Response of different organic mulch treatments on yield and quality of Camellia oleifera

Uneven seasonal rainfall results in insufficient water supply and low yelds of Camellia oleifera growing in mountainous and hilly areas without irrigation conditions. To assess the effectiveness of mulching on the yield and quality of three cultivars of C. oleifera ('Hengdongdatao', 'Huashuo' and 'Xianglin 210') and its influence of preserving soil moisture, a field experiment was conducted in 2016 in Changning, Hunan. Mulching materials of ecological pad (T1), straw (T2), straw and ecological pad (T3), gravel (T4), sawdust (T5) and camellia shell (T6) were tested and compared with un-mulched (CK). The mulch material with the strongest cooling effect in high temperature weather was T2. The possible reason is that the surface roughness of the mulching material is good for reflecting light. T3 was the most effective at maintaining soil moisture. The reason is that straw and ecological pad increased the thickness of the cover layer and their small pore size, thus the evaporation rate decreased. It can appropriately stable the temperature in high-temperature weather and can better maintain the soil moisture to provide adequate water for growth. T1showed soil moisture by 14.93%, 14.98%, 14.89% for three cultivars, respectively. All treatments increased yield compared to CK. T1 showed the highest yield and was higher than CK by 58%, 61% and 124% for Hengdongdatao, Huashuo, and Xianglin 210, respectively. Mulching with T1 (40.23% and 39.63%) resulted in the highest oil content ratio in 'Hengdongdatao' and 'Huashuo' and mulching with T4 (36.93%) resulted in highest oil content ratio in 'Xianglin 210'. Treatment of the 'Xianglin 210'cultivar with T1 was re-tested in 2017. In all months analyzed, related indicators measured were significantly different compared with CK. This research suggests that mulching organic material to C. oleifera hilly area is an effective measure to solve seasonal drought and increase yield when there are no irrigation conditions present.