蓄水保墒抗旱造林技术探析

干旱问题已逐渐成为世界性问题,我国受干旱灾害影响较为严重,干旱和半干旱地区的总面积已经超过了国土面积的50%。干旱灾害严重影响苗木的成活率,需要采取抗旱造林技术,通过蓄水保墒等措施,降低土壤环境的水分消耗速度,改善苗木生长环境。基于此,分析蓄水保墒抗旱造林技术的研究进展,探讨蓄水保墒技术和抗旱造林技术的应用。     

抗旱节水造林综合配套技术

我国北方地区干旱严重,水保造林工程损失很大。在造林实践中,用ABT生根粉溶液喷根、树周地膜覆盖和根部土壤施用保水剂的抗旱节水造林综合配套技术,可有效提高造林成活率。较详细地介绍了ABT生根粉、地膜和抗旱保水剂的作用、选用及苗木栽植技术。     

油松容器苗与裸根苗造林效果调研

按照立地条件的不同,采用随机抽样法,对齐家川水土保持工程重点示范区南小河沟流域油松容器苗与裸根苗的造林效果进行了调查与分析。结果表明:不同立地条件下,油松容器苗造林成活率、幼树高生长量均高于裸根苗,而且不同坡位间两种苗木造林成活率差异呈现自下坡而上坡递减的规律。     

黄土丘陵区造林技术研究

在半干旱黄土丘陵区,为进一步提高造林成活率、保存率,及增进造林早期苗木生长量,采用径流集存与合理密植,覆盖,吸水剂沾根和施肥等抗旱造林技术,效果显着。     

辽西半干旱地区整地技术对造林效果影响的分析

春季干旱是影响辽西地区造林成活率的主要因素之一。为此,在雨季来临前进行整地,可以有效地改善造林地土壤的理化性质,提高土壤水分含量,加强造林地的空气对流,改善造林地立地条件;同时采取苗木在出圃前要灌足结冻水、化冻水和起苗水,真正提高苗木的含水率等技术措施,利用优质苗木进行造林。在确保用优质苗木造林的前提下,采用合理的整地技术是确保辽西地区造林成功的关键。     

困难立地造林综合技术要点

在当前的生态建设中,造林用地与农业用地的矛盾日益突出,但又有大量的立地条件差的林地因造林成功率低而闲置。积极探索困难立地条件下的营造林技术,提高造林成活率和保存率,增加森林植被覆盖率,对贯彻落实"绿水青山就是金山银山"的生态发展理念,具有非常重要的意义。基于此,对造林作业设计、整地、优化树种结构、苗木处理、抗旱造林技术利用、后期抚育管理等方面的经验进行总结,为立地条件差的地区的营造林行动提供参考。     

甜柿抗旱造林新技术应用研究

甜柿栽培经济效益高、水土保持效果好,但因苗期在北方干旱半干旱地区造林成活率低,严重影响着其大面积推广。研究表明:保水剂能显著提高干旱半干旱地区土壤含水量,大幅度提高甜柿建园成活率并对生长量有明显影响,单独使用时以株施50g为宜;综合应用ABT生根粉+SAP高效抗旱保水剂+地膜覆盖多因素配套技术效果最好,可使造林成活率达到98%以上,宜在生产中大力推广。     

宁南山区沙棘截干抗旱造林技术

宁南山区气候干旱 ,沙棘造林成活率低。 1994年以来 ,彭阳县大面积推广秋季沙棘截干造林技术 ,增强了苗木抵御寒、旱、风灾害的能力 ,成活率年均提高 6个百分点 ,保存率提高 10个百分点 ,植株萌蘖能力增强 ,成林郁闭速度加快 ,取得了明显成效。简要介绍了沙棘截干抗旱造林方法     

