Increasing the Environmental Sustainability of Greenhouse Vegetable Production by Combining Biochar Application and Drip Fertigation—Effects on Soil N2_{2}O Emissions and Carbon Sequestrations

Drip fertigation with reduced fertilizer and water inputs has been widely used in greenhouse vegetable production in China. However, farmers usually do not apply additional organic material with a high carbon content, although soil organic carbon (SOC) concentrations are mostly below the optimum level for vegetable production. Returning straw or biochar to fields is an effective strategy for sustainability and environmental friendliness. We tested whether drip fertigation, (DIF) combined with maize straw (DIF+S) or biochar (DIF+BC), is a suitable option to improve SOC sequestration over eight growing seasons, and how these options affect soil N$_{2}$O emissions and yields or partial factor productivity of applied N (PFP$_{N}$) of crops over three growing seasons. During the winter–spring growing season, DIF+BC significantly reduced soil N$_{2}$O emission by 61.2% and yield-scaled N$_{2}$O emission by 62.4%, while increasing the tomato yield and PFP$_{N}$ compared with DIF. Straw incorporation had similar trends but without significant effects. Conversely, straw and biochar incorporation increased N$_{2}$O emission during the autumn–winter season. The structural equation model indicated N$_{2}$O emission was dominantly driven by soil NH$_{4}$$^{+}$-N concentration, temperature and moisture. The N$_{2}$O emission factor decreased significantly with increased PFP$_{N}$. Moreover, the contribution of biochar to the increased SOC was approximately 78%, which was four times higher than that of straw incorporation. Overall, the results highlighted the potential of drip fertigation with biochar incorporation to mitigate N$_{2}$O emissions, improve PFP$_{N}$ and significantly increase SOC storage, which could all contribute to maintaining environmental sustainability and soil quality of greenhouse vegetable production

Heavy metal and nutrient concentrations in top- and sub-soils of greenhouses and arable fields in East China – Effects of cultivation years, management, and shelter

Although greenhouse vegetable production in China is rapidly changing, consumers are concerned about food quality and safety. Studies have shown that greenhouse soils are highly eutrophicated and potentially contaminated by heavy metals. However, to date, no regional study has assessed whether greenhouse soils differ significantly in their heavy metal and nutrient loads compared to adjacent arable land. Our study was conducted in Shouguang County, a key region of greenhouse vegetable production in China. Soil samples down to soil depths of 3 m were taken from 60 greenhouse vegetable fields of three different ages (5, 10, and 20 years) and from 20 adjacent arable fields to analyze the concentrations of heavy metals, nutrients, and soil physio-chemical parameters. A comparison of greenhouse soils with adjacent arable fields revealed that for greenhouses, (a) micro (heavy metals: Cu, Zn, and Mn) and macronutrients (Nmin, Olsen-P, available K) were significantly higher by a factor of about five, (b) N:P:K ratios were significantly imbalanced towards P and K, and (c) topsoil (0–30 cm) concentrations of the above-mentioned micro- and macronutrients increased with years of vegetable cultivation. In contrast, the soil concentrations of the heavy metals Cr and Pb were lower in greenhouse soils. Heavy metal concentrations did not vary significantly with soil depth, except for the micronutrients Cu and Zn, which were between 1- and 3-fold higher in the topsoil (0–30 cm) than in the subsoil (30–300 cm). The Nemerow pollution index (PN) was 0.37, which was below the recommended environmental threshold value (PN < 1). Structural equation model analysis revealed that soil nutrient concentrations in greenhouse soils are directly related to the input of fertilizers and agrochemicals. Lower values of soil Pb and Cr concentrations in greenhouses were due to the sheltering effect of the greenhouse roof, which protected soils from atmospheric deposition due to emissions from nearby industrial complexes

A geostationary orbit microwave multi-channel radiometer

The geostationary orbit microwave multi-channel radiometer has the advantages of high real-time performance and large coverage, which plays an important role in typhoon, strong precipitation detection, and medium-to-short-term meteorological/oceanic forecasting. However, due to the difficulty in engineering development of the payload, its application on-orbit has not yet been achieved at present. To satisfy the requirements of fine and quantitative application of satellite observation data, a geostationary orbit microwave multi-channel radiometer with a 10-m-caliber is developed, in which the spatial resolution at horizontal polarization is better than 24 km at 54 GHz. In geostationary orbit microwave multi-channel radiometer, a quasi-optical feed network covering nearly 28 frequency octave bands and ranging from 23.8 to 664 GHz is proposed to solve the technical problem of multi-frequency sharing in the system. Meanwhile, a high-precision reflector preparation method and a high-precision unfolding scheme are proposed, which are considered as a solution for the large-diameter reflector with a high maintaining surface accuracy. A high-precision antenna prototype with 0.54-m is developed, and the tests are performed to verify the key technologies, such as the preparation of high-precision grating reflectors at the micron level, high surface accuracy detection, and sub-millimeter wave antenna electrical performance testing. The results indicate that measured main beam efficiency of the 664 GHz antenna is better than 95.5%. In addition, the system sensitivity is greater than 1.5 K, and the calibration accuracy is better than 1.8 K, according to the results of an analysis of the multi-channel radiometer’s essential parameters and calibration errors

