不同土层加入生物质炭对盐分淋洗的影响

生物质炭作为土壤调理剂,能够显著地改良和培肥土壤,但对盐渍化土壤盐分淋洗的影响缺乏研究和了解。本研究采用土柱模拟试验,将蘑菇棒生物质炭以质量比10%,添加到内蒙古河套地区硫酸盐盐渍化土壤0~20 cm,0~35 cm和0~70 cm的土层中,并进行淋洗,测定淋出液和土壤盐分及主要盐分离子含量,以期了解生物质炭对土壤盐分和主要盐分离子洗脱的影响。结果表明:加入生物质炭的土柱,淋洗液出流的时间提前了34~37 d,电导率降低至5 m S·cm-1,需要的时间缩短了94~101 d;比起0~20 cm和0~70 cm土层加入生物质炭处理,0~35 cm土层加入生物质炭淋出液出流时间最早,盐分洗脱的效果最好。生物质炭对盐分离子淋洗也产生不同的影响,促进Na+、K+和Mg2+的洗脱,但抑制Ca2+洗脱;在淋洗初期生物质炭促进Cl-和SO42-洗脱,后期促进了HCO3-和CO32-的洗脱。可见,生物质炭可用作盐渍化土壤调理剂,不仅缩短盐分洗脱时间,而且还可以提高洗盐效率。     

硅对盐胁迫下葡萄幼苗生理效应的影响

以酿酒葡萄"赤霞殊"(Cabernet Sauvignon,CS)1年生扦插苗为试材,采用营养液水培系统,研究了根施外源硅(K2SiO3·9H2O,Si)对盐(50 mmol/L NaCl)胁迫下赤霞珠葡萄幼苗叶片生理生化特性的影响.结果表明:盐胁迫处理下,葡萄幼苗叶片超氧阴离子(O2-')产生速率加快,过氧化氢(H2O2)、丙二醛(MDA)含量和相对膜透性增加;超氧化物歧化酶(SOD),过氧化物酶(POD)和过氧化氢酶(CAT)活性增强;组织含水量降低;施用2.0mmol/L Si明显抑制了O2-、H2O2和MDA的积累,增加了组织含水量,并进一步提高了抗氧化酶SOD和POD的活性.说明外源Si可通过提高盐胁迫下葡萄幼苗体内的抗氧化酶活性,从而降低活性氧(ROS)水平,一定程度上减轻盐胁迫对植株所造成的细胞膜脂过氧化伤害,增强其耐盐性.     

Reclamation of Alkali Soils: Influence of Amendments and Leaching on Transformation and Availability of Phosphorus

