Objective To study the influences of different soil management methods on soil temperature, soil moisture and Citrus reticulata growth in citrus orchard during summer drought season.
Method The experiment was carried out in Beibei, Chongqing using Ziyangxiangcheng (Citrus junos Sieb. ex Tanaka) Zhenwogan (Citrus reticulata cv. Orah) as the material. Four soil management systems, including rotary tillage weeding (CK), mechanical weeding mulch (MWM), chemical weeding mulch (CWM) and weed living mulch (WLM), were used during the summer drought seasons of 2016 and 2017. We measured the temperature at soil layers of 0 (surface),10, 20 and 30 cm depth, the moisture at 0−10, 10−20 and 20−30 cm soil layers, the maximum crack width of surface, citrus root activity and autumn shoot growth, and summarized the costs of different soil management systems.
Result The shallower the soil layer, the greater the fluctuation of soil temperature and water content. In general, the daily average temperature, maximum temperature and daily temperature range of each soil layer under different soil managements were CK > CWM > MWM > WLM. Under extreme high temperature weather (air temperature 41 ℃), the highest soil surface temperatures of CK , CWM , MWM and WLM were 69.6, 45.6, 37.5 and 35.0 ℃, respectively. The water contents of different soil layers were the highest in WLM and MWM, and the lowest in CK. The water content in 0−10 cm soil layer of CK was significantly lower than those of other treatments. For both citrus root activity and autumn shoot growth, the results were MWM > CWM > CK > WLM. The costs of different soil management systems were in order of CK > WLM > MWM > CWM.
Conclusion Considering the effect, cost and operability, the flat or gentle slope citrus orchard should be practiced with MWM soil management during summer drought season.
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