黑龙江西部地表覆盖保墒的抗旱造林技术

增强土壤蓄水保墒性能,是提高干旱半干旱区造林质量的重要举措之一.以黑龙江西部为背景,选取覆膜、覆秸秆和覆沙3种地表覆盖措施,采用对比的研究方法,探讨半干旱区地表覆盖保墒的抗旱造林技术.结果表明:3种地表覆盖措施不同程度提高了土壤含水率,平均提高幅度分别达58.93％,32.91％和24.97％,且以降水较少的春季最为明显;3种覆盖措施造林成活率分别提高了13.9,11.7和10.6百分点,与对照差异显著.对应地表覆盖处理下的樟子松,2008-2013年间的年均高生长量提高了23.35％,5.08％和9.64％;通过对3种地表覆盖材料及相应处置费用的市场经济核算,其造林成本分别比对照增加了4.4％,9.3％和9.2％.采用隶属函数值法,以造林成活率、造林初期6a的年均高生长量和初期造成成本提高幅度为指标,对各处理措施进行评价和排序,其结果为:覆膜＞覆沙＞覆秸秆＞对照.     

四翅滨藜引种驯化造林试验初报

四翅滨藜为准常绿灌木,具有耐干旱、寒冷、盐碱的特点,营养成分丰富,是极具价值的优良饲料灌木。四翅滨藜适生范围广,能在生态环境恶劣的干旱荒漠、黄土高原、盐碱荒滩和沙地上生长。通过四翅滨藜造林试验,作为引种树种与乡土树种相比具有较强的适应性,表现出较高的造林成活率及较大的苗木生长量;据测定:当年苗木的根、枝、叶生物量分别为56.24 g、251.86 g、97.46 g,单株的生物量最大可达857.3 g;苗木当年生长节律变化表明,4月12日造林后到6月上旬,苗木处于缓苗期,苗高生长量极为缓慢,从6月上旬开始苗木进入速生期,苗高生长量加快,8月下旬开始苗木生长速度减慢。     

中国华北地区近40年物候春季变化

根据华北地区7个观测站物候资料,分析了华北地区1963-1996年及北京1963-2005年物候春季的变化特征及其与气温的关系。结果表明:华北地区的物候春季有明显提早来临的趋势,而造成这一变化的主要因素是本地区近40 a来冬春季气温的明显上升。其中1963-1996年间华北地区1-3月及4月的平均气温分别上升了2.3℃与1.7℃,物候春季起止日期分别提前了9d和4d,因而使得春季长度也延长了5d;北京1963-2003年间1-3月及4月的平均气温分别上升了3.5℃与2.6℃,物候春季的起止日期分别提前了11d和10d,但春季长度没有明显变化。     

天津半干旱地区不同种植年限菜田土壤微生物变化特征的研究

对天津周边半干旱地区不同种植年限的菜田土壤微生物状况调查研究表明 ,该地区土壤微生物以细菌为主 ,夏季微生物总量大大高于冬季 ;随着种菜年限的增加 ,耕层和亚耕层微生物总量都有增加趋势 ,其中细菌和放线菌增加明显 ,真菌有下降趋势 ;真菌类群分析表明 ,少数纤维素分解菌 ,如青霉 (Penicillium)、木霉 (Trichoderma)等为优势菌 ,而糖和木质素分解菌仅占少数。用尖孢镰刀霉 (Fusariumuoxysporum)、大肠杆菌 (Escherichia coli)接种不同种菜年限土壤 ,检测土壤拮抗菌状况发现 ,拮抗菌仅在种植年限长的老菜田的放线菌中发现。表明北方半干旱地区菜田土壤细菌为优势菌 ,主要存在于土壤微孔隙中 ;而适于生活在土壤疏松大孔隙中的真菌数量极少。应注意土壤结构的改良 ,为丰富土壤微生物提供良好的生态环境     

天津半干旱地区不同种植年限菜田土壤微生物变化特征的研究

对天津周边半干旱地区不同种植年限的菜田土壤微生物状况调查研究表明 ,该地区土壤微生物以细菌为主 ,夏季微生物总量大大高于冬季 ;随着种菜年限的增加 ,耕层和亚耕层微生物总量都有增加趋势 ,其中细菌和放线菌增加明显 ,真菌有下降趋势 ;真菌类群分析表明 ,少数纤维素分解菌 ,如青霉 (Penicillium)、木霉 (Trichoderma)等为优势菌 ,而糖和木质素分解菌仅占少数。用尖孢镰刀霉 (Fusariumuoxysporum)、大肠杆菌 (Escherichia coli)接种不同种菜年限土壤 ,检测土壤拮抗菌状况发现 ,拮抗菌仅在种植年限长的老菜田的放线菌中发现。表明北方半干旱地区菜田土壤细菌为优势菌 ,主要存在于土壤微孔隙中 ;而适于生活在土壤疏松大孔隙中的真菌数量极少。应注意土壤结构的改良 ,为丰富土壤微生物提供良好的生态环境     

