Sustainable Intensification and Large-scale Operation of Cultivated Land Use at the Farmers’ Scale:A Case Study of Shandong Province,China

Sustainable intensification of cultivated land use(SICLU) and large-scale operations(LSO) are widely acknowledged strategies for enhancing agricultural performance.However,the existing literature has faced challenges in precisely defining SICLU and constructing comprehensive indicators,which has hindered the exploration of factors influencing LSO within the SICLU framework.To address this gap,we integrated self-efficacy theory into the design of an index framework for evaluating SICLU.We subsequently employed econometric models to analyze the significant factors that impact LSO.Our findings reveal that SICLU can be divided into four key dimensions:intensive management,efficient output,resource conservation,and ecological environment optimization.Furthermore,it is crucial to incorporate belief-based cognitive factors into the index system,as farmers’ understanding of fertilizer and pesticide application significantly influences their willingness to engage in LSO.Moreover,we identify grain market turnover as the most influential factor in promoting LSO,with single-factor contribution rates reaching 70.9% for cultivated land transfer willingness and 62.5% for the total planting areas.Interestingly,unlike irrigation and agricultural machinery inputs,increased labor inputs correspond to larger planting areas for farmers.This trend may be attributed to reduced labor availability because of rural labor migration,whereas the reduction in irrigation and agricultural input is contingent on innovations in production practices and the transfer of cultivated land management rights.Importantly,SICLU dynamically influences LSO,with each index related to SICLU having an optimal range that fosters LSO.These insights offer valuable guidance for policymakers,emphasizing farmers as their central focus,with the adjustment of input and output factors as a means to achieve LSO as the ultimate goal.In conclusion,we propose research avenues for further enriching the SICLU framework to ensure that it aligns with the specific characteristics of regional agricultural development.

Modelling the dead fuel moisture content in a grassland of Ergun City,China

The dead fuel moisture content(DFMC)is the key driver leading to fire occurrence.Accurately estimating the DFMC could help identify locations facing fire risks,prioritise areas for fire monitoring,and facilitate timely deployment of fire-suppression resources.In this study,the DFMC and environmental variables,including air temperature,relative humidity,wind speed,solar radiation,rainfall,atmospheric pressure,soil temperature,and soil humidity,were simultaneously measured in a grassland of Ergun City,Inner Mongolia Autonomous Region of China in 2021.We chose three regression models,i.e.,random forest(RF)model,extreme gradient boosting(XGB)model,and boosted regression tree(BRT)model,to model the seasonal DFMC according to the data collected.To ensure accuracy,we added time-lag variables of 3 d to the models.The results showed that the RF model had the best fitting effect with an R2value of 0.847 and a prediction accuracy with a mean absolute error score of 4.764%among the three models.The accuracies of the models in spring and autumn were higher than those in the other two seasons.In addition,different seasons had different key influencing factors,and the degree of influence of these factors on the DFMC changed with time lags.Moreover,time-lag variables within 44 h clearly improved the fitting effect and prediction accuracy,indicating that environmental conditions within approximately 48 h greatly influence the DFMC.This study highlights the importance of considering 48 h time-lagged variables when predicting the DFMC of grassland fuels and mapping grassland fire risks based on the DFMC to help locate high-priority areas for grassland fire monitoring and prevention.

Development of ensemble learning models to evaluate the strength of coal-grout materials

In the loose and fractured coal seam with particularly low uniaxial compressive strength(UCS),driving a roadway is extremely difficult as roof falling and wall spalling occur frequently.To address this issue,the jet grouting(JG)technique(high-pressure grout mixed with coal particles)was first introduced in this study to improve the self-supporting ability of coal mass.To evaluate the strength of the jet-grouted coal-grout composite(JG composite),the UCS evolution patterns were analyzed by preparing 405 specimens combining the influential variables of grout types,curing time,and coal to grout(C/G)ratio.Furthermore,the relationships between UCS and these influencing variables were modeled using ensemble learning methods i.e.gradient boosted regression tree(GBRT)and random forest(RF)with their hyperparameters tuned by the particle swarm optimization(PSO).The results showed that the chemical grout composite has higher short-term strength,while the cement grout composite can achieve more stable strength in the long term.The PSO-GBRT and PSO-RF models can both achieve high prediction accuracy.Also,the variable importance analysis demonstrated that the grout type and curing time should be considered carefully.This study provides a robust intelligent model for predicting UCS of JG composites,which boosts JG design in the field.

