Produtividade de tubérculos e acúmulo, partição e exportação de nutrientes em duas cultivares de batata sob influência do manejo do nitrogênio
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Data
2021-02-05
Autores
Fernandes, Fabiana Morbi [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O nitrogênio (N) é o segundo nutriente mais absorvido pela cultura da batata (Solanum tuberosum L.), exercendo grande influência no crescimento e desenvolvimento da cultura e na produção de tubérculos. A nutrição mineral equilibrada é fundamental para alcançar elevada produtividade de tubérculos de batata. No entanto, o N pode estimular o crescimento das plantas e, consequentemente, a absorção da maioria dos nutrientes por elas, tornando importante o conhecimento das exigências nutricionais ao longo do ciclo de desenvolvimento da cultura da batata. Dessa forma, o objetivo deste trabalho foi avaliar o acúmulo e a partição de matéria seca (MS) e nutrientes ao longo do ciclo, bem como a produtividade de tubérculos e a exportação de nutrientes de duas cultivares de batata em função de diferentes manejos da adubação nitrogenada. Foram conduzidos seis experimentos, em condições de campo, sendo três com a cultivar Agata e três com a cultivar Electra. Os experimentos foram realizados em três locais diferentes, localizados no município de Botucatu-SP, durante a “safra de inverno-primavera”, dos anos de 2016 (Locais 1 e 2) e 2017 (Local 3). O Local 1 de condução dos experimentos foi a Fazenda Experimental Lageado, enquanto os Locais 2 e 3 foram áreas particulares de produção de batata. Nos seis experimentos, o delineamento experimental utilizado foi o de blocos casualizados, com quatro repetições. Os tratamentos foram constituídos por cinco formas de manejo do N: M1: 80 kg ha-1 de N no sulco de plantio + 80 kg ha-1 de N na amontoa [10 dias após a emergência (DAE)] + 80 kg ha-1 de N aos 30 DAE + 80 kg ha-1 de N aos 45 DAE; M2: 80 kg ha-1 de N no sulco de plantio + 80 kg ha-1 de N na amontoa; M3: 160 kg ha-1 de N no sulco de plantio; M4: 80 kg ha-1 de N no sulco de plantio; M5: testemunha (sem aplicação de N). Foram realizadas seis épocas de coletas de plantas, que foram realizadas aproximadamente aos 10, 24, 45, 59, 74 e 85 DAE [24, 39, 60, 74, 89 e 99 dias após o plantio (DAP)]. As duas cultivares apresentaram crescimento lento até o início da fase de formação dos tubérculos, e a partir desse período o acúmulo de MS foi intensificado, com uma fase de estabilização próximo ao final do ciclo. A época em que as plantas de batata apresentaram o pico de crescimento ocorreu por volta dos 55 DAP, enquanto que para os tubérculos ocorreu por volta dos 70 DAP. Os tratamentos com as maiores doses de N proporcionaram maiores incrementos no acúmulo de MS para as duas cultivares, consequentemente, também promoveram incrementos nas quantidades de macronutrientes acumuladas nos tubérculos e na planta inteira. No entanto, a resposta ao N, bem como a influência deste no acúmulo e partição de nutrientes, variaram em função da condição de cultivo (local). Com exceção do S, todos os macronutrientes apresentaram maior época de demanda antes ou coincindiu com o período em que houve a máxima produção de MS. O comportamento das duas cultivares foi semelhante em relação à resposta ao N e absorção dos macronutrientes pela planta e, de maneira geral, a ordem de extração de nutrientes para as duas cultivares foi: K > N > Ca > P > Mg > S, e esta não foi afetada pelo manejo de N. O Ca foi o nutriente que apresentou a menor quantidade exportada pelos tubérculos (4%), independentemente do manejo de N estudado, em relação a quantidade total de nutrientes extraídas pelas plantas das duas cultivares de batata. Em média, 88% do N, 67% do P, 49% do K, 47% do Mg e 51% do S absorvidos pela planta foram exportados pelos tubérculos colhidos. Para alcançar os níveis máximos de produtividade de tubérculos, as cultivares estudadas absorveram entre 136 e 190 kg ha-1 de N e, dessa forma, sob baixa disponibilidade de N, a partição de MS e N para os tubérculos é limitada, reduzindo a produtividade de tubérculos.
