MACRONUTRIENTS IN THE Eucalyptus Dunnii Maiden ROWS SUBMITTED TO POTASSIUM FERTILIZATION IN VARIABLE CHARGE SOILS

Abstract

The contribution of nutrient cycling from eucalyptus residues in an Integrated Crop-Livestock System (ICLS) extracting potassium (K) in deeper layers and releasing on the surface should be further investigated in soils with variable charge. The objectives of this study were to evaluate the effects of K rates (0, 100, 200 and 300 kg ha-1 yr-1 of K2O) applied on the soil surface in the entire area in rows of ICLS with eucalyptus, and relate these doses to macronutrient levels in the soil. The implemented experimental design was a randomized complete block using a split plot with three replications. The plot consisted of two rows and subplot by K rates. Soil fertility attributes were conducted at 6, 12 and 30 months after the start of the experiment. Medium to high concentrations of K were observed in profile up to 12 months, and very low concentrations of K were observed in the profile 30 months after the experiment was initiated. High concentrations of Ca, Mg were observed throughout the profile favoring saturation in an effective cation exchange capacity (ECEC). However, high K saturation in ECEC was observed at 6 and 12 months, and this decreased at 30 months of study. No leaching was observed, although acidity was high.

Potassium fertilization for white oat and maize in integrated crop‐livestock system under no‐tillage

“…The ICLS with trees success does not only demand adequate combinations of crops, forages and tree components, but also the proper management of fertilization, which may increase the efficiency of uptake and use of soil nutrients (Rengel & Damon, 2008). The improvement in maintenance of soil moisture, which is promoted by the tree component, has been determinant in the availability of potassium (K) to the plants because the movement of the soil solution can be driven by differences in water potential (mass flow) or concentration (diffusion) (Schneider et al., 2018). Concerning K, some studies showed the importance of this nutrient within integrated systems (Ferreira et al., 2009, 2011; Schneider et al., 2018), but few evaluate the efficiency of use of this nutrient by cultures within ICLS.…”

“…However, in ICLS with trees, forest species influence the growth and development of agricultural crops (Carvalho et al., 2010; Mugunga et al., 2017; Rozados‐Lorenzo et al., 2007) due to changes in (i) microclimate, with decreasing air temperature and increasing air and soil moisture (Karvatte et al., 2016); (ii) amount (photon flux density) and quality (for example, changes in red:far‐red ratio) of solar radiation that reaches crops between trees lines (Beaudet et al., 2011; Ligot et al., 2016; Paciullo et al., 2011), which can be further associated with different plants physiological responses (Almeida et al., 2005; Baldissera et al., 2016; Kang et al., 2008); and (iii) nutrient dynamics, mainly interfering in quantity, availability and cycling (Bernardi et al., 2017; Diel et al., 2014; Karam et al., 2013; Schneider et al., 2018).…”

“…(iii) nutrient dynamics, mainly interfering in quantity, availability and cycling (Bernardi et al, 2017;Diel et al, 2014;Karam et al, 2013;Schneider et al, 2018).…”

“…The improvement in maintenance of soil moisture, which is promoted by the tree component, has been determinant in the availability of potassium (K) to the plants because the movement of the soil solution can be driven by differences in water potential (mass flow) or concentration (diffusion) (Schneider et al, 2018). Concerning K, some studies showed the importance of this nutrient within integrated systems (Ferreira et al, 2009(Ferreira et al, , 2011Schneider et al, 2018), but few evaluate the efficiency of use of this nutrient by cultures within ICLS. Thus, the present work endeavors to evaluate nutrition and dry matter (DM) yield of white oat and maize, as well as maize grain yield and K use efficiency by the crops in succession (white oat -maize), in an ICLS with trees submitted to K fertilization.…”