Liming and Phosphating on growth, nutritional status and mycorrhizal colonization of yellow strawberry guava

Strawberry guava (Psidium cattleyanumm Sabine) is a species native to southern Brazil which exhibits significant potential for economic exploitation. The objective of this study was to evaluate the growth response of strawberry guava subjected to liming and phosphate fertilizer in pre-planting. The treatments consisted of four lime levels: 0; 33.3; 66.6 and 100 % of the dose needed to increase the pH in water to 6.0, and four phosphorus (P) doses: 0; 83.3; 166.6 and 250 kg ha-¹ of P2O5. Plant growth parameters were evaluated for three years. In the years 2018 and 2019, the mineral composition of leaves, photosynthethic pigment indices and mycorrhizal colonization on strawberry guava roots were measured. Liming and phosphate fertilizer altered neither plant growth nor the photosynthetic pigment indices and there was no interaction between the factors studied and the remaining variables evaluated. However, liming promoted increases in the Ca and Mg shoot content, and the phosphate fertilizer increased the levels of shoot P in the third year of growth. Mycorrhizal colonization was stronger when the P soil levels were low, which could explain the absence of response to phosphate fertilization on plant growth for the first three years after planting.

Nutritional status of peach trees in Brazils main commercial peach-growing region / Estado nutricional do pessegueiro na principal região produtora de pêssego para indústria no Brasil

O presente trabalho teve como objetivo caracterizar nutricionalmente plantas de pessegueiro na região produtora de Pelotas, RS. Foram amostrados 65 pomares de pessegueiros das cultivares Maciel, Granada, Esmeralda e Sensação nos municípios de Pelotas, Canguçu e Morro Redondo no ciclo produtivo de 2018. As amostras foliares, após secas e moídas, foram analisadas quanto aos seus teores de nitrogênio (N), fósforo (P), potássio (K), cálcio (Ca), magnésio (Mg), boro (B), cobre (Cu), ferro (Fe), manganês (Mn) e zinco (Zn) e os resultados foram apresentados em distribuições de frequência nas classes de suficiência indicadas para a cultura na região além da correlação entre os nutrientes. Observou-se maiores deficiências nos teores de nitrogênio, cobre, ferro e zinco. Entretanto, para a maioria das amostras, os teores de potássio encontraram-se na classe acima do normal, encontrou-se correlações entre P/Ca, P/Cu, Ca/P, Ca/Mg e Ca/B. É possível constatar a carência do uso de ferramentas para avaliar o estado nutricional dos pomares, principalmente a diagnose foliar, o que levou ao uso inadequado de fertilizantes e consequentemente um desbalanço nutricional das plantas.

This study set out to assess the nutritional status of peach trees in the commercial peach-growing region of Pelotas, Rio Grande do Sul. The sample includes 65 peach orchards of the Maciel, Granada, Esmeralda, and Sensação cultivars in the municipalities of Pelotas, Canguçu, and Morro Redondo during the 2018 agricultural cycle. After drying and grinding the leaf samples for an analysis of their nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), boron (B), copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn) content, the results were presented in frequency distributions divided into classes based on the nutrient requirements indicated for the crop in the region, in addition to the correlations between the nutrients. Greater deficiencies were observed in nitrogen, copper, iron, and zinc content. However, potassium content was found in the above normal class for most of the samples, and there were correlations between P/Ca, P/Cu, Ca/P, Ca/Mg, and Ca/B. An insufficient use of the tools to assess the nutritional status of the orchards was observed, especially the leaf diagnosis, which led to the inappropriate use of fertilizers and the consequent nutrient imbalance in the plants.

Nutritional status of peach trees in Brazils main commercial peach-growing region / Estado nutricional do pessegueiro na principal região produtora de pêssego para indústria no Brasil

O presente trabalho teve como objetivo caracterizar nutricionalmente plantas de pessegueiro na região produtora de Pelotas, RS. Foram amostrados 65 pomares de pessegueiros das cultivares Maciel, Granada, Esmeralda e Sensação nos municípios de Pelotas, Canguçu e Morro Redondo no ciclo produtivo de 2018. As amostras foliares, após secas e moídas, foram analisadas quanto aos seus teores de nitrogênio (N), fósforo (P), potássio (K), cálcio (Ca), magnésio (Mg), boro (B), cobre (Cu), ferro (Fe), manganês (Mn) e zinco (Zn) e os resultados foram apresentados em distribuições de frequência nas classes de suficiência indicadas para a cultura na região além da correlação entre os nutrientes. Observou-se maiores deficiências nos teores de nitrogênio, cobre, ferro e zinco. Entretanto, para a maioria das amostras, os teores de potássio encontraram-se na classe acima do normal, encontrou-se correlações entre P/Ca, P/Cu, Ca/P, Ca/Mg e Ca/B. É possível constatar a carência do uso de ferramentas para avaliar o estado nutricional dos pomares, principalmente a diagnose foliar, o que levou ao uso inadequado de fertilizantes e consequentemente um desbalanço nutricional das plantas.(AU)

This study set out to assess the nutritional status of peach trees in the commercial peach-growing region of Pelotas, Rio Grande do Sul. The sample includes 65 peach orchards of the Maciel, Granada, Esmeralda, and Sensação cultivars in the municipalities of Pelotas, Canguçu, and Morro Redondo during the 2018 agricultural cycle. After drying and grinding the leaf samples for an analysis of their nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), boron (B), copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn) content, the results were presented in frequency distributions divided into classes based on the nutrient requirements indicated for the crop in the region, in addition to the correlations between the nutrients. Greater deficiencies were observed in nitrogen, copper, iron, and zinc content. However, potassium content was found in the above normal class for most of the samples, and there were correlations between P/Ca, P/Cu, Ca/P, Ca/Mg, and Ca/B. An insufficient use of the tools to assess the nutritional status of the orchards was observed, especially the leaf diagnosis, which led to the inappropriate use of fertilizers and the consequent nutrient imbalance in the plants.(AU)