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Based on DEA model, the wholesale efficiency of 14 cities in Liaoning province was measured. From the perspective of input and output, the wholesale efficiency of each city in Liaoning Province was systematically studied to evaluate the development of the wholesale industry in Liaoning Province. The results show that the wholesale efficiency in Liaoning province is generally low, but the returns to scale are increasing. The efficiency level varies greatly among different cities, and the reasons for non-DEA effective wholesale investment in different cities are different.

China has recently seen a substantial increase in integrated rice-crayfish (Procambarus clarkii) culture (IRCC). However, grain yield reductions (GYR) with rice plants having normal vegetative growth but failed filling are becoming common in IRCC, and the driving factors remain unclear. Here, we tried to identify the mechanisms behind this GYR mode in the Jianghan Plain, China, by investigating the soil properties, grain yield parameters, and plant mineral content in five IRCC plots experiencing GYR and an adjacent paddy-upland rotation plot (CK). The results showed slight to extreme GYR (11–82%) in the IRCC plots compared to those in CK. The translocation of phosphorus from shoot to grain during the productive stage of rice plants was inhibited in IRCC plots (26–71%) compared to CK (75%). The grain yield and phosphorus translocation coefficient correlated strongly (r > 0.95) with zinc uptake in aboveground rice organs which was significantly lower in IRCC than in CK. We conclude that this GYR in IRCC plots is not due to decreased macronutrients availability or heavy metals toxicity in IRCC soils, but the insufficient uptake of zinc by IRCC rice plants. We recommend Zn foliar spray or introducing Zn efficient rice cultivars as potential mitigation measures. [ABSTRACT FROM AUTHOR]

China has experienced an increase in integrated rice–crayfish (Procambarus clarkii) culture (IRCC) in rice paddies. However, whether the current regime degrades phosphorus (P) fertility in rice paddies remains unclear. To assess changes in P fertility, the surface soil (0–20 cm) of high‐yield rice paddies with 3, 6, and 10 consecutive years of IRCC was sampled in Honghu County in the Jianghan Plain region, China. Adjacent fields planted with long‐term rotations of rice and dry‐season crops (RRD) were also sampled. Total P (TP), available P (Pa), organic P (Po) compounds, and P fractions in soils were intensively assessed using chemical digestion, NaHCO3 extraction, 31P nuclear magnetic resonance, and sequential chemical extraction. IRCC significantly increased organic matter, total nitrogen, TP, Fe(II), and S2− contents of rice paddy soils and nutrient concentrations in the surface water, with a distinct decrease in total Fe and pH. Consecutive IRCC greatly influenced P fertility. Continuous P accumulation in rice paddy soils accelerated greatly, with a mean increase of approximately 43 mg·kg−1·yr−1. Pa was 67% higher after 3 years of IRCC, compared with RRD, but 78% lower after 10 years. Consecutive IRCC induced a decrease in Po compounds, with a mean decrease in TPo of approximately 20 mg·kg−1·yr−1. Long‐term consecutive IRCC increased transformation of Pa, Fe(II)–P, and Po into Ca–P and Fe(III)–P, increasing mean Ca–P and Fe(III)–P concentrations by approximately 69 and 7 mg·kg−1·yr−1, respectively. Our results suggested that long‐term consecutive IRCC degrades P fertility in rice paddies, and implementing IRCC in high‐yield rice paddies is not recommended. [ABSTRACT FROM AUTHOR]