吉林省西部盐碱化区热力景观特征分析

吉林省西部地区的生态问题以湿地退化的盐碱化闻名,已严重影响到区域的生态环境与社会经济可持续发展.该区域的盐碱化是否会与国内外其他生态退化区一样,成为热力洼地型的盐尘暴源地,危及吉林省乃至黑龙江省的农业区的生态安全与社会经济的可持续发展,这个问题需进行必要的科学评估.利用2000～2013年的MODIS归一化植被指数、地表温度、雪盖等数据产品,采用长时间序列分析和地理空间相关性原理方法,计算了MODIS表征地表储热性能的昼夜地温指数.结果显示,盐碱化区域没有形成热力洼地,冬半年的雪盖和云的分布也显示盐碱退化区并未“干涸”.该区域需要注意控制好地下水水位,防止真正的热力洼地的出现.     

基于GIS黄淮海平原典型区域土壤盐渍化等级判别分析

研究目的在于对以河南封丘为例的黄淮海平原典型区域土壤盐渍化等级进行判别分析;运用判别分析方法获取不同盐渍化等级的判别表达式,利用GIS技术对判别表达式中相关变量指标进行空间分析,最后综合二者结果进行判别分析;通过对部分样品指标测定,参照前人标准评定等级,进而得出其障碍等级的判别式,可以有效减少盐碱障碍等级判别的指标测定数目,然后利用GIS技术对判别指标进行空间分析。研究表明,封丘境内约有12%区域存在轻度盐渍化;结合GIS技术可以有效提高判别效率,提供及时的土壤信息,对于指导农业生产具有重要意义。     

地面覆盖方式对新垦盐碱地的抑盐和增产效果研究

采用塑料地膜、细沙、秸秆3种覆盖材料,研究了不同地面覆盖方式对新垦盐碱荒地的抑盐、脱盐和玉米的增产效果。结果表明,不同覆盖材料和方式均有显著的增产作用,其中全膜覆盖效果最好,其次是覆细沙5cm,覆秸秆3000kg/hm2。的增产率最小。覆盖处理对O～20cm土层的盐分均有很好的脱盐效果,可减弱休闲季土壤0-40cm土层的返盐。秸秆覆盖和细沙覆盖各层的含水量与覆盖量正相关。     

大棚蔬菜土壤盐渍化治理技术研究

针对大棚蔬菜土壤次生盐渍化问题,通过进行水旱轮作、灌水洗盐、不同改良荆改良等一系列试验,比较得出水旱轮作降盐增产效果明显,灌水洗盐也有一定效果,可推广应用.     

农业生态环境敏感性地域分布及整治对策

农业生态环境日益恶化,越来越引起社会各界的关注。有效的综合整治农业生态环境,已经成为科学界面临的一个挑战。中国农业主要面临的生态环境问题是水土流失、盐渍化和酸雨,三种农业生态环境在空间上存在着相关性。对于三种生态环境问题,提出的控制对策如下:盐渍化的治理对策为合理用水、施肥,种植合适的耐盐作物;酸沉降治理对策为种植抗酸作物和采用化学调控方法降低降对作物的损害;水土流失使用生态恢复工程和生态重建工程进行治理。     

土壤盐渍化特性和施肥方法对氮肥氨挥发影响初步研究

采用“静态吸收法”研究了土壤盐渍化类型、程度和施肥方法对氮肥氨挥发损失特征的影响。结果表明:①盐渍化类型不同氨挥发损失特征不同,碱化土壤上氨挥发速率较高但持续时间较短;盐化土壤上氨挥发速率相对较低但氨挥发持续时间较长;②盐渍化土壤上氮肥氨挥发损失高于非盐渍化土壤,氨挥发量、挥发持续时间随着盐渍化程度的增加而增加;③施肥方法对盐渍化土壤上氮肥氨挥发损失有不同影响,在5个典型土壤上,氨挥发损失量均为表施>混施>深施;④在中度盐化土壤上,混施、深施的氨挥发量远高于其他土壤。说明在盐化程度较高的土壤上,仅仅通过改进施肥方法不能完全抑制氨挥发损失,需要通过其他措施,如降低土壤盐渍化程度来减少氨挥发损失。     

Organic manure stimulates biological activity and barley growth in soil subject to secondary salinization

