生物炭还田对棕壤氮素利用及玉米生长的影响

发布时间：2018-11-18 18:27

【摘要】：多年来,我国氮肥施用量持续增加,氮肥利用效率却难以显著提高,大量氮素通过氨挥发、氧化亚氮排放、淋溶作用等途径损失,不仅造成了巨大的资源浪费,也引起了严重的土壤酸化、富营养化等农业面源污染问题,极大地制约了农业可持续发展。自20世纪肥料化工兴起之时,寻找有效的抑制氮肥损失的途径便成为学术界关注的热点。近年新兴的生物炭技术有可能为提高肥料利用效率、降低氮素损失提供一整套新的解决方案。因此,明确生物炭还田对作物的吸氮规律以及肥料氮素的分布特征对指导生物炭还田改土、提高氮肥利用效率意义重大。为研究生物炭还田对玉米氮素利用的影响,于2012年至2013年在沈阳农业大学南院试验场开展了盆栽15N同位素示踪试验,监测生物炭还田条件下农田土壤的氨挥发、氧化亚氮排放和氮素淋溶以及无机氮素的动态分布和肥料15N的归趋；于2013年在沈阳农业大学棕壤长期定位试验站开展了田间试验,研究不同生物炭施用量对玉米生长动态、干物质积累以及产量品质的影响。其中,盆栽试验设置3个处理,(1)CK不施生物炭不施氮肥, (2)N常规施肥不施生物炭,(3)NB生物炭与氮肥配施(生物炭用量为1.64%,相当于田间用量40 t.hm-2),盆栽试验所用尿素的15N丰度为10%。田间试验设置5个处理,(1)B0不施氮肥且不施生物炭,(2)B20不施氮肥只施20 t.hm-2生物炭,(3)NB0常规施肥不施生物炭,(4)NB20氮肥与20t.hm-2生物炭配施,(5)NB40氮肥与40 t.hm-2生物炭配施。氨挥发测定采用半封闭式酸吸收法,氧化亚氮排放通量测定采用密闭箱-气相色谱法,土壤速效氮含量测定采用连续流动注射分析法,利用元素分析仪测定植物和土壤的氮素含量,TOC分析仪测定淋溶液的全氮含量,同位素质谱仪测定各样品的15N同位素丰度。主要研究结果概括如下：1.田间试验表明,与B0相比,B20处理玉米产量显著降低20.55%。与NB0相比,NB20处理显著提高了根系活力,促进玉米的穗部干物质积累,改善了玉米的品质,提高玉米的产量6.07%。NB40处理由于过度降低土壤容重导致出苗率下降,同时过度增加土壤的碳氮比促使微生物与玉米争氮,最终导致品质下降,产量降低13.88%。可见,适量生物炭与氮肥配施可以促进玉米生长发育和品质形成,一次性大量施炭(40 t.hm-2)对当季作物生长不利。2.与B0相比,B20处理玉米的吸氮量显著降低了16.9%;与NB0相比,NB20处理玉米的吸氮量增加5.6%,而NB40处理减少了15.3%。生物炭提高了籽粒中氮素含量,与NB0相比,NB20处理籽粒的氮素含量显著提高17.13%。可见,适量生物炭与氮肥配施促进作物对氮素的吸收,提高土壤氮素的利用效率。3.盆栽试验表明,与N相比,NB处理的玉米吸氮量显著增加7.20%；土壤的氧化亚氮排放显著降低了26.67%,土壤的氮素淋溶损失显著降低了47.48%,共减少由氨挥发、氧化亚氮排放和淋溶所引起的土壤氮素损失34.11%。生物炭与肥料配施可以增加作物的吸氮量,抑制土壤的氧化亚氮排放、降低了氮素的淋溶损失。4.盆栽15N示踪试验表明,与N相比,NB处理玉米对肥料15N的吸收量减少7.98%,氮肥利用率低3.6%；土壤中肥料15N残留量增加了17.03%,残留率高6.4%；总体而言,肥料15N损失量降低了27.55%,损失率低3.7%。可见,生物炭降低了肥料氮素的当季可利用性,但增加了土壤对肥料氮素的固持作用,显著减少了肥料氮素以氨挥发、氧化亚氮排放和淋溶三种途径的损失。综上所述,适量生物炭与氮肥配施可促进玉米对氮素的吸收,提高玉米产量；生物炭可以减少氮素的淋溶和氧化亚氮排放损失,降低化肥中氮素的当季利用率,增加了氮在土壤中的持留,促进了土壤自身氮素的有效化和向植物体的转移,为实现减量施肥创造了条件。
[Abstract]:In that past year, the application rate of the nitrogen fertilizer in China has been continuously increase, the use efficiency of the nitrogen fertilizer is not obviously improved, and a great amount of nitrogen is lost through the methods of ammonia volatilization, nitrous oxide emission, leaching, and the like, not only causing great resource waste, but also causing serious soil acidification, The problems of agricultural surface source pollution, such as eutrophication, have greatly restricted the sustainable development of agriculture. In the light of the rise of fertilizer and chemical industry in the 20th century, it has become the focus of the academic circles to find effective ways to restrain the loss of nitrogen fertilizer. In recent years, the new bio-carbon technology has the potential to provide a whole set of new solutions for improving the utilization efficiency of the fertilizer and reducing the loss of nitrogen. Therefore, it is of great significance to make clear that the nitrogen absorption law of the biological carbon and the distribution of the nitrogen in the fertilizer can be used to guide the remediation of the biological carbon and improve the utilization efficiency of the nitrogen fertilizer. In order to study the effect of the biochar on the nitrogen utilization of the corn, a pot-pot 15N isotope tracing test was conducted in the southern courtyard of Shenyang Agricultural University from 2012 to 2013, and the ammonia volatilization of the soil under the condition of the biological carbon was monitored. The effects of the application of different biochar on the growth of maize, the accumulation of dry matter and the quality of the yield were studied in the long-term location test station of brown soil in Shenyang Agricultural University in 2013. In the pot experiment, three treatments were set, (1) CK was not applied to biochar, no nitrogen fertilizer was applied, (2) N was not applied to biochar, and (3) NB bio-carbon and nitrogen fertilizer were applied (the amount of biochar was 1.64%, which was equivalent to the field amount of 40 t. hm-2), and the 15N abundance of urea used in the pot experiment was 10%. In field experiment, 5 treatments were set, (1) B0 was not applied with nitrogen fertilizer and no biochar was applied, (2) B20 nitrogen fertilizer was applied only to 20 t. hm-2 biological carbon, (3) NB0 was not applied to biological carbon, (4) NB20 nitrogen fertilizer was applied to 20t.hm-2 