Effect Of Biochar On Trifoliate Orange Seedling Growth And Fruit Quality Of Nanfengmiju

Citrus growing regions are mainly distributed in the hilly areas of Southern China, of which soil type(color) is either red or yellow. Due to long time unscientific culture and fertilization management, the soil in citrus production districts was severely acidified and possesses less available mineral nutrients, which severely affect the yield and quality of citrus fruits. At present, lime is often used to adjust soil acidification, but its negative effect is obvious. Lime could harm soil beneficial microorganisms, reduce soil organic carbon(SOC) content, result in soil compaction, and get soil back to acidified situation again. Studies showed that the biochar can improve acidic soil and thus promote growth in most crops, which can avoid the disadvantages caused by the use of lime. The purpose of this study is to test the effect of biochar on acidic soil, investigate the influence of biochar on the growth of potted Poncirus trifoliata seedlings and on fruit quality of Nanfengmiju in citrus orchard.In order to evaluate the effects of biochar on citrus seedlings cultivated in Gannan acidic red soil matrix, the Poncirus trifoliata growth after applying with 3% and 5% of biochar under greenhouse condition was investigated. Results showed that,1. Plant height and shoot diameter of Poncirus seedlings were significantly increased once biochars were amended to soils, which was further evidenced by augmented plant biomass and leaf net photosynthetic rate.2. In order to explore the mechanism of biochar promoting Poncirus seedlings growth, we did analysis on two different aspects of Poncirus root: root system architecture(RSA) and arbuscular mycorrhizal fungi(AMF). For RSA, the root surface area and root tip number were significantly increased by the usage of biochar, which is consistent with the above ground part growth. AMF colonization rate was not significantly affected under biochar treatment as expected.3. However, 454 pyrosequencing analysis revealed that the root AMF diversity increased after biochar applification.4. In addition, we found that biochar application resulted in the increase of soil p H, SOC and available mineral nutrients concentration.Inferred from results we get, the positive effects of biochar on the growth performance of Poncirus seedlings could be attributed to the substantially augmentation of soil fertility, optimized RSA, and altered AMF species composition.In order to explore the effects of biochar on citrus fruit, biochar was applied in the trenches around the rain-dropping sphere of Nanfengmiju fruit-bearing tree in Nanfeng county. After one year treatment, Nanfengmiju fruit was collected and several main fruit quality indices were analyzed. The results showed that,1. Effect of biochar on the fruit weight, edible rate, vitamin C, total soluble solution, and titratable acid was not significant.2. Interestingly, applied with a dosage of 6.0Kg/tree biochar significantly reduced the thickness of segment membrane, a negative index for fruit mastication property. The result indicated that biochar could improve mastication property of Nanfengmiju fruits, and thus increase its commodity quality.