Effect of Mulching and/or Watering on Soil Moisture for Growth and Survival of the Transplanted Tree Seedlings in Dry Period

Dry mulch, as soil moisture conservation techniques, is seldom practiced for growth and survival of transplanted tree seedlings in dry period in Eritrea. Field experiment was conducted at Halhale, Eritrea with Dry Hyparrhenia rufa, as a mulch, on a flat basin for growth and survival of seedlings of Grevillea robusta and Acacia polyacantha subspecies Campylacantha by involving four management practices: 1) mulching and watering basins (MW);2) no-mulching but watering basins (NMW);3) mulching but no-watering basins (MNW);4) no-mulching and no-watering basins (NMNW). The experimental design was CRD with three replications. MW and NMW were watered 180 litters (20 litters/month) but MNW and NMNW were not watered at all. Parameters such as soil moisture content of the basin, early growth performance of seedling and survival rate of the seedlings were studied. The result indicated that there were statistically significant differences (p < 0.05) among the treatment for soil moisture content and early growth performance of the seedlings. The average volumetric water content (VWC%) on 0 - 20 cm soil depth at the end of dry period of MW, NMW, MNW, and NMNW were 10.08%, 7.7%, 6.3% and 3.9% respectively. Mean height increment of seedlings of G. robusta of MW (100 cm), NMW (83.3 cm), MNW (31.5 cm) and NMNW (9 cm) were recorded, while the mean height increments of seedlings of A. polyacantha subsp. Campylacantha of MW (48 cm), NMW (25 cm), MNW (4.5 cm) and NMNW (3 cm) were recorded. The mean survival rate of G. robusta was 91.8% of which the highest (100%) survival rate was recorded under MW, NMW and MNW, but the lowest (66.7%) was recorded by NMNW. All seedlings of A. polyacanth subsp. Campylacantha were survived, irrespective of the treatments. The study concluded that soil moisture content, early growth performance of seedlings, and survival rate of transplanted tree seedling was improved by application of mulch.

不同控水处理对油茶容器苗生长和生理特性的影响

为培育须根发达、生长旺盛的油茶容器壮苗,以‘大别山1号’油茶容器苗为试验材料进行盆栽控水试验,比较不同控水处理条件下油茶容器苗成活率、生长量及生理指标的差异。结果表明,油茶容器苗基质持水量控制在70%~90%时,油茶容器苗成活率、生长势和抗逆性较好。本研究可以为改进油茶育苗技术和提高油茶造林成活率提供参考。

岷江上游干旱河谷地区不同覆盖处理对几种苗木生长的影响

为了提高岷江干旱河谷地区造林成活率和保存率,开展了乡土树种岷江柏、刺槐、榆树以及引进树种辐射松等4个树种造林试验研究,对黑地膜、白地膜、石块覆盖以及不加覆盖物(对照)4种处理方式的成活情况与生长情况等进行观察分析。结果表明:从处理方式上看,表现为覆盖处理均较对照好。其中以白地膜处理下表现最好,成活率达83.25%,保存率达79.18%;黑地膜表现次之,成活率与保存率分别为80.75%和76.75%;石块处理下,分别为75.50%和71.05%;而对照仅为65.5%和54.27%。从不同树种的生长表现上看,岷江柏表现最好,成活率与保存率分别达到92.00%和88.00%;榆树较好,二者分别达到91.67%和85.67%;刺槐次之,二者分别为81.67%和74.67%;辐射松最差,成活率仅为54.20%,保持率仅为54.03%。

岷江上游干旱河谷造林技术试验研究

岷江干旱河谷是我国西部生态环境最恶劣的地区之一。为给该地区植被的恢复与重建过程中提供理论依据,本实验针对其特点,从造林树种选择及其造林方法进行了研究。本试验选择了抗旱能力相对较强的针叶树种:岷江柏、油松、辐射松、白皮松与阔叶树种:密牧豆、元宝枫、榆树、刺槐进行研究,发现岷江柏的成活率最高,达到了89.6%,其次白皮松(89.5%)>榆树(86.7%)>油松(85.8%),都达到了85%以上,再次是刺槐(78.9%);元宝枫(59.1%)、密牧豆较差(53.0%),辐射松最低(50.5%)。同时还开展了采用黑地膜、白地膜、石块覆盖以及不加覆盖物(对照)4种处理方式对林木成活与生长的研究,结果表明:从处理方式上看,表现为覆盖处理均较对照好,其中以白地膜处理下表现最好,成活率达81.8%,黑地膜表现次之,而对照最差,生长量也以白地膜处理下表现最好,对照最差。

地膜覆盖边缘效应对土壤水分及杨树苗生长的影响

针对杨树地膜覆盖扦插苗在苗床不同部位的生长差异现象,应用美洲黑杨湘林-75无性系1年生苗,采取不同苗木及苗床部位双因子试验设计方法,进行扦插育苗试验。结果显示:种苗不同部位扦插育苗的保存率、地径和苗高年生长量均无显著差异。在地膜仅覆盖苗床上面而裸露侧面情况下,由于地膜的边缘效应,边行土壤在8月中旬的土壤含水率比苗床中部下降10.8%;两边行与苗床中部苗木比较,成活率下降24.0%,地径下降38.1%,苗高下降38.2%,均达极显著差异水平。因此,育苗时床宽与所选地膜的宽度要匹配,使苗床侧面及边行也处于地膜的有效覆盖之内;并且,边行扦插时不宜太靠边。

侧柏幼树覆盖试验

在太行山南部石灰岩中山区,以侧柏2年生幼树为研究对象,选择地膜、生态垫、秸秆、石块等材料进行覆盖保墒试验,用EM50自动测定土壤含水量,在生长期结束后对侧柏地径、苗高、生物量、成活率进行调查。试验结果表明:覆盖石块、渗水地膜能起到明显的保墒作用,茎、叶、总生物量、幼树高生长量明显高于其他处理,地径、主根、侧根的生长受影响不大。