唐古拉地区天然牧草长势及生长发育的气象条件分析

应用沱沱河气象站2003年-2006年的气象资料,对位于唐古拉山的天然牧草长势和生育期进行监测分析。结果表明：5-9月份,牧草长势呈现单峰态变化,以7月或8月最高;与降水量相比,植被长势对气温变化的响应更为敏感;影响青草期中后期牧草长势的气候因子主要是降水量,尤其是7、8月份的降水量。     

种植密度与行距对秋闲田饲用甜高粱草产量的影响

为了秋闲田饲用甜高粱丰产丰收,探索其高产栽培技术。采用列区试验设计与软件IBM.SPSS.Statistics.v22 的LSD法,对秋闲田饲用甜高粱的种植密度与播种行距进行了单株生产力及其草产量的比较试验。结果表明：种植密度与行距对秋闲田饲用甜高粱单株生产力、草产量均具有重要影响。明确了秋闲田饲用甜高粱高产配套栽培技术的优化组合：单株生产力最大的优化组合为A1B4,即种植密度为7.50 万株/hm2 与播种行距为40 cm 的配置;获得最高产量的优化组合为A2B4,即种植密度为22.50 万株/hm2与播种行距为40 cm的配置。研究结果为秋闲田种植饲用甜高粱的生产实践提了供理论依据和技术支撑。     

混播草种及其比例对黔草4号鸭茅草地产量的影响

[目的]探明黔草4号鸭茅的混播草地组合与草地产量。[方法]以黔草4号鸭茅单播为对照,在贵州省德江县共和乡建植不同混播比例的鸭茅+白三叶+多年生黑麦草、鸭茅+白三叶+高羊茅、鸭茅+白三叶共9种混播草地处理,研究不同处理对牧草高度、产量、叶茎比、豆荷比的影响。[结果]鸭茅+白三叶+多年生黑麦草(2∶1∶1)草地的产量达101 610 kg/hm~2,极显著高于其他处理,同时叶茎比为2.98,草地质量好,为最优草种组合与混播比例。[结论]该试验为筛选适宜贵州黔草4号鸭茅草地建植的最佳草种组合和混播比例提供依据。     

吡喹酮及其主要代谢产物在草鱼体内代谢动力学研究

[目的]研究吡喹酮及其主要代谢产物在草鱼体内的代谢动力学规律。[方法]运用高效液相色谱法(HPLC),研究淡水草鱼在单次口灌给药10 mg/kg剂量条件下,鱼体各组织中吡喹酮(PZQ)及吡喹酮一羟基代谢物(M1)的药动学差异。[结果]草鱼血浆、肠道、肝脏和肾脏内PZQ在各个时间点的药物浓度存在极显著差异(P0.01);PZQ在血浆、肠道、肝脏和肾脏的达峰时间分别为1.0、0.5、1.0和1.0 h,而药物峰浓度为0.41、0.45、0.72和0.44 mg/L,M1在血浆、肠道、肝脏和肾脏的达峰时间分别为48.0、0.5、6.0和48.0 h,而药物峰浓度为0.72、0.45、0.42和0.42 mg/g。这表明PZQ在草鱼体内吸收分布快,M1的达峰时间滞后于PZQ。二者达峰浓度相似表明M1是PZQ在草鱼体内主要代谢物。PZQ在血浆、肠道、肝脏和肾脏的消除半衰期(t_(1/2))分别为16.41、4.77、37.16和8.74 h,M1在血浆、肠道、肝脏和肾脏的消除半衰期(t_(1/2))分别为124、71、246和162 h,其消除半衰期明显比PZQ长,说明在鱼体中M1的残留时间比PZQ更长。[结论]在实际生产中,应注意对M1的检测。     

气力式免耕播种机试验研究

针对我国天然草场严重退化及现有牧草播种机对禾本科及小粒牧草种子适应性差和难以均匀播种的问题,研制生产了气力式牧草免耕播种机.通过对9BQM-3.0型气力式牧草免耕播种机做排种试验进行性能和生产试验研究,测量其各行排量一致性变异系数,苜蓿是3.41％,披碱草是6.04％,玉米是7.33％;总排量稳定性变异系数,苜蓿是1.6％,披碱草是3.77％,玉米是2.8％,地轮滑移率是4.3％,纯工作时间生产率是3.596 hm2/h,班次时间生产率是3.500 hm2/h.通过试验表明,该排种装置通用性良好,适用性广,播种均匀,可实现高速单粒体排种,其各项指标均达到了设计要求,为以后气力式牧草免耕播种机的设计提供依据,同时加快其推广应用.     

