【作者】 刘方春；

【导师】 刘春生；

【作者基本信息】 山东农业大学 ， 土壤学， 2008， 博士

【摘要】 随着现代化农业的不断发展,化肥在农业生产中的地位越来越重要,但由化肥的施用带来的问题也越来越多,尤其是较低的利用效率及其给环境、农产品等带来的系列危害越来越受到人们的重视,因此,各种缓效肥料的研究成为现阶段土壤学研究的热点问题之一。褐煤是一种重要的肥料基质,在我国已探明的保有储量就达1300多亿t。本试验采用室内试验同盆栽、大田试验相结合的方法,研究了不同处理方法对褐煤中腐殖酸含量及其特性的影响,并以活化前后的腐殖酸样品为吸附基质,探讨了其对N、P、K等养分离子的吸附特性。利用活化后腐殖酸的吸附特性制成腐殖酸缓效肥,以土肥混合法及大田淋溶的试验方法研究了该肥料中各养分离子的释放规律及硝酸盐的淋溶特性,并通过菠菜及杨树的盆栽试验探讨了腐殖酸缓效肥对作物产量、品质和土壤酶活性、养分及理化特性的影响,主要研究结果如下:1. H3PO4和HCl处理能在一定程度上提高阳离子交换能力,但对腐殖酸含量及光学性质基本无影响。一定强度的HNO3能使腐殖酸含量增加25%以上,阳离子交换能力有了很大程度的提高,且其随硝酸强度的变化过程要明显滞后于腐殖酸含量的变化过程,光学性质发生了很大的变化。不同褐煤达到最佳处理效果的条件也不尽相同。2.适宜的固液比例可提高铵单位吸附量;在试验pH(1.51<pH<7.04)范围内,介质pH升高有利于铵氮的吸附。随pH的升高,分配系数逐渐增大,在较低pH(<4.03)时,主要以物理吸附为主,而在较高pH (>4.03)时,化学交换占主导地位,经硝酸处理后褐煤样品的分配系数Kd和吸附量Q明显大于未处理样品的Kd和Q。腐殖酸对铵氮的吸附等温式可用Freundlich等温曲线描述,其动力学吸附方程用Elovich方程拟合最佳。3.未经硝酸处理的样品(S1)在pH为4.7时,对磷吸附量和分配系数有一最大值,而经硝酸处理后的样品(S2)随着pH的升高,吸附量和分配系数一直减小。且经硝酸处理后,样品对磷的单位吸附量和分配系数有了较大程度的降低。随平衡溶液浓度的升高,两样品对磷的单位吸附量也不断升高,其吸附规律可用Langmuir方程来加以描述,在第60min和90min时,两样品对磷的吸附基本达到吸附平衡,其吸附动力学可用Elovich和双常数方程进行拟合。4.随着平衡溶液浓度的不断升高,褐煤腐殖酸对钾离子的单位吸附量不断增加。其吸附等温式可用Langmuir方程和Temkin方程来加以描述。S2对钾离子的吸附能力有了明显的提高,在适宜浓度条件下,其吸附量可提高41.1%。随pH的不断升高,S1和S2对钾离子吸附的分配系数逐渐增大,且pH的升高在一定程度上加快了吸附反应的速度。低pH时,两样品吸附能力差别不大,而高pH时,S2对钾离子的吸附能力远大于S1。其动力学吸附规律用Elovich方程描述最佳。在固液比例分别为0.04和0.06时,两样品对钾离子的吸附量达最大。5.在投入养分量相等的条件下,化学肥料各养分离子的释放主要集中在前12 h,其释放量显著高于腐殖酸肥料,而在96h以后,腐殖酸肥料的释放量均要高于化学肥料。其中在氮肥释放过程中,NH4+是前期主要的释放形式,而随着时间不断延长,NO3--N成为主要的释放形式。腐殖酸肥料的施用能在一定程度上抑制NO3--N向地下迁移。6.纯氮素处理的菠菜产量最高;腐殖酸肥料的施用显著改善了菠菜营养品质,降低菠菜体内硝酸盐含量,提高硝酸还原酶活性,增加Vc含量等。施用腐殖酸肥料N素利用率提高,增加了土壤速效磷的含量,促进了钾的消耗。自制的腐殖酸缓效肥料处理降低了土壤的pH,提高了土壤中蔗糖酶、碱性磷酸酶、多酚氧化酶的活性,同时降低土壤脲酶活性,但对过氧化氢酶活性影响不大。更多还原

