稻草还田对土壤-稻麦体系硅与锌吸收利用的影响

发布时间：2018-06-02 07:54

本文选题：稻草还田 + 硅　；参考：《西南大学》2017年硕士论文

【摘要】：锌是植物和人类必需的矿质元素,有关锌的研究一直受到广泛关注。硅通常被认为是植物的“有益元素”,近年来有关高等植物对硅的吸收、转运越来越受到人们的关注。我国每年秸秆资源年产量已超过8.4亿t,水稻秸秆(稻草)是主要秸秆资源之一,实施稻草还田是改良和培肥稻田土壤的的重要农业措施。稻草富含硅,但有关稻草还田对水稻和小麦硅、锌吸收的影响少见报道,且已有的研究多为短期试验。因此,本研究利用稻-麦轮作长期定位试验,研究了长期稻草还田下,土壤有效硅、有效锌含量变化以及稻麦对硅、锌吸收的影响;并通过盆栽试验,研究不同硅、锌水平下水稻对硅、锌吸收及其互作的影响;通过模拟试验探究在淹水条件下稻草腐解及硅、锌的养分释放规律。以期为稻草还田后锌硅营养管理提供科学依据。主要研究结果如下:(1)长期定位试验表明,稻草还田对水稻、小麦籽粒和秸秆锌含量无明显影响,稻草还田(S)与不施肥(CK)处理、稻草还田配施化肥(NPKS)与化肥(NPK)处理水稻籽粒锌含量(平均为19.8 mg·kg~(-1))和小麦(平均为47.7 mg·kg~(-1))差异不显著;从不同试验年份水稻和小麦各处理籽粒和秸秆锌含量看,年际间波动较小基本保持稳定。稻草还田对小麦籽粒硅含量影响小,不同施肥处理小麦籽粒硅含量基本维持在0.16%左右,且年际差异较小;但是稻草还田显著提高了小麦茎叶中硅含量和吸收量,稻草还田配施化肥(NPKS)比化肥(NPK)处理小麦叶、茎硅含量分别显著提高1.4、0.8个百分点,小麦地上部硅吸收量提高47.4%。稻草还田显著提高了水稻颖壳、叶、茎器官中硅含量和吸收量,NPKS处理水稻颖壳、叶、茎器官中硅含量分别较NPK处理显著提高2.2、2.8、1.7个百分点;地上部硅吸收量提高27.6%;地上部吸收多余的硅主要积累在茎和叶中,而籽粒中的硅积累反而有略微降低。稻麦吸收过多的硅对锌的吸收有降低的趋势,NPKS处理较NPK处理地上部锌吸收量水稻降低12.3%,小麦降低4.6%。本试验条件下稻草还田量7.5t·hm~(-2)·a-1,平均每年可补充锌376.4 g·hm~(-2),补充硅642.0 kg·hm~(-2);稻草还田显著提高了土壤有效锌含量,NPKS较NPK土壤有效锌增加0.33mg·kg~(-1);稻草还田尽管带入了大量硅,但是土壤中的有效硅并没有显著提高,稻草还田后硅的存在形态及转化有待深入研究。盆栽试验条件下,不同硅水平下(0、100、200、400 mg·kg~(-1))施锌(5 mg·kg~(-1))和不施锌处理间水稻籽粒产量无显著差异。水稻各器官锌含量依次为茎根籽粒叶颖壳,硅含量依次为颖壳叶茎籽粒。水稻成熟期,施用硅肥茎、颖壳以及地上部锌吸收量均有一定下降。硅、锌肥对茎和籽粒锌分配比例有明显交互作用,随着硅浓度增加水稻地上部对锌的吸收降低,促进茎中的锌向籽粒转运。施用锌肥水稻地上部硅的吸收无显著差异,水稻各器官中硅的分配比例差异不显著。水稻成熟期,硅、锌肥对土壤有效锌、有效硅存在正互作效应,施锌加低浓度硅土壤有效硅含量为47.9 mg·kg~(-1),不施锌土壤有效硅含量为33.0 mg·kg~(-1)。即在一定范围内,硅锌肥配施土壤有效硅较单施硅肥显著增加。水田淹水模拟试验结果表明,淹水120天后不同秸秆添加量(5、7.5、10 g·kg~(-1))腐解率为66.1%~73.7%。各处理秸秆腐解规律趋于一致:前期腐解较快,后期腐解速率逐渐降低,且秸秆腐解率随着秸秆量的增加有降低趋势。淹水条件下,水稻秸秆锌与硅释放规律不同,锌的释放表现为前期较快、后期缓慢增加的特征;而硅的释放率则一直处于缓慢增加状态。淹水15d水稻秸秆锌的平均释放率为81.5%,120d为87.2%;15d硅的平均释放率为20.4%,120d硅平均释放率为64.6%。添加水稻秸秆可有效提高土壤有效锌和有效硅含量,秸秆添加量对土壤有效锌有显著影响,随水稻秸秆还田量的增加而升高;但是添加量对土壤有效硅没有显著影响。淹水条件下,土壤Eh前期显著降低,土壤有效锌显著降低,而有效硅有效增加;120d在不添加秸秆的情况下,土壤有效锌从1.20下降至0.56 mg·kg~(-1),添加秸秆后降至0.60~0.66mg·kg~(-1);在不添加秸秆情况下,土壤有效硅从122.2上升至191.1 mg·kg~(-1),添加秸秆后上升至241.0~243.8 mg·kg~(-1)。土壤增加的有效硅一部分来自于秸秆释放的硅,一部分来自于土壤自身硅的活化。综上所述,稻草还田向土壤补充大量硅后,显著提升稻麦茎叶硅含量和吸收量;然而稻草还田尽管显著提高了土壤有效锌含量,但是对稻麦锌的吸收无明显影响,可能原因是稻麦吸收过多的硅抑制了对锌的吸收。有关硅对锌吸收的影响机制都有待进一步研究。
[Abstract]:Zinc is a essential mineral element for plants and human beings. The research on zinc has been widely concerned. Silicon is usually considered as a "beneficial element" of plants. In recent years, more and more attention has been paid to the absorption and transport of silicon in higher plants. The annual yield of straw resources in China has exceeded 840 million T, and rice straw (straw) is the main straw in China. Straw returning is one of the most important agricultural measures to improve and fertilize paddy soil. Rice straw is rich in silicon, but the effect of rice straw returning to rice and wheat and the absorption of silicon and zinc is rarely reported, and most of the existing studies are short-term tests. Therefore, the long-term rice wheat rotation experiment was used to study the long-term rice straw returning. The effect of soil available silicon, the content of effective zinc and the effect of rice and wheat on the absorption of