It is of great importance to study the changes in reference evapotranspiration (ET0) and the factors that influence it to ensure sustainable and efficient water resource utilization. Daily ET0 data calculated using the Penman–Monteith method from 37 meteorological stations located within Guangdong Province in the humid zone of southern China from 1960 to 2020 were analyzed. The trend analysis and Mann–Kendall test were used to analyze the time series changes in ET0 and major climatic factors (air temperature (T), relative humidity (RH), sunshine duration (SD), and wind speed (u2)) for over 61 years. Sensitivity and contribution analyses were used to evaluate the driving factors of ET0. The main findings of the study are as follows: (1) the trend in average annual ET0 time series in Guangdong slightly increased at a trend rate of 1.61 mm/10a over the past 61 years, with most stations experiencing an increase in ET0. During the same period, air temperature significantly increased, while RH and SD decreased; u2 also decreased. (2) Sensitivity analysis showed that ET0 was more sensitive to RH and T than SD and u2, with ET0 being most sensitive to RH in spring and winter and T in summer and autumn. (3) The contribution analysis showed that T was the dominant factor for ET0 variation in Guangdong, followed by SD. SD was found to be the dominant factor in ET0 changes in areas where the “evaporation paradox” occurred, as well as in spring and summer. The study concludes that the climate in Guangdong became warmer and drier over the past 61 years, and if the current global warming trend continues, it will lead to higher evapotranspiration and drought occurrence in the future.

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Anthocyanin is the main color-forming substance of mango peel, and bagging is an important technical measure to regulate the formation of fruit apparent color. In this paper, using 'Renong1' and 'Ono' as materials, combined with computer image recognition and liquid chromatography technology, the differences and accumulation characteristics of anthocyanins in the peel before and after bagging were compared. Using computer image recognition technology, the skin color of different mango varieties before and after bagging can be quickly screened and identified. Ten indicators such as second-order moment and third-order moment are used for feature extraction, and then the principal component analysis of the indicators is carried out through MATLAB, and the results are obtained. The results showed that five major anthocyanins could be identified in the peels of two different mango cultivars before and after bagging. For the two mango varieties, the accumulation patterns of anthocyanins after bagging were exactly opposite. Bagging of the light-dependent variety ‘Renong1’ inhibited the accumulation of anthocyanins in the peel, while ‘Ono’ accumulated anthocyanins after bagging, showing pigmentation independent of light. This indicates that the bagging technique can be used to breed new red mango varieties with more easily colored skins. This study provides a theoretical basis for the cultivation of new mango varieties, color metabolism and regulation research, and has important application value. At the same time, combined with computer image recognition technology, it provides a fast and efficient detection method for the preliminary screening of plant anthocyanin components.

Phosphorus (P) is one of the mineral nutrients that exhibit a high propensity for fixation in soil. Interplanting herbage is considered as a mode to produce green orchards that can effectively improve soil quality and ecological function. To assess the impacts of intercropping herbage on the morphological characteristics and availability of P in the acidic soil of mango ( Mangifera indica L .) orchards, three kinds of soil (clean tillage [CK], intercropping Stylosanthes guianensis [SC], and intercropping Cynodon dactylon (L.) Pers. [CC]) were collected from a tropical mango orchard during a 4-year field study. This study determined the morphological characteristics of P in the water-stable aggregates and bulk soil, analysed the bacterial-fungal community structure and diversity, and evaluated the correlation between the environmental factors, P fractions, and microbial communities. This study showed that interplanting S. guianensis and C. dactylon enhanced the availability of soil P by increasing the organic P, and partial inorganic P (Al-P and Fe-P) in the 0.25–2 mm aggregate compared with the CK. In addition, interplanting herbage also altered the structure and diversity of soil bacterial-fungal community. A Mantel analysis revealed that the structure of the bacterial community had a greater influence on the P fractions compared to bacterial α-diversity. The fungal community had minimal impact on the P fractions. Interestingly, the Nitrospira, Candidatus-Udaeobacter, Pseudolabrys, MND1, Tepidisphaera, Aquicella, unclassified-Vicinamibacterales, ADurb.Bin063‒1, Humicola, and Purpureocillium contribute to the availability of soil P. In conclusion, interplanting herbage favors the activation of soil P in the acidic soil of mango orchards.