南疆盐渍化土壤水氮高效利用及迁移模拟研究

发布时间：2018-03-01 21:27

本文关键词： 生理生态指标水氮利用效率模拟水氮迁移规律水氮耦合机理　出处：《塔里木大学》2017年硕士论文　论文类型：学位论文

【摘要】：本文通过设置两个不同盐分水平,3个灌水处理(3500 m3.hm-2、4100 m3.hm-2、4700m3.hm-2)与3个施氮处理(160 kg.hm-2、260 kg.hm-2、360 kg.hm-2)不同的水氮处理,系统研究了南疆地区不同盐渍化土壤下不同水氮处理对棉花的生态指标、水氮利用效率、水氮迁移规律的影响,模拟土壤中水分和硝态氮动态变化,揭示不同盐渍化土壤水氮耦合机理并提出了适合当地的水氮生产模式。为提高南疆盐渍化地区的棉花产量、水氮利用效率,节约水肥资源提供理论依据,对改良盐渍化土壤防止环境污染,防止次生盐渍化的发生有着重要的意义。试验及模拟取得的主要结论如下:1.中度盐渍化土壤比轻度盐渍化土壤出苗期早2-3天,在W_HF_H处理下棉花各个生育期出现时间无明显差异。棉花的株高随着施氮量和灌溉水量的增加呈逐渐上升的趋势,随着盐分胁迫的增加棉花株高不断降低,相同施氮量的条件下对株高的影响程度为W_HW_MW_L。在两种盐分土壤上适当的节水节氮对棉花的生长发育影响不大。棉花茎粗受盐分影响不显著,茎粗在高肥和中肥处理时达到最高,在相同的施氮水平下对茎粗的影响为W_HW_MW_L,棉花茎粗在水肥耦合W_HFM处理时达到最大值。植株叶面积指数在两种盐分土壤上不同水氮处理下的生长过程表现为先增加后减小,同一灌溉水平下对叶面积指数影响表现为F_HFMFL,同一施氮水平下对棉花叶面积影响程度为W_HW_MW_L。2.棉花干物质累积量变化规律呈现“S”型,两种盐渍化土壤在同一施肥水平下,干物质的累积量随灌水量的增加而增加,同一灌水水平下增加施肥量促进棉花干物质量的累加,当施肥量达到一定程度后,高施肥量对棉花干物质量影响不显著,在灌水量为4700 m3.hm-2施氮量为260 kg.hm-2时达到最大,干物质累积量的形成最佳的水氮耦合为W_HFM。3.盐分对产量的影响较大,抑制了棉花的生长发育,当施氮量为260 Kg.hm-2,灌水量为4700 m3.hm-2即W_HFM处理时,棉花籽棉产量最高。棉花的水氮利用效率在灌水量超过4100m3.hm-2、施氮量超过260 Kg.hm-2即W_MFM处理后会降低,因此使棉花水氮利用效率最佳水氮耦合为W_MFM处理。在两种盐渍化土壤上,棉花植株吸氮量在80 Kg.hm-2-350 Kg.hm-2、65.4 Kg.hm-2-334.8 Kg.hm-2之间,氮肥在高氮中水条件下吸收利用率最大。4.结果表明在W_MF_H处理下水分向下运移明显,土壤水分主要分布在60-80 cm,此时的土壤水分分布更接近于棉花主根系分布位置,从而更有利于棉花对水分的吸收,预测结果可知此时土壤含水率达到0.17 cm3.cm-3既符合棉花种子萌发所需的最低含水率要求0.168cm3.cm-3,又可以节约水资源。在W_HFM处理下氮素累积峰值出现在60-80 cm处,土壤硝态氮含量接近于棉花主根系分布位置,在这个范围内有助于棉花的生长。
[Abstract]:The ecological indexes of cotton treated with different water and nitrogen treatments under different salinization soils in southern Xinjiang were systematically studied by setting up two different salt levels, three irrigation treatments (3500m3.hm-2N 4100m3.hm-21000m3.hm-2) and three nitrogen application treatments (160kg.hm-2260kg.hm-2 + 360 kg.hm-2). The effects of water and nitrogen use efficiency and water and nitrogen migration on soil water and nitrate dynamic changes were simulated. The coupling mechanism of water and nitrogen in different salinized soils was revealed, and a suitable water and nitrogen production model was put forward, which provided theoretical basis for improving cotton yield, water and nitrogen utilization efficiency and saving water and fertilizer resources in the salinized areas of southern Xinjiang. It is of great significance for improving salinized soil to prevent environmental pollution and to prevent secondary salinization. The main conclusions of the experiment and simulation are as follows: 1. The emergence period of moderate salinized soil is 2-3 days earlier than that of mild salinized soil. There was no significant difference in the occurrence time of cotton at different growth stages under WHFH treatment. The plant height of cotton increased gradually with the increase of nitrogen application and irrigation water, and decreased with the increase of salt stress. Under the same nitrogen application rate, the influence degree on plant height was WW _ W _ W _ L _ L. the effect of appropriate water-saving nitrogen saving on cotton growth and development was not significant in two kinds of salt soils, but the stem diameter was the highest in high and medium fertilizer treatments, but the effect of salt on cotton stem diameter was not significant. Under the same nitrogen application level, the effect on stem diameter was WHW _ W _ MWL, cotton stem diameter reached the maximum when water and fertilizer coupled WHFM treatment, and the growth process of plant leaf area index under different water and nitrogen treatments on two salt soils was increased first and then decreased. The effect of FHFMFL on leaf area index under the same irrigation level is FHFMFL, and the influence degree on cotton leaf area under the same nitrogen application level is WHWW _ W _ W _ W _ W _ L _ 2.The change of dry matter accumulation of cotton is "S" type, and the two salinized soils are at the same fertilization level. The accumulation of dry matter increased with the increase of irrigation amount, and the increase of fertilizer amount promoted the accumulation of dry matter quality of cotton under the same irrigation level. When the amount of fertilizer applied reached a certain degree, the effect of high fertilizer amount on the dry matter quality of cotton was not significant. When the irrigation amount was 4700 m ~ 3 路hm ~ (-2) and the nitrogen application rate was 260 kg.hm-2, the best water-nitrogen coupling of dry matter accumulation was WHFM.3.The salt had a great effect on the yield and inhibited the cotton growth and development. The yield of cotton seed cotton was the highest when the amount of nitrogen applied was 260Kg.hm-2 and the amount of irrigation was 4700m3.hm-2 (WHFM). The water and nitrogen use efficiency of cotton decreased when the irrigation amount was more than 4100m3.hm-2 and the amount of nitrogen applied was more than 260m3.hm-2, that is, WMFM treatment. Therefore, the best water-nitrogen coupling was WMFM treatment. The nitrogen uptake of cotton plants was between 80 Kg.hm-2-350 Kg.hm-2 and 65.4 Kg.hm-2-334.8 Kg.hm-2 on two salinized soils. The results showed that under the treatment of WMFH, the water moved down obviously, and the soil moisture was mainly distributed at 60-80 cm, and the distribution of soil water was closer to the distribution of cotton main root system. Thus, it is more favorable for cotton to absorb water, The predicted results showed that the soil moisture content of 0.17 cm3.cm-3 could not only meet the minimum water content requirement of cotton seed germination 0.168 cm ~ (-3) cm ~ (-3), but also save water resources. The nitrogen accumulation peak appeared in 60-80 cm under WHFM treatment. The nitrate content of soil is close to the distribution of cotton main root system, and it is helpful to cotton growth in this range.
【学位授予单位】：塔里木大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S156.4;S562

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