Optimization of environmental variables in habitat suitability modeling for mantis shrimp Oratosquilla oratoria in the Haizhou Bay and adjacent waters

Habitat suitability index(HSI)models have been widely used to analyze the relationship between species abundance and environmental factors,and ultimately inform management of marine species.The response of species abundance to each environmental variable is different and habitat requirements may change over life history stages and seasons.Therefore,it is necessary to determine the optimal combination of environmental variables in HSI modelling.In this study,generalized additive models(GAMs)were used to determine which environmental variables to be included in the HSI models.Significant variables were retained and weighted in the HSI model according to their relative contribution(%)to the total deviation explained by the boosted regression tree(BRT).The HSI models were applied to evaluate the habitat suitability of mantis shrimp Oratosquilla oratoria in the Haizhou Bay and adjacent areas in 2011 and 2013–2017.Ontogenetic and seasonal variations in HSI models of mantis shrimp were also examined.Among the four models(non-optimized model,BRT informed HSI model,GAM informed HSI model,and both BRT and GAM informed HSI model),both BRT and GAM informed HSI model showed the best performance.Four environmental variables(bottom temperature,depth,distance offshore and sediment type)were selected in the HSI models for four groups(spring-juvenile,spring-adult,falljuvenile and fall-adult)of mantis shrimp.The distribution of habitat suitability showed similar patterns between juveniles and adults,but obvious seasonal variations were observed.This study suggests that the process of optimizing environmental variables in HSI models improves the performance of HSI models,and this optimization strategy could be extended to other marine organisms to enhance the understanding of the habitat suitability of target species.

Patterns of forest composition and their long term environmental drivers in the tropical dry forest transition zone of southern Africa

Background:Tropical dry forests cover less than 13%of the world's tropical forests and their area and biodiversity are declining.In southern Africa,the major threat is increasing population pressure,while drought caused by climate change is a potential threat in the drier transition zones to shrub land.Monitoring climate change impacts in these transition zones is difficult as there is inadequate information on forest composition to allow disentanglement from other environmental drivers.Methods:This study combined historical and modern forest inventories covering an area of 21,000 km^2 in a transition zone in Namibia and Angola to distinguish late succession tree communities,to understand their dependence on site factors,and to detect trends in the forest composition over the last 40 years.Results:The woodlands were dominated by six tree species that represented 84%of the total basal area and can be referred to as Baikiaea-Pterocarpus woodlands.A boosted regression tree analysis revealed that late succession tree communities are primarily determined by climate and topography.The Schinziophyton rautanenii and Baikiaea plurijuga communities are common on slightly inclined dune or valley slopes and had the highest basal area(5.5-6.2 m^2 ha^(-1)).The Burkea africana-Guibourtia coleosperma and Pterocarpus angolensis-Dialium englerianum communities are typical for the sandy plateaux and have a higher proportion of smaller stems caused by a higher fire frequency.A decrease in overall basal area or a trend of increasing domination by the more drought and cold resilient B.africana community was not confirmed by the historical data,but there were significant decreases in basal area for Ochna pulchra and the valuable fruit tree D.englerianum.Conclusions:The slope communities are more sheltered from fire,frost and drought but are more susceptible to human expansion.The community with the important timber tree P.angolensis can best withstand high fire frequency but shows signs of a higher vulnerability to climate change.Conservation and climate adaptation strategies should include protection of the slope communities through refuges.Follow-up studies are needed on short term dynamics,especially near the edges of the transition zone towards shrub land.

