Prevention and Control of Agricultural Non-Point Source Pollutions in UK and Suggestions to China

Currently, the world is facing challenges of maintaining food production growth while improving agricultural ecological environmental quality. The prevention and control of agricultural non-point source pollution, a key component of these challenges, is a systematic program which integrates many factors such as technology and its extension, relevant regulation and policies. In the project of UK-China Sustainable Agriculture Innovation Network, we undertook a comprehensive analysis of the prevention and control technology, technology extension systems and related policy measures of agricultural non-point source pollution in UK. We then proposed the promotion of prevention and control of agricultural non-point source pollution in China. Considering the current agricultural resources and environment countermeasures of “one control”(control over the total quantity of the agricultural water and agricultural water environment pollution), “two reduction”(reduction in quantities of fertilizers and pesticides), and “three basic countermeasures”(resource utilization, recycling, and mitigate harm from treatment of livestock and poultry wastes, agricultural plastic films and crop straws), we suggested that in the near future source control and process prevention should be technical priorities. Optimization and reduction of chemical fertilizer, combined use of chemical and organic fertilizers, land utilization management, agricultural sector adjustment and integration of crop production with animal husbandry should be the key technologies. The role of non-governmental technical service should be promoted. Government subsidies, ecological compensations and other forms of economic means could be used to encourage famers actively participate in the prevention and control of nitrogen and phosphorus losses and pollution in soil and water systems. Related technical documents and regulations should be more specific, clear, and practical. Collection, transmission and analysis of non-point source pollution data relying on modern information approaches should also be incorporated in the non-point source control projects. The prevention and control of non-point source pollution from agriculture should be integrated into the overall national economic and social development planning, and be unified with the industry optimization and economic development indicators to improve the quality of ecological civilization construction, aiming at the sustainable economic and social development in China

Understanding the Cooperative Interaction between Myosin II and Actin Cross-Linkers Mediated by Actin Filaments during Mechanosensation

AbstractMyosin II is a central mechanoenzyme in a wide range of cellular morphogenic processes. Its cellular localization is dependent not only on signal transduction pathways, but also on mechanical stress. We suggest that this stress-dependent distribution is the result of both the force-dependent binding to actin filaments and cooperative interactions between bound myosin heads. By assuming that the binding of myosin heads induces and/or stabilizes local conformational changes in the actin filaments that enhances myosin II binding locally, we successfully simulate the cooperative binding of myosin to actin observed experimentally. In addition, we can interpret the cooperative interactions between myosin and actin cross-linking proteins observed in cellular mechanosensation, provided that a similar mechanism operates among different proteins. Finally, we present a model that couples cooperative interactions to the assembly dynamics of myosin bipolar thick filaments and that accounts for the transient behaviors of the myosin II accumulation during mechanosensation. This mechanism is likely to be general for a range of myosin II-dependent cellular mechanosensory processes

Conservation Tillage Technology: A Study on the Duration from Awareness to Adoption and Its Influencing Factors—Based on the Survey of the Yellow River Basin in China

Studying the dynamic duration of technology adoption helps farmers weigh and select different attributes and stages of conservation tillage techniques. In this study, non-parametric K-M survival analysis and discrete duration models were employed to estimate the time taken by farmers in the Yellow River Basin region to transition from awareness to the adoption of conservation tillage techniques between 2002 and 2020. The results indicate (1) The duration from awareness to adoption of conservation tillage technology is relatively short. (2) The likelihood of farmers postponing adoption decisions is highest in the initial 10 years and gradually decreases over time, suggesting negative time dependency. (3) Controlling for proportional hazards assumptions, it was found that factors such as education level and social learning positively influence the duration from awareness to adoption of conservation tillage techniques. Extreme weather variations and household labor migration delay the adoption time for farmers. In the process of promoting and implementing conservation tillage techniques, it is essential to consider the issue of intertemporal technology choice, stimulate farmers’ intrinsic demand, shorten the time interval from awareness to adoption, and ultimately improve technology adoption rates

Linear, nonlinear dynamics, and sensitivity analysis of a vibratory ring gyroscope

ABSTRACT: The linear and nonlinear dynamic responses of a vibratory ring gyroscope are investigated in this study focusing on the response mechanism of such a vibratory gyroscope. It is found that the nonlinear equations governing the drive and sense directions are coupled through both inertial linear and geometric nonlinear terms. Nonlinear responses are studied based on the full coupled nonlinear dynamic equations. The varying amplitude on the sense direction is analyzed for different input angular rates. The effect of nonlinearity on the ring gyroscope system is performed by comparing the results of nonlinear responses to those of linear responses. The contributions of some parameters to the amplitude responses and gyroscope sensitivity are analyzed, the conclusions of which provide guidelines to improve the sensitivity of the vibratory ring gyroscopes. Keywords: Vibratory ring gyroscope, Amplitude responses, Nonlinear effect, Sensitivit

