【作者】 王金鑫；

【导师】 危常州；

【作者基本信息】 石河子大学 ， 作物栽培学与耕作学， 2013， 博士

【摘要】 新疆地处亚欧大陆中心，属于干旱地区，土壤中的全锌含量大多超过我国和世界土壤平均含量，但有效态含量却较低。我国在上世纪80年代进行第二次土壤普查时确定以土壤有效锌含量0.5mg·kg^-1为新疆石灰性土壤作物施锌临界指标，这一指标已经延用30余年，而目前新疆的农业生产水平、土壤养分状况以及棉花栽培品种等均同30年前相比发生了重大变化，这一标准显然缺乏时效性依据。本研究以新疆石灰性土壤为主要研究对象，了解新疆土壤锌的丰缺状况，研究锌肥对棉花产量及品质的影响，并建立新疆土壤锌丰缺指标。在研究新疆不同土壤有效锌及锌组分含量的基础上，选择新疆、山东和江苏三种石灰性土壤进一步研究了土壤因素对土壤有效锌及锌组分含量的影响，通过吸附-解吸附模型阐明土壤环境因子对土壤锌有效性影响机理，以期为新疆石灰性农田土壤合理施用锌肥、提高棉花产量提供理论指导。本研究的主要结论如下：（1）新疆3种类型土壤有效锌平均含量为灰漠土(0.51mg·kg^-1)＜棕漠土(0.57mg·kg^-1)＜潮土(0.69mg·kg^-1)，变异系数为棕漠土＜潮土＜灰漠土。不同地区土壤有效锌含量较为接近，但全锌含量差异明显。南疆土壤全锌含量高于北疆土壤，而北疆土壤全锌变异较大。在土壤锌组分中，松结有机态锌（WBO）、碳酸盐结合态锌（CARB）、氧化锰结合态锌（OxMn）、紧结有机态锌（SBO）、无定形结合态锌（AOFe）平均含量均为灰漠土＜棕壤土＜潮土。WBO、CARB、SBO分配率与土壤CaCO₃含量和物理性粘粒含量高度相关。WBO、CARB及SBO分配率与土壤物理性粘粒含量呈（极）显著正相关。交换结合态锌（Exc）与WBO呈显著正相关。WBO与CARB呈显著正相关。石灰性土壤有效锌含量与WBO、CARB含量呈显著正相关。（2）施锌在多数土壤上对棉花具有增产作用，能够显著促进棉花地上部生物量、产量的积累，提高棉花锌吸收量，但对根生物量影响无明显规律。棉花相对产量与土壤有效锌含量呈极显著正相关，新疆土壤缺锌的临界指标为0.6mg·kg^-1，目前新疆石灰性耕地土壤锌有效性多处于中、低水平。（3）施锌促进了棉花干物质的积累，显著提高棉花产量，提高了单株结铃数、衣分和单铃重，单纯土施锌肥棉花增产率为1.14%⁴.80%，喷施锌肥后棉花增产率为1.10%⁶.11%；增加了棉花对氮、磷、钾肥料的吸收利用，P/N由0.26升高到为0.30，K/N由1.04升高到1.34；施锌方式处理间，喷施锌肥对棉花纤维长度、整齐度及伸长率无显著影响，土施10kg·hm^-2、20kg·hm^-2显著降低了马克隆值，土施0kg·hm^-2显著增加了棉花比强度；土施锌肥处理间，土施锌肥显著增加了棉花纤维长度和比强度，降低了棉花马克隆值及整齐度。土壤施锌是提高棉花单株结铃数的重要途径。在稳定提高单株结铃数的基础上，花期喷施锌肥不但促进单铃重增加，而且提高了棉花对氮磷钾的吸收，进而达到施锌棉花高产，肥料高效，品质优良的目的。（4）添加不同比例CaCO₃均显著降低了土壤有效锌含量，其作用顺序为CaCO₃添加比例20%＞10%＞5%＞0%，CaCO₃对土壤有效锌含量的影响为高砂土＞棕壤土＞灰漠土，有效锌含量和CaCO₃含量高度负相关，灰漠土中两者相关性最好（r=-0.8628**）。培养360天后高砂土、棕壤土、灰漠土有效锌含量降幅分别为52%～77%，52%～59%，36%～58%。不同培养时间下同一土壤有效锌含量为1d＞5d＞30d＞90d＞180d＞360d。不同类型土壤中的锌主要以Res和COFe组分存在，分别占到全锌含量的71.0%～73.2%和11.6%～19.9%，Exc所占比例最少。WBO组分含量在三种类型土壤中所占比例较为接近。添加CaCO₃后Exc、WBO大幅降低，而CARB大幅增加，其余锌组分变化幅度不大。3种土壤对Zn²⁺的吸附-解吸附性能差别较大，随平衡液Zn²⁺浓度的增加土壤对Zn²⁺吸附量增加，表现为高砂土＜棕壤土＜灰漠土，随吸附量的增加Zn²⁺解吸量也逐渐增加，但远小于土壤对Zn²⁺吸附量；3种土壤对Zn²⁺吸附均可用Freundlich方程描述，以高砂土Freundlich方程拟合最佳（P＜0.01）。Freundlich方程常数A、K值为高砂土＜棕壤土＜灰漠土。不同盐分处理下，盐分含量低的土壤有效锌含量高；在不同培养时间下，土壤有效锌含量缓慢降低，培养360天后降幅分别为4.3%，25.6%，23.5%，30.3%。土壤锌组分变化幅度较大的主要有WBO、CARB和SBO。土壤WBO组分含量均上升，CARB和SBO组分含量下降。盐分含量越低（0.28%），CARB和SBO含量也较低，而WBO组分含量越高。这几种组分含量的变化主要发生在最初的30天，在180天时趋于稳定。不同盐分含量的土壤Zn²⁺吸附动力学曲线相似，对Zn²⁺的吸附量随吸附时间的延长而增加，相同吸附时间盐分含量越高，吸附量越大；土壤对Zn²⁺的吸附均可用Langmuir、Freundlich和Temkin吸附方程进行描述，以Freundlich吸附方程拟合最佳。Zn²⁺解吸量随吸附量的增加而增加，盐土对Zn²⁺的解吸量远远小于土壤对Zn²⁺的吸附量，在吸附量相同时，土壤盐分含量降低Zn²⁺解吸量增加。淋洗盐分后，土壤对Zn²⁺的最大吸附量减少，吸附强度减弱。土壤CaCO₃含量、盐分含量对土壤Zn²⁺吸附和解吸附显著相关，高CaCO₃含量、高盐分的土壤锌有效性低。因此，不同类型的石灰性土壤、盐土要相应调整锌肥施用量和施用方法。更多还原

【Abstract】 Xinjiang, which is located in the center of the Eurasian Continent, is an arid area. Thetotal zinc content of the soil is significantly higher than the average contents of China and theworld, but the available zinc content is limited. The soil available zinc content,0.5mg·kg^-1,was set as the critical index of zinc to calcareous soil crops in Xinjiang when the secondnational general survey of soil was conducted. This index has been in use for over30years.However, with the fast development of agricultural productivity, especially in cottonproduction in Xinjiang, soil nutritional status, and cotton varieties of Xinjiang have changedconsiderably after the subsequent decades, this standard no longer accurately reflects soil Znsupply threshold. Then, to evaluate a Zn fertility index that accurately reflect soil real Znstatus is not only valuable for understanding