秸秆还田对石灰性土壤Zn迁移转化及冬小麦Zn吸收的影响

发布时间：2018-04-03 07:05

  本文选题：石灰性土壤　切入点：秸秆还田　出处：《西北农林科技大学》2017年博士论文

【摘要】：Zn作为必需微量营养元素,在人体生长发育过程中起着重要作用,人体Zn缺乏已受到全世界普遍关注。在土壤-植物-动物(人)连续系统中,土壤Zn缺乏是导致作物可食部分Zn含量低下,最终导致人体Zn缺乏的重要原因。在我国,小麦作为北方人口的主食,主要分布在北方的石灰性土壤地区,该地区土壤有效Zn含量多处于Zn潜在缺乏水平(DTPA-Zn含量0.5~1.0 mg kg-1),生产的小麦籽粒Zn营养品质低下,难以满足人体对Zn的营养需求,进而对该地区人群的身体健康构成严重威胁。因此,提高石灰性土壤Zn有效性,对于改善小麦Zn吸收及小麦籽粒Zn营养品质,最终缓解以小麦为主食人群的Zn缺乏具有重要意义。植物根系对Zn的吸收不仅取决于土壤有效Zn含量的高低,还与Zn在土壤中的扩散迁移能力有关。尽管土施Zn肥是一种有效地提高石灰性土壤有效Zn含量的重要措施,但是其对于Zn在土壤扩散迁移影响甚微,最终导致对小麦Zn吸收及籽粒Zn营养品质的改善效果不佳。研究发现,新鲜有机物料腐解产生的活性有机碳组分如溶解性有机质能与土壤Zn离子发生络合或者螯合作用生成可溶性有机Zn复合物,进而显著提高土壤Zn的有效性和移动性。农作物秸秆还田作为减少环境污染、提高能源转化效率、维持和改善农田土壤质量和生产力的重要措施在我国已得到广泛应用。然而,关于农作物秸秆降解产生的活性有机碳组分对于石灰性土壤外源Zn有效性和形态转化、Zn扩散迁移规律及其冬小麦Zn吸收和籽粒Zn营养品质的影响,目前鲜有报道。因此,本研究通过4个培养和为期两年的田间试验探究了秸秆还田对石灰性土壤有效Zn含量、Zn扩散迁移规律及形态转化、小麦Zn吸收及籽粒Zn生物有效性的影响。主要结果如下:(1)田间填埋培养试验探究了秸秆还田对石灰性土壤DTPA-Zn含量及外源Zn老化的影响。结果表明,单独秸秆还田对石灰性土壤有效Zn含量(DTPA-Zn)及土壤Zn各形态组分没有产生显著影响,而单独施Zn显著提高土壤DTPA-Zn及各组分Zn含量,其中松结有机态Zn(Lom-Zn)含量提高了近4倍。与单施Zn肥相比,尽管秸秆还田与Zn肥配施对土壤DTPA-Zn、各形态Zn及外源Zn肥无效化比率的影响不显著,但通过微孔扩散模型计算发现秸秆还田与Zn肥配显著提高了土壤Zn的表观扩散系数和老化速率。(2)半扩散池室内模拟试验研究了秸秆还田和外源施Zn对石灰性土壤Zn扩散迁移的影响。结果表明,单独秸秆还田不会对石灰性土壤DTPA-Zn扩散迁移产生影响。虽然单施Zn肥显著提高了土壤DTPA-Zn含量及DTPA-Zn的扩散迁移能力,但在培养45 d里土壤DTPA-Zn主要被限制在离施肥区15 mm以内,而且整个装置中外源Zn的DTPA-Zn回收率也不足40%。当秸秆还田和Zn配施时,培养45 d土壤DTPA-Zn的最远扩散距离可达20 mm,而且整个装置外源Zn肥的DTPA-Zn回收率提高到了45%。此外,对lom-zn进行分组发现,秸秆还田配施zn肥较单独施zn显著增加了有效性较高的富里酸结合态zn组分的含量,这可能是导致土壤dtpa-zn扩散迁移能力和外源zn肥dtpa-zn回收率提升的主要原因。(3)室内模拟试验评价了不同有机质含量的石灰性土壤上外源zn有效性及形态转化对秸秆还田的响应。结果表明,375℃高温处理是一种有效的移除石灰性土壤有机质,但不会对其他土壤性质产生显著影响的方法。有机质移除75%以后,土壤dtpa-zn含量随着lom-zn含量的减小而显著降低,表明石灰性土壤原有有机质决定着石灰性土壤有效zn含量的高低。外源施zn显著的提高土壤dtpa-zn、lom-zn含量及土壤zn转移因子,但随着时间推移提升效果均逐渐降低,这是由于施入石灰性土壤(特别是有机质含量相对较低的土壤)的外源zn随着时间推移逐渐被碳酸盐矿物和粘土矿物(蒙脱石)吸附固定进而转化为无效态zn。此外,在土施zn条件下,秸秆还田显著提高了土壤zn转移因子,降低了zn分配指数,表明秸秆还田促进了土壤无效态zn向有效态zn组分的转化,进而极大地抑制了石灰性土壤上外源zn的无效化过程,这种抑制效果在有机质含量相对较高的土壤上表现更为明显。(4)田间填埋培养试验评价了不同有机物料对于石灰性土壤外源zn有效性及形态转化的影响。结果表明,在土施zn肥的条件下,外源有机物料添加均可以有效的提高石灰性土壤dtpa-zn、lom-zn含量及土壤zn转移因子,降低土壤zn分配指数,而且各有机物料表现为鸡粪玉米秸秆=生物菌肥黄腐酸。尽管鸡粪和生物菌肥改善石灰性土壤外源zn有效性效果较好,但是综合考虑环境和经济效益,农作物秸秆配合土施zn肥仍是提高潜在缺zn石灰性土壤zn有效性的最佳选择。(5)两年的冬小麦田间试验研究了秸秆还田和外源施zn对石灰性土壤zn有效性及冬小麦zn吸收的影响。试验结果表明,单独秸秆还田没有对土壤有效zn、各形态zn含量及小麦zn吸收量产生影响。单施zn肥土壤dtpa-zn、lom-zn含量及zn转移因子均提高1倍以上,但小麦zn携出量仅提高了5%,而且zn肥当季利用率及dtpa-zn转化率分别低于0.1%和20%。秸秆与zn肥配施土壤dtpa-zn、lom-zn含量及zn转移因子与单施zn结果相似,但小麦zn携出量却提高了10%,zn肥的利用率也提高至0.15%。此外,相关分析表明,土壤dtpa-zn、lom-zn含量及zn转移因子均与小麦zn携出量及各部分zn含量呈显著正相关关系。由此可知,除土壤dtpa-zn含量外,lom-zn含量和土壤zn转移因子也可以作为评价石灰性土壤zn有效性高低的指标。(6)通过对两季田间试验冬小麦籽粒zn营养品质的分析发现,单独秸秆还田并没有对小麦籽粒zn含量及其生物有效性产生影响。单施zn肥和秸秆还田配施zn肥均显著提高冬小麦籽粒zn含量,其中秸秆还田配施zn处理小麦籽粒zn含量最高可达39.5mgkg-1。采用植酸/zn摩尔比和人体zn吸收量(taz)对小麦籽粒zn生物有效性进行评价发现,秸秆还田配施zn肥对冬小麦籽粒植酸/zn摩尔比的降幅最大,对小麦籽粒taz的提高效果最好。此外,对小麦籽粒fe和mn分析表明,秸秆还田配施zn肥在改善小麦籽粒Zn营养品质的同时并不会对小麦籽粒Fe和Mn含量及其生物有效性产生影响。综上所述,本研究可得到如下结论:(1)秸秆还田配合土施Zn肥在改善石灰性土壤有效Zn含量的同时,也显著的提高有效Zn在土壤中的扩散迁移能力;(2)土壤原有有机质决定着石灰性土壤DTPA-Zn含量的高低,而外源有机物料(包括作物秸秆)可以通过抑制石灰性土壤对外源Zn的吸附固定,从而提高石灰性土壤外源Zn肥的有效性;(3)秸秆还田配合土施Zn肥可以显著地提高石灰性土壤上冬小麦对Zn的吸收和籽粒Zn含量及其生物有效性。因此,尽管秸秆还田配合土施Zn肥对于小麦籽粒Zn含量的提高作用尚未达到小麦籽粒Zn强化的目标含量,但是在我国秸秆还田大面积推广应用的大背景下,土施Zn肥在提高石灰性土壤上冬小麦Zn吸收和籽粒Zn营养品质方面仍具有较大潜力。
