Studies on the mineral nutrition and fertilization of the passion fruit plant (Passiflora edulis f. flavicarpa): II - placement of fertilizer phosphorus

1 - Tagged superphosphate was applied to 2.5 year old passion fruit plants from a commercial plantation established in a sandy loam. 2 - 100 grams of the fertilizer were distributed in the following ways: in a circular furrow 20 cm deep around the plant 40 cm from the stems; in a circular strip 10 cm wide, 40 cm from the stems; in six holes around the plants, 40 cm from the stems 20 cm deep, 2.5 cm in diameter. 3-10 grams of the fertilizer in 1 l of water were sprayed to the leaves. 4 - Three weeks after the treatments were made leaf samples were taken for analysis. 5 - Determinations of specific activities both in the leaves and in the fertilizer used have shown that P in the plant was derived from the superphosphate m the following relative proportions (by making the first treatment equal to 100): circular furrow = 100; circular strip = 120; holes = 30; foliar spray = 230.A localização do superfosfato (marcado com P32) no maracujá em produção foi estudada em condições de plantação comercial. Verificou-se que as aplicações em sulcos circulares ou faixas superficiais ao redor da planta tem eficiência equivalente sendo esses métodos três vezes superiores à localização do adubo em furos no solo. A pulverização foliar, por sua vez, mostrou-se 20 vezes mais eficiente que a aplicação no solo de acordo com os dois primeiros métodos

Estudos sobre a nutrição mineral do milho: II - deficiências de macronutrientes na variedade Piranão

Corn plants, Piranão variety, were grown in nutrient solution, complete and with omission of one macronutrient each time, in order to gain information on the effects of treatments on growth, symptoms of deficiency, and mineral composition of the leaves. The following symptoms of deficiency were obtained: Nitrogen -- plants underdeveloped; "V" shaped chlorosis beginning in the older leaves followed by drying and necrosis; Phosphorus - older leaves dark green with a purple hve; Potassium - plants underdeveloped; marginal chlorisis and necrosis in the older leaves; iron induced chlorosis in the younger leaves; Calcium - plants very underdeveloped due to death of apical merystem; younger leaves showing tip and marginal chlorosis and afterwards necrosis and break down of the tissue; wide whitish areas in the younger leaves; Magnesium - plants very underdeveloped; internerval chlorosis in older leaves first, proceeding to the young ones; Sulfur - absence of marked symptoms, except for a slight chlorosis in the younger leaves. Dry matter production obeyed the following decreasing order: Complete, minus S, minus P, minus K, minus Mg, minus N and minus Ca. Ears were obtained only in treatments complete and minus S. Top/root ratio decreased according to this order: minus S, complete, minus K, minus Mg, minus N, minus P and minus Ca. The macronutrient content for the treatment complete was the following respectively for lower and upper, leaves: N - 2.76 and 2.52%; P - 0.59 and 0.53%; K - 2.25 and 2.26%;Ca - 2.17 and 1.85;Mg - 0.82 and0.66;S - 0.38 and 0.32. The values of the element corresponding to each treatment were: N - 1.84 and 1.22 (that is: lower leaves in the minus N plants had 1 84% N, whereas the upper leaves in same treatment had 1.22% N; P - 0.14 and 0.17%; K - 0.29 and 0.78%; Ca - 0.29 and 0.05; Mg -0.09 and 0.05%; S- 0.31 and 0.26%.Foram induzidos sintomas de carência de macronutrientes no milho, var. Piranão, exceto no caso do enxofre. Os níveis foliares de N, P, K, Ca, Mg e S foram determinados nas plantas sujeitos à nutrição completa e às deficiências de macronutrientes