Formas químicas, disponibilidade de manganês e produtividade de soja em solos sob semeadura direta

Carrot is one of the most consumed vegetables in Brazil, where the cultivars currently grown present a high yield potential and nutritional demand, which require constant adjustments in fertilization programs for the crop. This study aimed at determining reference values and diagnostic indices by using the DRIS method in three phenological stages of the carrot crop (around 40 and 70 days after sowing and at harvest), as well as evaluating the possibility of early diagnosis for nutritional limitations. For determining the DRIS norms, a database was obtained from leaf samplings, root yields and leaf contents of N, P, K, Ca, Mg, S, B, Cu, Mn and Zn, in carrot commercial fields. The nutritional limitation order was generated as a function of the fertilization response and optimum range of leaf contents. The reference values for K, Ca, Mg, S and Mn were similar in all sampling times. N, P, B, Cu and Zn varied with the stages sampled, indicating the need to standardize the sampling times for these nutrients. Mn, K and Mg were the most limiting nutrients for the crop growth, while Zn and B were the least limiting. There was a correlation between the diagnoses performed at early stages and those performed at harvest for K, Ca, Mg, S and Mn, indicating the possibility of early diagnosis for the deficiency of these nutrients.

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“…These conditions led to the low availability (Moreira et al 2006), causing deficiency in carrot plants.…”

Section: Resultsmentioning

confidence: 99%

DRIS indices in three phenological stages of the carrot crop

Gonçalves

Aquino

Dezordi

et al. 2017

Pesqui. Agropecu. Trop.

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“…Rates to raise the base saturation to 70%, calculated in accordance to procedures recommended by Raij et al (1997), were 3,030, 3,380, and 2,485 kg ha December 17, 1998and January 26, 1999, respectively. Malavolta, Vitti, and Oliveira (1997 recommended sampling only one leaf at the blossoming, but an additional date was considered because Mn deficiencies in soybean and Zn deficiencies in corn have been frequent in the initial periods of crop development but subsequently disappear eventually (Pauletti, 1999;Moreira et al, 2006). Twenty open trifoliolate leaves per plot (third leaf from the top) were collected.…”

Section: Methodsmentioning

confidence: 99%

“…However, this explanation may not always be correct because high extractable soil Zn and Mn have been found in surface layers of soils under NT, even when the pH and OM are high (Teixeira et al, 2003;Moreira et al, 2006;Moreira et al, 2016). Soratto and Crusciol (2008) did not observe decreases in Mn, Fe and Zn absorption by black oat cultivated in a Red Latosol under NT when high rates of lime were used.…”

Section: Introductionmentioning

confidence: 97%

“…In many cases, these high micronutrient levels in the soils were attributed to the application of high rates of N to maize (Zea mays L.) and/or monocultures of grass, which cause a reduction in the pH and, consequently, increases in the availability of certain micronutrients (Grove & Blevins, 1988;Follett & Peterson, 1988;Edwards, Wood, Thurlow, & Ruf , 1992). However, it is known that the increased availability of certain micronutrients, chiefly Mn and Zn, is highly related to the increase of OM in the surface soil (Teixeira et al, 2003;Moreira, Prochnow, Kiehl, Martin-Neto, & Pauletti, 2006;Martin-Rueda et al, 2007;Santiago et al, 2008;Motschenbacher et al, 2014;Moreira et al, 2016). On the other hand, Zn and Mn deficiencies have been noticed especially in corn and soybean crops under NT.…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, Zn and Mn deficiencies have been noticed especially in corn and soybean crops under NT. In addition, micronutrient deficiencies may increase with increasing time under NT because OM can bind with some micronutrients and decrease their availability (Tisdale, Nelson, & Beaton, 1985;Moreira et al, 2006;Moreira et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

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<b>Effect of liming on micronutrient availability to soybean grown in soil under different lengths of time under no tillage

et al. 2017

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ABSTRACT. The effect of liming on the availability of micronutrients to soybean cultivated during different numbers of years under no tillage (NT) was investigated. The treatments consisted of the number of years under NT (three, six, and nine years) and five rates of lime (0, 33, 67 and 100% of the amount calculated to raise soil base saturation to 70%) broadcast on soil surface plus the rate of 100% broadcast with incorporation in the 0-0.20 m layer of a clayey Red Oxisol. Soil and leaf samples were collected at two vegetative stages of the crop (vegetative V4 and blossoming R2). The soil was sampled at depths of 0-0.05, 0.05-0.10, 0.10-0.20, and 0.20-0.30 m. Surface liming had little effect on extractable soil micronutrient and nutrient concentrations in soybean leaves. In the area with three years under NT, all liming rates decreased the extractable soil Zn up to a depth of 0.20 m. Lime incorporation decreased the extractable soil Mn in the surface layer. There were no differences in the extractable soil micronutrients and nutrient concentrations in soybean leaves as a function of the number of years under NT. These data suggest that broadcasting lime at current rates on soils under NT does not necessarily lead to micronutrient deficiencies.Keywords: copper, iron, manganese, zinc, no till.Efeito da calagem na disponibilidade de micronutrientes para soja, cultivada em solo sob diferentes tempos de cultivo em plantio direto RESUMO. Avaliou-se o efeito da calagem sobre a disponibilidade de micronutrientes à soja cultivada em solo, com diferentes tempos de cultivo sob sistema de semeadura direta (SD). Os tratamentos consistiram de número de anos sob SD (três, seis e nove anos) e cinco doses de calcário (0, 33, 67 e 100% da quantidade necessária para elevar a saturação por bases a 70%), aplicadas em superfície, mais a dose 100% incorporada na camada 0-0,20 m de um Latossolo Vermelho argiloso. Amostras de solo e de folha foram coletadas em dois estádios de vegetação da soja (V4: estádio vegetativo e R2: florescimento pleno). O solo foi amostrado nas profundidades de 0-0,05, 0,05-0,10, 0,10-0,20 e 0,20-0,30 m. A calagem superficial exerceu pouco efeito sobre os teores de micronutrientes no solo e nas folhas de soja. Na área com três anos sob sistema de SD todas as doses de calcário reduziram os teores de Zn até a profundidade de 0,20 m. A incorporação de calcário diminuiu o teor de Mn da camada superficial. Os teores de micronutrientes no solo e as concentrações nas folhas da soja não variaram com os anos de cultivo sob SD. Estes dados sugerem que as doses atualmente empregadas de calcário aplicadas na superfície de solos sob SD não necessariamente conduzem a deficiências de micronutrientes.Palavras-chave: cobre, ferro, manganês, zinco, plantio direto.

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