Assessing the coordination of regional water and soil resources and ecological-environment system based on speed characteristics

The effects of intensive nitrogen (N) fertilizations on spatial distributions of soil microbes in bioenergy croplands remain unknown. To quantify N fertilization effect on spatial heterogeneity of soil microbial biomass carbon (MBC) and N (MBN), we sampled top mineral horizon soils (0-15 cm) using a spatially explicit design within two 15-m2 plots under three fertilization treatments in two bioenergy croplands in a three-year long fertilization experiment in Middle Tennessee, USA. The three fertilization treatments were no N input (NN), low N input (LN: 84 kg N ha−1 in urea) and high N input (HN: 168 kg N ha−1 in urea). The two crops were switchgrass (SG: Panicum virgatum L.) and gamagrass (GG: Tripsacum dactyloides L.). Results showed that N fertilizations little altered central tendencies of microbial variables but relative to LN, HN significantly increased MBC and MBC:MBN (GG only). HN possessed the greatest within-plot variances except for MBN (GG only). Spatial patterns were generally evident under HN and LN plots and much less so under NN plots. Substantially contrasting spatial variations were also identified between croplands (GG > SG) and among variables (MBN, MBC:MBN > MBC). This study demonstrated that spatial heterogeneity is elevated in microbial biomass of fertilized soils likely by uneven fertilizer application in bioenergy crops.

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Nitrogen Fertilization Elevated Spatial Heterogeneity of Soil Microbial Biomass Carbon and Nitrogen in Switchgrass and Gamagrass Croplands.

Accurately understanding the relationship between grain production and economic development is of great practical significance for ensuring national food security and coordinating inter-regional economic development. Using 2012 counties as research units, we analyzed the spatial coordination between grain production and economic development in China using the coupling of grain and economy (CGE) index, as well as the curve of gravity center and thematic map series methods based on statistical data from counties between 2000–2017. The results showed that: (1) Grain production was weakly coordinated with the economic development in China; but this coordination was enhanced. (2) China’s conversion between various types of grain production and economic development mainly occurred in the central and western regions, which are characterized by a much higher grain agglomeration level than the economic agglomeration level. (3) The northeastern region was prone to the grain agglomeration, the central and western regions were characterized by a grain-economy balance and the eastern region was dominated by economic agglomeration. (4) The increase of China’s CGE gradually increased from the southwest to northeast. Therefore, we proposed that the government should pay more attention to grain circulation in the eastern region and main grain-producing areas in central region should develop an accurate benefit compensation system, support leading grain processing enterprises and implement cultivated land protection policies in order to ensure national food security.

Trends towards Coordination between Grain Production and Economic Development in China

ABSTRACT China is issuing a warning regarding the ‘unprecedented’ hurdles it faces in safeguarding its food security. The substantial conversion of farmland for non-grain cultivation is exacerbating the situation, necessitating urgent investigation into the underlying causes. Nonetheless, previous studies have revealed a dearth of village-level analysis and have been marred by a bias stemming from econometric methodologies. To remedy this, the present paper employs a sophisticated approach combining econometric modelling and machine learning techniques to unravel the intricate driving forces at the village level. The study yields three principal findings. Firstly, the availability of farmland, poverty incidence, and the age of village leaders exert a detrimental influence on non-grain use of farmland (NGUF). Secondly, a conglomerate of factors, such as the aging rural workforce, income levels, positively impact the planting of non-grain crops, with remarkably increasing effects. Finally, it is pivotal to acknowledge that the influencing factors display sensitivity to the spatial scale examined. Village-level research provides a comprehensive overview, transcending individual household decisions. Collectively, this study underscores the indispensability of incorporating the underlying principles into policy formulation. Township and county authorities should craft guidelines, policies, and regulations in accordance with the ascertained village-level drivers, rather than relying solely on household-level determinants.

The battle of crops: unveiling the shift from grain to non-grain use of farmland in China?