生草对南疆温室桃园土壤理化性状的影响

研究生草措施对温室桃园土壤环境和养分的影响,为温室桃栽培优质生产提供理论支持。以温室桃园为研究对象,设置行间种植三叶草和小黑麦为处理,以清耕为对照,测定温室桃园土壤理化性质、体积质量、孔隙度及养分含量的变化。结果表明,温室桃园行间种植三叶草和小黑麦能减缓土壤温度变化幅度,提高土壤含水量,降低土壤水溶性总盐含量,显著增加0～20 cm土层和20～40 cm土层土壤有机质及养分含量,其中种植三叶草的效果好。生草能增加土壤pH,显著降低0～20 cm土壤体积质量,增加土壤总孔隙度。温室桃园生草可以有效调节土壤温度,改善土壤结构和通透性,提高土壤肥力。     

草牧场防护林带对牧草质量和草场生产力影响的评价

草牧场防护林对牧草质量和草场生产力的影响是评价草牧场防护林效益的关键。本文在分析草场土壤背景值的基础上,分别对牧草营养期和绿果期,用牧草营养物质含量和能量指标评价了4年生白城杨(Populux×xiaozuanica)林带对几种主要牧草质量的影响。用牧草生物量和单位面积能量评价林带对草场生产力的影响。结果表明:营养期的牧草磷和粗蛋白含量分别提高0.012％和1.365％,无氮浸出物含量降低2.025％,牧草质量得到了改善;草场生物量和能量分别增加131.5kg/ha和741.4MJ/ha,提高了草场生产力。绿果期的牧草磷、粗蛋白、无氮浸出物和粗纤维含量与林带的存在无关、各草种粗脂肪的加权平均含量明显降低(降低值为0.634％),说明林带对牧草质量产生不良影响。但单位重牧草能量增加了0.175MJ/kg,使单位面积牧草能量提高634MJ/ha。各草种单位重能量加权平构值在10H和15H处较大,与林网内净辐射量较大位置相一致。     

坪安2号对早熟禾草坪中禾本科杂草防除效果的研究

[目的]解决早熟禾草坪中禾本科杂草的防除难题。[方法]采用坪安2号、坪安3号加草坪抑制荆对早熟禾草坪中的禾本科杂草进行防除试验。[结果]坪安2号300倍液对早熟禾草坪中的禾本科杂草防除效果较好。[结论]坪安2号可有效防除早熟禾草坪中禾本科杂草,且对草坪安全,环境污染小。     

Grass carp (Ctenopharyngodon idella) grazing on duckweed (Spirodela polyrhiza)

The aims of this experiment were (1) toquantify the ability of grass carp to processduckweed and (2) to assess indirect changes inwater chemistry and phytoplankton community,caused by grass carp feeding. Yearling grass carp sized 126 ± 7.7 mm (TL) and19.6 g in weight were kept in 9 laminate tanksof 1 m³ for 14 days. Two stockingdensities (2 and 6 fish per m³) anda control without fish were used. Standard growthrate (SGR) of grass carp fed exclusively onduckweed was 0.70% body weight (BW) d^–1and food conversion ratio (FCR) reached 2.0(average water temperature =21.1 ± 3.8 °C). Daily food intakewas 0.2 g of duckweed dry weight (DW), i.e.,1% of average BW of grass carp. SGR ofduckweed growing in 20 × 20 cm floatingenclosures, differed significantly[F(6,2) = 417.9; p = 0.002] between the twostocking densities of grass carp and thecontrol tanks (without fish). Mean SGR ofduckweed was 0.02 g g^–1 day^–1 and thehighest SGR was recorded in the control tanks.Both decrease in NH₄-N and increase inNO₂-N concentrations differedsignificantly between the treatments[F(2,2) = 45.3; p = 0.02 and F(2,2) = 19.2; p = 0.04 respectively]. Changes in other nitrogenand phosphorus components (NO₃-N, TN, TPand PO₄-P) caused by stocking of grasscarp were not significant. Biomass ofphytoplankton, dominated by filamentous algaeand blue-greens, increased proportionately tostocking density of grass carp. Althoughduckweed has a large potential for nutrientremoval, the most common pathway for thenutrients released through grass carp grazingif duckweed cover is loose is theirincorporation into phytoplankton biomass.     

Dietary folic acid requirement determined for grass shrimp, Penaeus monodon

A feeding trial was conducted to determine the dietary folic acid requirement of juvenile grass shrimp, Penaeus monodon. Purified basal diets were formulated using vitamin-free casein as the protein source. Graded levels (0, 1, 2, 5, 10, 15, 30, and 60 mg folic acid/kg diet) of folic acid were added to the basal diet, resulting in eight dietary treatments in the experiment. Each diet was fed to three replicate groups of shrimp initially averaging 0.79±0.01 g for 8 weeks. Shrimp fed diets supplemented with 2 mg folic acid/kg diet had greater (P<0.05) weight gain and hepatopancreatic folic acid concentrations than shrimp fed the unsupplemented control diet. Feed efficiency (FE) was highest in shrimp fed the diets supplemented with 2 mg folic acid/kg diet, followed by the groups fed 1 mg/kg, then the control group. Hepatosomatic index (HSI) was highest in shrimp fed the control diet, followed by 1 mg folic acid/kg and lowest in shrimp fed diets supplemented with 2 mg folic acid/kg. Weight gain percentage, hepatopancreatic folic acid concentration and hepatosomatic index of the shrimp analyzed by broken-line regression indicated that the adequate dietary folic acid concentration in growing P. monodon is 1.9–2.1 mg/kg diet.