leads this expansion. In these new areas, the soil and soil conditions of the Cerrado biome have low natural fertility, with low availability of phosphorus (P) and potassium (K), and low organic matter (OM), in addition, the climate is characterized by the presence of accentuated and frequent water deficit. Therefore, the lack of nutrients in the soil combined with climatic conditions influence the development of the crop. In this context, the objective was to evaluate the nitrogen, phosphate and potassium fertilization given to the importance of these nutrients in the eucalyptus crop and its limitations in the soil under study. The experiment was conducted at Fazenda Renascença, an agricultural fund managed by Cargill Agrícola S / A, located in the municipality of Três Lagoas / MS, from September 2011 to July 2017, in a Entisols. A randomized block design with four treatments and five replications. The treatments were composed rates of nitrogen (N) (0, 70, 105 and 140 kg ha-1), P (0, 40, 70 and 100 kg ha-1 P2O5) and K (0, 90, 135 and 180 kg ha-1 K2O). Each plot was composed of 56 plants, distributed in seven lines of eight plants each, totaling 420 m2. In the planting lines, the seedlings of clone I144 (Eucalyptus urophylla) were spaced at 2.5 m and in between lines at 3.0 m. The following were evaluated: wood productivity; nutrient concentrations in leaves; foliar productivity, nutrient concentrations and transfer of foliage; the availability of macronutrients in soil; nutrient balance in leaves and soil (isometric log ratio); production, nutrient concentrations and their accumulation in the biomass and the efficiency in the use of the nutrients. Nitrogen, phosphate and potassium fertilization increased biomass production, wood volume and nutrient stock in biomass. N rates influenced leaf and leaf N concentrations in leaf balances of [N | P], [K | Ca, Mg] and [Ca | Mg and K cycling and did not interfere in leaf productivity, P, K, Ca, Mg and S contents in the soil and nutrient utilization efficiency. The P rates influenced positively the transfer of P and K to soil, in the leaf balance of [N | P] levels in soil P and did not interfere with leaf productivity, soil K, Ca, Mg and S contents and nutrient utilization efficiency. The K rates influenced positively K concentrations and negatively Mg concentrations in leaf and leaf, K and Mg transfer to soil, in the leaf swings of [K | Ca, Mg] and [Ca | Mg] and the soil of [K, Ca, Mg | H + Al] and [K | Ca, Mg] in the efficiency of N utilization and did not interfere in leaf productivity and soil P, Ca, Mg and S contents.
The areas of eucalyptus cultivation have occupied new regions of Brazil, being that the state of Mato Grosso do Sul leads this expansion. In these new areas, the soil and soil conditions of the Cerrado biome have low natural fertility, with low availability of phosphorus (P) and potassium (K), and low organic matter (OM), in addition, the climate is characterized by the presence of accentuated and frequent water deficit. Therefore, the lack of nutrients in the soil combined with climatic conditions influence the development of the crop. In this context, the objective was to evaluate the nitrogen, phosphate and potassium fertilization given to the importance of these nutrients in the eucalyptus crop and its limitations in the soil under study. The experiment was conducted at Fazenda Renascença, an agricultural fund managed by Cargill Agrícola S / A, located in the municipality of Três Lagoas / MS, from September 2011 to July 2017, in a Entisols. A randomized block design with four treatments and five replications. The treatments were composed rates of nitrogen (N) (0, 70, 105 and 140 kg ha-1), P (0, 40, 70 and 100 kg ha-1 P2O5) and K (0, 90, 135 and 180 kg ha-1 K2O). Each plot was composed of 56 plants, distributed in seven lines of eight plants each, totaling 420 m2. In the planting lines, the seedlings of clone I144 (Eucalyptus urophylla) were spaced at 2.5 m and in between lines at 3.0 m. The following were evaluated: wood productivity; nutrient concentrations in leaves; foliar productivity, nutrient concentrations and transfer of foliage; the availability of macronutrients in soil; nutrient balance in leaves and soil (isometric log ratio); production, nutrient concentrations and their accumulation in the biomass and the efficiency in the use of the nutrients. Nitrogen, phosphate and potassium fertilization increased biomass production, wood volume and nutrient stock in biomass. N rates influenced leaf and leaf N concentrations in leaf balances of [N | P], [K | Ca, Mg] and [Ca | Mg and K cycling and did not interfere in leaf productivity, P, K, Ca, Mg and S contents in the soil and nutrient utilization efficiency. The P rates influenced positively the transfer of P and K to soil, in the leaf balance of [N | P] levels in soil P and did not interfere with leaf productivity, soil K, Ca, Mg and S contents and nutrient utilization efficiency. The K rates influenced positively K concentrations and negatively Mg concentrations in leaf and leaf, K and Mg transfer to soil, in the leaf swings of [K | Ca, Mg] and [Ca | Mg] and the soil of [K, Ca, Mg | H + Al] and [K | Ca, Mg] in the efficiency of N utilization and did not interfere in leaf productivity and soil P, Ca, Mg and S contents.
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Palavras-chave
Eucalyptus, Fertilização, Macronutrientes, Biomassa, Relações log isométricas (ilr), Fertilization, Macronutrients, Biomass, Isometric log ratio (ilr)