[Abstract]:Zn as a micronutrient, plays an important role in the process of human growth and development, lack of human Zn has been paid more attention all over the world. In soil - plant - animal (human) in a continuous system, the soil Zn is the lack of crop edible part of Zn content is low, the ultimate cause of human body Zn deficiency. In China, wheat as a staple food in northern population, mainly distributed in calcareous soil in North China, the content of soil Zn in this region at the Zn level (0.5~1.0 potential lack of DTPA-Zn content mg kg-1), the production of Zn in wheat kernel nutritional quality is low, it is difficult to meet the nutritional needs of the human Zn, which poses a serious threat to the the area of the health of the people. Therefore, to improve the effectiveness of Zn in calcareous soil, to improve the Zn uptake of wheat and wheat grain Zn nutritional quality, and ultimately ease eating wheat population Zn deficiency has important significance. Plant root Zn uptake depends not only on the level of soil available Zn content, is also related to Zn diffusion in soil migration. Although soil Zn fertilizer is an effective and important measure to improve the effective content of Zn in calcareous soil, but the soil Zn in the diffusion migration have little effect, resulting in the poor Zn uptake of wheat grain Zn and improve nutritional quality. The study found that organic carbon produced fresh solutions of organic materials such as corrosion of the dissolved organic matter can generate complex or chelation of soluble organic compound Zn with soil Zn ion, and greatly improve the effectiveness of Zn in the soil and crop straw as mobility. To reduce environmental pollution, improve energy conversion efficiency, maintain and improve soil quality and productivity is an important measure in our country has been widely used. However, the crop straw degradation Active organic carbon produced for calcareous soil is effective and exogenous Zn transformation, Zn diffusion and influence of winter wheat Zn Zn uptake and grain nutritional quality, is rarely reported. Therefore, this research through the 4 culture and field experiments for two years of straw on calcareous soil Zn the content of Zn, diffusion and transformation, and affect the validity of the Zn uptake of wheat grain Zn organisms. The main results are as follows: (1) test to study the effect of straw on calcareous soil DTPA-Zn content and exogenous Zn aging training field landfill. The results show that the single straw on calcareous soil available Zn content (DTPA-Zn) and various forms of soil Zn fractions did not produce a significant effect, and the application of Zn alone significantly increased soil DTPA-Zn and the component content of Zn, which loosely combined organic Zn (Lom-Zn) content increased by nearly 4 times and single. Application of Zn fertilizer, although straw and Zn fertilizer on soil DTPA-Zn, influence the morphology of Zn and exogenous Zn fertilizer void ratio is not significant, but through the pore diffusion model, found that straw and Zn fertilizers significantly increased soil Zn apparent diffusion coefficient and the rate of aging. (2) semidiffusion the indoor pool was studied of straw and exogenous Zn diffusion effect on the migration of Zn in calcareous soil. The results showed that straw alone will