Constructing a knowledge system for theoretical research and practical application in macroecosystem science.

Ecological research in the 21st century has entered a new stage of ecosystem science. Macroecosystem science, as the engine and frontier direction of ecosystem science, is focusing on the mutual feedbacks among "environmental change-ecosystem-human well-being-social development", based on the systemic cognitive framework of "multiple elements-multiple processes-multiple functions-multiple scales-multiple dimensions". It is committed to developing integrated research methods of "cross media-cross interface-cross time and space-cross level-cross disciplinary", concentrating on the cascading relationships and process mechanisms of "resource environment-system structure-ecological process-functional service" and "system construction-state evolution-resource and environment effect-regulation and supervision", and understanding the evolution laws of macroecosystem and the scientific principles of human regulation.

Quantitative characterization system for macroecosystem attributes and states.

Macroecosystem science is dedicated to exploring and understanding the mechanisms underlying ecosystem structure, function, and processes. Accurately measuring and quantitatively describing the basic properties and state changes of ecosystem, and establishing corresponding measurement methods and dimensional systems, are key steps in promoting the development of macroecosystem research. Therefore, based on traditional ecosystem element attributes such as biology and soil, as well as researches on biological traits at the levels of organs, individuals, and species, constructing measurement methods and dimensional systems that quantitatively characterize the intrinsic properties and state changes of ecosystem, and developing new macroecosystem research theories and application systems, are fundamental theoretical and methodological issues that urgently need to be addressed in macroecosystem science research.

Cognitive dimensions, scales, and multidisciplinary coordinate systems in macroecosystem science.

Over the past century, ecology has evolved from classical or fundamental ecological studies into a new stage of ecosystem ecology or ecosystem science. This evolution has laid the theoretical groundwork for large-scale and global ecological research, fostering an integration of biology, geography, and environmental science, and promoting interdisciplinary collaboration between natural sciences, humanities, and socio-economics. Throughout the process of integration, ecology has absorbed concepts from other disciplines to form a unique scientific knowledge and concept system framework.

Asymmetric environmental responses on evapotranspiration in Tibetan Plateau grassland.

Evapotranspiration (ET) from the Tibetan Plateau (TP) grasslands plays a critical role in regulating water storage in the Asian Water Tower. However, the patterns, drivers, and responses of ET to climate change remain largely understudied due to limited observational data. This study integrated eddy covariance and long-term remote sensing data to examine the spatial patterns of ET and its drivers across the TP, comparing these patterns with those in other grassland ecosystems of the Northern Hemisphere.

Multi-elemental stoichiometric ratios of atmospheric wet deposition in Chinese terrestrial ecosystems.

Intense human activities have significantly altered the concentrations of atmospheric components that enter ecosystems through wet and dry deposition, thereby affecting elemental cycles. However, atmospheric wet deposition multi-elemental stoichiometric ratios are poorly understood, hindering systematic exploration of atmospheric deposition effects on ecosystems. Monthly precipitation concentrations of six elements-nitrogen (N), phosphorus (P), sulfur (S), potassium (K), calcium (Ca), and magnesium (Mg)-were measured from 2013 to 2021 by the China Wet Deposition Observation Network (ChinaWD).

Manipulating Identical Filter Redundancy for Efficient Pruning on Deep and Complicated CNN.

The existence of redundancy in convolutional neural networks (CNNs) enables us to remove some filters/channels with acceptable performance drops. However, the training objective of CNNs usually tends to minimize an accuracy-related loss function without any attention paid to the redundancy, making the redundancy distribute randomly on all the filters, such that removing any of them may trigger information loss and accuracy drop, necessitating a fine-tuning step for recovery. In this article, we propose to manipulate the redundancy during training to facilitate network pruning.

Atmospheric wet organic nitrogen deposition in China: Insights from the national observation network.

Organic nitrogen (N) is an important component of atmospheric reactive N deposition, and its bioavailability is almost as important as that of inorganic N. Currently, there are limited reports of national observations of organic N deposition; most stations are concentrated in rural and urban areas, with even fewer long-term observations of natural ecosystems in remote areas. Based on the China Wet Deposition Observation Network, this study regularly collected monthly wet deposition samples from 43 typical ecosystems from 2013 to 2021 and measured related N concentrations.

[Ecosystem principles and main issues in regional ecological restoration and environmental governance in China].

