Summary The productivity of species‐diverse plant assemblages strongly depends on the temporal dynamics of nutrient uptake by competing neighbouring plants. Our understanding, however, of how rates of nitrogen (N), phosphorous (P) and potassium (K) uptake might change through time between neighbouring plant species under field conditions is still very limited. Here, we specifically measure the temporal trajectories of N, P and K uptake by staple food plants such as wheat (Triticum aestivum L.), barley (Hordeum vulgare L.) and maize (Zea mays L.) when growing either in monocultures or in intercropping systems. We ask how (i) plant species combinations, (ii) N fertilization and (iii) film mulching might affect key indexes of N, P and K uptake over time. We fit logistic models to characterize the nutrient uptake trajectories. Maximum cumulative N, P and K uptake (kg ha−1) by wheat and barley were significantly greater in wheat–maize or barley–maize intercropping systems than in wheat or barley monocultures. Cumulative nutrient uptake by intercropped maize (either with wheat or with barley) was reduced by interspecific competition at early growth stages, but it increased rapidly after wheat and barley were harvested. Maximum cumulative N and P (but not K) uptake by intercropped maize were significantly higher than the uptake by monoculture maize, particularly when N fertilizer or film mulching was applied. Intercropping induced a significant temporal niche differentiation in maximum daily nutrient uptake rates (kg ha−1 day−1) between intercropped species. Fertilization had much stronger effects on maximum cumulative nutrient uptake of maize than that of wheat and barley. Mulching significantly increased the maximum cumulative nutrient uptake of maize and advanced the time to reach its maximum daily P and K uptake rates. Our study provides evidence of an important temporal niche differentiation mechanism (‘temporal complementarity’) in nutrient uptake rates between neighbouring plant species. A better understanding of temporal trajectories of interspecific nutrient uptake rates remains crucial if we want to maximize the nutrient‐use efficiency and sustain overyielding (i.e. high food production) in plant species‐diverse systems such as intercropping.
Local anesthetic of ropivacaine was demonstrated to reduce the postoperative pain in elderly patients. This study investigated the pharmacokinetics of ropivacaine at different concentrations in elderly patients subjected to fascia iliaca compartment block. Forty patients with femoral neck fracture at American Society of Anesthesiologists (ASA) I–II status, undergoing fascia iliaca compartment block (FICB) were randomized to two groups receiving 0.7 ml/kg of solution containing 0.375% ropivacaine (group L) or 0.5% ropivacaine (group H). Samples of venous blood were obtained immediately at different time points after FICB, and the total and free plasma concentrations of ropivacaine were measured by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). Statistical analysis was carried out using a pharmacokinetic calculation program (DAS 3.0). Visual Analogue Scale (VAS) scores were significantly decreased after FICB in both groups, and VAS score in group H was lower compared with group L. The total maximum plasma concentration (Cmax) and the free Cmax of ropivacaine in group H was higher than that in group L (P<0.05). The decrease of the total and free plasma concentration was operation time-dependent. Neither group showed signs of central nervous system and circulatory system toxicity. On the basis of these results, the concentrations of 0.375 and 0.5% ropivacaine held an efficiently analgesic effect for FICB, suggesting that ropivacaine can be employed in analgesic therapy. However, both concentrations have a potentially theoretical risk of local anesthetics poisoning, suggesting that a lower concentration may be a safer option for a single large volume of FICB.
The Tudigou porphyry Cu deposit is located in the central part of the southern Qinling belt. Copper mineralization is closely associated with monzogranite porphyry.Zircon LA-ICP-MS U-Pb dating of monzogranite porphyry suggests that the ages of magmatism at Tudigou vary between 150 ± 1 and 148 ± 1 Ma and overlap with the molybdenite Re-Os age of 150-148 Ma, indicating that the Tudigou intrusion and associated mineralization formed during the Late Jurassic. The enrichment in largeion lithophile elements, depletion in high-field-strength elements, high Ba/Th and La/ Yb ratios, and negative correlation between Dy/Yb and La/Sm ratios, together with narrow ranges of ε Hf (t) values (ε Hf (t) = À4.0 to +1.4) suggest monzogranite porphyry was derived from a metasomatized lithospheric mantle with minor crustal components contribution, which is also evidenced by the lead isotopic result. The La/Yb ratios of 30 Mesozoic plutons in the southern Qinling belt were used to calculate the Moho depth, which suggests that the magmatism and mineralization in the region occurred during lithosphere thinning in response to the tectonic transition from compression to extension transitional regime. The calculated oxygen fugacity of the Late Mesozoic porphyry deposits in the Qinling-Dabie orogen have identical ΔFMQ values (averaging +1.4 to +2.4). However, the V/Sc ratios (the proxy for water content) are distinct among different deposit sizes, indicating that the dissolved water in the magma plays a critical role in porphyry-type mineralization.
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