The use of humic substances in agriculture has increased in recent years, and leonardite has been an important raw material in the manufacture of commercial products rich in humic and fulvic acids. Leonardite-based products have been used to improve soil properties and to help plants cope with abiotic and biotic stresses. In this study, the effects of two commercial leonardites and an organic compost, in addition to a control treatment, were assessed for pot-grown olive plants over a period of fourteen months on soil properties, tissue elemental composition and dry matter yield (DMY). Three organic amendments were applied at single and double rates of that set by the manufacturer. The study was arranged in two experiments: one containing the seven treatments mentioned above and the other containing the same treatments supplemented with mineral nitrogen (N), phosphorus (P) and potassium (K) fertilization. Overall, organic compost increased soil organic carbon by ~8% over the control. In the experiment without NPK supplementation, N concentrations in shoots and P in roots were the highest for the compost application (leaf N 12% and root P 32% higher than in the control), while in the experiment with NPK supplementation, no significant differences were observed between treatments. Total DMY was ~10% higher in the set of treatments with NPK in comparison to treatments without NPK. Leonardites did not affect significantly any measured variables in comparison to the control. In this study, a good management of the majority of environmental variables affecting plant growth may have reduced the possibility of obtaining a positive effect on plant nutritional status and growth from the use of commercial leonardites. The leonardites seemed to have caused a slight effect on biological N immobilization. This is not necessarily an advantage or a drawback; it is rather a feature that must be understood to help farmers make better use of these products.

O cultivo de feijão de grãos especiais ainda é restrito no Brasil. Portanto, os objetivos foram: i) avaliar os efeitos da interação linhagem x ambiente nos caracteres que controlam o desempenho agronômico e o tempo de cozimento em linhagens de feijão de grãos especiais e ii) identificar linhagens de alto desempenho agronômico e de reduzido tempo de cozimento. Para isso, 29 linhagens de feijão de grãos especiais foram avaliadas em diferentes locais, anos e épocas de cultivo. Interação linhagem x ambiente significativa foi observada para todos os caracteres avaliados. As linhagens Light Red Kidney, Red Kanner, Montcalm, Chinock e BRS Radiante apresentaram produtividade de grãos similar nos quatro ambientes. As linhagens avaliadas possuem ciclo semi-precoce ou precoce e têm características morfológicas desejáveis. Os seguintes valores de claridade de tegumento de grãos foram obtidos para feijão branco (72,85 a 82,25), rajado (33,06 a 62,57), vermelho (24,51 a 43,69), verde (57,01 a 62,36) e rosa (49,95 a 55,60). O tempo de cozimento variou de 14 min e 38 seg a 36 min e 21 seg. As linhagens de feijão de grãos especiais de tegumento vermelho (Light Red Kidney, Red Kanner, Montcalm e Chinock) e de tegumento rajado (BRS Radiante) apresentam alto desempenho agronômico e reduzido tempo de cozimento nas condições avaliadas

The objective of this work was to evaluate the genetic variability of common bean lines for cycle, weight of 100 grains, grain yield, cooking time, and grain calcium and iron concentrations. Twenty-four common bean lines were evaluated in two crop cycles (2010 and 2011). The ¯Z index was used for the selection of superior lines for most of the traits. The DF 06-19, DF 06-03, DF 06-17, DF 06-20, DF 06-11, DF 06-14, DF 06-01, DF 06-08, DF 06-22, and DF 06-04 lines showed high grain yield. All lines were of semi-early cycle and of fast cooking. The DF 06-08 and DF 06-23 lines showed high calcium concentration in grains (>1.4 g kg-1 dry matter - DM), and the DF 06-09, DF 06-03, DF 06-04, and DF 06-06 lines presented high iron concentration in grains (>0.95 g kg-1 DM) in the two crop cycles. The DF 06-09 and DF 06-03 carioca lines present high agronomic performance and high iron concentration in grains. The DF 06-17 and DF 06-08 black lines present high agronomic performance and high calcium concentration in grains. The selection of the DF 06-09, DF 06-03, DF 06-17, and DF 06-08 lines is recommended.

Growth, grain yield and calcium, potassium and magnesium accumulation in common bean plants as related to calcium nutrition

Adaptability and stability methods to identify promising common bean advanced lines for cultivation in Rio Grande do Sul State, Brazil