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981.
我国橡实资源的开发利用 总被引:2,自引:0,他引:2
我国橡实资源非常丰富 ,有 7属 3 0 0多种 ,分布广泛 .据统计 ,我国约有橡实林 1.3 3× 10 7~ 1.67× 10 7hm2 ,年产橡实 60~ 70亿 kg.橡实营养丰富 ,橡仁含淀粉 5 0 %~ 70 %、可溶性糖 2 %~ 8%、单宁 0 .2 6%~ 17.74%、蛋白质 1.17%~ 8.72 %、油脂1.0 4%~ 6.86%、粗纤维 1.13 %~ 5 .89%、灰分 1.3 0 %~ 3 .40 % ;橡壳也含有大量的色素和单宁等成分 .橡实全身是宝 ,其开发利用的前景十分广阔 .对橡仁、橡壳进行综合利用 ,可以生产出淀粉、色素及一系列副产品 ,利用率将近 10 0 % ,几乎不产生任何污染 .同时还可以将橡实淀粉加工成变性淀粉等系列产品 ,从而提高产品的科技含量和经济价值 .我国橡实资源的开发利用不容乐观 ,存在资源破坏严重等系列问题 .为此 ,提出了旨在充分发挥资源优势、扩大利用规模、提高经济效益的开发利用的对策 . 相似文献
982.
983.
通过地史变迁、冰川影响、地形特点、生态条件的分析与植株原始形态的调查检测 ,提出四川盆地的马尾松种源是我国古老马尾松的原始类型。由于盆地的特殊地形 ,使马尾松渡过冰期的影响得以保存而生长到现在。经检测该地区马尾松针叶树脂道数目最少 ,只有大多数种源的一半 ,条叶型苗木比例最高 ,比大多数种源高 2 6倍。树脂道少与条叶型苗木多都是较为原始的形态特征 ,证明四川盆地种源属于原始类型 ,是马尾松地理起源种群。又由于盆地东南部与外界沟壑相连 ,植物基因交流渠道通畅 ,使得马尾松从原始分布区 ,经过渡地带不断进化繁衍到全国各地 相似文献
984.
985.
986.
987.
988.
Management of subterranean clover (Trifolium subterraneum L.) understory grown with loblolly pine (Pinus taeda L.) and slash pine (Pinus elliottii Engelm.) resulted in differences in both clover yield and pine diameter. Loblolly and slash pines were planted into a subterranean clover pasture in 1984. Suppression of warm season herbaceous vegetation by applying herbicides or disking the site in late summer resulted in significantly greater subterranean clover production than on the control site where no additional understory management was applied. Pine species had no effects on clover yield. The N content of the pine foliage on the blocks managed with herbicide application or disking generally was significantly greater than the control from the 5th through 7th growing seasons (1988–1990). The dbh of the pine trees in the disked and herbicide treatments was greater than the control after the 7th growing season (1990). 相似文献
989.
This study examined the hypothesis that incorporation of Gliricidia sepium (Jacq.) Walp.) (gliricidia), a fast-growing, nitrogen-fixing tree, into agroforestry systems in southern Malawi may be used
to increase the input of organic fertilizer and reduce the need for expensive inorganic fertilizers. The productivity of maize
(Zea mays L.), pigeonpea (Cajanus cajan L.) and gliricidia grown as sole stands or in mixed cropping systems was examined at Makoka Research Station (latitude 15°
30′ S, longitude 35° 15′ E) and a nearby farm site at Nazombe between 1996 and 2000. Treatments included gliricidia intercropped
with maize, with or without pigeonpea, and sole stands of gliricidia, maize and pigeonpea. Trees in the agroforestry systems
were pruned before and during the cropping season to provide green leaf manure. Maize yields and biomass production by each
component were determined and fractional light interception was measured during the reproductive stage of maize. Substantial
quantities of green leaf manure (2.4 to 9.0 Mg ha−1 year−1) were produced from the second or third year after tree establishment. Green leaf manure and fuelwood production were greatest
when gliricidia was grown as unpruned sole woodlots (c. 8.0 and 22 Mg ha−1 year−1 respectively). Improvements in maize yield in the tree-based systems also became significant in the third year, when c. 3.0 Mg ha−1 of grain was obtained. Tree-based cropping systems were most productive and exhibited greater fractional light interception
(c. 0.6 to 0.7) than cropping systems without trees (0.1 to 0.4). No beneficial influence of pigeonpea on maize performance
was apparent either in the presence or absence of gliricidia at either site in most seasons. However, as unpruned gliricidia
provided the greatest interception of incident solar radiation (>0.9), coppicing may be required to reduce shading when gliricidia
is grown together with maize. As pigeonpea production was unaffected by the presence of gliricidia, agroforestry systems containing
gliricidia might be used to replace traditional maize + pigeonpea systems in southern Malawi.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
990.
To optimize biomass and crude protein (CP) production for leucaena (Leucaena leucocephala) in southern Texas, field trials
were conducted with treatment combinations of three levels of phosphorus (P) , two levels of Mg and two levels of soluble
trace element mixture (STEM). The P was banded in the soil while the Mg and micronutrient blend were applied to the foliage.
A combination of P (22 kg ha-1), Mg and STEM fertilizers significantly increased biomass from 2555 kg ha-1 to 3028 kg ha-1. This treatment was associated with an increase in leaf CP from 27.9% to 31.0%. P fertilizer had no significant effect on
leaf P, but significantly increased leaf nitrogen (N) and leaf copper (Cu). A foliar spray of Mg significantly increased leaf
N, P, and Cu. A foliar spray of a complete micronutrient blend increased leaf Cu. Biomass production was correlated positively
(decreasing order) with leaf Cu, N, and Mg and negatively with Zn. Leaf N was positively correlated with leaf P and calcium.
The critical tissue concentrations (CTC) (where 90% of predicted maximum leaf protein was obtained) were 0.18% and 4.49 mg
kg-1 for leaf P and Cu, respectively.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献