不同覆盖方式对越橘园土壤温度的影响

通过设置锯末、白色园艺地布+锯末、黑色园艺地布+锯末、白色园艺地布和黑色园艺地布5种土壤覆盖方式,以不覆盖为对照,利用土壤温度监测记录仪对越橘生长期（5月-10月）不同深度土层土壤温度进行连续监测,分析不同覆盖方式对越橘园10 cm、20 cm和30 cm土层土壤温度的影响。结果表明,不同覆盖方式在整个越橘生长期内均有调节土壤温度的效果,不同覆盖方式对不同深度土层土壤日平均温度的变化趋势总体相似。锯末覆盖处理的土壤温度在越橘生长前期（5月-8月）低于对照,在越橘生长后期（9月-10月）高于对照,且土壤温度日变幅显著低于对照,说明锯末覆盖处理的保温效果最好;黑色园艺地布覆盖处理的保温效果次之,且黑色园艺地布和黑色园艺地布+锯末覆盖处理在整个越橘生长期内的土壤温度均高于对照,辽宁地区春季和秋季气温较低,适当提高土壤温度有利于越橘根系生长和树体发育。而白色园艺地布覆盖处理和白色园艺地布+锯末覆盖处理的土壤温度均低于对照,且白色园艺地布覆盖处理的保温效果较差。因此,辽宁地区越橘园推荐采用黑色园艺地布并添加锯末的土壤覆盖方式具有良好的可行性和实用性。     

Effects of ambient temperature on growth performance and carcass traits of male growing White Pekin ducks

ABSTRACT

1. An experiment was conducted to investigate the effects of ambient temperature on growth performance and carcass traits in male growing Pekin ducks from 14 to 42 d of age in order to establish their optimal temperature requirements.

2. A total of 216 14 d old male White Pekin ducks were allocated randomly to six environmentally controlled chambers with ambient temperature set at 20°C, 22°C, 24°C, 26°C, 28°C, and 30°C from 14 to 42 d of age, respectively.

3. As ambient temperature increased from 20°C to 30°C, the body weight and weight gain decreased linearly or quadratically (P < 0.05) and was accompanied by linearly decreasing feed intake (P < 0.05). According to broken-line regression, the upper critical level of ambient temperature during the growing period for body weight, weight gain, and feed conversion ratio were 27.4°C, 27.4°C, and 26.0°C, respectively.

4. The weight of breast meat, leg meat, and abdominal fat decreased linearly or quadratically as ambient temperature increased and declined to a minimum when the temperature increased to 30°C (P < 0.05). The percentage of breast meat and abdominal fat showed a linear or quadratic decreasing response to increasing temperature, but leg meat percentage increased as temperature increased and reached maximum at 30°C (P < 0.05). According to broken-line regression, the upper critical ambient temperatures during the growing period for breast meat weight and percentage were 25.5°C and 25.6°C, respectively.

5. It was concluded that both growth performance and breast meat of growing ducks were sensitive to increasing ambient temperature and this should be kept below the upper critical temperature during the growing period in order to optimise growth performance and carcass traits at market age.     

内蒙古赤峰市2017年生长季气候概况及其对农业生产的影响评价

选取内蒙古赤峰市2017年4—9月气温、降水量、日照时数等要素,通过数理统计,分析了赤峰市作物生长季气候概况、主要气象灾害及其对农业的影响。分析结果表明：（1）赤峰市2017年生长季平均气温为18.1℃,比常年偏高1.0℃;降水量为387.0 mm,比常年偏多8%;日照时数为1 637 h,比常年偏多48 h;（2）赤峰市2017年生长季内主要气象灾害有干旱、暴雨洪涝、龙卷风、大风、冰雹等,给农业生产造成一定损失;（3）赤峰市2017年生长季内光热条件充足,水分条件南部适宜、北部稍差,气象条件对农业生产利大于弊。     

青海省海南地区近30年≥0 ℃积温变化趋势分析

积温是作物与品种特性的重要指标之一,对积温农业气象重要指标的研究,对于指导农牧业生产具有十分重要的现实意义。本研究通过利用青海省海南藏族自治州共和、兴海、贵南、同德和贵德5县气象站的地面观测资料,对该地区近30年来≥0 ℃年积温的变化,主要农作物、牧草生育期的变化及其生育期≥0 ℃的积温变化做了分析,得出该地区大部分农作物及牧草的生育期有所缩短,开始期有所提前。由于近10年该地区升温明显,热量条件充足,各地≥0 ℃年积温有所增加,农作物及牧草发育期的积温增多,为该地区农作物及牧草的生长发育提供了充足的热量条件,对于该地区适时调整农牧业结构提供了依据。     

