Effects of Straw Biochar on Growth and Nitrogen Absorption and Utilization of Maize

Zhu Junke; Feng Weiyi; Yang Gongxian; Qin Xiaochun; Wang Yuzhe; Zhang Lihua; Lan Yubin

doi:10.14083/j.issn.1001-4942.2025.09.013

Abstract：A two-year consecutive field plot experiment was conducted in this study to investigate the effects of applying 0,10,20 and 30 t/hm2 biochar(labeled as C0,C10,C20 and C30)on dry matter accu-mulation,nitrogen uptake and translocation in different organs of maize at silking stage(R1)and maturity stage(R6),as well as the contents of different forms of nitrogen in different soil layers(0～10,10～20,and 20～30-cm).The results showed that the dry matter accumulation of maize at the maturity stage decreased with the increase of biochar application rate,and that of each biochar treatment significantly lower than that of C0.At the silking stage,only C10 treatment in 2020 and C30 treatment in 2021 were significantly lower than that of C0.The nitrogen accumulation at the silking stage varied with years and biochar application rates.In 2020,it was significantly higher in C20 and C30 treatments than that of C0,while in the other treatments(including all biochar treatments in 2020),it was lower than that of C0,and most showed significant differences.At the maturity stage,the plant nitrogen accumulation in all biochar treatments in both of the two years was signifi-cantly lower than that of C0.In 2020,the nitrogen translocation amount and translocation rate of leaves in C20 and C30 treatments were significantly higher than that of C0,which was significantly lower in C10 treatment than that of C0.While in 2021,they decreased with the increase of biochar application rate,and were signifi-cantly lower in C20 and C30 treatments compared to C0.The nitrogen translocation amount and translocation rate of stems increased with the increase of biochar application rate in 2020,while in 2021,they showed de-creasing first and then increasing,and the index levels in 2021 were significantly higher than those in 2020.The harvest index and nitrogen harvest index of maize in biochar treatments were significantly increased.The contents of total nitrogen,ammonium nitrogen and nitrate nitrogen in 0～20-cm soil layer showed an upward trend with the increase of biochar application rate.In 2021,the ammonium nitrogen content in 0～10-cm soil layer and the nitrate nitrogen content in 10～20-cm soil layer in most biochar treatments were significantly higher than those of C0.In conclusion,excessive application of biochar(C20 and C30 treatments)could im-prove the soil's ability to retain nutrients and reduce nutrient loss,but it might reduce the absorption of nutri-ents by crops.It was recommended to apply 10 t/hm2 of biochar in production,and if necessary,combined with quick-acting nitrogen fertilizer to balance soil nutrient retention and crop nutrient demand.This conclusion could provide a scientific basis for the rational use of biochar to improve soil fertility.