Inter-relation between soybean yield and soil compaction under degraded pasture in Brazilian Savannah

Abstract

SUMMARYThe Cerrado (Brazilian Savannah) plays an important economic and financial role in the nation, since the pastures of this biome feed cattle for half of the domestic bovine meat productivity, and its agricultural fields produce a third of the country's grain. The variability and spatial dependence between the soil physical attributes and soybean yield were evaluated in a crop rotation planted on a degraded brachiaria pasture, on a dystroferric

Correlations of soybean yield with soil porosity and bulk density of an Oxisol

“…For the yield components, the average values for number of pods per plant, number of grains per pod, mass of 100 grains, grain mass per plant, plant population and plant height were, respectively, 25, 2.0, 15.8 g, 6.9 g, 36.5 plants m -2 and 75.8 cm, different from those obtained by Dalchiavon et al (2011), who evaluated the soybean grain yield under no-tillage, in the region of Selvíria, and lower in terms of number of pods per plant, number of grains per pod and grain mass per plant attributes, whose values corresponded, respectively, to 72.2 g, 2.2 g and 23 g. The number of pods per plant was lower than that of 36.6 obtained by Queiroz et al (2011), who studied the soybean grain yield in an Oxisol, in a crop rotation with brachiaria pasture, and of 72.2 observed by Dalchiavon & Carvalho (2012), evaluating soybean grain yield cultivated in a Oxisol under no-tillage. Possibly, the number of pods per plant was lower due to the increase in the soil bulk density, since, under stress conditions, the plant formed few grains in the pods, because the main biological objective of the crop is the dissemination of the species (Carvalho et al 2004).…”

“…Grain yield was low (Table 1), with an average value of 2,659 kg ha -1 , lower than the national average of 3,362 kg ha -1 (Conab 2017) and also lower in relation to that reported by Rosa Filho et al (2009) of 3,317.5 kg ha -1 , by Queiroz et al (2011) of 3,270 kg ha -1 and by Dalchiavon et al (2011) of 4,639.4 kg ha -1 . However, it is much higher than that of 1,215 kg ha -1 found by Lovera (2015), all carried out in the same soil under no-tillage in the region of Selvíria.…”

“…The mass of 100 grains (15.8 g) was very close to that of 15.9 g obtained by Lovera (2015) and less than the 16.4 g obtained by Carvalho et al (2004), studying the effect of soybean cultivated under notillage in an Oxisol, because, according to the authors, the mass of 100 grains is the one that presents the lowest percentage variation due to changes in the growing environment. The plant height (75.8 cm) was higher than that of 68.0 cm verified by Queiroz et al (2011). It is noteworthy that, when it exceeds 65 cm, it is indicated as the desired height of plants for mechanical harvesting (Bonetti 1983).…”

“…In geostatistics, maps made from estimates of a studied variable can represent the spatial variability. Studies related to soil compaction, which use its bulk density as an indicator attribute, have shown that its increase may cause, in general, a decrease in agricultural yield (Lima et al 2007, Queiroz et al 2011. In view of that, this study aimed to compare methods for determining soil porosity and density, as well as to analyze correlations between soybean grain yields with some attributes of soil mass-volume relationships, in order to indicate those that were more efficiently related to soybean yield, as well as to study the spatial variability of soil attributes and yield components of this crop.…”

Soybean Yield, Soil Porosity and Soil Penetration Resistance under Mechanical Scarification in No-Tillage System

“…When the corn was harvested for silage the soil penetration resistance was higher until 0.12 meter; because in this system the traffic of machines is higher. The soil penetration resistance evaluated was higher than 3.0 Mpa, and it was considered a value above the critical level of 2.27 Mpa (Beutler, N. A. Centurion, J. F. Centurion, & Silva, 2006;Freddi, Centurion, Duarte, & Leonel, 2009) Vol. 10, No.…”