高寒牧区黑麦和箭筈豌豆混播对草产量和营养品质的影响研究

为筛选适宜甘肃高寒牧区的箭筈豌豆与黑麦混播组合及比例，采用裂区设计，研究了3个箭筈豌豆品种（绿箭1号、绿箭2号和绿箭431）与黑麦新品系C33在不同混播比例（0∶100、20∶80、30∶70、40∶60、50∶50、60∶40、70∶30、80∶20、100∶0）下的生产性能及营养品质。结果表明，从混播组合看，A?（C33×绿箭1号）的平均干草产量（7.16 t·hm^-2）和综合评价值（0.860）较高；从混播比例看，B?（60∶40）的平均干草产量（8.01 t·hm^-2）和综合评价值（0.691）最高；混播组合和混播比例间的交互作用表明，A?以B?比例混播时干草产量（9.03 t·hm^-2）和综合评价值（0.711）最高。     

河道淤泥和堆肥蛭石混合发酵制备基质及其育苗效果

农村河道清淤产生的淤泥,体量大、有机物浓度高,处置不当会造成二次污染。现代农业的工厂化育苗需求大量的营养土,就地取土导致耕地退化。该研究利用功能微生物发酵淤泥制备育苗基质,研究不同菌株发酵基质的物理和生物学性状,基质培育西瓜苗的生长、生理参数和抗逆性能。结果表明:微生物处理均能够提升淤泥基质物理和生物学性能,同时能够提升育苗质量。其中Trichoderma harzianum T83(T83)、Bacillus amyloliquefaciens IAE(BIAE)菌株发酵基质性能最好。相较于对照处理基质的最大持水量、总孔隙度、毛管孔隙度、通气孔隙度,T83处理分别增加了64.25%、52.65%、45.05%、56.11%;BIAE处理分别增加了101.17%、45.43%、61.43%、38.14%。相较于对照处理西瓜苗的株高、鲜质量、干质量、叶绿素含量、根系活力、根际真菌、细菌数量,T83处理分别增加了66.85%、52.07%、72.16%、43.13%、54.93%、110.62倍、1.63倍;BIAE处理分别增加了80.40%、57.34%、82.37%、54.88%、46.40%、67.26%、2.60倍、2.94倍。T83和BIAE处理西瓜苗叶片过氧化氢酶和超氧化物歧化酶酶活显著增加,根系丙二醛含量显著降低。真菌菌株T. harzianum T83和细菌菌株B. amyloliquefaciens IAE发酵淤泥,能够显著提升其农用品质,为淤泥高附加值化农用提供一条可行的途径。     

不同基质对苹果幼树生长发育及叶片生理特性的影响

本研究旨在筛选出适合苹果幼树栽培的基质配方。以2年生富士芽苗为试材,采用玉米秸杆、园土、草炭土、珍珠岩和牛粪为基质原料,研究不同基质配方对苹果幼树的生长、生物量、根系形态特性和叶片生理特性等参数的影响。研究结果表明:T3(园土:草炭土:牛粪:珍珠岩=2:3:1:1)和T4(园土:玉米秸秆:牛粪:珍珠岩=2:3:1:1)基质最佳,其理化性质理想,栽培的苹果幼树生长量(苗高、茎粗、新梢长、新梢粗、地上部干物质重)、根系发育情况(根系总长、根表面积、根体积、根尖数)和叶片生理特性(净光合速率、蒸腾速率、气孔导度和胞间CO_2浓度)等指标都显著高于对照,根冠比和根平均直径则显著低于对照。因此,腐熟后的玉米秸杆完全可代替草炭土在苹果幼树容器栽培中使用,T4基质可作为培育苹果容器大苗的优良基质在生产上推广应用。     