【Abstract】 Now, low N use efficiency and high environmental risk of chemical N fertilizer are worldwide concerned, which may be overcomed by using new slow-release fertilizers. So, the study on slow release fertilizer has very important practice meanings to the production in agriculture and forestry, etc. The brown coal is a kind of important raw material of the fertilizer and its reserve in our country is up to more than 130 billion tons. Simulative experiments, potted experiments and field experiments are used to study the effects of N、P、K concentration, equilibrium time and pH value on the adsorption of humic acid extracted from Shanxi brown coal. Humic acid fertilizer was manufactured through the adsorption characteristic. At the same time, release characteristic of N、P、K and the effect of this humic acid fertilizer on spinach and poplar were studied. The purpose of this research was to offer basic data for the production of humic acid slow-release fertilizers, the main results are as follows:1. The effects of various kinds of inorganic acid on the content, cation exchange capacity and optics nature of humic acid in brown coal were studied .The results showed that the content and the optics nature were not affected by Phosphoric acid and Hydrochloric acid treatment ,but the cation exchange capacity can be increased to some extent .The content of humic acid can be increased by 25 per by suitable for intensity Nitric acid, The cation exchange capacity can be greatly increased and the optics characteristic was greatly changed too. The best conditions would be different to different brown coal.2. With the increase of NH4+ concentration, adsorption capacity of NH4+ increased. The adsorption of NH4+ on humic acid could be well described by Freundlich equation and its kinetics adsorption fit Elovich equations best. Under the condition of pH lower than 7.04, pH increase of medium was great of advantage of NH4+ adsorption and could improve the velocity of adsorption reaction. Under the condition of pH lower than 4.03, physical adsorption was the dominant. However, under the condition of 4.03<pH<7.04, chemical exchange was dominant. The distribution coefficient and adsorption capacity of the experimental humic acid treated by nitric were significant higher than that of the brown coal without treated by nitric acid. The adsorption capacity could be increased by 58.73% at the optimal condition. On the whole, chemical exchang played a more important role on NH4+ adsorption. Adsorption capacity rose markedly in the beginning of the adsorption process, however, it slowed down later. While suitable ratio of solid to liquid could increase unit adsorption until the ratio increase to some extent, then the unit adsorption would decrease.As to sample one and sample two, when the ratio was0.04 and 0.03, the unit adsorption reach maximum being 34.9、72.2 mg g -1 respectively.3. pH increase of medium was of great disadvantage of P adsorption and could decrease the velocity of adsorption reaction. As to the sample one, the distribution coefficient and adsorption capacity were the maximum at pH being 4.7. Even the pH was higher, as to the second sample, the distribution coefficient and adsorption capacity weres decreased. Besides, the distribution coefficient and adsorption capacity of the experimental humic acid treated by nitric were significant lower than that of the brown coal without treated. With the increase of P concentration in the medium, adsorption capacity of P+ increased too. Adsorption capacity rose markedly in the beginning of the adsorption process, however, it slowed down later. Suitable ratio of solid to liquid could increase the unit adsorption. The adsorption of P on humic acid could be well described by Langmuir equation and its kinetics adsorption fit Elovich equations best.4. pH increase of medium was of great advantage of K+ adsorption and could improve the velocity of adsorption reaction. Under the condition of pH<4.4, physical adsorption was the dominant. However, under the condition of 7.12<pH<12.95, chemical exchange was dominant. The distribution coefficient and adsorption capacity of the experimental humic acid treated by nitric were significant higher than that of the brown coal without treated. The adsorption of K+ on humic acid could be well described by Langmuir equation and its kinetics adsorption fit Elovich equations best. The adsorption capacity of the experimental humic acid treated by nitric was higher than that of the brown coal without treated. Suitable ratio of solid to liquid could increase the unit adsorption, when the ratio was 0.06 and 0.04, the unit adsorption reach maximum being 0.079gg-1 and 0.094 g g-1 respectively.5. With equal-nutritional quantity, the release of chemistry fertilizer was main in the first and second time, which is significantly higher than humic acid fertilizer. However, the release of the humic acid fertilizer was higher than the chemical fertilize in the successive time. NH4+-N was the domination in ealier stage, while NO3--N was the main form latter. Applying humic acid fertilizers could refrain the leaching of NO3--N to some extent.6. All fertilizer treatments were significantly out-weighted the CK and the treatment of N pure was the highest but was not significant all. With equal-nutritional quantity, humic acid fertilizer apparently decreased the NO3--N content and increased the content of Vc, soluble sugar and chlorophyll content. Compared with inorganic fertilizer, humic acid fertilizer increased N utilization and available P and comsumption K in soil. Humic acid fertilize reduced the pH, improved the activities of alkalinr phosphatase, invertase and polyphenol oxidase. At the same time it decreased the activities of urease, but there was no effect on the activities of catalase.更多还原