Shoot and root development of brachiaria grass (Urochloa ruziziensis) under different levels of soil density

Pacheco, Leandro Pereira; Miguel, Andressa Selestina Dalla Côrt São; Souza, Edicarlos Damacena de; Carvalho, Ícaro Camargo de; Petter, Fabiano André; Silva, Rayane Gabriel da; Silva, Camila Menezes Rodrigues da

doi:10.21475/ajcs.2016.10.10.pne85

Cited by 2 publications

(3 citation statements)

References 20 publications

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“…Failure of Urochloa fine roots to penetrate deeper in the soil may have been partially caused by limitation of rootability caused by higher bulk soil density (negative correlation found in this study; Appendix S1: Figure S1). Urochloa fine‐root sensitivity to bulk soil density has also been reported by Pacheco et al (2016). As Al saturation is high already in the 10‐ to 20‐cm soil layer (Table 1), Al toxicity may be a further impeding factor.…”

Section: Discussionsupporting

confidence: 75%

Belowground competition and niche partitioning between the Babassu palm and Urochloa grass in eastern Amazonian pastures

de Alencar Pageú,

de Deus Ribeiro Lima,

Diniz

et al. 2023

Ecosphere

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Much of deforested Amazonia is dominated by pastures planted with exotic Urochloa (syn Brachiaria) grass, containing interspersed, ruderal Babassu palm (Attalea speciosa). This two‐species system offers the opportunity to investigate how two very competitive species interact. We investigated three monospecific Urochloa pastures containing dispersed Babassu palm clusters in the eastern periphery of Amazonia. We mapped 0‐ to 50‐cm Babassu and Urochloa root profiles at three distances representing contrasting relative dominance: “within clusters” (0.4–0.6 m from adult palm, Babassu‐dominated), “close” (2.5–4.0 m), and “far” (>8.0–10.0 m, Urochloa‐dominated). Total Babassu root share count was 76.0% within Babassu clusters, as opposed to Urochloa root share count (80.0%) far from clusters, confirming our experimental dominance gradient. Babassu and Urochloa root diameter composition differed strongly, whereas 44.6% of all Babassu roots were mid‐diameter or coarse; 83.0% of all Urochloa roots were fine graminoid. Vertical root profiles likewise differed: Babassu coarse and mid‐diameter roots concentrated within clusters at 20–50 cm depth, well protected against disturbance, though Babassu mid‐diameter roots did extend up to 10 m, indicating active foraging at long distances. By contrast, Urochloa mid‐diameter and coarse roots concentrated in the topsoil (70.4% in top 20 cm). Notably, 45.0% of all Urochloa fine roots but only 29.3% of deeper rooting Babassu concentrated in the top 0–10 cm. Both Urochloa mid‐diameter (R = 0.49) and fine roots (R = 0.40) correlated positively with Urochloa aboveground biomass. Fine‐root fine‐scale variability was high, with high‐density hotspots of both species in the topsoil. Babassu vertical root profiles were unaffected by the degree of interspecific competitive confrontation, whereas Urochloa fine roots were significantly shallower within than outside of Babassu clusters. Though differing Babassu and Urochloa vertical root profiles do support the notion of niche expansion caused by Babassu clusters within the vast Urochloa pastures throughout Amazonia, we also find a strong horizontal and vertical niche overlap with no indication of fine‐scale root segregation, indicating direct competition between both species, possibly in a dynamic state of “mutual invasability.” In practical terms, our findings call for the diversification of Amazonian pastures beyond this two‐species system in order to increase productivity and ecological efficiency.

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Section: Discussionsupporting

confidence: 75%

Belowground competition and niche partitioning between the Babassu palm and Urochloa grass in eastern Amazonian pastures

de Alencar Pageú,

de Deus Ribeiro Lima,

Diniz

et al. 2023

Ecosphere

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“…Considering that the experimental area was in the fourth consecutive year under NTS with the same cropping systems, this addition of organic material (straw and root) to the soil became even more substantial. Thus, due to the strong correlation between shoot dry mass and root dry mass in U. ruziziensis grass (PACHECO et al, 2016), the intensity of the soil processes promoted by the root system of this forage when intercropped can also be affected, leading to non-significant differences in comparison to maize as single crop. On the other hand, maize/U.…”

Section: Resultsmentioning

confidence: 99%

“…Soratto et al (2013b), studying early N application for the sowing of common bean, also found that its yield was little influenced by the previous cropping system (maize and maize intercropped with U. ruziziensis grass). In addition, it should be considered that agricultural systems are complex, which requires a holistic view of the processes and impacts of these agroecosystems (PANKHURST et al, 1995, OLIVEIRA et al, 2016. However, in the splitting schemes 30-60-00, 30-00-60, 00-60-30 and 00-45-45, this attribute was superior when the common bean was cultivated in succession to maize as single crop and intercropped with U. ruziziensis grass.…”

Section: Resultsmentioning

confidence: 99%

Nitrogen Accumulation and Export by Common Bean as a Function of Straw and N Splitting in No-Tillage System

Mingotte

Leal

Almeida³

et al. 2021

Rev. Caatinga

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Determining nitrogen (N) accumulation and export by common bean as a function of straw and of the splitting of this nutrient is very important, aiming at the management and sustainability of agricultural systems. This study aimed to determine the N accumulation and export by common bean as a function of Zea mays and Urochloa ruziziensis grass straw (maize, maize/U. ruziziensis intercropping and U. ruziziensis) and splitting of top-dressing N fertilization. The experiment was conducted in Jaboticabal-SP-Brazil, during the 2012/13 crop season, in a Red Eutrophic Oxisol (Eutrudox) in no-tillage under irrigation. The experimental design was a randomized block with split plots with four replicates, totaling 120 subplots sized in 25m2 each. The plots consisted of the cropping systems prior to common bean: maize, maize/ U. ruziziensis intercropping and U. ruziziensis. The subplots were composed of ten top-dressing N fertilization splitting schemes (NS) at the phenological stages V3, V4 and R5 in different combinations. Common bean grain yield differs among cropping systems and as a function of top-dressed N split application. U. ruziziensis grass as single crop promotes greater N accumulation in common bean shoots compared to maize and its intercropping with U. ruziziensis grass. Regardless the cropping system, top-dressing N application in a single dose (90 kg ha-1) at V4 leads to similar accumulations and exports to those found in the absence of N fertilization. Splitting schemes with N application at the R5 stage increase the exports of this nutrient by common bean in succession to maize and its intercropping with U. ruziziensis grass.

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Shoot and root development of brachiaria grass (Urochloa ruziziensis) under different levels of soil density

Cited by 2 publications

References 20 publications

Belowground competition and niche partitioning between the Babassu palm and Urochloa grass in eastern Amazonian pastures

Belowground competition and niche partitioning between the Babassu palm and Urochloa grass in eastern Amazonian pastures

Nitrogen Accumulation and Export by Common Bean as a Function of Straw and N Splitting in No-Tillage System

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