Risk Path Identification and Research of Digital Trade Enterprises Based on the DEMATEL-ISM-MICMAC Model

As the world ’s largest trading country, it is very important to ensure the stable operation of digital trading enterprises in the digital economy. Therefore, it is necessary to study the identification and influence path of risk factors. Based on the literature analysis method and expert interview method, this paper determines 18 risk factors of digital trade enterprises, and then divides the risk into two dimensions of internal and external factors to form the risk path identification index system of digital trade enterprises. The DEMATEL ( Decision Making Trial and Evaluation Laboratory ) -ISM ( Interpretative Structure Method-Cross-Impact ) -MICMAC ( Matrix Multiplication Applied to Classification ) method was used to quantitatively reveal the comprehensive influence degree of each influencing factor. And the reason degree and centrality of its impact on the risk of China ’s digital trade enterprises are divided into strong ( weak ) driving type according to the value of reason degree greater than zero ( less than zero ). Further analysis of the hierarchical structure and overall influence relationship of the risk factors of China ’s digital trade enterprises, the causes of the seven levels of China ’s digital trade enterprise risk are obtained. Then, combined with the dependence of each key risk factor and the size of the driving force, the risk factors are divided into four quadrants, and the interaction between the risk factors is revealed. The results show that the key factors affecting enterprises are financial risk, decline of digital trade, increase of trade barriers, aggravation of digital financial risk spillover and aggravation of supply chain crisis. Based on the algorithm, this study identifies the risk factors and ways that affect Chinese digital trade enterprises. The research results can provide theoretical risk path guidance for the risk management of enterprise risks, and provide scientific decision-making basis for enterprises when facing risks

The complete mitochondrial genome of Tachycines (Gymnaeta) zorzini (Orthoptera: Rhaphidophoridae)

In this study, we elucidated the complete mitochondrial genome (mitogenome) of Tachycines (Gymnaeta) zorzini (accession number MW322826). The circular mitogenome is 15,369-bp-long, including 13 protein-coding genes (PCGs), 22 tRNA genes, two rRNA genes, and a non-coding control region. The overall base composition is as follows: A, 42.16%; T, 31.75%; C, 15.97%; G, and 10.12%; a slight A + T bias of 73.91%. Phylogenetic analysis of some species of Ensifera revealed that Tachycines (Gymnaeta) zorzini was closer to Tachycines (Tachycines) minor, Tachycines, and Diestrammena are monophyletic

A Near-Field Imaging Method Based on the Near-Field Distance for an Aperture Synthesis Radiometer

For an aperture synthesis radiometer (ASR), the visibility and the modified brightness temperature (BT) are related to the Fourier transform when the distance between the system and the source is in the far-field region. BT reconstruction can be achieved using G-matrix imaging. However, for ASRs with large array sizes, the far-field condition is not satisfied when performing performance tests in an anechoic chamber due to size limitations. Using far-field imaging methods in near-field conditions can introduce errors in the images and fail to correctly reconstruct the BT. Most of the existing methods deal with visibilities, converting near-field visibilities to far-field visibilities, which are suitable for point sources but not good for extended source correction. In this paper, two near-field imaging methods are proposed based on the near-field distance. These methods enable BT reconstruction in near-field conditions by generating improved resolving matrices: the near-field G-matrix and the F-matrix. These methods do not change the visibility measurements and can effectively image both the point source and the extended source in the near field. Simulations of point sources and extended sources in near-field conditions demonstrate the effectiveness of both methods, with F-matrix imaging outperforming near-field G-matrix imaging. The feasibility of both near-field imaging methods is further validated by carrying out experiments on a 10-element Y-array system

Array Configuration Design for Mirrored Aperture Synthesis Radiometers Based on Dual-Polarization Measurements

In mirrored aperture synthesis (MAS), the antenna array determines the rank of the transformation matrix connecting the cross-correlations to the cosine visibilities. However, the transformation matrix is rank-deficient, resulting in errors in the reconstructed brightness temperature (BT) image. In this paper, the signal propagations for the vertically polarized wave and horizontally polarized wave are analyzed. Then, the optimization model of the antenna array based on dual-polarization is established. The optimal array configurations are presented, with the corresponding transformation matrices being almost column full ranks. Simulation results demonstrate the validity of the proposed optimization model

Non-Uniform Synthetic Aperture Radiometer Image Reconstruction Based on Deep Convolutional Neural Network

When observing the Earth from space, the synthetic aperture radiometer antenna array is sometimes set as a non-uniform array. In non-uniform synthetic aperture radiometer image reconstruction, the existing brightness temperature image reconstruction methods include the grid method and array factor forming (AFF) method. However, when using traditional methods for imaging, errors are usually introduced or some prior information is required. In this article, we propose a new IASR imaging method with deep convolution neural network (CNN). The frequency domain information is extracted through multiple convolutional layers, global pooling layers, and fully connected layers to achieve non-uniform synthetic aperture radiometer imaging. Through extensive numerical experiments, we demonstrate the performance of the proposed imaging method. Compared to traditional imaging methods such as the grid method and AFF method, the proposed method has advantages in image quality, computational efficiency, and noise suppression