Effects of Differential Shading on Summer Tea Quality and Tea Garden Microenvironment.

Shading is an effective agronomic technique to protect tea plants from intense sunlight. However, there are currently very few studies on more effective shading methods to improve the quality of summer tea. In this study, 'Longjing43' plants were grown under four different shading treatments for 14 days, with no shading as the control. Among the four shading treatments, double-layer-net shadings had the most positive impact on the tea quality, resulting in higher levels of amino acids but lower levels of tea polyphenols. Additionally, double-layer-net shadings provided more suitable microenvironments for tea plants. The tea leaves in T4 (double nets 50 cm above the plant canopy) contained 16.13 mg∙g-1 of umami and sweet amino acids, which was significantly higher than in other treatments. T4 had the lowest air temperature and the most suitable and stable soil water content. Interestingly, the ratio of red light to far-red light in T4 was only 1.65, much lower than other treatments, which warrants further study. In conclusion, the microenvironment induced by shading can greatly affect the tea quality, and double-layer-net shading is better for improving the quality of summer tea.

Combining habitat area and fragmentation change for ecological disturbance assessment in Jiangsu Province, China.

Understanding where and how human land use causes ecological consequences is essential for habitat conservation. However, the assessment of the ecological disturbance caused by human land use is usually shaped by the area change in ecological land. The comprehensive evaluation of ecological disturbance based on the losses and gains of ecological patches is neglected. This paper analyzed the land use change between agricultural land, construction land, and ecological land from 1995 to 2015 in Jiangsu Province of eastern China. The ecological disturbance was quantificationally evaluated by a proposed index that considered both the changes of habitat area and fragmentation caused by the losses and gains of ecological landscape patches. The findings showed that there was a slight increase in area of ecological land in Jiangsu Province; however, ecological fragmentation was becoming severe with the growth of human land use, which, in turn, resulted in increased ecological disturbance. The losses and gains in the area and fragmentation of ecological land were comprehensively reflected using the proposed ecological disturbance index. Negative ecological disturbance was more likely to be observed at the edge of the city centers, ecologically sensitive areas, and counties with low area ratios of ecological land. Ecological governance policies should be formulated and implemented based on quantity, quality, and spatial relationships between human land use and ecological disturbance.

[Application of the LUR Model in the Prediction of Spatial Distributions of Soil Heavy Metals].

Using the Jintan District of Changzhou City, Jiangsu Province as an example, the LUR model was used to study the spatial distribution of heavy metals and to simulate the spatial distribution of heavy metals in the study area. Compared with the traditional LUR model and the ordinary Kriging interpolation model, the following conclusions were obtained. ① The soil heavy metal content in the study area was highly and significantly correlated with land factors, with the main factor of land use and influencing factors of heavy metals in the soil environment (P<0.01). In terms of influencing factors, the soil Cu and Zn contents were significantly correlated with the area related to traffic in a 2000 m buffer area and 2000 m buffer zone, respectively. The soil Cr, Cu, and Zn contents were significantly correlated with OM, Corg, TC, and TN (P<0.01). ② The R2 of the LUR-S models of the spatial distribution of the heavy metals, Pb, Cr, Cu, and Zn, in the study area were improved by 0.041, 0.406, 0.102, and 0.501, respectively, compared with the traditional LUR model. The accuracy test R2 values were improved by 0.1477, 0.0116, 0.2310, and 0.081, respectively; and the RMSE was reduced by 2.413, 0.631, 1.112, and 2.138, respectively. It was shown that the LUR-S model, which considered the source-sink relationship, had a higher accuracy than the traditional LUR model and ordinary Kriging interpolation model. ③ The LUR-S model was more suitable for the prediction of the spatial distribution of heavy metals with lower pollution and smaller variations, while results for the prediction of the heavy metals with higher pollution and larger variations were worse.

[Climate suitability for tea growing in Zhejiang Province].

It is important to quantitatively assess the climate suitability of tea and its response to climate change. Based on meteorological indices of tea growth and daily meteorological data from 1971 to 2010 in Zhejiang Province, three climate suitability models for single climate factors, including temperature, precipitation and sunshine, were established at a 10-day scale by using the fuzzy mathematics method, and a comprehensive climate suitability model was established with the geometric average method. The results indicated that the climate suitability was high in the tea growth season in Zhejiang Province, and the three kinds of climate suitability were all higher than 0.6. As for the single factor climate suitability, temperature suitability was the highest and sunshine suitability was the lowest. There were obvious inter-annual variations of tea climate suitability, with a decline trend in the 1970s, less variation in the 1980s, and an obvious incline trend after the 1990s. The change tendency of climate suitability for spring tea was similar with that of annual climate suitability, lower in the 1980s, higher in the 1970s and after the 1990s. However, the variation amplitude of the climate suitability for spring tea was larger. The climate suitability for summer tea and autumn tea showed a decline trend from 1971 to 2010.