Abstract

Phosphorus (P) availability to plants in reclaimed alkali soils was the main objective of this study, which was also focused on P transformations, decrease in Olsen‐P content, and magnitude of P lost in leachate in course of amendment application and leaching. Liquid sodium bicarbonate (NaHCO₃) was added to nonalkali soils to set up four ESP (exchangeable sodium percentage) levels (viz., 2.9, 25.0, 50.0, and 75.0), but actual ESP levels obtained were 2.9, 24.6, 51.2, and 75.3. Amendments (viz., gypsum and pyrites) and P treatments (viz., 0 and 50 mg P Kg^?1) were mixed with dry, sieved soil before filling into PVC (polyvinyl chloride) drainage columns, which were then compacted to uniform bulk density and leached with deionized water for 30 days. Results indicated that the pH and electrical conductivity (EC) of the soils increased with increase in ESP level of the soil but decreased with amendment application. Phosphorus addition to alkali soils decreased the pH on day 30, but it could not affect the EC of the soils. Successive increase in the ESP level of the soil increased the pH and EC off the leachate. Gypsum‐amended soils exhibited lower pH and EC values than pyrite‐amended soils. The EC of the leachate decreased sharply with time in amended soils, but the pH decreased slowly. Phosphorus addition affected the leachate pH earlier than the soil pH. Cumulative volume of leachate decreased with increasing ESP levels, but it increased with amendment and phosphorus application. Leaching of P increased with increase in ESP levels, and the maximum cumulative loss of P was 11.2 mg Kg^?1 in the 75.3 ESP soil. Cumulative P lost in the pyrite‐amended soils was higher than the gypsum‐amended soils. Phosphorus leaching in the gypsum‐amended soils stopped at day 10 and beyond, but it continued until day 30 in the pyrite‐amended soils. Part of the applied P in alkali soils was also lost along with the native P, whereas it was protected in the nonalkali soils. OlsenP increased with increasing ESP levels, and alkali soils invariably contained higher Olsen P than nonalkali soils. At day 30, alkali soils contained much higher Olsen P (12.6 mg Kg^?1) than nonalkali soils (5.9 mg Kg^?1). In general, there was a decrease in the Olsen P with both of the amendments, but it decreased more with pyrites than with gypsum. Phosphorus added through monopotassium phosphate (KH₂PO₄) remained extractable by Olsen's extractant up to day 30. Results also indicated that percent distribution of ammonium chloride (NH₄Cl)‐P, calcium (Ca)‐P, and unknown P increased with rising ESP levels but iron (Fe)‐aluminum (Al)‐bound P and residual P decreased. Percent distribution of Ca‐P and unknown P exhibited an increase with time also. Unamended alkali soils contained more NH₄Cl‐P than amended ones. Iron and Al‐ bound P and residual P increased more with pyrites, whereas formation of Ca‐P and unknown P was enhanced with gypsum. Applied P tended to convert more into NH₄Cl‐P, Ca‐P, and residual P than to Fe‐Al‐bound P or unknown P fractions. Models developed to estimate Olsen P and P concentration in leachate, through pH or EC, have application value for P management in alkali soils that are leached after application of amendments.     

不同烤烟品种在吉安烟区的生态适应性研究

以K326为对照,在吉安烟区研究了6个引进烤烟品种的生育期、植物学性状、烤后烟叶评吸质量、外观质量、内在质量、产量及烟叶等级结构等。结果表明:粤烟97和云烟97较其它品种更适应当地的生态条件,其烤后烟叶的总糖、还原糖含量及钾氯比明显高于K326,单位面积产值及烟叶等级也有所提高。     

季节性冻融土壤盐分离子组成与冻结层盐分运移规律研究

该文对冻融过程中土壤盐分离子组成及冻结层盐分运移规律进行研究,在内蒙古河套灌区永联试验站开展了冻融期土壤水盐及其离子成分监测试验,分析了冻融期地温、冻结层深度、地下水埋深与水质、土壤含水率、土壤盐分及离子组成的变化规律,通过离子相关性分析确定了土壤盐分运移的主控离子成分和盐分类型,进一步利用二元水盐体系相图探讨了冻融期主控盐分的运移规律。结果表明:冻融期地温梯度变化主要发生在0～1.0 m范围土层中,地下水埋深在冻融期变化趋势为快速增大-缓慢增大-减少,地下水矿化度均值在融化期显著降低;研究区地下水中变异性最大的离子为Na~+、Cl~–和SO_4~(2–),土壤盐分运移和扩散是地下水矿化度变化的主要原因;土壤中Na~+、Cl~–与SO_4~(2–)与含盐量相关系数高于0.9,冻融期土壤盐分浓度变化的主控盐分类型为氯化钠和硫酸钠;冻结层积盐或者脱盐取决于土壤盐分梯度和不同盐分的共饱和点,研究区最大氯化钠浓度(质量分数1.55%)和最大硫酸钠浓度(2.01%)均低于各自的共饱和点,当冻结前土壤溶液浓度梯度为正(从上到下浓度增大)时,冻结层易积盐,反之冻结层主要表现为脱盐。研究对阐明冻融期冻结层盐分累积规律的成因具有重要意义。     