silicon and zinc, and the effects of rice on the absorption and interaction of silicon and zinc under different levels of silicon and zinc were studied by pot experiments. The main research results were as follows: (1) long term location test showed that rice straw returning to rice, wheat grain and straw zinc content had no obvious effect, rice straw returning (S) and non fertilization (CK) treatment, rice straw returning with fertilizer (NPKS) and chemical fertilizer (NPK) treatment of rice grain zinc content (average 19.8 mg. Kg~ (-1)) and wheat (average 4) The difference of 7.7 mg. Kg~ (-1)) was not significant. From the different years of rice and wheat, the grain and straw zinc content, the interannual fluctuation was basically stable. The effect of rice straw returning to the grain silicon content was small, the grain silicon content of different fertilized treatments was about 0.16%, and the interannual difference was small, but the rice straw returned to the field. The content and absorption of silicon in the stem and leaf of wheat increased significantly. The rice straw returned to field and fertilizer (NPKS) treated wheat leaves compared with chemical fertilizer (NPK). The silicon content of the stem increased by 1.4,0.8 percentage points, the uptake of silicon in the upper part of the wheat was increased by 47.4%. straw returning to the field, and the content and absorption of silicon in the rice glumes, leaves and stem organs were significantly improved, and NPKS was used to treat the rice glumes. The content of silicon in the shell, leaf and stem increased by 2.2,2.8,1.7 percentage points, and the absorption of silicon in the upper part of the ground increased by 27.6%, and the superfluous silicon in the upper part of the ground was mainly accumulated in the stems and leaves, but the accumulation of silicon in the grain decreased slightly. The absorption of the silicon in the rice and wheat with excessive absorption was reduced, and the NPKS treatment was compared with the NPK treatment. The amount of zinc absorption in the upper ground was reduced by 12.3%, and the yield of rice straw returned to 7.5t. Hm~ (-2). A-1 under the 4.6%. experiment. The average supplemental zinc was 376.4 g hm~ (-2) per year and 642 kg hm~ (-2) supplemented with silicon. Rice straw returned to the field significantly increased the content of available zinc in soil. A large amount of silicon, but the available silicon in the soil did not significantly increase, and the existence form and transformation of silicon after rice straw returned to field need to be studied. Under the pot experiment, there was no significant difference in grain yield between different silicon levels (0100200400 mg. Kg~ (-1)) Shi Xin (5 mg. Kg~ (-1)) and non zinc treatment. Root grain Ye Yingke, the content of silicon in turn is the grain of glume and stem. In the mature period of rice, the application of silicon fertilizer stems, the spikelet and the zinc absorption of the upper part of the ground decreased to a certain extent. The