Priming effect and its regulating factors for fast and slow soil organic carbon pools: A meta-analysis

The priming effect (PE) plays a critical role in the control of soil carbon (C) cycling and influences the alteration of soil organic C (SOC) decomposition by fresh C input.However,drivers of PE for the fast and slow SOC pools remain unclear because of the varying results from individual studies.Using meta-analysis in combination with boosted regression tree (BRT) analysis,we evaluated the relative contribution of multiple drivers of PE with substrate and their patterns across each driver gradient.The results showed that the variability of PE was larger for the fast SOC pool than for the slow SOC pool.Based on the BRT analysis,67%and 34%of the variation in PE were explained for the fast and slow SOC pools,respectively.There were seven determinants of PE for the fast SOC pool,with soil total nitrogen (N) content being the most important,followed by,in a descending order,substrate C:N ratio,soil moisture,soil clay content,soil pH,substrate addition rate,and SOC content.The directions of PE were negative when soil total N content and substrate C:N ratio were below 2 g kg~(-1)and 20,respectively,but the directions changed from negative to positive with increasing levels of this two factors.Soils with optimal water content (50%–70%of the water-holding capacity) or moderately low pH (5–6) were prone to producing a greater PE.For the slow SOC pool,soil p H and soil total N content substantially explained the variation in PE.The magnitude of PE was likely to decrease with increasing soil pH for the slow SOC pool.In addition,the magnitude of PE slightly fluctuated with soil N content for the slow SOC pool.Overall,this meta-analysis provided new insights into the distinctive PEs for different SOC pools and indicated knowledge gaps between PE and its regulating factors for the slow SOC pool.

The quality attribute of watershed ecosystem is more important than the landscape attribute in controlling erosion of red soil in southern China

Landscape and quality attributes are major ecosystem characteristics closely associated with soil conservation service(SCS).However,the intrinsic mechanisms by which these two attributes influence SCS are still unclear.Therefore,this study quantitatively analyzed the landscape pattern,ecological quality,and SCS in the Lianshui River watershed(a typical soil and water loss area of red soil in southern China)and its sub-watersheds in 2019.The boosted regression tree model was used to explore the influence of 15 factors(i.e.,landscape and quality attributes)on SCS at the sub-watershed scale.According to the results,compared with the landscape attribute,the quality attribute of the watershed ecosystem could better explain the spatial heterogeneity of SCS across 66 sub-watersheds.The overall degree of influence of five quality factors on SCS reached 57.81%,with the highest being the normalized differential build-up and bare soil index(NDBSI),at 25.11%.Among 10 landscape factors,aggregation had the greatest influence on SCS,at 28.64%.The relationships between key influencing factors and SCS were nonmonotonic and non-linear,with threshold effects.For example,NDBSI values of 0.18e0.41 had a positive influence on SCS,while NDBSI values of 0.41e0.65 had a negative influence on SCS.The findings broaden our understanding of the response of SCS to changes in landscape and quality attributes at the sub-watershed scale,and could offer comprehensive support for soil erosion management in the watershed ecosystem.

Comparison and correction of IDW based wind speed interpolation methods in urbanized Shenzhen