准噶尔盆地荒漠灌丛草地土壤呼吸变化及其对土壤温、湿度的响应

本研究利用Li-8100开路式土壤通量测量系统对新疆准噶尔盆地古尔班通古特沙漠南缘荒漠灌丛草地生长季土壤呼吸速率进行了观测,分析了该地土壤呼吸特征及其与土壤温、湿度的关系。研究表明各层土壤温、湿度随着季节表现出明显的周期性变化特征,不同深度土壤温、湿度垂直梯度明显。荒漠灌丛草地土壤呼吸白天呈"双峰型"曲线;生长季土壤呼吸速率白天高于夜晚,草地土壤呼吸速率约为裸地的4倍;裸地夜间土壤表现为碳吸收过程。白天土壤呼吸速率与土壤温、湿度呈负相关关系,夜间为正相关关系;生长季白天土壤水分条件对土壤呼吸速率的影响更大,而夜间土壤温、湿度对土壤呼吸过程的影响均小于白天。该研究为明确干旱区碳收支过程提供一定的理论依据。     

环境温度对育成鸡某些营养生理指标的影响

采用人工气候试验证实,星杂288,70—140日龄育成小母鸡对环境温度的适应范围较宽。平均温度8.6—20.2℃均适合小母鸡的生长发育。冷凉温度(8.6℃)下自由采食时,小母鸡每只每天的能量食入量比中等温度(20.2℃)下多1.6—54.6卡,日粮食入量多0.7—18.2克,日增重多1.73—2.01克;但能量损失较大,每克增重多消耗277卡。育成小母鸡最适宜的生长温度为15—20℃。     

5年模拟增温后矮嵩草草甸群落结构及生产量的变化

5年模拟增温后观察表明,植物生长期4～9月暖室内10cm、20cm地下土壤平均增温1.86℃,10cm、20cm地上空气平均增温1.15℃,地表0cm平均增温1.87℃,且增温在植物生长初期大于生长末期及枯黄期。在模拟增温初期年生物量比对照高,增温5年后生物量反而有所下降。增温使禾草类植物种增加,杂草减少。从表面来看,增温可使植物生长期延长,利于增大生物量,实际受热效应作用,植物发育生长速率加快,植物成熟过程提早,生长期反而缩短,加之玻璃纤维的存在使暖室内外温度交换减缓,减少了温度日变化,限制干物质积累,终久导致生物量减少。这说明小气候的作用,环境条件诱发土壤结构变化,植被的种群结构也随之改变,甚至出现演替的过程,全球变暖不仅对植物的生物生产力影响较大,而且对植被类型的演替有着不可忽视的作用。     

Correlates of stocking rate and overgrazing in the Leliefontein Communal Reserve,central Namaqualand

We investigate the correlates of stocking rate in the Leliefontein communal reserve and attempt to provide a mechanistic explanation of the controlling factors. We further speculate on how high stocking rates are maintained in relation to the current state of the rangeland and grazing practices in the region. Stepwise regression revealed that over 80% of the variance in stocking rate could be explained by the mean maximum temperature during the hottest month, February. Deeper investigation revealed that the proximity of the West Coast played an important role in moderating temperature across the reserve. Areas further inland were not only hotter in summer, but were also colder in winter. We speculate that despite large differences in rainfall, the temperature gradient results in a shorter growing season and hence lower productivity of areas further inland. Mean annual rainfall was a very poor predictor of stocking rate and explained less than 5% of the variance in stocking rate across the reserve. Within a single village district, the stocking rate over time was, however, correlated with rainfall over the same period, indicating that stocking rates are determined by primary productivity and are at, or close to, the ecologioal carrying capacity. We further argue that continuous grazing of the lowlands during the growing season has resulted in the lowlands becoming dominated by annuals and unpalatable shrubs. Due to the shallow-rooted nature of annuals, the vegetation has become more sensitive to temperature effects. The reliability and seasonality of the rainfall in Namaqualand are seen as important factors contributing to the seasonal abundance of annuals and the viability of the current grazing system in the region.     

高羊茅和狗牙根草坪草品种在重庆地区的引种试验

引自百绿集团的6个草坪草品种,在重庆地区进行2年的坪用性状评价。结果表明,供试品种在该地区均可终年生长。5个高羊茅品种中以Vegas表现最好,叶色浓绿,生长速度适中,盖度居供试品种之首,对该区高温高湿和高温干旱2个越夏因子均可适应;其次为Barlexas。狗牙根BarCd8USAI耐高温干旱,抗病性强,茎细叶窄,但叶色偏淡,冬季停止生长早,早春生长速度缓慢。     

高寒山区优良豆科牧草——道恩杂三叶

道恩杂三叶作为红三叶的替代种 ,是云南省滇东北和滇西北≥ 1 0℃的年积累≤ 1 6 0 0℃的高寒地区优良的豆科牧草品种。在云南省中甸县播种第二年干物质产量可达 1 0 92t/hm2 ,第二、第三年的平均产量高于云南省温带地区生长表现较好的红三叶、紫花苜蓿、鸭茅和杂交黑麦草等品种。