not spread the influence on the migration of DTPA-Zn in calcareous soil. Although Zn fertilizer significantly increased the content of DTPA-Zn and DTPA-Zn diffusion of soil migration, but in the training of 45 D in soil DTPA-Zn is mainly restricted within from fertilization area 15 mm, DTPA-Zn and Zn in the recovery of the whole device is less than 40%. when the rate of straw and Zn fertilizer, cultivation of 45 d soil DTPA-Zn is the diffusion distance of up to 20 mm, and the The whole device and the DTPA-Zn recovery of exogenous Zn fertilizer rate increased to 45%. in addition, the lom-zn group found that straw fertilizer Zn fertilizer was lower than single Zn application significantly increased the effectiveness of high fulvic acid content of Zn components, which may lead to soil dtpa-zn diffusion main reason and exogenous force Zn fertilizer dtpa-zn recovery rate increased. (3) the indoor simulation test to evaluate the efficacy of exogenous Zn and speciation in response to straw of different organic matter content in calcareous soil. The results show that the high temperature of 375 DEG C treatment is an effective removal of organic matter in calcareous soil, but did not have a significant impact on the other soil properties. The organic matter removal after 75%, dtpa-zn content of soil decreased as the concentration of lom-zn decreased significantly, showed that the calcareous soil original organic matter determines the effective content of Zn in calcareous soil. The level of external source Application of Zn significantly increased soil dtpa-zn, lom-zn content and Zn of soil transfer factor, but as time goes on to enhance the effect of decreased, which is due to the calcareous soil (especially a relatively low organic matter content of soil) exogenous Zn with the passage of time gradually by the salt mineral carbonate and clay mineral adsorption (Meng Tuoshi) fixed and then into invalid state zn. in addition, in soil Zn under the condition of straw returning significantly increased soil Zn transfer factor, reduces the Zn distribution index showed that straw returning promoted soil available to invalid state Zn conversion of Zn components, which greatly inhibited the invalidation process on calcareous soil of exogenous Zn and this inhibitory effect is manifested in relatively high organic matter content of soil is more obvious. (4) the experimental evaluation of different organic materials on calcareous soil of exogenous Zn effectiveness and transformation of training field landfill Effect. The results show that the application of Zn fertilizer in soil under the condition of exogenous organic materials were added can effectively improve the calcareous soil dtpa-zn, lom-zn content and Zn of soil transfer factor, reduce soil Zn distribution index, and the organic materials for chicken manure corn straw = biological fertilizer fulvic acid. While chicken manure and biological fertilizer improved effect of exogenous Zn on calcareous soil is good, but considering the environmental and economic benefits, crop straw with soil fertilizer Zn is still the best choice to improve soil Zn availability potential of Zn. Lack of lime (5) effects of two years