Efeito da adubação fosfatada no crescimento, produtividade e acúmulo de fósforo e amido em mandioca para indústria
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Data
2019-02-21
Autores
Magolbo, Luis Augusto de Souza
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
RESUMO No Brasil a maioria das lavouras de mandioca cultivadas para fins industriais tem sido colhida com dois anos, mas nessa modalidade de cultivo, pouco se conhece sobre o padrão de acúmulo e distribuição de matéria seca (MS). A nutrição mineral adequada da planta é um dos fatores essenciais para aumentar o crescimento da mandioca e seu acúmulo de biomassa. O fósforo (P) tem sido o nutriente que promove as respostas mais acentuadas na cultura da mandioca, e por ele participar da síntese de amido nas plantas, é de se esperar que seu fornecimento em quantidades adequadas possa aumentar o crescimento da planta e as produtividades de raízes e de amido. Assim, o objetivo deste trabalho foi de avaliar o crescimento, a produtividade e o acúmulo de fósforo e amido em mandioca de indústria ao longo dos ciclos vegetativos, cultivada sob diferentes níveis de adubação fosfatada. A cultivar utilizada foi a IAC - 14 e o delineamento experimental utilizado foi o de blocos casualizados, em esquema de parcela subdividida, com quatro repetições. As parcelas foram constituídas por três níveis de fornecimento de P (P - 0 = sem adubação com P; P - 80 = adubação com 80 kg ha-1 de P2O5 no sulco de plantio; P - 160 = adubação com 160 kg ha-1 de P2O5 no sulco de plantio); e as subparcelas por 11 épocas de coleta de plantas no decorrer do ciclo. Conclui-se que o fornecimento de P teve pouca influência sobre o crescimento e produtividade da mandioca de indústria no primeiro ciclo vegetativo, mas no segundo ano a biomassa das plantas e a produtividade de raízes foram maiores sob a maior dose de P. Plantas de mandioca fertilizadas com a maior dose P absorveram mais P em ambos os ciclos vegetativos, mas o acúmulo de amido nas raízes e na planta inteira só foi mais elevado sob alto fornecimento de P durante o segundo ciclo vegetativo. No primeiro ciclo vegetativo a absorção máxima de P e as produtividades máximas de raízes e amido ficaram entre 14,7 - 19,4 kg ha-1 , 29,7 - 33,9 t ha-1 e 7,8 - 9,0 t ha-1 , respectivamente. A absorção máxima de P e as produtividades máximas de raízes e amido no segundo ano ficaram entre 15,8 - 20,8 kg ha-1 , 50,9 - 60,8 t ha-1 e 15,9 - 19,5 t ha-1 , respectivamente.
ABSTRACT In Brazil, most of the cassava crops grown for industrial purposes have been harvested with two years, but in this modality of cultivation, little is known about the pattern of accumulation and distribution of dry matter (DM). Adequate mineral plant nutrition is also one of the essential factors to increase cassava growth and its biomass accumulation. Phosphorus (P) has been the nutrient that promotes the most pronounced and most frequent responses in cassava cultivation, and because it participates in the synthesis of starch in plants, it is expected that its supply in adequate quantities may increase the plant growth and yield of root and starch. Thus, the objective of this work was to evaluate the growth, yield and accumulation of phosphorus and starch in cassava of the industrial use under different levels of phosphate fertilization. The cultivar used was IAC - 14. The experimental design was a randomized complete block design with four replications. The main plots were represented by three levels of P supply (P - 0 = without fertilization with P; P - 80 = fertilization with 80 kg ha-1 P2O5 in the planting groove; P - 160 = fertilization with 160 kg ha-1 P2O5 in the planting groove); and the sub-plots for 11 times of plant sampling throughout the cycle. It was concluded that the supply of P had little influence on the growth and productivity of the industrial cassava in the first year of cultivation, but in the second year plant biomass and root productivity were higher under the highest P. cassava fertilized with the highest P-dose absorbed more P in both years of cultivation, but the accumulation of starch in the roots and in the whole plant was only higher under high P supply during the second year of cultivation. In the first year of cultivation the maximum P absorption and the maximum yield of root and starch were between 14.7 - 19.4 kg ha-1 , 29.7 - 33.9 t ha-1 , and 7.8 - 9.0 t ha-1 , respectively. The maximum P absorption and the maximum yield of root and starch in the second year were between 15.8 - 20.8 kg ha-1 , 50.9 - 60.8 t ha-1 , and 15.9 - 19.5 t ha-1 , respectively.
ABSTRACT In Brazil, most of the cassava crops grown for industrial purposes have been harvested with two years, but in this modality of cultivation, little is known about the pattern of accumulation and distribution of dry matter (DM). Adequate mineral plant nutrition is also one of the essential factors to increase cassava growth and its biomass accumulation. Phosphorus (P) has been the nutrient that promotes the most pronounced and most frequent responses in cassava cultivation, and because it participates in the synthesis of starch in plants, it is expected that its supply in adequate quantities may increase the plant growth and yield of root and starch. Thus, the objective of this work was to evaluate the growth, yield and accumulation of phosphorus and starch in cassava of the industrial use under different levels of phosphate fertilization. The cultivar used was IAC - 14. The experimental design was a randomized complete block design with four replications. The main plots were represented by three levels of P supply (P - 0 = without fertilization with P; P - 80 = fertilization with 80 kg ha-1 P2O5 in the planting groove; P - 160 = fertilization with 160 kg ha-1 P2O5 in the planting groove); and the sub-plots for 11 times of plant sampling throughout the cycle. It was concluded that the supply of P had little influence on the growth and productivity of the industrial cassava in the first year of cultivation, but in the second year plant biomass and root productivity were higher under the highest P. cassava fertilized with the highest P-dose absorbed more P in both years of cultivation, but the accumulation of starch in the roots and in the whole plant was only higher under high P supply during the second year of cultivation. In the first year of cultivation the maximum P absorption and the maximum yield of root and starch were between 14.7 - 19.4 kg ha-1 , 29.7 - 33.9 t ha-1 , and 7.8 - 9.0 t ha-1 , respectively. The maximum P absorption and the maximum yield of root and starch in the second year were between 15.8 - 20.8 kg ha-1 , 50.9 - 60.8 t ha-1 , and 15.9 - 19.5 t ha-1 , respectively.
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Palavras-chave
Palavras - chave: Manihot esculenta. Matéria seca. Análise de crescimento. Produtividade de raízes., Keywords: Manihot esculenta. Dry matter. Growth analysis. Root yield.