排序方式： 共有3条查询结果，搜索用时 15 毫秒
1
1.
A. H. Shoga'a Aldeen N. M. Majid A. M Azani Awang Noor Abd. Ghani Shukri Mohamed 《Journal of Sustainable Forestry》2013,32(3):286-309
Yemen is one of the world's least developed countries and experiences problems of scarcity of natural agricultural resources as well as soil erosion and degradation. Agroforestry systems (AFS) are being promoted as a more appropriate land use system than monocropping systems (MCS) worldwide. Unfortunately, long-term studies on agroforestry and other land use systems (LUS) do not exist in Yemen. Agroforestry in the Rima'a region has started to deteriorate and many farmers turned to (MCS). This study was conducted in the Rima'a Valley, near Alsharq town, Dhamar, Yemen. The study evaluates the soil nutrients, organic matter (OM), and other soil properties such as pH, bulk density, and porosity under AFS and compares it with soil under MCS. Standard procedures for soil sampling and analyzing were used to collect and analyze 36 composite samples from Site 1 and 36 composite samples from Site 2 from six cropping systems (treatments). The results showed that there were significant variations in relation to LUS. Agroforestry practices—mixed trees with coffee (S1), and Cordia africana L. with coffee (S2) have higher nitrogen concentration (0.17–0.26%) as compared to the Ziziphus spina-christi L. with maize (S3) and the monocropping maize (S5), (<0.16% in both Sites 1 and 2). Similar results were seen on the effect of the different LUS on the soil P, K, and OM contents at the two sites (p < .01). While soil N, P, and soil K were higher under agroforestry systems S1, and S2 in both sites, it was the lowest in S5 in both sites. It can be concluded that agroforestry has more favorable effects on soil fertility and other soil properties. The government should establish programs and campaigns to disseminate AFS technology and promote the importance of agroforestry in soil conservation. 相似文献
2.
New Forests - The genus Aquilaria (Thymelaeaceae) is widely used for the production of agarwood, and includes several valuable plantation species in Southeast Asia. To understand appropriate... 相似文献
3.
Tanaka Kenzo Reiji Yoneda Mohamad Alias Azani Nik Muhamad Majid 《Journal of Forest Research》2008,13(2):137-142
Leaf hairs may assist in maintaining high leaf water use efficiency in tropical secondary forest tree species. We compared
leaf temperature, transpiration, photosynthesis and water use efficiency between hairy and depilated leaves in Mallotus macrostachyus (Euphorbiaceae), to determine the role of leaf hair in leaf water use efficiency (WUE) in tropical degraded secondary forest
in Malaysia. Measurements were made on five mature individuals growing in sun-exposed conditions and five in shaded conditions.
The hair dry weight per unit leaf area was significantly greater in sun leaves than in shade leaves. The transpiration rate
(Trmax) of depilated leaves in sun-exposed conditions was slightly higher than in hairy leaves in both morning and afternoon measurements.
In contrast, Trmax in the shade leaves was almost identical in hairy and depilated leaves. Leaf stomatal conductance (g
s) in the morning showed almost the same value among leaf types and light conditions. In the afternoon, g
s slightly decreased from the morning values in both sun and shade conditions. In the morning, the leaf water use efficiency
(A
max/Trmax) in both conditions did not differ significantly between hairy and depilated leaves. However, in the afternoon, WUE in the
depilated leaves was significantly lower than in hairy leaves in sun-exposed conditions. These observations suggest that leaf
hairs in M. macrostachyus contribute to the high leaf water use efficiency in drought conditions, such as high vapor pressure deficit experienced at
midday in degraded tropical secondary forests. 相似文献
1