biological carbon, and (5) NB40 nitrogen fertilizer was applied to 40 t. hm-2 biological carbon. A semi-closed acid absorption method is adopted for the determination of the ammonia volatilization, the determination of the nitrogen oxide emission flux is carried out by adopting a closed box-gas chromatography, a continuous flow injection analysis method is adopted for the determination of the quick-acting nitrogen content of the soil, and the nitrogen content of the plant and the soil is determined by using an element analyzer, The total nitrogen content of the leaching solution was determined by the TOC analyzer and the 15N isotopic abundance of each sample was determined by the isotope mass spectrometer. The main findings are summarized as follows: 1. The field experiment showed that the yield of B20 treated with B20 was significantly reduced by 20. 55% compared with that of B0. and compared with the NB0, the NB20 treatment obviously improves the vitality of the root system, promotes the dry matter accumulation of the ear part of the corn, improves the quality of the corn, improves the yield of the corn by 6. 07%, At the same time, the carbon-nitrogen ratio of the soil is excessively increased, and the nitrogen of the microorganism and the corn is promoted, the quality is reduced, and the yield is reduced by 13.88%. It can be seen that a proper amount of carbon and nitrogen fertilizer can promote the growth and quality of the corn, and a large amount of carbon (40 t. hm-2) can be applied to the seasonal crop. The nitrogen uptake of B20 treated with B20 was decreased by 16. 9% as compared with that of B0, and the amount of nitrogen uptake by NB20 in the treatment of corn increased by 5. 6% compared with that of NB0, while the treatment of NB40 was reduced by 15. 3%. The nitrogen content in the grain was increased by the biochar, and the nitrogen content in the treated seeds of the NB20 was significantly increased by 17.13% as compared with that of the NB0. It can be seen that proper amount of biological carbon and nitrogen fertilizer can promote the absorption of nitrogen and improve the utilization efficiency of soil nitrogen. The pot experiment showed that the nitrogen content of the treated corn was significantly increased by 7. 20% in comparison with that of N. The nitrogen emission of the soil was significantly reduced by 26. 67%, and the loss of nitrogen leaching in the soil was significantly reduced by 47. 48%, and the volatilization of ammonia was reduced. Soil nitrogen loss caused by nitrous oxide and leaching was 34. 11%. the application of the biological carbon and the fertilizer can increase the nitrogen absorption capacity of the crops, inhibit the emission of the nitrous oxide of the soil, and reduce the leaching loss of the nitrogen. The results showed that, compared with N, the uptake of fertilizer 15N by NB decreased by 7. 98%, the utilization rate of nitrogen fertilizer was 3. 6%, the residue of 15N in the soil increased by 17. 03%, and the residual rate was 6. 4%; in general, the loss of 15N in the fertilizer was reduced by 27. 55% and the loss rate was 3. 7%. It can be seen that the biochar reduces the seasonal availability of the nitrogen in the fertilizer, but increases the solid-holding effect of the soil on the nitrogen of the fertilizer, and obviously reduces the loss of the fertilizer nitrogen in the three ways of ammonia volatilization, nitrous oxide emission and leaching. In conclusion, proper amount of biological carbon and nitrogen fertilizer can promote the absorption of nitrogen and improve the yield of the corn, and the biological carbon can reduce the leaching of nitrogen and the loss of nitrous oxide emission, reduce the seasonal utilization rate of nitrogen in the fertilizer, increase the retention of the nitrogen in the soil, the effect of the nitrogen of the soil and the transfer of the soil to the plant body are promoted, and conditions are created for realizing the reduction and fertilization.
【学位授予单位】：沈阳农业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S513

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