外来牧草入侵风险评估体系研究

风险评估是预防外来物种入侵的有效手段，为科学评价外来牧草的入侵风险，防止盲目引种带来生态安全威胁，本研究将频度分析法与层次分析法结合，建立外来牧草入侵风险评估指标体系；该体系由5个一级指标和18个二级指标组成，包括外来牧草的入侵性、适应性、扩散性、生物学特性、危害性、防除难度等方面；本研究中，利用4种禾本科外来入侵牧草和3种禾本科外来牧草对构建的评估体系进行验证，并利用该体系对外来牧草柳枝稷（Panicum virgatum L.）进行了入侵风险评估实例研究，得出其入侵风险为中等，主要体现在适应性强和扩散性强方面。本研究建立的评估体系，可初步明确柳枝稷入侵风险的主要来源，为外来牧草的引种管理提供参考。     

Elevated [CO2] and warming increase the macronutrient use efficiency and biomass of Stylosanthes capitata Vogel under field conditions

Stylosanthes capitata Vogel is a C3 forage legume widely cultivated in tropical and subtropical pastures. However, the nutrient dynamics of this species under future climate change is unknown. Therefore, this study aimed to evaluate the nutrient content, nutrient accumulation, nutrient use efficiency and growth of S. capitata exposed to increased [CO₂] and temperature under field conditions using two levels of atmospheric [CO₂] (ambient and elevated—600 ppm) and two canopy temperature (ambient and elevated—2°C). Treatments were applied at field conditions, for 30 days, using a free-air carbon dioxide enrichment (FACE) and a free-air temperature-controlled enhancement (T-FACE) systems. Warming showed no effects on macronutrient content, but increased the accumulation of nitrogen, potassium, calcium, magnesium and sulphur, the nutrient use efficiency and root dry mass. Elevated [CO₂] alone had no effect on most of the parameters evaluated. However, the combination of elevated [CO₂] with warming improved the nutrient accumulation, nutrient use efficiency and whole-plant growth more than under isolated conditions of elevated [CO₂] or warming. Based on our short-term results, we concluded that an increment of atmospheric [CO₂] and temperature will benefit S. capitata growth, suggesting no alterations in the actual fertilizer programs for this species.     

阿拉善荒漠草地8种牧草营养物质季节动态及营养均衡价评价

探讨了阿拉善荒漠草地珍珠柴(Salsola passerina)、霸王(Zygophyllum xanthoxylon)、红砂(Reaumuria soon-gorica)、绵刺(Potaninia mongolica)、梭梭(Haloxylon ammodendron)、盐爪爪(Kalidium foliatum)、沙鞭(Psammochloavillosa)和牛心朴子(Cynanchum komarovii)8种牧草营养物质含量的季节动态,并以粗蛋白质对其营养均衡价进行了比较。结果表明:8种牧草的粗蛋白质、粗脂肪、无氮浸出物、钙含量和钙磷比随着牧草的生长期呈先增加后降低的趋势,粗蛋白质含量6月最高,为7.86%~19.18%,1月最低,为5.25%~9.24%;粗脂肪、无氮浸出物、钙含量及钙磷比分别为0.81%~9.63%,26.19%~52.58%,0.12%~1.93%和0.86%~16.00%。粗纤维含量随植物生长呈降低趋势,且8种牧草的含量差异性较大,范围为9.56%~43.01%;粗灰分含量随生长期没有明显的季节动态规律;磷含量随牧草的生长而降低,范围0.04%~0.20%。牧草营养均衡价的评价表明:8种牧草营养均衡价(NB)依次为:梭梭绵刺珍珠柴霸王红砂盐爪爪牛心朴子沙鞭。     

云南黄牛对6种牧草瘤胃降解规律的研究

采用尼龙袋法评定了云南黄牛对六种牧草的DM、CP、NDF和ADF有效降解率,并对牧草降解模型中的参数和有效降解率与牧草中营养成分的相关性进行了分析。试验结果显示：六种牧草DM的有效降解率为苜蓿干草粉最高,和一年生黑麦草粉差异不显著（P>0.05）,和依次降低的苜蓿草块、光叶紫花苕粉、大麦秸粉、非洲狗尾草粉间差异极显著（P<0.01）;六种牧草CP的有效降解率为苜蓿干草粉最高,和依次降低的苜蓿草块、一年生黑麦草粉、光叶紫花苕粉、大麦秸粉、非洲狗尾草粉间差异极显著（P<0.01）;六种牧草NDF和ADF的有效降解率为苜蓿干草粉最高,和苜蓿草块差异不显著（P>0.05）,和依次降低的一年生黑麦草粉、光叶紫花苕粉、大麦秸粉、非洲狗尾草粉间差异极显著（P<0.01）。综合测定的各个营养指标分析,云南黄牛对不同牧草的利用率大小为：苜蓿干草>苜蓿草块≈一年生黑麦草>光叶紫花苕>大麦秸>非洲狗尾草。牧草降解模型中的参数和有效降解率均与牧草营养成分中的CP含量呈较强的正相关,而与NDF和ADF含量呈较强的负相关。     

