Although soil warming and water scarcity are frequently associated with reductions in soybean productivity and biological nitrogen fixation (BNF), their combined effects remain poorly understood. This study evaluated how soil temperature and water regime influence nodulation, BNF efficiency, plant physiology and metabolism, soil enzymatic activity, and rhizosphere microbial communities in soybean plants grown at two soil temperatures (24°C and 36°C) under two water regimes: well‐watered (WW) and water deficit (WD). The WD treatment was the main limiting factor, reducing plant growth, nodule number, and biomass, ureide accumulation, and integrated BNF indices. Surprisingly, nodular efficiency and photosynthetic rate were higher under WD. Root‐zone warming under adequate water availability promoted greater plant and nodule biomass, higher ureide accumulation, and increased integrated BNF efficiency despite a reduction in nodule number. In addition, soil warming increased malondialdehyde and citrate concentrations in shoots as well as nodular concentrations of N, P, K, S, and B. Soil enzymatic activities and rhizosphere bacterial community structure varied among treatments, whereas fungal communities remained relatively stable. Overall, water deficit structured BNF limitation, while soil warming modulated metabolic responses. These results indicate that water availability and soil temperature jointly regulate biological nitrogen fixation and soil–plant–microbe interactions in soybeans, highlighting the importance of considering these factors together when developing management strategies under climate change scenarios.
Camila Domingos Cabral, G. A. Apaza-Castillo, A. S. Lorenzi et al.· Physiologia Plantarum : An I...· 0 citations
This study evaluated the agronomic potential and environmental impact of a macrophyte-based fertilizer (OMF) in maize cultivation. OMF was previously characterized in accordance with regulatory standards and applied to sandy loam and clayey soils at six rates (0, 2, 4, 6, 8, and 10 g dm⁻³). The experimental design also included a mineral fertilizer (MF) control receiving N, P, and K amounts equivalent to the 10 g dm⁻³ application, arranged in a randomized block design. After 45 days in greenhouse conditions, maize biomass and total nutrient accumulation, soil macronutrient concentrations, and the activities of arylsulfatase, β-glucosidase, and acid phosphatase were quantified. Basal soil respiration (BSR) and nutrient leaching were also evaluated through laboratoy-based analyses. OMF increased BSR, with CO₂ release in sandy loam and clayey soils highest under OMF (11.5; 10.7 mg g⁻¹), moderate under sludge compost (7.06; 7.51 mg g⁻¹), and lowest in unfertilized soil (2.34; 3.40 mg g⁻¹). OMF also promoted linear increases in soil P, K, Ca, Mg, and S, as well as in maize biomass and total N, P, and K accumulation. However, the highest OMF dose achieved only 20–31% of MF biomass. Moreover, organic fertilizers consistently reduced NO₃⁻-N, NH₄⁺-N, and K⁺ leaching compared with MF. In sandy soil, NO₃⁻-N leaching decreased by 31.2% and 38.5%, NH₄⁺-N by 45.6% and 37.4%, and K⁺ by 71.3% and 24.3% under SSC and OMF, respectively. In clayey soil, reductions reached 44.6% and 46.4% for NO₃⁻-N, 24.0% and 20.9% for NH₄⁺-N, and 35.9% and 15.7% for K⁺ under SSC and OMF, respectively. OMF offers environmental advantages by decreasing NO₃⁻-N leaching and supplying a slow-release K⁺ source, although it remains less effective than mineral fertilizer in promoting maize growth.
Paulo Sergio Costa Trindade, Andre Luiz de Freitas Espinoza, João Henrique Silva da Luz et al.· Journal of soil science and...· 0 citations
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