木耳菌糠酸解液的脱毒效果

为探讨木耳菌糠酸解液的脱毒效果,测定脱毒前后酸解液中还原糖、硫酸根离子、乙酸和糠醛的质量浓度。实验结果表明:酸解液脱毒前后的还原糖质量浓度分别为6.22、3.82 g/L,还原糖浓度降低了38.6%;硫酸根质量浓度分别为18.90、1.91 g/L,大部分硫酸根离子被去除。乙酸质量浓度分别为2.13、1.97 g/L,降低不明显。糠醛质量浓度分别为0.734、0.124 g/L,糠醛浓度降低了412.5%。菌糠酸解液脱毒前酒精度为零,脱毒后酒精度0.58%(w/v),说明脱毒效果比较显著。该结论为利用菌糠酸解液生产酒精提供了理论基础。     

基于空间功能值的矿粮复合区三生空间重构

在分析矿区对"三生空间"分布影响基础上,重构三生空间,实现空间优化和协调发展。该文以江西省上饶市弋阳县旭光乡矿粮复合区为研究区域,借助每个村庄斑块所表现出的住户数量来表示生活空间功能值,采用地区修正后的单位面积价值当量法测算得到生态和生产空间功能值,并基于AVC(吸引力、生命力和承载力)理论调整"三生空间"布局。结果表明:矿区对生产-生活-生态空间具有一定的负面影响,表现为"三生空间"功能值与矿区距离成反比;生产-生活-生态空间无序镶嵌分布,具有少数集中、大多数分散的特点;经过空间重构,提高了三生空间功能值,空间格局由无序向规整转变。通过以AVC理论和空间功能值为空间重构理论依据重构后,生态空间功能值由23587.22万元增加到24 307.13万元,生产-生活-生态空间有序镶嵌、多数集中、少数零星分布。     

The effects of density and artificial substrate on intensive shrimp Litopenaeus vannamei nursery production

Recirculating aquaculture systems (RAS) can be installed indoors, allowing year-round production of tropical animals in nearly any climate. A nursery phase is commonly used in Litopenaeus vannamei production since it allows for enhanced biosecurity and better quantification of animals while reducing space requirements. However, it is unclear whether animal density and inclusion of artificial substrate may improve shrimp performance during the nursery phase. In this experiment, we compared shrimp production parameters in two stocking densities with or without the use of an artificial substrate by creating four treatments: low-density LD; 1500 PL/m⁻³, low-density with substrate LDS, high-density HD; 3000 PL/m⁻³), and high-density with substrate (HDS). The LDS and HDS treatments included 0.46-m² of high-density polyethylene 2.5-cm mesh as a substrate, which increased the tank surface area by 21 %. Each treatment was randomly assigned to four 160-l culture tanks, each with a biofilter. The shrimp had an initial weight of 4 mg and were grown for 50 days. The low-density treatments had significantly higher dissolved oxygen (DO) and pH than the high-density treatments (P ≤ 0.001). Specifically, LDS had the highest DO and pH followed by the LD, HD, and HDS treatments, respectively. High-density treatments had significantly higher NO₂-N levels than low-density treatments during week 2 of the experiment when an unusually high concentration of nitrite was observed. FCR was significantly lower in both low-density treatments than in high-density treatments. At harvest, the total biomass (kg m⁻³) was significantly higher in high-density treatments than in low-density treatments (P ≤ 0.001), and the HDS treatment had a significantly greater biomass output than HD. Producers should consider artificial substrate and higher densities during nursery production to maximize shrimp production; however, the effects on water quality should also be taken into account.     

