生物炭和AM真菌配施对连作辣椒生长和土壤养分的影响

研究生物炭和丛枝菌根(arbuscularmycorrhizal,AM)真菌对连作辣椒生长和土壤养分的影响,可为辣椒连作土壤改良和新型肥料的开发提供理论依据。采用温室盆栽试验,设置4个生物炭添加水平(0、1%、2%、3%), 2个接菌水平接菌(+AM)和不接菌(-AM)]。辣椒生长60 d后收获并测定其生理指标、土壤酶活性及土壤养分含量。结果表明,施加生物炭和接种AM真菌处理促进了连作辣椒的生长,提高了辣椒叶片净光合速率、蒸腾速率、气孔导度和叶绿素含量。接种AM真菌对辣椒的促生效果弱于生物炭,而生物炭和AM真菌配施的促生效果最佳。接种AM真菌促进辣椒对P吸收的效果优于生物炭;但对于K吸收来说,施加生物炭的效果优于接菌。生物炭(3%)和AM真菌配施条件下,辣椒根部N、P、K含量分别较对照(0生物炭和-AM处理)显著提高74.04%、106.42%和78.82%。生物炭(3%)与AM真菌配施处理菌根侵染效果最佳,侵染率高达58.96%,较0生物炭+AM处理提高41.59%。土壤pH随生物炭添加量的增加呈增加趋势,但差异不显著。土壤脲酶、蔗糖酶活性随生物炭添加量的增加呈增加趋势,且差异显著,接种AM真菌处理对其影响不显著。土壤速效钾、有效磷、有机质含量随生物炭添加量的增加而增加,接种AM真菌对土壤有机质含量、阳离子交换量(CEC)无显著影响。土壤速效钾、有效磷、碱解氮含量均在生物炭(3%)和AM真菌配施条件下达最大。与单一处理相比,生物炭和AM真菌配施在促进连作辣椒生长、改善连作土壤养分方面具有显著的协同增效作用,尤其是3%生物炭与AM真菌配施条件下效果最佳。

Effects of biochar and arbuscular mycorrhizal fungi on the growth of continuous cropping pepper and soil nutrient status

In this study, a pot experiment was conducted to investigate the synergistic effects of biochar and arbuscular mycorrhizal (AM) fungi on the alleviation of the continuous cropping obstacles of pepper, improve soil nutrient status, and further provide theoretical foundations for continuous cropping soil improvement and new fertilizer development. A total of eight treatments were set as growth conditions of pepper consisting of four biochar addition levels (0, 1%, 2%, and 3%) with or without AM fungal inoculations (+AM and -AM), each treatment was replicated four times. Peppers were harvested after 60 days, and the physiological index, soil enzyme activity, and soil nutrient content were analyzed. Results showed that the biochar+AM treatments significantly promoted the growth of successive cropping pepper and increased the net photosynthetic rate (P_n), transpiration rate (T_r), stomata conductance (G_s), and chlorophyll content in pepper leaves. The treatments of only AM fungi inoculation also showed an increase in the growth and yield of peppers; however, biochar+AM had the best combined treatment effect. The effect of only AM fungal inoculation on P absorption in pepper plants and fruits showed a better result compared with that of only biochar, while the effect was opposite on K absorption. Moreover, the contents of N, P, and K in the root of pepper treated with 3% biochar+AM fungi increased by 74.04%, 106.42%, and 78.82%, compared with 0 biochar without AM fungi (control), respectively. The mycorrhizal infection rate under the treatment of 3% biochar+AM was 58.96%, which was 41.59% higher than that of the control. Soil pH and activities of urease and sucrase increased with an increase in biochar application; although, there was no significant difference in pH. AM inoculation showed not significant effects on soil enzyme activity. In addition, the available contents of K, P, and organic matter in the soil also increased with an increase in biochar application. The most significant improvement was achieved under the 3% biochar+AM treatment, while the treatment of only AM fungal inoculation showed no marked effect on these indexes. In conclusion, biochar, especially the treatment of 3% biochar+AM, had a significant synergistic effect on the growth and soil nutrient improvement of the continuous cropping pepper.