屠宰加工线上瘦肉型猪胴体瘦肉率估测方法的研究

应用逐步回归分析法对瘦肉型猪的瘦肉率估测技术进行了研究 ,所选性状均为在屠宰加工线上能直接快速测定的胴体指标。结合肉品加工过程中对腿臀肉的需求 ,将腿臀比纳入回归模型 ,建立了一个可用于屠宰加工线上快速估测胴体瘦肉率的回归方程。     

Estimation of taper rates and volume of smaller-sized logs in spotted gum saw timber plantations in Southeast Queensland,Australia

Spotted gum (Corymbia citriodora subsp. variegata) is a popular tree species for hardwood saw timber plantations in Southeast Queensland (SEQ), Australia. In many parts of the world, logs up to 10cm top diameter are considered to be merchantable logs and acceptable at sawmills. However, due to the higher handling costs of smaller-sized logs, sawmills in SEQ are only buying logs with a top diameter of 25cm and larger. This necessitates the determination of the volume of logs with top diameters between 10 and 25cm. This paper compares the taper rates of different sizes of spotted gum logs and estimates the stem volume of spotted gum logs between 10 and 24.94cm diameter. Analysis showed that there is a statistically significant difference between the mean taper rates of bottom (30.5–64.2cm diameter) and top parts of stems (10–24.94cm diameter) at harvesting age. Using only the average taper rate of large diameter logs would underestimate the log volume of smaller-diameter logs. The average length of spotted gum logs between 10 and 24.94cm was found to be 19.27 m. Therefore, by the sawmill declining to use 10–24.94cm diameter logs, approximately 0.55m³ of log volume per tree at harvesting age would be lost.     

不同粗度苹果苗木与定植后生长结果关系的研究

1986—1989年在四川盐源果场对不同粗度的金冠、红星、富士苹果苗木定植后的生长结果情况进行了研究。结果表明:定植时的苗木粗度与定植后的树体生长量及单株产量有着密切的关系。培育1.5cm以上茎粗的苹果苗木有利于加速生长,早成形,早开花结果,提高早期产量。     

应用灰色系统模型测定人工林材积生长率方法的初步探讨

本文以沐川县森林经营所柳杉、杉木人工林的材积生长率调查资料为例,分别用7个龄阶的材积生长率数据,建立材积生长率计算的GM(1,1)模型,用以模拟并预测材积生长率,获得了满意的预测效果,不仅预测的精度高,而且符合林木生长规律。在林业生产实践中,用灰色系统模型预测人工林材积生长率有其适用价值。     

金沙江干热河谷区番木瓜生物学特性研究

本文对金沙江干热河谷各区番木瓜(Carica papaya L.)进行了连续三年的生物学特性观察及果实理化分析。其结果表明:树高和树干横断面积每年仅有一次生长高峰,生长量与温度、相对温度呈正相关,而与日照小时数无明显相关。果实中的营养成份突出地表现为含水量高、维生素C含量高、酸含量低及可溶性固形物含量偏低等。单果重偏轻。不同品种或品系间在生物学特性方面存在着较大差异。     

柏木生长量及生长率的研究

本文研究了柏木生长量与树龄的关系、生长率与树龄的关系,提出了用来描述这种关系的几个简单公式。这些简单公式能比较方便和比较精确地根据树龄测定出柏木的生长量和生长率。     

样木解析法及其在材积表编制中的应用

本文提出一种材积表编制样本资料收集的新方法──样木解析法。即在标准地中采用随机或机械抽样方法选取样木，进行树干解析，获得样木生长过程；通过建立树皮系数与树皮率回归模型，将样木解析后的各龄阶去皮直径和去皮树积转化为带皮直径和带皮材积；一株样木可获得龄阶数个编表样本。经四川林校林场楠木材积表编制实践，有减少编表样本收集工作量、消耗林木少的优点，且能达到精度要求，为珍稀树种材积表编制样本资料收集提供了新的依据。     

仔猪早期断奶适宜时间的研究

将12窝长×内杂交一代仔猪分成四组,分别在21、35、49和60日龄断奶,饲粮以玉米、豌豆为主,增重结果表明:21日龄断奶,第一周日增重只有34克,前两周内平均日增重(101克)仅为未断奶的其他三组均值(201克)的50％,第三周增重速度与未断奶组相同。35日龄断奶,第一周日增重(238克)为未断奶的其他二组均值(325克)的73％,第二周即赶上未断奶组的增重速度。49日龄以后断奶对仔猪生长几乎无不良影响。74日龄对各组平均体重无明显差异。屠宰结果表明:断奶时间对仔猪内脏器官形态发育无明显影响。四川目前条件下,养猪生产上可试行35—49日龄断奶。     

Bark thickness and bark volume of Pinus patula in South Africa

In South Africa, tree volume tables and volume functions are usually based on the under bark stem volume. Many forest management studies, however, give the estimated over bark volume, in which case equations are required that estimate bark volume and possibly bark thickness as a function of DBH and tree height. This study deals with the evaluation of geographical regions and tree characteristics on bark thickness and bark volume of Pinus patula in South Africa.     

马尾松材积生长量及经济效益的预测

本文研究材料取自广元、巫山、洪雅、威远、荣县等9市县的不同起源及林龄的马尾松材积生长量调查的393个固定与临时标准地。以林龄X为自变量,材生长率Y为因变量,拟合了14个预测生长量的回归式,其中以Y=0.0369+3.8202/X式的相关性最为显著且又符合马尾松的生长规律,故用此式预测了荣县现实的马尾松林分未来10年每公顷材积总生长量可达125.7m~3。全县15037.8公顷的材积总生长量达188.7万m~3,可获产值2.5亿元,收入大于投资的本利和,培育前景与经济效益都极为壮观。