基于支持向量机的土壤主要盐分离子高光谱反演模型

快速、无损、定量地获取土壤盐分离子组成及含量是盐渍化土壤治理、改良和利用的重要依据。以新疆盐渍化土壤为研究对象,应用高光谱分析技术获取不同区域土壤盐分离子的特征光谱,在对光谱数据去噪、数据变换基础上分析了鲜样(T1)、风干(T2)和干燥(T3)3类土壤,过2、1、0.15 mm筛处理对离子含量光谱拟合模型精度的影响,建立了基于支持向量机的土壤主要盐分离子光谱反演模型,并对模型的精度和普适性进行了检验。结果表明:土壤原始特征光谱与盐分离子含量均不存在显著相关性,最大相关系数为Na+的0.41;通过光谱数据变换能够明显增强特征波段与离子含量的相关性,K+、Na+、Mg2+、Ca2+、SO_4~(2-)、Cl-和HCO-3的最优变换形式分别为(lgR)'、(lgR)'、R'、(lgR)'、CR、R'和CR,T1处理构建的拟合模型均不能很好地反演离子含量,T3处理的模型估测精度优于T2,土壤粒径越细对土壤离子含量的光谱反演效果越好。分析各处理模型的决定系数和标准误差表明,经T3处理、过0.15 mm筛所构建的离子拟合模型预测精度最高,其中K~+、Na~+、Ca2+和SO_4~(2-)的RPD分别为2.153、2.674 5、2.051和2.786 4,以未参与建模和检验的石河子垦区土样对4种离子模型的普适性检验,其R2分别为0.621 4、0.689 7、0.614 4和0.650 7,说明构建的模型适于估算该区域土壤K+、Na+、Ca2+和SO_4~(2-)的含量。     

Salt Separation Processes in the Saltcedar Tamarix ramosissima (Ledeb.)

Salt cedars (Tamarix) are invasive halophytic species and heavy water consumers. However, Tamarix possesses interesting characteristics accounting for its opportunistic and resilient abilities: analogous to a miniature photodesalinization machine, it thrives on saline soils toxic to most plants. Here we observe, document, and reveal the salt separation process of T. ramosissima. Specimens were cultivated under controlled artificial conditions, then analyzed by microscopic and spectroscopic techniques. Tamarix ramosissima is shown to produce varied morphologies of salt crystal aggregates from vesiculated trichomes and possess the ability to separate anions and cations. Sodium chloride, potassium chloride (KCl), and potassium sodium sulfate [K_2.25Na_1.75(SO₄)₂] were major exuded salt crystal phases, with smaller quantities of other phases present. Compositions of crystals exuded by individual plants were consistent with compositions of the soils they grew on. Although T. ramosissima may be an invasive nuisance, it may possess other worthwhile attributes such as the potential to be a viable phytoremediator and environmental indicator.     

Significance of salt transport patterns in rice varieties differing in salt tolerance

Abstract

The absorption mechanisms for Na, K, SO₄ and Cl were tested in a salt tolerant (PVR 1) and a salt sensitive (GEB 24) rice varieties. The salt tolerant variety accumulated significantly larger amounts of Na than the salt sensitive variety. Further, PVR 1 absorbed SO₄ from Na₂SO₄ in preference to that from K₂SO₄. The absorption patterns for K and Cl were similar in both the varieties. It is concluded that the capacity of plant species to accumulate greater amounts of Na is a reflection of their halophytic feature.     

国防教育对高校新生的心理适应性的作用

为探究高校国防教育对大学新生心理适应性的作用,笔者用自编的经过信效度检验的测量问卷,对某高校部分新生进行测试,并用SPSS软件进行结果分析。分析结果表明,国防教育对提升新生入学后的心理适应性有显著作用。     

甘蓝型油菜对华北坝上冷凉环境的适应性

针对华北坝上冷凉区短季类经济作物缺乏,芥菜型油菜品质差、产量低等问题,于2017-2018年在农业农村部张北农业资源与生态环境重点野外观测试验站,引种了甘蓝型双低油菜品种华油杂62,以当地传统芥菜型油菜品种大黄为对照,监测了两品种的叶面积指数、角果净光合速率日变化、地上部干物质积累量、养分积累量和油菜农艺性状、产量等。结果表明,华油杂62较大黄生育期长约10d,平均叶面积指数高23.36%~36.73%;角果净光合速率不及大黄,N、P、K积累量高于大黄;干物质快速增长期延长21d,干物质积累潜值高46.86%;菜子产量较大黄高22.8%~54.0%。甘蓝型油菜华油杂62对华北坝上冷凉区的地理气候环境有较好的生态适应性,具有替代区域传统芥菜型油菜的优势。