18种果园常用豆科绿肥作物微量元素含量分析

为了筛选出适合果园微量元素补充的绿肥种质,使绿肥能够更好的在果园中得到应用,测定18种果园常用豆科绿肥植物体内微量元素铁、锌、锰、铜的含量,并对不同作物进行了比较。结果显示：4种微量元素含量最高的是铁元素,其次是锌和锰,铜含量最低;在供试的18种绿肥作物中,狗爪豆花期植物体内4种元素总含量最高,达到了1082 mg/kg;铁含量最高的是狗爪豆（870 mg/kg）;锌含量最高的是狗爪豆（105 mg/kg）;锰含量最高的是小豆（120 mg/kg）;铜含量最高的是狗爪豆（26 mg/kg）。初步认为,狗爪豆对果园土壤微量元素补充能力最强,扁荚山黧豆对果园土壤微量元素补充能力最弱。     

Effects of incorporating cowpea in a subtropical grass pasture on forage production and quality and the performance of cows and calves

The increasing cost of N fertilizer has stimulated an interest in sourcing protein from warm‐season legumes among beef cattle producers in the tropical/subtropical areas of the world. The objective of this study was to evaluate effects of two strategies of incorporating cowpea [Vigna unguiculata (L.) Walp.] into bahiagrass (Paspalum notatum Flügge) pastures on the herbage characteristics and performance of grazing cow–calf pairs. The study was conducted in Ona, Florida, USA, from May to August in 2007 and 2008. Experimental units were 1·0 ha. Treatments were bahiagrass pasture alone (control), 50:50 bahiagrass–cowpea pasture (cowpea), bahiagrass pasture with a cowpea creep grazing area (0·1 ha, creep grazing) and bahiagrass pasture with a creep‐fed concentrate [(creep feeding; 10 g kg^?1 body weight (BW)]. The cowpea pastures had lower herbage mass [HM, 1·8 vs. 3·7 t ha^?1] and herbage allowance [HA, 0·8 vs. 1·4 kg DM kg^?1 live weight (LW)] compared with the other treatments. Cowpea had greater CP (CP, 160 g kg^?1) and in vitro digestible organic matter (IVDOM), (600 g kg^?1) than bahiagrass (110 and 490 g kg^?1 respectively); however, cowpea HM was only 0·9 t ha^?1 in May and 0·7 t ha^?1 in June, but it did not persist in July and August. Calves receiving the creep feeding treatments had greater average daily gain (0·8 vs. 0·7 kg d^?1) than calves in other treatments. Further research is necessary to exploit the superior nutritive value of cowpea in grazing systems in the south‐eastern USA.     

铅胁迫对禾本科牧草生长、生理及Pb2+富集转运的影响

采用苗期盆栽试验,对14份禾本科牧草种质材料进行不同浓度(0,10,50,100,200,300 mg/kg)铅(Pb)胁迫处理,通过对株高、分蘖数、地上/地下生物量、脯氨酸含量、抗氧化酶(SOD、POD、CAT)活性、地上部与根中Pb²⁺含量等指标的测定与分析,探究Pb胁迫对禾草生长生理以及Pb²⁺富集转运的影响。结果表明,随着Pb浓度的增加,14份材料的株高、分蘖数、地上生物量均呈先上升后下降的趋势,地下生物量则逐渐降低,通过综合评价,来自土耳其的长穗冰草G₅具有较强的耐Pb性。随着Pb浓度的增加,地上部与根中Pb²⁺含量逐渐升高,富集系数逐渐降低,转移系数逐渐降低(披碱草G₇与G₈除外),根中Pb²⁺含量显著高于地上部,为Pb²⁺的主要富集器官,披碱草地上部Pb²⁺含量高于其他材料,具有较强的Pb富集转运能力。7份材料的生理指标测定结果表明,随着Pb浓度的增加,7份材料的脯氨酸含量逐渐上升,CAT活性逐渐下降,POD和SOD活性则呈先上升后下降的趋势。     

吉林省中西部地区优良牧草引种试验

通过对9个豆科牧草和11个禾本科牧草的引种试验,参照层次分析法综合分析了20个优良牧草的抗寒性、产量特性和品质特性.结果表明:公农一号苜蓿Medicago sativa cv.Gongnong NOⅠ,紫花苜蓿品种Medicago sativa cv.AC Lonview,公农无芒雀麦Bromus inermis cv.bromegrass,紫花苜蓿品种M.sativa cv.Rangelander和M.sativa cv.Algonquin居前5位,抗寒性强、产量高,品质优良,可在吉林省中西部地区推广应用.