of winter wheat were studied between straw and exogenous Zn absorption in Calcareous soil the effectiveness of the Zn and Zn of winter wheat. The results showed that no separate straw on soil available Zn, Zn and Zn in all forms of wheat absorption effect. Zn fertilizer soil dtpa-zn, content of lom-zn and Zn Transfer factor was increased more than 1 times, but the Zn uptake of wheat increased by only 5%, but when the season Zn fertilizer utilization rate and the conversion rate of dtpa-zn and 20%. were less than 0.1% Zn of straw and fertilizer of soil dtpa-zn, lom-zn content and Zn transfer factor and single application of Zn were similar, but the wheat uptake is Zn increased by 10%, the use of Zn fertilizer rate increased to 0.15%. in addition, correlation analysis showed that soil dtpa-zn, lom-zn content and Zn transfer factors are taken out of wheat Zn has a significant positive correlation between the amount and the content of Zn. Therefore, the content of soil dtpa-zn, also can be used to evaluate the efficiency of lime soil Zn and soil Zn content index of lom-zn transfer factor (6). Through the analysis of the two season field experiment of winter wheat Zn nutrition found that straw alone had no effect on Zn content of wheat grain and its bioavailability. Zn fertilizer and straw returning Tian fertilizer Zn fertilizer significantly increased the Zn content of winter wheat, including straw fertilizer treatment Zn Zn content of wheat grain is up to 39.5mgkg-1. by phytic acid mole ratio of /zn and human Zn uptake (TAZ) to evaluate the effectiveness of wheat Zn biological, straw fertilizer by Zn Fertilizer on winter wheat phytic acid molar ratio of /zn grain is the largest, best of wheat grain TAZ increase effect. In addition, show that the Fe and Mn analysis on wheat grain, straw fertilizer Zn fertilizer in improving the nutritional quality of wheat grain Zn also does not have an impact on wheat grain Fe and Mn content and its bioavailability. In summary, in this study, the following conclusions can be obtained: (1) straw application with Zn fertilizer in improving the soil available Zn in calcareous soil at the same time, also improve the effective diffusion of Zn in soil migration; (2) the original soil organic matter was determined in Calcareous The soil DTPA-Zn content, and exogenous organic materials (including crop straw) can be fixed by adsorption of exogenous Zn inhibited the calcareous soil, thereby enhancing the effectiveness of exogenous Zn fertilizer in calcareous soil; (3) the straw with soil Zn fertilizer can significantly improve the calcareous soil of winter wheat on the absorption of Zn and the grain content and bioavailability of Zn. Therefore, although the straw application with Zn fertilizer to improve soil Zn content of wheat grain has not yet reached the target content of wheat grain Zn enhancement, but in the straw in large areas of application in the background, application of Zn fertilizer in soil increased on calcareous soil in winter Zn uptake of wheat and grain nutritional quality, Zn still has great potential.

【学位授予单位】：西北农林科技大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：S141.4;S512.11
，

本文编号：1704121