【作者】 梁涛；

【导师】 黄建国；

【作者基本信息】 西南大学 ， 植物营养学， 2010， 硕士

【摘要】 磷是植物生长发育必需的大量营养元素之一,是植物完成其生活周期必不可少的营养元素,对作物高产及保持品种的优良特性据有明显作用。植物体需要的磷主要从土壤磷库中获得。作为土壤磷库的重要组成部分,土壤有机磷对土壤肥力和植物营养有着重要的影响,其对植物的作用愈来愈受到关注。本文以潮土为例探讨磷素存在形态问题,结合土壤的物理形态.团聚体,旨在为磷素在土壤中的存在形态及定位提供理论上的依据和实践方法,为磷肥的合理利用提供科学的理论依据。结果表明：1.潮土团聚体的分配情况：潮土中团聚体的组成以0.25 mm～5 mm含量最高,含量在60.72%～77.98%之间；其次是>5 mm,含量在11.90%～25.82%之间；<0.25 mm最少,含量在7.09%～13.68%之间。潮土团聚体的主体为0.25 mm～5 mm团聚体,长期施用有机肥处理的小团聚体有减少的趋势。2.潮土有机磷总量变化：增施磷肥能增加有机磷及无机磷的含量,其中有机肥对增加潮土有机磷及无机磷含量的作用最为明显。但1.5MNPK处理的有机肥量比MNPK有机肥量施用量增加50%,而有机磷的含量只比MNPK增加12.9%,这说明当有机肥施用量达到一定程度再去增施对增加潮土有机磷含量效果有限；施肥处理中秸秆与有机肥配合使用能明显增加无机磷的含量,效果要好于单独施用有机肥,施肥处理对无机磷的影响与有机磷大致相同。3.潮土不同磷组分的变化：潮土中的有机磷组分里,ML-OP含量最高,所占比重也最大,MR-OP居中,L-OP和HR-OP含量和比重最小。而作为主要形态的ML-OP在各个处理中的含量由低到高分别是CK< NPK< sNPK< MNPK2< MNPK<1.5MNPK；潮土中的无机磷组分里,Ca10-P含量最高,所占比重也最大,然后依次是O-P> Ca8-P、Al-P、Fe-P和Ca2-P,而作为主要形态的Ca10-P,含量稳定,几种处理相差不大,在潮土中稳定存在。4.潮土团聚体中有机磷变化：三种不同的团聚体,从大到小,相比对照,各个施肥处理的有机磷含量都呈现增加的趋势,不同处理团聚体中的有机磷增加幅度大致相同,尤其是0.25 mm～5 mm和<0.25mm增幅几乎相同,这可能是由于这两种团聚体联系较为紧密有关。在不同粒径下,增加幅度最大的都是>5 mm级的1.5MNPK,增幅为88.36%,这说明有机肥增施对增加潮土大颗粒团聚体中有机磷的效果最为显著。相同处理,不同粒级的有机磷组分都表现出和总有机磷大致相同的趋势。从大到小,不同组分的有机磷都有不同程度的增加。全磷则不同于有机磷,三个级别的团聚体全磷含量几乎一致,这说明全磷的含量在团聚体中的分配较为稳定,不受团聚体颗粒大小的影响,有效磷在不同团聚体中的变化趋势与有机磷也大致相同,这可能是因为有机磷特别是L-OP和ML-OP是有效磷的一种主要成分,有效磷受有机磷影响较为明显。5.潮土团聚体中无机磷及有效磷变化：各处理中,有效磷含量从高到底的次序是1.5MNPK, MNPK, MNPK2, sNPK, NPK、CK,施肥处理的有效磷含量都明显高于对照处理,无机有机肥配合施用可显著提高土壤有效磷的含量。通过相关性和通径分析可以得出：有效磷的磷源主要是中等活性有机磷,中等稳定性有机磷和活性有机磷。作物对几种无机磷的利用能力的顺序为Ca2-P>Ca8-P>Al-P>Fe-P>O-P≈2a10P,植物对潮土无机磷的利用主要是Ca2-P、Ca8-P、Al-P、Fe-P四种,而这四种有效性较高的无机磷组分占总无机磷组分的比例22.3%～49.9%。因此潮土中的无机磷组分一半以上都是极难被植物利用的无效态。在长期施肥条件下,就无机磷而言,最重要的有效磷提供组分是Al-P,其次是Ca8-P。6.有机磷、无机磷及全磷在潮土不同团聚体中的分配：潮土团聚体的主体为0.25mm～5mm团聚体,在相同处理的情况下,与对照相比,所有不同粒径团聚体的有机磷、无机磷总量都有不同程度的增加,其中>5mm级的有机磷总量增幅最大,0.25mm～5mm级的无机磷总量增幅最大；不同粒级的有机磷组分及有效磷与总有机磷的趋势大致相同；而全磷的含量较稳定,不受团聚体大小的影响；潮土中无机磷在团聚体中的分配主要由团聚体本身在潮土中的含量决定,有机磷在同团聚体的分配也呈现出类似的现象。更多还原