soil Zn abundance in this area but also withimportant agricultural practical significance. Therefore, this study was conducted to evaluatethe state of soil Zinc in calcareous soils of Xinjiang, and to research the effects of Znapplication on yield and quality of cotton, finally to establish a soil available Zn critical indexfor cotton cultivation in Xinjiang area.On the base of studying the content of soil available Zn and Zinc fraction in differentsoils of Xinjiang region, three calcareous soils from Xinjiang, Shandong and Jiangsu wereselected to investigate the effects of soil factors such as CaCO₃, soil salinity on soil availableZn and Zn fraction, to clarify the mechanism of soil factors on soil available Zn content by theadsorption and sorption models. This research aims to provide theoretical guidance to applyZn fertilizer reasonably and improve the yield of cotton. The major conclusions of the studyare as follows.（1） The average available zinc content in three types of soils was aquic soil (0.69mg·kg^-1)>brown desert soil (0.57mg·kg^-1)>grey desert soil (0.51mg·kg^-1), the coefficient of variationwas gray desert soil>aquic soil>brown desert soil. Soil available Zn concentration was similarin different soil types in Xinjiang, however, the total Zn content varied greatly. Soil total zinccontent in southern Xinjiang was higher than that of northern Xinjiang, and with greatervariability.In the Zn fractal content, the component’s contents of SBO, CARB, OxMn, WBO andAOFe were aquic soil>brown desert soil>grey desert soil. The percentages of WBO, CARBand SBO were highly relevant to the contents of CaCO₃and physical clay. The relativepercentages were significantly or highly significantly positive correlatted in physical claycontent and WBO, CARB, SBO. The content of WBO remarkably influenced the content ofExc. There was a significant positive correlation between WBO and CARB. The content ofsoil available Zn was remarkably influenced by WBO and CARB.（2） Zinc application contributes to cotton yield in most of soil types, and improve thebiomass of the shoot of cotton, the accumulation of yield, and increases the zinc uptake ofcotton, but its effect on the biomass of roots is not noticeable. The relative yield of cotton andavailable zinc content of soil are positively related. The critical index of zinc deficiency is0.6mg·kg^-1. At present the available zinc contents of the calcareous soils in Xinjiang are mostly at medium or low levels.（3） Zn application significantly increased the yield of cotton, improve the biomass ofcotton, contributed to boll number per plant, boll weight and lint percentage. Soil applicationof Zn on cotton yield increasing rate was ranging from1.14%to4.80%, while foliarapplication of Zn was ranging from1.10%to6.11%; Application of Zn fertility increased N、P and K absorption of cotton. The P/N rate increased from0.26to0.30and K/N rate increasedfrom1.04to1.34; under the different Zn application practices, foliar application of Zn can notobviously improve the fiber length, uniformity and elongation of cotton, however, soilapplication of Zn20kg·hm^-2significantly reduce the micron value; soil application of Zn at10kg·hm^-2and20kg·hm^-2significantly improve the fiber length and strength, decrease theuniformity and micron value. Soil application Zn is an important way to improve the bollnumber. On the base of improving boll number stably, foliar application of Zn at floweringstage not only improve the boll weight, but also improve the adsorption of N, P, K.