Nitrogen (N) is the second most taken up nutrient in the potato crop (Solanum tuberosum L.), having a great influence on the development and growth of the crop and tuber yield. Mineral nutrition in a balanced way is essential to achieve high tuber yield. However, N can stimulate the growth of plants and, hence, the uptake of most nutrients by them, making it important to know the nutritional requirements throughout the development cycle of the potato crop. The objective of this study was to assess the uptake and partition of dry matter (DM) and nutrients along the growth cycle, as well as the tuber yield and nutrient removal in two potato cultivars as affected by five N managements. Six field experiments were conducted, tree with the cultivar Agata and three with the cultivar Electra. The experiments were conducted in three different sites, in Botucatu, São Paulo State, during the “winter-spring season”, during 2016 (Site-year 1 and 2) and 2017 (Site-year 3). The Site-year 1 was located at Lageado Experimental Farm, while Site-years 2 and 3 were located in commercial potato fields. In the six experiments, the experimental design was randomized complete blocks, with four replications. The treatments consisted of five N management strategies: M1: 80 kg N ha-1 at planting furrow + 80 kg ha-1 at hilling [10 days after emergence (DAE)] + 80 kg ha-1 at 30 DAE + 80 kg ha-1 at 45 DAE; M2: 80 kg N ha-1 at planting furrow + 80 kg ha-1 at hilling; M3: 160 kg N ha-1 at planting furrow; M4: 80 kg N ha-1 at planting furrow; M5: a control (without N fertilization). Plant samples were collected at 10, 24, 45, 59, 74 and 85 DAE [i.e., 24, 39, 60, 74, 89, and 99 days after planting (DAP)]. The two cultivars showed slow growth until the beginning of the tuber growth stage, and from this period the accumulation of DM was intensified, with a stabilization phase near the end of the cycle. The period when the potato plants showed the peak of growth occurred at around 55 DAP, while for tubers it occurred at around 70 DAP. Treatments with the highest N rates provided greater DM accumulation increments in both cultivars, consequently, also provided increases in uptake of macronutrients in tubers and whole plant. However, the response to N, as well as its influence on nutrient uptake and partition, varied according to the growth condition (site-year). Exception for S, all macronutrients had a higher demand period just before or coincided with the period when there was the maximum production of DM. The performance of the two cultivars was similar in relation to the N response and macronutrients uptake by the plant and, in general, the order of nutrient uptake for the two cultivars was: K > N > Ca > P > Mg > S, and this was not affected by N managements. Calcium was the nutrient that presented the lowest amount removed by the tubers (4%), regardless of the N management studied, in relation to the total amount of nutrients extracted by the plants of the two potato cultivars. On average, 88% of N, 67% of P, 49% of K, 47% of Mg, and 51% of S taken up by the plant were removed by the tubers. To achieve the maximum levels of tuber yields, the cultivars studied took up at least between 136 and 190 kg ha-1 of N and, therefore, under low availability of N, the partition of DM and N for the tubers is limited, reducing tuber yield.
Nitrogen (N) is the second most taken up nutrient in the potato crop (Solanum tuberosum L.), having a great influence on the development and growth of the crop and tuber yield. Mineral nutrition in a balanced way is essential to achieve high tuber yield. However, N can stimulate the growth of plants and, hence, the uptake of most nutrients by them, making it important to know the nutritional requirements throughout the development cycle of the potato crop. The objective of this study was to assess the uptake and partition of dry matter (DM) and nutrients along the growth cycle, as well as the tuber yield and nutrient removal in two potato cultivars as affected by five N managements. Six field experiments were conducted, tree with the cultivar Agata and three with the cultivar Electra. The experiments were conducted in three different sites, in Botucatu, São Paulo State, during the “winter-spring season”, during 2016 (Site-year 1 and 2) and 2017 (Site-year 3). The Site-year 1 was located at Lageado Experimental Farm, while Site-years 2 and 3 were located in commercial potato fields. In the six experiments, the experimental design was randomized complete blocks, with four replications. The treatments consisted of five N management strategies: M1: 80 kg N ha-1 at planting furrow + 80 kg ha-1 at hilling [10 days after emergence (DAE)] + 80 kg ha-1 at 30 DAE + 80 kg ha-1 at 45 DAE; M2: 80 kg N ha-1 at planting furrow + 80 kg ha-1 at hilling; M3: 160 kg N ha-1 at planting furrow; M4: 80 kg N ha-1 at planting furrow; M5: a control (without N fertilization). Plant samples were collected at 10, 24, 45, 59, 74 and 85 DAE [i.e., 24, 39, 60, 74, 89, and 99 days after planting (DAP)]. The two cultivars showed slow growth until the beginning of the tuber growth stage, and from this period the accumulation of DM was intensified, with a stabilization phase near the end of the cycle. The period when the potato plants showed the peak of growth occurred at around 55 DAP, while for tubers it occurred at around 70 DAP. Treatments with the highest N rates provided greater DM accumulation increments in both cultivars, consequently, also provided increases in uptake of macronutrients in tubers and whole plant. However, the response to N, as well as its influence on nutrient uptake and partition, varied according to the growth condition (site-year). Exception for S, all macronutrients had a higher demand period just before or coincided with the period when there was the maximum production of DM. The performance of the two cultivars was similar in relation to the N response and macronutrients uptake by the plant and, in general, the order of nutrient uptake for the two cultivars was: K > N > Ca > P > Mg > S, and this was not affected by N managements. Calcium was the nutrient that presented the lowest amount removed by the tubers (4%), regardless of the N management studied, in relation to the total amount of nutrients extracted by the plants of the two potato cultivars. On average, 88% of N, 67% of P, 49% of K, 47% of Mg, and 51% of S taken up by the plant were removed by the tubers. To achieve the maximum levels of tuber yields, the cultivars studied took up at least between 136 and 190 kg ha-1 of N and, therefore, under low availability of N, the partition of DM and N for the tubers is limited, reducing tuber yield.
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Palavras-chave
Batata, Fertilidade do solo, Plantas nutrição, Adubação, Solanum tuberosum, Potato, Nitrogen fertilization, Plant nutrition