沈阳市城市表土中微生物区系变化的初步研究

在沈阳市远郊-近郊-市区等不同城市化水平区内选取林地、草地和路边土几种不同利用方式下的表层土壤,对土壤中的微生物状况进行了初步分析。结果表明,随着城市化水平的提高,土壤中微生物的数量表现为明显的减少趋势。其中变化较大的是细菌,而真菌和放线菌的变化不明显。     

Sediment denitrification in waterways in a rice-paddy-dominated watershed in eastern China

Purpose

Rice-paddy-dominated watersheds in eastern China are intensively cultivated, and lands with two crops receive as much as 550–600 kg?ha^–1?year^–1 of nitrogen (N), mainly through the addition of N-based fertilizers. However, stream N concentrations have been found to be relatively low. Waterways in the watersheds are assumed to be effective “sinks” for N, minimizing its downstream movement. We directly measured net sediment denitrification rates in three types of waterways (ponds, streams/rivers, and a reservoir) and determined the key factors that control net sediment denitrification. Such information is essential for evaluating the impact of the agricultural N cycle on the quality of surface water.

Materials and methods

The pond–stream–reservoir continuum was sampled every 2 months at nine sites in an agricultural watershed between November 2010 and December 2011. Net sediment N₂ fluxes/net sediment denitrification rates were determined by membrane inlet mass spectrometry and the N₂/Ar technique. A suite of parameters known to influence denitrification were also measured.

Results and discussion

Net denitrification rates ranged between 28.2?±?18.2 and 674.3?±?314.5 μmol N₂–N?m^–2?h^–1 for the streams, 23.7?±?23.9 and 121.2?±?38.7 μmol N₂–N?m^–2?h^–1 for the ponds, and 41.8?±?17.7 and 239.3?±?49.8 μmol N₂–N?m^–2?h^–1 for the reservoir. The mean net denitrification rate of the stream sites (173.2?±?248.4 μmol N₂–N?m^–2?h^–1) was significantly higher (p?<?0.001) than that of the pond sites (48.3?±?44.5 μmol N₂–N?m^–2?h^–1), and the three types of waterways all had significantly higher (p?<?0.01) mean net denitrification rates in summer than in other seasons. Linear regression and linear mixed effect model analysis showed that nitrate (NO₃ ^?–N) concentration in surface water was the primary controlling factor for net sediment denitrification, followed by water temperature. Using monitoring data on NO₃ ^?–N concentrations and temperature of the surface water of waterways and an established linear mixed effect model, total N removed through net sediment denitrification in the pond–stream–reservoir continuum was estimated at 46.8?±?24.0 t?year^–1 from July 2007 to June 2009, which was comparable with earlier estimates based on the mass balance method (34.3?±?12.7 t?year^–1), and accounted for 83.4 % of the total aquatic N. However, the total aquatic N was only 4.4 % of the total N input to the watershed, and thus most of the surplus N in the watershed was likely to be either denitrified or stored in soil.

Conclusions

High doses of N in a rice-paddy-dominated watershed did not lead to high stream N concentrations due to limited input of N into waterways and the high efficiency of waterways in removing N through denitrification.     

Patterns in trace elements in lichens

Water, Air, & Soil Pollution - Epiphytic lichens were sampled in a Dutch national monitoring survey, which was carried out twice within 5 yr. The samples were analyzed by neutron activation...     

Trace metals in precipitation in Sweden

Trace metals (Cd, Cu, Fe, Mn, Pb, and Zn) concentrations in atmospheric precipitation have been routinely monitored in Sweden since the autumn of 1983. Concentrations are highest in southern Sweden and decrease northward. It is postulated that the long range transport of anthropogenic pollutants from the rest of Europe is the major source of Cd, Pb, and Zn in precipitation. Evidence for this hypothesis is that enrichment factors indicate anthropogenic origin, and Swedish atmospheric emissions of Zn and Cd are 2 to 3 times smaller than deposition fluxes. Also, Cd, Pb, and Zn concentrations are correlated in both space and time and are also well correlated with exSO₄ ⁺, a substance known to be of anthropogenic origin transported long distances.     