Influences of agricultural land use composition and distribution on nitrogen export from a subtropical watershed in China

Despite the significant impacts of agricultural land on nonpoint source (NPS) nitrogen (N) pollution, little is known about the influence of the distribution and composition of different agricultural land uses on N export at the watershed scale. We used the Soil and Water Assessment Tool (SWAT) to quantify how agricultural distribution (i.e., the spatial distributions of agricultural land uses) and composition (i.e., the relative percentages of different types of agricultural land uses) influenced N export from a Chinese subtropical watershed, accounting for aquatic N retention by river networks. Nitrogen sources displayed high spatial variability, with 40.7% of the total N (TN) export from the watershed as a whole derived from several subwatersheds that accounted for only 18% of the watershed area. These subwatersheds were all located close to the watershed mouth. Agricultural composition strongly affected inputs to the river network. The percentages of dry agricultural land and rice paddy fields, and the number of cattle together explained 70.5% of the variability of the TN input to the river network among different subwatersheds. Total N loading to the river network was positively correlated with the percentage of dry land in total land areas and the number of cattle within subwatersheds, but negatively with the proportion of paddy fields. Distribution of agricultural land uses also affected N export at the mouth of the watershed. Moreover, N retention in the river network increased with increasing N transport distance from source subwatershed to the watershed mouth. Results provide important information to support improved planning of agricultural land uses at the watershed scale that reduces NPS nutrient pollution

Effects of Feedstock and Pyrolysis Temperature on Biochar Adsorption of Ammonium and Nitrate

<div><p>Biochar produced by pyrolysis of biomass can be used to counter nitrogen (N) pollution. The present study investigated the effects of feedstock and temperature on characteristics of biochars and their adsorption ability for ammonium N (NH₄⁺-N) and nitrate N (NO₃⁻-N). Twelve biochars were produced from wheat-straw (W-BC), corn-straw (C-BC) and peanut-shell (P-BC) at pyrolysis temperatures of 400, 500, 600 and 700°C. Biochar physical and chemical properties were determined and the biochars were used for N sorption experiments. The results showed that biochar yield and contents of N, hydrogen and oxygen decreased as pyrolysis temperature increased from 400°C to 700°C, whereas contents of ash, pH and carbon increased with greater pyrolysis temperature. All biochars could sorb substantial amounts of NH₄⁺-N, and the sorption characteristics were well fitted to the Freundlich isotherm model. The ability of biochars to adsorb NH₄⁺-N followed: C-BC>P-BC>W-BC, and the adsorption amount decreased with higher pyrolysis temperature. The ability of C-BC to sorb NH₄⁺-N was the highest because it had the largest cation exchange capacity (CEC) among all biochars (e.g., C-BC400 with a CEC of 38.3 cmol kg⁻¹ adsorbed 2.3 mg NH₄⁺-N g⁻¹ in solutions with 50 mg NH₄⁺ L⁻¹). Compared with NH₄⁺-N, none of NO₃⁻-N was adsorbed to biochars at different NO₃⁻ concentrations. Instead, some NO₃⁻-N was even released from the biochar materials. We conclude that biochars can be used under conditions where NH₄⁺-N (or NH₃) pollution is a concern, but further research is needed in terms of applying biochars to reduce NO₃⁻-N pollution.</p></div

Correlations between mass of NH₄⁺-N adsorbed per mass of biochar at equilibrium (Qe) and content of C (a), content of O (b), atomic ratio O/C (c), atomic ratio H/C (d), atomic ratio (O+N)/C (e) and CEC of corn-straw biochar (f), respectively.

<p>The symbols ▪, , ▴ and ▾ represented pyrolysis temperatures at 400°C, 500°C, 600°C and 700°C, respectively.</p

Regression parameters of isotherms for expressing adsorption of solution NH₄⁺-N to W-BC, C-BC and P-BC at different pyrolytic temperatures.

<p>Regression parameters of isotherms for expressing adsorption of solution NH₄⁺-N to W-BC, C-BC and P-BC at different pyrolytic temperatures.</p

Sorption of NH₄⁺-N and NO₃⁻-N by W-BC500, C-BC500 and P-BC500 with different treatments in 50 mg L⁻¹ aqueous solutions.

<p>Note: Different letters indicate significant difference for the results and the adsorbed amounts of NH₄⁺-N and NO₃⁻-N were compared separately.</p><p>Sorption of NH₄⁺-N and NO₃⁻-N by W-BC500, C-BC500 and P-BC500 with different treatments in 50 mg L⁻¹ aqueous solutions.</p