（4） Exteral calcium carbonate remarkably decreased the content of soil available Zncontent, the order of available Zn reduction was CaCO₃20%>10%>5%>0%. The order ofCaCO₃impacts on the content of soil available Zn was Paddy soil>Brown soil>Gray desertsoil. The content of soil available Zn was highly negative relevant to the contents of CaCO₃and the correlation was best in Gray desert soil（r=-0.8628**）. The falling range of soilavailable Zn of Paddy soil, Brown soil and Gray desert soil, cultured360days, were52%～77%,52%～59%,36%～58%. The available Zn of soils under different incubation timewas1d>5d>30d>90d>180d>360d. Res and COFe were the main fractions in differenttype soils, which were71.0%～73.2%and11.6%～19.9%, and the proportion of Exc wasthe least. The proportion of WBO was rather nearly in three types soils. Exc and WBOreduced and CARB increased significantly, other Zn fractions change little. The adsorption-desorption characteristics of3types was different. The capacity of Zn²⁺adsorbed by soilswas Paddy soil＜Brown soil＜Gray desert soil, the adsorption capacity increased with theinitial concentration of Zn²⁺addition. It was also observed that the amount of desorbed Znfrom Zn absorbed soil increased with the amount of soil adsorbed Zn, but much lower thanthat soil adsorbed Zn; Zn²⁺adsorption curves of3types soil could be well described byFreundlich equation with best fitness by Paddy soil （P＜0.01）. The adsorption reactionconstant A and K of Freundlich equation were Paddy soil＜Brown soil＜Gray desert soil.The content of soil available Zn was high when the soil salinity was low; the content ofsoil available Zn reduced with increasing of equilibrium time, and the falling range were4.3%,25.6%,23.5%,30.3%under cultured360days. WBO, CARB and SBO were the mainZn fraction changing largely. WBO fraction increased while CARB and SBO decreasedsignificantly. The content of WBO increased with increasing of soil sanility, while CARB andSBO decreased. These changes mainly happened in the first30days, and steady in180days.Kinetic curves of different soil salinity were similar, the adsorption of Zn increased withincreasing of equilibrium time. The higher soil salinity content, at the same equilibrium time,the more amount of adsorption; The Freundlich model was better than the Langmuir andTemkin models to decribe adsorption isotherms process. The sorption amount of Zn²⁺ increased with equilibrium time, higher salt content lead to less Zn desorption in salinity soil,the adsorption amount of Zn increased with decreasing soil salinity. The buffering capacityand adsorption intensity of soil Zn decreased by leaching.There is a close relationship between the content of soil CaCO₃, soil salinity and Zn²⁺amount in soils desorption-sorption process. The high CaCO₃content or high salinity content,lead to lower available Zn. Therefore, adjust in the application amount and methods of Znfertilizer are needed for different types of calcareous soils and saline-alkali soils.更多还原