不同蔗叶生物炭施用量对甘蔗产量及养分吸收利用的影响

Effects of different sugarcane leaf biochar application rates on sugarcane yield and nutrient uptake and utilization

【目的】研究蔗叶源生物炭不同施用量对甘蔗产量及氮磷钾养分吸收利用的影响,以期为蔗叶生物炭在甘蔗生产中的科学施用及实现养分高效利用提供理论依据。【方法】于2021—2022年开展田间试验和15N同位素示踪桶栽试验,以桂柳05136和桂糖42为供试品种,设CK(对照,不施蔗叶生物炭)、T1(蔗叶生物炭用量2.7 t/ha)、T2(蔗叶生物炭用量5.4 t/ha)和T3(蔗叶生物炭用量10.8 t/ha)4个处理,对比分析不同蔗叶生物炭用量对甘蔗收获期蔗茎和蔗叶产量、氮磷钾养分含量和吸收累积量、氮肥吸收量及氮肥利用率的影响。【结果】与CK相比,施入不同用量的蔗叶生物炭对蔗叶产量无显著影响(P>0.05,下同),但均可不同程度提高甘蔗蔗茎产量,且随蔗叶生物炭施用量增加,蔗茎产量呈先升高后降低的变化趋势,在T2处理达最高,且差异达显著水平(P<0.05,下同)。施用蔗叶生物炭,蔗茎与蔗叶氮、磷含量及地上部氮、磷吸收累积量均无显著变化,T2处理显著提高2022年大田试验蔗叶磷吸收累积量及桶栽试验蔗茎氮、磷吸收累积量。大田试验下,施用蔗叶生物炭较CK显著提高蔗茎钾含量,2021年和2022年增幅分别为31.3%~38.2%和10.5%~29.5%。蔗茎钾含量T2处理与T1处理相当,并在2022年显著高于T3处理。但在桶栽试验下,施用蔗叶生物炭对蔗茎、蔗叶及尾梢钾含量均无显著影响。施用蔗叶生物炭提高了大田试验蔗茎及地上部钾吸收累积量,其中,蔗茎增幅18.2%~45.6%,地上部增幅13.5%~32.8%,且以T2处理最高。施用蔗叶生物炭对甘蔗氮、磷养分生理利用效率无显著影响,但大田试验的钾养分生理利用效率显著降低14.7%~23.1%(2021年)和6.0%~19.5%(2022年)。15N同位素示踪进一步表明,蔗茎的氮肥吸收量最高,占总吸收量的46.5%~54.2%,蔗叶和尾梢的氮肥吸收量相当,分别占总吸收量的23.3%~27.5%和22.6%~28.0%。施用不同用量蔗叶生物炭,蔗叶与尾梢的氮肥吸收量差异不显著。T2处理较其他处理显著提高蔗茎氮肥吸收量36.5%~37.5%及氮肥利用率18.1%~24.2%。【结论】施用不同用量蔗叶生物炭对氮、磷的吸收因不同年份有所差异,但有利于提高甘蔗产量及蔗茎对钾的吸收,5.4 t/ha生物炭用量下蔗茎产量及钾吸收量最高,且显著促进蔗茎对氮肥的吸收及提高氮肥利用率,可作为推荐的适宜施用量。

【Objective】The effects of different sugarcane leaf biochar application rates on sugarcane yield and nitrogen,phosphorus and potassium nutrient uptake and utilization were studied in order to provide a basis for scientific application of sugarcane leaf biochar to promote sugarcane growth and achieve high nutrient utilization.【Method】Field experiment and pot experiment were conducted in 2021-2022 by using 15N isotope tracer technique.Guiliu 05136 and Guitang 42 were used as test varieties.Four treatments were set up:CK(control,no sugarcane leaf biochar application),T1(sugarcane leaf biochar,2.7 t/ha),T2(sugarcane leaf biochar,5.4 t/ha)and T3(sugarcane leaf biochar,10.8 t/ha).The yield,nitrogen,phosphorus and potassium content and accumulation rate of stems and leaves during the harvest period of sugarcane were analyzed.Moreover,fertilizer nitrogen uptake and nitrogen use efficiency were also studied.【Result】Compared with CK,the application of different amounts of sugarcane leaf biochar had no significant effect on leaf yield(P>0.05,the same below),but increased stem yield to different degrees,and with the increase of sugarcane leaf biochar application,stem yield showed a trend of first increase and then decrease,and reached the highest level in T2 treatment,which showed a significant difference(P<0.05,the same below).There were no significant changes in nitrogen and phosphorus content in stems and leaves,and nitrogen and phosphorus uptake accumulation rate in aboveground.However,T2 treatment significantly increased the phosphorus accumulation rate of sugarcane leaf in field trail,and the nitrogen,phosphorus accumulation rate of stem in pot trail in 2022.The application of sugarcane leaf biochar increased potassium content in stems by 31.3%-38.2%in 2021 and 10.5%-29.5%in 2022,respectively in field trial,where T2 treatment was equivalent to T1 treatment and significantly higher than T3 treatment in 2022.The application of sugarcane leaf biochar had no significant effect on the potassium content of stems,leaves and tail in pot trial.Biochar application increased the accumulation of potassium absorption in the stem and aboveground in the field,and increased by 18.2%-45.6%in stems and by 13.5%-32.8%in aboveground,and the highest was found in T2 treatment.However,no significant differences was found in physiological use efficiency of nitrogen and phosphorus.The physiological utilization efficiency of potassium was significantly reduced by 14.7%-23.1%(2021)and 6.0%-19.5%(2022)in field trial.The tracer of 15N isotope further showed that stem had the highest nitrogen fertilizer uptake,accounting for 46.5%-54.2%of the total nitrogen uptake,while leaves and tails had the equivalent nitrogen uptake,accounting for 23.3%-27.5%and 22.6%-28.0%of the total nitrogen uptake respectively.There was no significant difference in nitrogen fertilizer absorption in leaves and tails under different sugarcane leaf biochar application rates,but T2 treatment significantly increased the stem nitrogen fertilizer uptake by 36.5%-37.5%and the nitrogen use efficiency by 18.1%-24.2%compared with other treatments.【Conclusion】In this study,the nitrogen and phosphorus uptake under sugarcane leaf biochar with different dosage is different in different years,but it is beneficial to improve the sugarcane yield and the potassium uptake of stems.At the same time,5.4 t/ha sugarcane leaf biochar treatment not only has the highest stem yield and potassium uptake in stems,but also significantly promotes the uptake of nitrogen fertilizer in stems and improves the nitrogen use efficiency,so it can be used as the recommended suitable application rate.