Total mixed ration silage containing elephant grass for small‐scale dairy farms

Alternatives need to be addressed for reducing losses in elephant grass (EG; Pennisetum purpureum) silages. Furthermore, smallholders lack information on the nutritional aspects of dairy farms. The aim of this study was to evaluate total mixed ration silage (TMR) combining fresh EG and concentrate ingredients, creating the following treatments: (i) EG silage (control); (ii) EG, corn and soya bean meal; (iii) EG, corn, soya bean meal and molasses; (iv) EG, citrus pulp and soya bean meal; and (v) EG, citrus pulp, soya bean meal and molasses. Five replicates of each treatment were ensiled in 15‐L plastic jars. The fermentation profile, chemical composition, microbial counts and aerobic stability were assessed. Three contrasts were tested, as follows: (i) control vs. TMR; (ii) TMR with corn vs. TMR with citrus pulp; and (iii) TMR with molasses vs. TMR without molasses. Variables were analysed through the PROC MIXED procedure of the SAS at the 5% level. The TMR had better fermentation profile, lower effluent production and longer aerobic stability compared to control. When the effect of corn was compared to citrus pulp among the TMR, silages with citrus pulp showed lower fermentation losses, non‐protein nitrogen and effluent production. The aerobic stability also improved with citrus pulp. Molasses did not affect the fermentation profile. Overall, lactic acid was the primary acid in all TMR. Nitrogen source (e.g., soya bean meal) can be used without compromising the fermentation process. TMR with citrus pulp showed better results than corn. TMR may be an alternative to optimize the use of EG on smallholdings.     

芸薹素内酯对稻草基质育秧水稻秧苗生理特性及栽后生长的影响

【目的】筛选出机插水稻基质育秧芸薹素内酯(BR)适宜的施用方法及最佳用量。【方法】以中早39为供试材料,采用稻草基质旱育秧方式,探究BR不同处理方式和浓度对机插早稻秧苗生理特性及栽后生长的影响。【结果】施用BR可以提高秧苗的抗氧化保护酶活性,降低丙二醛含量,增加可溶性蛋白含量、总糖含量及C/N,秧苗根系活力提高了13.24%~48.31%,利于形成抗性强的健壮秧苗;喷施方式对提高秧苗超氧化物歧化酶、过氧化物酶、过氧化氢酶活性效果最佳,基施方式对降低秧苗丙二醛含量效果最好。施用适量BR也可促进秧苗机插后长出新叶、新根及返青,喷施方式效果最好;浸种、喷施方式还能增强秧苗机插后20~30 d的单株分蘖力。【结论】播种前和出苗后进行两次适量的BR处理,有利形成壮苗和栽后活棵返青及分蘖,以播前0.15 mg/L浸种和秧苗1叶1心期0.10 mg/L喷施效果为好。     

3周龄蛋鸡体质量性连锁遗传效应分析

以白莱航鸡、绿壳蛋鸡为亲本,构建F2资源群体,进行蛋鸡早期体质量遗传评估。结果表明:Z染色体基因对蛋鸡早期体质量加性遗传方差有贡献;遗传模型固定效应包括品种、世代及近交系数;蛋鸡F2分离群体3周龄体质量遗传力为0.52±0.03,其中Z染色体遗传力为0.07±0.02。蛋鸡早期体质量遗传评估时应考虑性染色体连锁遗传效应的影响;3周龄蛋鸡体质量属于中等偏高遗传力性状,可通过个体选育获取遗传进展。     

浑善达克沙地杨树水分利用特征

为探究浑善达克沙地杨树的水分利用特征。本文利用氢和氧同位素示踪技术,测定了降雨、土壤水与地下水的δ18O值,利用多元线性混合模型定量计算了杨树对不同土层土壤水分的利用比例。结果表明:①浑善达克沙地大气降雨方程线为:δDLWML=7.84δ^18OLWML+9.12,斜率比全国降雨方程偏小,体现了研究区降雨少,蒸发大的气候特征;②土壤含水量与地下水位埋深、降雨量、植物生长期的变化有着显著的相关关系。降雨量较大与地下水位埋深较浅的时期,土壤含水量明显增大,在植物生长前期和中期,土壤含水量明显较低;③杨树在雨季,利用了大量的浅层土壤水(0~40 cm),在较为干旱的旱季,利用了大量的深层土壤(160~200 cm)水与少量的地下水。