Trends in soil science in Switzerland

Phytoremediation is an emerging technology based on the use of green plants to remove, contain, inactivate or destroy harmful environmental pollutants. Recent developments in Europe and the USA show that the approach is somewhat different on both sides of the Atlantic. In Europe, phytoremediation has more basically been research driven and, based on the outcomes, applications have been envisaged. By contrast, the approach in the USA is more application and experience driven. In spite of a growing track record of commercial success, more demonstration projects are needed to prove that phytoremediation is effective in order to rigorously measure its underlying economics, and to expand its applications. More fundamental research is also required to better understand the complex interactions between pollutants, soil, plant roots and micro-organisms at the rhizosphere level, to increase the bioavailability of pollutants, to fully exploit the metabolic diversity of plants and, thus, to successfully implement this new green technology.     

不同种植模式下菜地土壤腐殖质组分特性的动态变化

通过在南京普朗克有机农场开展的9年长期定位监测,研究了有机(露地和大棚)和常规种植模式下蔬菜地耕层土壤有机碳和土壤腐殖质组分特性的动态变化。结果表明,有机露地、有机大棚和常规露地种植土壤有机碳含量分别从11.41、9.29、9.00 g k g-1提高至15.35、20.90、10.00 g kg-1;胡敏酸碳(CHA)分别从1.79、1.23、1.14 g kg-1提高至2.11、3.11、1.31 g kg-1;富里酸碳(CFA)分别从2.19、1.88、1.73 g kg-1提高至2.44、2.68、1.91 g kg-1。两种有机种植模式的土壤有机碳及腐殖质组分含量增加达到显著水平,而常规种植模式下的变化不显著。两种有机种植模式下表征土壤腐殖质品质的胡/富比(CHA/CFA)、胡敏酸占总腐殖物质的比例(PQ值)均高于常规种植模式,土壤富里酸的E4/E6值、色调系数(ΔlogK)值随着种植时间增加的幅度较常规种植模式更大,土壤胡敏酸芳化度呈现先降低后增高的趋势,但在常规种植下变化不明显。说明土壤在长期有机种植模式下不仅更有利于土壤有机碳的积累,而且能促进土壤腐殖化进程。     

Variation in ozone concentration in relation to local climate in south-west Sweden

Ozone (O₃) concentration and air temperature/relative humidity were monitored using diffusive samplers (weekly, 3 m above ground) and Tinytag loggers (10 min sampling, 1 m above ground, self-ventilating radiation shields), respectively, in the forested landscape of south-west Sweden, 40 km north-east of Gothenburg. Two forest sites were included, one at a hilltop (175 m a.s.l.), and one in a nearby (～1 km) valley (110 m a.s.l.). In addition, a valley site (～3 km from the forest sites, 60 m a.s.l.) in an agricultural landscape was included, where ozone was measured using both a UV-based monitor and diffusive sampling. At the agricultural site measurements of temperature and relative humidity were made using a radiation shield with forced ventilation and with Tinytags, as on the forest sites, in addition to observations of wind speed and the vertical temperature gradient. Furthermore, comparison with O₃ concentrations at urban and coastal sites in the region was made. The temperature dependent, systematic error of using a self-ventilating radiation shield was estimated and corrected for. It was found that the elevated forested site experienced higher O₃ concentrations and lower evening cooling rates in calm situations as compared to the forest site in the valley and in particular as compared to the agricultural site. This can be explained by a stronger coupling with the planetary boundary layer at the elevated site and more pronounced night-inversions at the valley sites. The difference in weekly O₃ concentration between the two forested sites was correlated with the difference in average minimum night-time temperature. The coastal site had the highest ozone concentrations, related largely, but not fully, to higher night-time O₃ concentrations. The urban site showed a depression in O₃ concentration associated with the combination of large NO emissions and slow air mixing during the morning traffic rush hours.