The functions and services of wetland ecosystems to human society have been generally recognized. Currently, most evaluations of wetlands are a comprehensive evaluation of their ultimate value. It is rare to discuss for energy and matter lost and transferred. In this study, emergy theory was used to assess the ultimate and intermediate service values of the Liaohe estuarine wetland ecosystem. Results show that its ultimate service value was $28.2 million, and its intermediate service value was $35,614.03 million. The 1263 time difference between intermediate and ultimate value shows that much server value was dissipated in the form of energy. In the ultimate service value, the value of adjusting the atmosphere was $8.02 million, accounting for 28.45% of the total value, and flood diversion and storage value was $6.98 million, accounting for 24.75%. These results illustrate that the most important service value of the Liaohe estuarine wetland ecosystem is to adjust the atmosphere and divert and store floods. In intermediate service value, maintaining-biodiversity value was $34,182 million, accounting for 95.98% of total value, showing that the Liaohe estuarine wetland plays an important role in species resources and regional seed banks.

Vigorously developing efficient water-saving agricultural technologies using the Yellow River Water is an important way to achieve sustainable use of water resources. In order to clarify the fluid movement characteristics inside the flow path of the emitter under complicated water quality conditions in a drip irrigation system using the Yellow River Water, the optimal simulation turbulence model for the flow field in the flow path of the emitter was determined by comparing the macroscopic hydraulic characteristics with the microscopic fluid motion characteristics of the fluid in the emitter. On this basis, the two-phase flow model was used to calculate and analyze the characteristics of water flow movement and particle transport in the emitter. The results show that the RNG (Re- normalization group) k-ε turbulence model was the most suitable for the simulation of the flow field in the emitter, considering the macroscopic hydraulic performance and microscopic anti-clogging ability of the emitter synthetically, and both the comprehensive calculation accuracy and the calculation efficiency. The pressure showed a step-like uniform decrease along the direction of water flow. The fluid flow showed the regional movement characteristics of the mainstream and non-mainstream regions. The energy dissipation mainly occurred at the sudden change sites of the flow path structure. The particle phase velocity was slightly lower than that of the water phase. The velocity at the near-wall surface was relatively lower than that at the center, and the velocity distribution along the depth direction of the flow path was relatively uneven. The sediment was mainly deposited in the first half of the flow path. This study can provide a theoretical basis for solving the emitter clogging in the drip irrigation systems applying water from the Yellow River.

Developing efficient water-saving irrigation technology is one of the important ways to solve the problem of water shortage in China. Rational allocation of drip irrigation filtration system is an important way to slow down the blockage of each component of drip irrigation system (such as emitters, solenoid valve, etc.). At present, many domestic and foreign manufacturers have produced many kinds of filter products, and many experts and scholars have done a lot of research on the hydraulic performance and filtration ability of the filter, but there is no comprehensive report on the filter features and its performances. Based on this, this paper comprehensively expounded the structure, performance characteristics, working principle and research progress of different types of filter, and the trends of filter research and product development were put forward in order to provide theoretical support for the wider application of drip irrigation technology and the construction of new countryside.