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The objective of this study was to evaluate the effects of different potassium (K) fertilization levels and defoliation intensities on performance of "BRS Zuri" guineagrass Megathyrsus maximus (Jacq.) B.K. Simon & S.W.L Jacobs (syn. Panicum maximum Jacq.). Treatments were the factorial arrangement of three K fertilization levels: 0 (control), 40, 80 kg K2O/ha/harvest) and two defoliation intensities (10‐ and 20‐cm stubble heights), distributed in a completely randomized design with five replications. The experiment was conducted in Araguaina, TO, Brazil, from October to January, 2020–2021 and 2021–2022. Plots were harvested four times per year with 21‐day regrowth interval. The 40 and 80 kg K2O/ha/harvest fertilization levels had greater HA than the control (5490 vs. 3,440 kg DM/ha, respectively). There was a K fertilization level × stubble height interaction on tiller population. There was greater tiller population at 20‐ than 10‐cm stubble height at 40 kg K2O/ha/harvest; however, no effect of stubble height was detected at 0 and 80 kg K2O/ha/harvest. Plots fertilized with 80 kg K2O/ha/harvest had greater tiller population than 40 kg K2O/ha/harvest, which was greater than control. Forage harvested at 10 cm had greater crude protein (CP) than 20‐cm stubble height (mean = 11.4% vs. 10.8%). Tissue K concentration increased from control to 40 kg K2O/ha/harvest, but there was no difference between 40 and 80 kg K2O/ha/harvest (mean = 1.1% vs. 3.5%). The combination of 40 kg K2O/ha/harvest and 20‐cm stubble height may be a desirable management strategy to promote Zuri guineagrass productivity in tropical regions. [ABSTRACT FROM AUTHOR]

Background: Grazing lands provide numerous ecosystem services, including the capacity to store large amounts of soil carbon (C); however, our understanding of the factors affecting soil C responses to management is inadequate. Methods: In this paper, we synthesized information about the impacts of grazing land management on soil C within the southeastern region of the United States. Results: Most studies (68%) demonstrated that proper management increased soil C stocks with an average C accumulation rate of 1.4 Mg C ha−1 year−1. The remaining (32%) studies showed no effect of management on soil C. None of the studies reported negative impacts of management on soil C. The largest increase in soil C (8 Mg C ha−1 year−1) was associated with the conversion of cropland to pastureland while overseeding legumes into grass pastures resulted in the lowest C sequestration rates (0.2 Mg C ha−1 year−1). Conclusions: Considering the rates of soil C accretion and the extensive area occupied by grazing lands, data in this synthesis confirm that the adoption of improved management practices can increase soil C sequestration in the southeastern United States. In addition, because most improved management practices can also have co‐benefits, they may be favorable for forage and livestock production and other ecosystem services. [ABSTRACT FROM AUTHOR]

Although land application of biosolids is an attractive option for beneficial reuse, it represents a complex challenge for government and private organizations. This 3‐year field study evaluated the agronomic impacts of reduced biosolids rates imposed by new regulations in Florida on bahiagrass (Paspalum notatum Flugge) herbage accumulation and nutritive value. Treatments consisted of a factorial combination of two phosphorus (P) sources (triple superphosphate and biosolids) applied at 0 (control), 20 (low), 40 (intermediate), and 60 kg total P ha−1 (high). Triple superphosphate plots received the same nitrogen (N) load (from ammonium nitrate) as the corresponding biosolids treatments. Bahiagrass herbage accumulation increased with increasing P and associated N rates. Bahiagrass annual herbage accumulation ranged from 2120 kg ha−1 in 2022 to 6970 kg ha−1 in 2020 and was 33%–80% less than previously published data. This was likely due to the reduced biosolids rates that did not supply sufficient N and P to sustain adequate forage production. Lesser herbage accumulation will likely lead to greater application of inorganic fertilizers, which generally have greater environmental footprint than biosolids. Biosolids generally resulted in either similar or greater bahiagrass crude protein, in vitro digestible organic matter, and tissue mineral concentrations than inorganic fertilizer. Similarly, no differences in bahiagrass N and P recovery between biosolids and inorganic fertilizer were observed. This study, along with a significant body of literature, demonstrated that biosolids have considerable fertilizer value and can be an effective alternative to commercial inorganic fertilizer while also providing environmental and economic benefits. Core Ideas: Biosolids application at P‐based rates decreases forage production and nutritive value.Reduced biosolids rates imposed by new regulations in Florida will have negative agronomic impacts.Biosolids are an effective alternative source of N and P to replace inorganic fertilizer. [ABSTRACT FROM AUTHOR]

This article examines the resilience of warm-season (C4) perennial grasses in challenging environmental and management conditions. C4 grasses are crucial for livestock nutrition in tropical and subtropical regions, and climate change may benefit their growth. The article discusses the anatomical and morphological differences that affect the resilience of C4 grasses to management practices. It also explores the distribution and physiological mechanisms of C4 grasses, as well as the impact of nitrogen management and defoliation on their growth and persistence. The article emphasizes the ability of C4 grasses to recover after grazing through the allocation of photosynthate and the storage of carbon and nitrogen. It also highlights the importance of proper soil nutrient and grazing management for maximizing forage production and reducing greenhouse gas emissions. [Extracted from the article]

Aeschynomene (Aeschynomene americana L.) is a warm‐season annual legume forage used in tropical and subtropical regions; however, there is limited information on agronomic and environmental benefits of aeschynomene when overseeded into bahiagrass (Paspalum notatum Flüggé) swards. The objective of this study was to evaluate the effects of overseeding aeschynomene or applying N fertilizer to existing bahiagrass on forage characteristics, atmospheric N fixation, and N2O‐N emissions. The study was conducted in Ona, FL, from April 2019 to March 2021. Treatments were the split‐plot arrangement of bahiagrass‐aeschynomene or bahiagrass monoculture (main plot) and N fertilization level (0 or 60 kg N ha−1; subplot), distributed in a randomized complete block design with four replicates. Nitrogen fixation was estimated in plots receiving no N fertilization. The static chamber technique was used to estimate N2O‐N emissions. Overseeding aeschynomene did not increase forage accumulation (mean = 1300 kg dry matter [DM] ha−1 harvest−1) or N2O emissions (mean = 15 g N2O‐N ha−1 per day), but increased forage crude protein (CP) concentration (from 98 to 108 g kg−1) when compared to bahiagrass monoculture. Nitrogen fertilization increased forage accumulation (from 1200 to 1400 kg DM ha−1 per harvest) but it did not affect aeschynomene N fixation (84% N derived from atmospheric fixation [Ndfa]). Nitrous oxide emissions had significant temporal variability across all treatments; however, there were no differences in accumulated N2O‐N emissions among treatments (mean = 2.4 kg N2O‐N ha−1 per year). Overseeding aeschynomene is an effective management practice to increase forage CP concentration in pastures without increasing N2O‐N emissions. Core Ideas: Overseeding aeschynomene into bahiagrass increased sward bahiagrass‐aeschynomene forage nutritive value.Nitrogen fertilization increased 18% forage accumulation of bahiagrass.Forage accumulation was the main factor affecting legume atmospheric N fixation.Overseeding aeschynomene into bahiagrass pastures had no impact on soil N2O‐N emissions. [ABSTRACT FROM AUTHOR]