Abstract:

To realize the resource utilization of agricultural straw waste， and to explore the effects of tobacco stalk carbon and nitrogen fertilizer on maize seedling growth， nutrient absorption， soil fertility and enzyme activities，pot experiment was carried out， in which two biochar levels （BC1，22.5 t·hm^-2， low carbon and BC2，67.5 t·hm^-2， high carbon） and two nitrogen fertilizer levels（N1， 180 kg·hm^-2， low nitrogen and N2， 270 kg·hm^-2， high nitrogen）were set without tobacco stalk carbon and nitrogen fertilizer as control （CK）， to analyze maize growth and nutrient uptake， soil nutrient content and enzyme activities after 60 days of maize growth. The results showed that， compared with CK， the application of tobacco stalk char and nitrogen fertilizer alone and in combination with each other significantly increased the maize growth，nutrient uptake， soil nutrient contents. And soil pH， total nitrogen and cation exchange were most significantly increased by N1+BC2 treatment， which were 1.29， 2.12 and 1.34 times higher than CK， respectively； soil organic matter， available nitrogen， available phosphorus， and available potassium were highest in N2+BC2 treatment， which were 3.4， 7.0， 1.5 and 2.5 times higher than CK， respectively. In addition， the soil treated with N2+BC1 had the maximum urease， sucrase and catalase activities， which were 74.74， 7.92 and 1.14 mL·100 g^-1 soil， respectively. Biochar and nitrogen fertilizer applications significantly enhanced the activities of sucrase and catalase， compared with CK， the improvements of two enzyme activities were up to 63%~88% and 24%~79%， respectively. The results showed that low biochar rate promoted the activities of urease， sucrase and catalase， while a high biochar rate inhibited the enzyme activities. Correlation analysis revealed that a significant correlation was established between the available nitrogen content and activities of sucrose and catalase but not with the urease activity； and highly significant positive correlations were detected among soil enzyme activities. The results might provide a reference for the effectiveness of recycling tobacco straw， and serve as a reference for new ideas for reducing fertilizer application and improving efficiency.

Key words: biochar, nitrogen fertilizer, corn, nutrient absorption, soil nutrients, enzyme activity

摘要：

为了实现农业秸秆废弃物资源化利用，探讨烟杆炭与氮肥对玉米苗期生长、养分吸收、土壤肥力及酶活性的影响，通过盆栽试验，以不施烟杆炭和氮肥为对照（CK），设置2个生物炭水平BC1（22.5 t·hm^-2，低炭）和BC2 （67.5 t·hm^-2，高炭），2个氮肥水平N1（180 kg·hm^-2，低氮）和N2 （270 kg·hm^-2，高氮），在玉米生长60 d后，分析玉米生长及养分吸收、土壤养分含量和酶活性变化。结果表明，与CK相比，烟杆炭、氮肥单独及二者配施均可显著提高玉米生长、养分吸收量及土壤养分含量。其中，土壤pH、全氮和阳离子交换量以N1+BC2处理增加效果最显著，分别为对照的1.29、2.12和1.34倍；土壤有机质、速效氮、速效磷和速效钾含量以N2+BC2处理最高，分别为对照的3.4、7.0、1.5和2.5倍。此外，N2+BC1处理的脲酶、蔗糖酶和过氧化氢酶活性最高，分别为74.74、7.92和1.14 mL·100 g^-1土。生物炭和氮肥施用均显著提高了土壤蔗糖酶和过氧化氢酶活性，与对照相比，提高幅度分别为63%~88%和24%~79%；烟杆炭与氮肥配施对3种土壤酶的影响表现为低炭促进，高炭抑制。相关性分析表明，速效氮含量与蔗糖酶和过氧化氢酶活性呈极显著正相关，与脲酶活性相关不显著；各酶活性之间呈极显著相关。结果可为烟杆循环利用提供科学参考，同时为农业生产中减肥增效提供新思路。

关键词: 烟杆炭, 氮肥, 玉米, 养分吸收, 土壤养分, 酶活性