火炬松种源木材气干干缩性的变异   总被引：4，自引：0，他引：4  

徐有明  江建军 《华中农业大学学报》1997,16(3):299-303

１０年生火炬松３１个种源间木材弦向（ＴＳ）、径向（ＲＳ）、纵向（ＬＳ）、体积气干干缩率（ＶＳ）和差异干缩（Ｔ／Ｒ）存在着显著的差异，各个性状的广义遗传力大于６０．５％，环境方差占方差总量的３４．９－＝６３．９％，种源内各个性状的变异大于种源间的变异。３１０棵样木线性相关分析表明在α＝０．０１水平上，树高、胸径、材积与ＴＳ、ＲＳ、ＬＳ、ＶＳ呈显著负要关，与Ｔ／Ｒ呈显著相关；晚材率、基本密度、气干密度  相似文献   

粗皮桉木材气干密度测定方法比较研究     

赵荣军  霍小梅  邢新婷  上官蔚蔚  任海青 《西北林学院学报》2012,(2):242-244,260

以我国粗皮桉人工林木材为试验材料,分别采用中国国家标准(GB/T 1933-2009)的直接测量法、X线密度仪和SilviScan木材材性快速测定仪对粗皮桉木材的气干密度进行了测定。结果表明,采用直接测量法、X线密度仪和SilviScan得到的粗皮桉木材试样的气干密度值之间有很好的相关性,并用近红外光谱方法对这些木材密度进行了快速预测,预测效果较好。该研究结果可为将来木材密度快速测定方法的研究和粗皮桉木材的科学合理利用提供依据。  相似文献   

Effect of tillage systems on pea crop infestation with weeds     

Andrzej Woźniak  Leszek Rachoń 《Archives of Agronomy and Soil Science》2019,65(7):877-885

In a multi-year experiment, weed infestation of pea crop in three tillage systems was analyzed: a) conventional tillage (CT), b) reduced tillage (RT), and c) no-tillage (NT), and in two terms: 1) at 2–3 pea leaves stage (23–25 stage in BBCH scale) and 2) at the flat pod stage (75–79 BBCH). Treatments conducted in the CT system included shallow ploughing and pre-winter ploughing in the autumn. In the RT system, both these treatments were replaced by double cultivation, whereas only glyphosate treatment was applied in the NT system. In both terms of weed infestation assessment, the highest number and air-dry weight of weeds were determined in the RT system, lower ones in CT and the lowest ones in the NT system. In the first term, the number of weeds m^?2 in the RT system was higher by 43.9% than in NT and by 26% than in CT system. Also in the second term was the weed number m^?2 in RT higher by 58.6% than in NT and by 27.9% than in CT. Tillage systems differentiated also weed mass in pea crop. In RT, it was 4-fold higher than in NT and over 2-fold higher than in CT.  相似文献