【Abstract】 Phosphorus is one essential macroelement to plant growth and development, and is the absolutely necessarity nutritional element of plant in the life cycle,, o but also has significant effect on keeping high productivity of crop and the good characteristic of crop cultivars.The plant P requirement is mainly from the soil.As an important component of soil phosphorus pool,soil organic P has important effect on the soil fertility and plant nutrition,thus its role on plant has been paid more and more attention to.In this study, a Fluvo-aquic soil was taken to evaluate phosphorus forms in combination with soil aggregates in order to provide theoretical basis and practical method for the forms and location of phosphate, and to provide scientific basis for rational use of phosphate. The results showed that:1. Composition of soil aggregates:The highest content in soil aggregates composition is the aggregates of 0.25 mm-5 mm, ranging from 60.72%-77.98%of the gross weight, followed by the aggregates of>5 mm, ranging from 11.90%-25.82%, and the lowest content for<0.25 mm, ranging from 7.09%～13.68%.The principal part is 0.25 mm-5 mm,long term fertilizer would decrease the content of small size of aggregates in Fluvo-aquic soil.2. Changes of soil organic phosphorus(OP):The increased application of P can increase the organic phosphorus and inorganic phosphorus content of the soil, and the organic manure was the most effective way to increase organic phosphorus content fluvo-aquic in soil. Compared to MNPK,1.5MNPK contain 50%more phosphorus, while only 12.9%more organic phosphorus content, it indicates that the continuous application of organic manure up to a certain level have limited effect to increase Fluvo-aquic soil organic phosphorus. Organic manure used in conjunction with straw can significantly increased levels of inorganic phosphorus, and has better effects than the application of alone organic fertilizer.3. Changes of soil inorganic phosphorus(iP):In Fluvo-acquic soil, among the fractions of organic phosphorus the ML-OP content is the highest with largest proportion, followed by MR-OP. While L-OP and HR-OP have the smallest content and proportion. As ML-OP is the main fraction, its content in different treatments varied from low to high, so ranked as CK<NPK<sNPK<MNPK2<MNPK<1.5MNPK. Among the inorganic phosphorus fractions of Fluvo-aquic soil, Ca10-P content is the highest, and also accounted for the largest proportion, followed by OP, Ca8-P, Al-P, Fe-P and Ca2-P. As Ca10-P is the main fraction, it’s content have little or no variation among treatments, so remain constant in fluvo-aquic soil.4. Changes of organic phosphorus(OP)and its fractions in Fluvo-aquic soil aggregates with different sizes:Organic phosphorus content shown the tendency to increase with almost same degree in soil aggregates from big to small particles, in all the treatments compared to CK. Especially in 0.25-5 mm and<0.25 mm particles, this may be due there close linkage. In different sizes, the biggest increase occurred in the aggregate of >5mm of 1.5MNPK, that is 88.36%, indicating that organic manure increase in macro aggregate organic phosphorus is most significant.In the same treatment, different fractions of organic phosphorus and total organic phosphorus variation have shown similar trends. From big to small particles, different components have different degrees of organic phosphorus increase. The total phosphorus of three aggregates contents was found almost identical, indicating that the distribution of total phosphorus in the aggregates is more stable and free from the impact of aggregate particle size, making it different from organic phosphorus. The variation tendency of available P in different aggregates is similar, this can be because L-OP and ML-OP are two major component of available phosphorus, therefore L-OP and ML-OP influence the available phosphorus more noticeable.5. Changes of available phosphorus(AP),inorganic phosphorus(iP)and its fractions in Fluvo-aquic soil aggregates with different sizes:In each treatment, the available phosphorus content order from high to low in succession was 1.5MNPK, MNPK, MNPK2, sNPK, NPK, CK. The available phosphorus content of fertilization treatment was significantly higher than CK. Inorganic and organic manure combination can significantly increase soil available phosphorus content. And analyzing the relativity and path can indicate that the major source of available phosphorus mainly is L-OP、ML-OP and MR-OP, and the ability of plants to use inorganic phosphorus is in order of Ca2-P> Ca8-P> Al-P> Fe-P> OP≈Ca10P,Plants mainly use Ca2-P, Ca8-P, Al-P, Fe-P, that are four inorganic fractions in fluvo-aquic soil, these four higher effective fractions are only 22.3%-49.9%of the total phosphorus. Therefore more than half of the inorganic phosphorus is almost ineffective in fluvo-aquic soil. In the long-term fertilization of inorganic phosphorus, the most important component to provide available P is Al-P, followed by Ca8-P.6. Distribution of total phosphorus(TP), organic phosphorus(OP) and inorganic phosphorus(iP) in different Loess soil aggregates:The main part of fluvo-aquic soil aggregate is 0.25-5mm, in the case of the same treatment, compared to CK, the organic an inorganic phosphorus content of all the aggregate have different extents of increase, among which>5mm have the biggest organic phosphorus increase, and the biggest inorganic phosphorus increase is in 0.25-5mm aggregates. Different fractions of organic phosphorus and available phosphorus have broadly similar trend with total organic phosphorus, and total phosphorus was rather stable, and was not subject to the influence of aggregate size. The distribution of inorganic phosphors in fluvo-aquic soil aggregates mainly decided by the aggregates content, and distribution of organic phosphorus showed a similar phenomenon.更多还原