Modern ecology is an analytical method and philosophical concept to solve major resource, environmental and ecological issues encountered during global sustainable development. In the long-term development processes, ecology constantly absorbed and integrated knowledge from related disciplines, forms a system of modern ecology and ecosystem science that closely related to climate system, biological system and socio-economic system, and raises ecosystem principles that directly support the practices of regional ecological restoration and environmental governance. The national needs in the new stage have given ecology a new mission.

Impacts of nitrogen fertilizer type and application rate on soil acidification rate under a wheat-maize double cropping system.

Nitrogen (N) fertilizer-induced soil acidification in Chinese croplands is well-known, but insight in the impacts of different N fertilizer management approaches (fertilizer type and rate) on soil acidification rates is very limited. Here, we conducted a field experiment on a moderate acid soil to quantify soil acidification rates in response to N fertilization by different fertilizer types and N rates through monitoring the fate of elements (mainly nutrients) related to H production and consumption. Two N fertilizer types (urea and NHCl) and three N rates (control, optimized and conventional, 0/120/240 kg N ha for wheat, 0/160/320 kg N ha for maize) were included.

Cropland acidification increases risk of yield losses and food insecurity in China.

Distinct cropland acidification has been reported in China due to nitrogen (N) fertilizer overuse. However, the impacts on food production and thereby on food security are largely unknown. Yield losses in the period 1980-2050 were therefore assessed by simulating soil pH changes combined with derived pH-yield relationships for wheat, maize and rice.

Impact of 13-years of nitrogen addition on nitrous oxide and methane fluxes and ecosystem respiration in a temperate grassland.

Nitrogen (N) fertilizer application and atmospheric N deposition will profoundly affect greenhouse gas (GHGs) emissions, especially nitrous oxide (NO) and methane (CH) fluxes and ecosystem respiration (R, i.e. CO emissions).

Responses of soil organic carbon turnover to nitrogen deposition are associated with nitrogen input rates: Derived from soil C evidences.

Elevated atmospheric nitrogen (N) deposition has exerted profound influences on ecosystems. Understanding the effects of N deposition on the dynamics of soil organic carbon (SOC) is important in the studies of global carbon cycle. Although many studies have examined the effects of N deposition on SOC turnover using N addition experiments, the effects were reported to be different across studies.

Cumulative and partially recoverable impacts of nitrogen addition on a temperate steppe.

Atmospheric nitrogen (N) deposition has been shown to decrease biodiversity and change nutrient cycles in terrestrial ecosystems. However, our understanding of ecological responses to chronic N addition and ecological recovery of grassland from N enrichment is limited. Here we present evidence from an 11-year grassland experiment with a range of N addition rates (0, 30, 60, 120, 240, and 480 kg N·ha ·yr ) in Inner Mongolia, China.

Enhanced acidification in Chinese croplands as derived from element budgets in the period 1980-2010.

Significant soil pH decrease has been reported in Chinese croplands in response to enhanced chemical fertilizer application and crop yields. However, the temporal and spatial variation of soil acidification rates across Chinese croplands is still unclear. We therefore assessed trends in soil acidification rates across provincial China for the period 1980-2010 by calculating inputs-outputs of major cations and anions in cropland systems.

Modeling soil acidification in typical Chinese cropping systems.

We applied the adapted model VSD+ to assess cropland acidification in four typical Chinese cropping systems (single Maize (M), Wheat-Maize (W-M), Wheat-Rice (W-R) and Rice-Rice (R-R)) on dominant soils in view of its potential threat to grain production. By considering the current situation and possible improvements in field (nutrient) management, five scenarios were designed: i) Business as usual (BAU); ii) No nitrogen (N) fertilizer increase after 2020 (N2020); iii) 100% crop residues return to cropland (100%RR); iv) manure N was applied to replace 30% of chemical N fertilizer (30%MR) and v) Integrated N2020 and 30%MR with 100%RR after 2020 (INMR). Results illustrated that in the investigated calcareous soils, the calcium carbonate buffering system can keep pH at a high level for >150years.

Model-Based Analysis of the Long-Term Effects of Fertilization Management on Cropland Soil Acidification.

Agricultural soil acidification in China is known to be caused by the over-application of nitrogen (N) fertilizers, but the long-term impacts of different fertilization practices on intensive cropland soil acidification are largely unknown. Here, we further developed the soil acidification model VSD+ for intensive agricultural systems and validated it against observed data from three long-term fertilization experiments in China. The model simulated well the changes in soil pH and base saturation over the last 20 years.