A pot experiment was performed to compare the impact of organic manure on soil enzymatic activity, respiration rate and the growth of two barley cultivars (Hordeum vulgare L.) differing in their salt tolerance under a simulated salinized environment. A plastic pot with a hole (2 cm in diameter) in the center of bottom was filled with an anthropogenic (paddy) soil and placed in a porcelain container containing NaCl solution (3.0 g L⁻¹) such that a secondary salinization process was simulated via upward capillary water movement along the soil profile. A treatment with neither organic manure nor simulated soil salinization was taken as a control (CK1). The organic manure was applied either inside or outside rhizobag made of nylon cloth (40 μm of pore size). The soil was treated with: 20 g kg⁻¹ rice straw (RS), 20 g kg⁻¹ pig manure (PM), or 10 g kg⁻¹ rice straw plus 10 g kg⁻¹ pig manure (RS+PM). No organic manure was added in an additional control treatment (CK2). The results indicated that the placement of organic manure both inside and outside rihzobags significantly increased the activity of urease, alkaline phosphatase and dehydrogenase, as well as respiration rate in both rhizosphere and bulk soils. Also, nutrient uptake by barley plants was enhanced in the treatments with organic manure amended either inside or outside rhizobags. The activity of these enzymes along with the respiration rate was higher in rhizosphere than in non-rhizosphere when organic manure was supplied inside rhizobags, while the opposite was found in the case of manure incorporated outside rhizobags. Among all the treatments, RS+PM treatment had most significant stimulating effects on enzymatic and microbial activity and shoot dry weight of barley, followed by PM and RS. Moreover, more significant stimulating effects on both enzyme activity and plant growth were achieved in the treatments with manure amended inside rhizobags than outside rhizobags. The results of the present study confirmed the view that incorporation of organic manure especially into soil-root zones is an effective low-input agro-technological approach to enhancing soil fertility and minimizing phytotoxicity induced by secondary salinization.     

土壤中水、热、盐耦合运移机理与模型的研究进展

土壤水、热、盐运移规律的研究是目前土壤学、农田灌溉、水土保持、环境科学等学科研究的一个热点问题,也是防治土壤次生盐碱化,提高土壤肥力和土壤生产效率的重点.为此,简要介绍了土壤水、热、盐运移基本理论的发展过程和国内外学者数十年来关于土壤水、热、盐的研究成果,并对土壤水、热、盐运移模型研究进行了一定的评价,讨论了目前该研究领域急需解决的问题,为进一步的研究提供帮助.     

Deficit irrigation under water stress and salinity conditions: The MOPECO-Salt Model

In both arid and semi-arid areas the use of saline water for irrigation is a common practice, even though it may cause a drop in crop yield and progressive soil salinization. In order to determine the most suitable irrigation strategy for higher yield, profitability, and soil salinity management of certain crops, the MOPECO-Salt Model has been developed. This model was first validated in the Eastern Mancha Agricultural System in Albacete (Spain) through a test carried out on onion crop in April-September 2009, where the simulated yield was 2% lower than the observed one. The model was then tested at Tal Amara Research Station in the Central Bekaa Valley Agricultural System (Lebanon) using data from a 5-year experiment on the effects of deficit irrigation on two cultivars of potato (Spunta: July-October 2001, and June-September 2002; and Agria: March-August 2004, 2005, and 2007). Furthermore, these results were compared with those obtained through AquaCrop, which does not currently assess crop response to salinity. Differences between observed and simulated yields were lower than 3% for MOPECO-Salt and up to 12% for AquaCrop. According to findings from simulations, the irrigation strategies without leaching fraction employed in both areas are remediable since the off-season rainfall is sufficient to wash out soluble salts supplied with irrigation water. Results showed that as much as 14.4% water could be saved when this strategy was adopted for onion crops.     

新疆盐渍化灌区水盐平衡现状及对

以新疆农七师127团灌区为研究对象，通过区域水盐监测、水盐平衡计算与分析，对现有水盐状况是否满足盐分控制要求作出评价，并提出对策措施。研究结果表明，现状的水盐平衡条件不能满足控制盐分要求，其中引进的盐分只有大约40%从平衡区内排出，有60%左右的盐分滞留在平衡区内，其结果势必加重区域内土壤盐渍化的程度。如果按现状灌排条件和灌溉用水水质状况预测，每年1.5m深土壤剖面的平均积盐量约为0.037%。 为保持研究区水盐的持续平衡状态，水量排引比需达到0.3左右。为此，在进一步加强明沟排水系统建设的同时，需增设田间暗管排水。