[Ecosystem services of Chongyi Hakka Terraces]. / 崇义客家梯田生态系统服务功能.

An economic evaluation of the main ecosystem services of Chongyi Hakka Terraces can help to demonstrate the contributions of the terrace system to Hakka society, on the basis of which the protection of Hakka Terrace system could be undertaken by the local government. In view of the social and economic characteristics of Chongyi Hakka Terrace ecosystem and its location, an index system was established to evaluate the service function, and a qualitative analysis was conducted for these functions and their importance. Besides, based on the data collected in 2014, with a combination of physical quality and economic value, a quantitative analysis was carried out for its nine ser-vice indicators. The findings were as follows: firstly, among the nine evaluation indicators, the phy-sical quality and the economic value of soil conservation both ranked the highest, the former being 76457 kg·hm-2 and the latter 105033 yuan·hm-2, accounting respectively for 72.2% and 30.0% of the total mass and total value of the Hakka Terrace ecosystem. Secondly, the unique service functions of Hakka Terrace ecosystem could be embodied in its cultural heritage and landscape, the corresponding economic values reaching up to 100000 yuan·hm-2 and 46333 yuan·hm-2 respectively, ranking the second and third highest among the nine indicators. Thirdly, the agricultural pro-ducts from the Hakka Terrace were vital welfare for the local residents, but their physical quality and the economic value only accounted for 6.1% and 10.4% of its total mass and total value respectively. As a result, the service functions of the Hakka Terrace ecosystem would be dramatically undervalued with respect to agricultural products only. These economic figures could reveal the huge contributions which the Hakka Terrace ecosystem had made to the society, not only raising awareness of the necessity to preserve the agricultural heritage by the administrators and the public, but also providing efficient data support for the government when making ecological compensation criteria for the Hakka Terrace system.

[Effects of reduced nitrogen application on the yield, quality, and economic benefit of sugarcane intercropped with soybean].

A two-factor field experiment of randomized block design was conducted in Guangzhou to investigate the effects of reduced nitrogen application on the yield, quality, and total biomass dynamic of sugarcane as well as the economic benefit of the sugarcane population under different sugarcane/soybean intercropping patterns. Neither N application nor intercropping pattern had significant effects on the yield and quality of sugarcane, and no significant differences were observed in the yield and quality of sugarcane among all treatments. The land equivalent ratio (LER) of sugarcane/soybean intercropping at different N application levels was from 1.36 to 2.12, suggesting that sugarcane/soybean intercropping had higher LER than monoculture sugarcane. The total dry matter (except root) of sugarcane in all treatments increased with plant growth, and the growth pattern fitted sigmoid function. At lower nitrogen application level, the eigenvalues of the dynamic dry matter accumulation model were more coordinative, compared with those at higher nitrogen application level, which meant that in the later case, sugarcane had an advanced peak growth time and shortened fast-growth duration, and thereby, its yield decreased. Therefore, it was possible to reasonably adjust nitrogen application level to improve the eigenvalues of the sugarcane dynamic dry matter accumulation model, and accordingly, to achieve high yield. The population economic benefit under sugarcane/soybean intercropping was 3.2%-26.3% higher at lower than at higher nitrogen application level, suggesting the increase of the economic benefit of sugarcane population under reduced nitrogen application. Among the treatments, 1:2 sugarcane/soybean intercropping had the best economic benefit.