Based on the 2-min average wind speed observations at 100 automatic weather stations in Shenzhen from January 2008 to December 2018,this study tries to explore the ways to improve wind interpolation quality over the Shenzhen region.Three IDW based methods,i.e.,traditional inverse distance weight(IDW),modified inverse distance weight(MIDW),and gradient inverse distance weight(GIDW)are used to interpolate the near surface wind field in Shenzhen.In addition,the gradient boosted regression trees(GBRT)model is used to correct the wind interpolation results based on the three IDW based methods.The results show that among the three methods,GIDW has better interpolation effects than the other two in the case of stratified sampling.The MSE and R2 for the GIDW’s in different months are in the range of 1.096-1.605 m/s and 0.340-0.419,respectively.However,in the case of leave-one-group-out crossvalidation,GIDW has no advantage over the other two methods.For the stratified sampling,GBRT effectively corrects the interpolated results by the three IDW based methods.MSE decreases to the range of 0.778-0.923 m/s,and R2 increases to the range of 0.530-0.671.In the nonstation area,the correction effect of GBRT is still robust,even though the elevation frequency distribution of the non-station area is different from that of the stations’area.The correction performance of GBRT mainly comes from its consideration of the nonlinear relationship between wind speed and the elevation,and the combination of historical and current observation data.

Change of impervious surface area and its impacts on urban landscape:an example of Shenyang between 2010 and 2017

Introduction:One of the most striking features of urbanization is the replacement of the original natural land cover type by artificial impervious surface area(ISA).However,the extent of the contribution of various environmental factors,especially the growth of 3D space to ISA expansion,and the scope and mechanism of their influences in dramatically expanding cities,are yet to be determined.The boosted regression tree(BRT)model was adopted to analyze the main influencing factors and driving mechanisms of ISA change in Shenyang,China between 2010 and 2017.Outcomes:The nearly complete-coverage ISA(≥0.7)increased from 42%in 2010 to 47%in 2017.The percentage of landscape with a high ISA fraction increased,while the landscape evenness and diversity of ISA decreased.The BRT analysis revealed that elevation,regional population density,and landscape class had the largest influences on the change of urban ISA,contributing 22.55%,18.16%,and 11.18%to the model,respectively.Conclusion:Overall,topographic and socioeconomic factors had the greatest influence on urban ISA change in Shenyang,followed by land use type and building pattern indices.The trend of high aggregation was strong in large commercial and residential areas.The 3D expansion of the city had an influence on its areal expansion.

Building a model-based personalised recommendation approach for tourist attractions from geotagged social media data

When travelling,people are accustomed to taking and uploading photos on social media websites,which has led to the accumulation of huge numbers of geotagged photos.Combined with multisource information(e.g.weather,transportation,or textual information),these geotagged photos could help us in constructing user preference profiles at a high level of detail.Therefore,using these geotagged photos,we built a personalised recommendation system to provide attraction recommendations that match a user’s preferences.Specifically,we retrieved a geotagged photo collection from the public API for Flickr(Flickr.com)and fetched a large amount of other contextual information to rebuild a user’s travel history.We then created a model-based recommendation method with a two-stage architecture that consists of candidate generation(the matching process)and candidate ranking.In the matching process,we used a support vector machine model that was modified for multiclass classification to generate the candidate list.In addition,we used a gradient boosting regression tree to score each candidate and rerank the list.Finally,we evaluated our recommendation results with respect to accuracy and ranking ability.Compared with widely used memory-based methods,our proposed method performs significantly better in the cold-start situation and when mining‘long-tail’data.

Development of machine learning multi-city model for municipal solid waste generation prediction

Integrated management of municipal solid waste(MSW)is a major environmental challenge encountered by many countries.To support waste treatment/management and national macroeconomic policy development,it is essential to develop a prediction model.With this motivation,a database of MSW generation and feature variables covering 130 cities across China is constructed.Based on the database,advanced machine learning(gradient boost regression tree)algorithm is adopted to build the waste generation prediction model,i.e.,WGMod.In the model development process,the main influencing factors on MSW generation are identified by weight analysis.The selected key influencing factors are annual precipitation,population density and annual mean temperature with the weights of 13%,11%and 10%,respectively.The WGMod shows good performance with R^(2)=0.939.Model prediction on MSW generation in Beijing and Shenzhen indicates that waste generation in Beijing would increase gradually in the next 3–5 years,while that in Shenzhen would grow rapidly in the next 3 years.The difference between the two is predominately driven by the different trends of population growth.