silicon, zinc fertilizer has a significant interaction effect on the proportion of zinc distribution in the stem and grain, and the absorption of zinc in the upper part of rice is decreased and the zinc transfer in the stem is promoted. There is no significant difference in the absorption of silicon in the upper part of the rice field with zinc fertilizer, and there is no significant difference in the proportion of silicon in each organ of rice. In the mature period of rice, silicon and zinc fertilizer have positive interaction effect on soil available zinc and effective silicon, the effective silicon content of the soil with zinc and low concentration of silicon is 47.9 mg. Kg~ (-1), and the effective silicon content in the non zinc application soil is 33 mg. Kg~ (-1). In a certain range, the application of silicon and zinc fertilizer to soil effective silicon was significantly higher than that of single application of silicon fertilizer. The results of water field flooding simulation test showed that the decomposition rate of different straw added (5,7.5,10 G. Kg~ (-1)) after 120 days of flooding was 66.1%~73.7%.. With the increase of straw, the release of zinc and silicon in rice straw was different, and the release rate of zinc showed a slow increase in the early stage, and the release rate of silicon was slowly increasing. The average release rate of 15d rice straw was 81.5%, 120d 87.2%, and the average release of 15d silicon. The rate of 20.4%, the average 120d silicon release rate of 64.6%. added rice straw could effectively increase the content of available Zn and available silicon, and the amount of straw added to soil effective zinc significantly increased with the increase of rice straw returning, but the amount of addition had no significant effect on soil available silicon. Under the condition of flooding, the early stage of soil Eh decreased significantly. Soil effective zinc decreased significantly, while effective silicon increased effectively, and 120d decreased from 1.20 to 0.56 mg. Kg~ (-1) without straw adding, and decreased to 0.60~0.66mg. Kg~ (-1) after adding straw. The soil available silicon increased from 122.2 to 191.1 mg. Kg~ (-1) without straw adding, and then increased to 241.0~243.8 mg. (-1). A part of the available silicon from the soil was derived from the silicon released from the straw, some of which came from the activation of the silicon in the soil. In summary, after the rice straw was returned to the soil with a large amount of silicon, the silicon content and absorption of the rice and wheat were significantly increased. However, although rice straw returned to the field significantly higher the content of the available zinc in the soil, the absorption of rice and wheat and zinc was not. The obvious reason is that the excessive absorption of silicon in rice and wheat inhibits the absorption of zinc. The mechanism of the influence of silicon on zinc absorption needs further study.
【学位授予单位】：西南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S141

【参考文献】