The objective of this study was to investigate five nutrient factors of the forest topsoil (0–20 cm), including pH, soil organic matter (SOM), total nitrogen (STN), available phosphorus (AP), and available potassium (AK). This study adopted the revised Nemerow index method to conduct a comprehensive quantitative evaluation on the soil nutrition contents, and using geostatistical method to address the spatial variability of soil properties in hilly and mountainous regions, southern China. Data were analyzed both statistically and geostatistically on the basis of semivariogram. Our results indicate that the soil is generally acidic, containing rich SOM and STN, but lacks AP and AK. Most of the sub-indexes of fertility were at grade III, showing a middle level. According to the coefficient of variations (CV), the five soil nutrient factors can be ranked in decreasing order as follows: AP > SOM > AK > STN > pH. There were differences between the sub-indexes of fertility, which could be ranked as follows: PSOM > PAK > PSTN > PpH > PAP. The semi-variation functions for the five soil nutrient factors studied here show some spatial structure features, over a range of 23–274 km. All nutrient factors had different nugget-to-sill ratios in each region, which varied from 10 to 50%, suggesting a strong or medium correlation. Thus, it can be concluded that the nutrient spatial distribution of the study area was the result of the combined action of structural factors and random factors, and the factors affecting the soil nutrients of the research area are highly complex. We will develop more targeted research plans about soil nutrients of study area in the next time.

A geostatistic investigation of the comprehensive evaluation of fertility and spatial heterogeneity of forest soil nutrients in hilly and mountainous regions of southern China

Based on Chinese county-level statistic data, this paper reveals spatial–temporal distribution and changing of grain production, by studying gravity centres of grain input–output regions in China from 1985 to 2009. According to the grain output, per-capita grain consumption, and population, the surplus grain of 2864 counties from 1985 to 2009 was calculated. And the counties with surplus grain value greater than zero and smaller than zero were respectively defined as grain input regions and grain output regions; they were respectively analysed by using the model of grain gravity centre. We found that there are four periods of spatial–temporal changing of gravity centres in grain input regions, and five periods in all output regions. According to the moving path of the gravity centres of input–output regions, 1990 was the turning point of completely entering into ‘grain supply from north to south period’. Spatial–temporal changing of grain-sown area and the arable land was the main driving mechanis...

Spatial–temporal changes in grain input–output and the driving mechanism in China since 1985

SPOT and ETM+ satellite images are used as the main source of information. The remote sensing image processing software ERDASIMAGINE and the geographic information system software ARCVIEWGIS have been used. The technical method and work flow of remote sensing dynamic monitoring of resources and ecological environment based on GIS are studied. The geometric correction, registration, filtering, fusion and information extraction of remote sensing images have been completed. Data mining and professional maps based on GIS are produced and updated. The key techniques are analyzed and studied. In addition, the natural ecological environment of the region was evaluated.

Research on Remote Sensing Dynamic Monitoring of Ecological Resource Environment Based on GIS

In traditional crop production, farmers considered cultivated land as uniform growth conditions and take the same plan. In fact, There is a obvious spatial heterogeneity on farmland inside. The differences of micro topography and soil fertility affect the crop growth and yield. In our research, a experimental field is selected in a farm in Heilongjiang province, China. We collected 123 topsoil (0-20 cm) samples, and measured soil organic matter (SOM), ammonium nitrogen (NH3-N), soil available phosphorus (SAP) and soil available potassium (SAK). After descriptive statistics analysis of surface soil nutrients and semivariogram analysis. The fitting model and parameters of each surface soil nutrients were given. Spatial heterogeneity exists in surface soil nutrients. Especially, the topsoil (0-20 cm) soil organic matter present obvious regional regularity. The spatial distribution map of surface soil nutrients were drawn by the Kriging interpolation method. The research of spatial heterogeneity of surface soil nutrients in small scale provide the basis for the model of variable rate fertilization.

Spatial heterogeneity of surface soil nutrients in small scale in the black soil region of Northeast China

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Spatial–temporal changes in grain input–output and the driving mechanism in China since 1985

Research on Remote Sensing Dynamic Monitoring of Ecological Resource Environment Based on GIS

Spatial heterogeneity of surface soil nutrients in small scale in the black soil region of Northeast China