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11.
车载式施肥机施撒装置系统的研究 总被引：2，自引：0，他引：2
化肥在农业中有着重要的地位,对农业的增产增收有着重要的影响。传统的施肥方式是人工施撤,它劳动效率低,劳动强度大,束缚了大量劳动力。同时,其撒肥均匀性和肥料的利用率也低,造成了环境污染。通过对摆杆阀门式、外槽轮式以及离心圆盘式三种施撒系统进行比较,摆杆阀门式施撒装置在肥量调节和施肥均匀性方面优于其他两种,故适合在实际中推广应用。 相似文献
12.
Objective: We dynamically measured serum inhibin B and estradiol in the early stage of hormonal stimulation to predict the ovarian response in in vitro fertilization (IVF) treatment. Methods: A total of 57 patients (<40 years of age) who un-derwent the first cycle of long protocol IVF or introcytoplasmic sperm injection (ICSI) treatment were included. Serum inhibin B, estradioi, follicle stimulating hormone (FSH) and luteinizing hormone (LH) levels were measured four times: (i) on Day 3 of the menstrual cycle (basal); (2) on the day before the first administration of gonadotrophin (Gn) (Day 0); (3) on Day 1 of Gn therapy; and (4) on Day 5 of Gn therapy. Comparisons of these measurements with ovarian responses and pregnancy outcomes were made and analyzed statistically. Results: (1) On Day 1 and Day 5 of recombinant FSH (rFSH) stimulation, ovarian response, i.e., numbers of follicles, oocytes, fertilized oocytes, and embryos, had a positive correlation (rS=0.46～0.61, P=0.000) with raised inhibin B and estradiol concentrations, but a negative correlation (rS=-0.67～-0.38, P=0.000 or P<0.01) with total rFSH dose and total days ofrFSH stimulation. (2) No significant variation (P>0.05) between the pregnant and non-pregnant groups on the basis of mean age or on all hormone concentrations at four times of the IVF cycle was observed. However, all the seven patients aged >35 years did not reach pregnancy. Conclusions: (1) Serum inhibin B and estradiol concentrations obtained shortly after Gn therapy may offer an accurate and early prediction of ovarian response; (2) Low levels of serum inhibin B and estradiol obtained shortly after Gn stimulation indicate the need for a longer period of Gn treatment and a higher daily dosage; (3) No obvious pregnancy difference among patients of age <35 years was found; however, IVF pregnancy outcome is significantly lower in women of age >35 years. 相似文献
13.
采用盆栽试验,研究了饱和铵贮库施肥法(NDSA-Nitrogendepotwithsaturatedammonium)对菠菜(SpinaciaoleraceaL.)产量和品质的影响。结果表明,与常规施肥法相比,NDSA施肥法和DCD(双氰胺)两者配施(NDSA2处理)则可显著提高菠菜产量。NDSA施肥法可大幅降低菠菜的硝酸盐含量,而DCD的效果并不明显。施氮可明显增加菠菜的Vc含量,其中以NDSA施肥法配施DCD效果最好。菠菜叶片Vc含量很高,相当于叶柄中的3倍。施氮和NDSA施肥法对菠菜可溶性糖影响不大,但DCD可明显增加菠菜的可溶性糖含量,同时降低了菠菜草酸的含量。 相似文献
14.
印天寿 《安徽科技学院学报》1993,(1)
土壤吸收力问题是我们近十多年来在农业化学理论与实践上注意到的一个新的问题。本文汇报我们在土壤吸收力比较研究方法与某些水稻土吸收力比较研究上所做的工作。目前这方面的工作国内外开展均不多,研究表明,土壤吸收力问题如得到充分的研究与应用,必将能够大大地丰富我们因地制宜的施肥理论和实践,在农业化学的教学、科研、生产上均有重要的理论价值和实践意义。是化学工作者服务于农学的一个重要方面。 相似文献
15.
Margaret Barnes Anne Roiko Rachel Reed Cath Williams Kerry Willcocks 《The Journal of perinatal education》2012,21(1):18-23
Assisted conception is becoming an increasingly more common treatment option for women and couples who experience fertility problems. Links have been made in the literature between assisted conception and a greater incidence of pregnancy or birth complications, low birth weight or premature babies, and babies with congenital abnormalities. In addition, evidence suggests that the experience of assisted conception may influence the development of early mothering relationships and impact parenting adjustment. Although this commentary article does not strategically review all available literature, it provides an overview of the health issues that women and families undergoing assisted conception have experienced or may experience. Through raising awareness and promoting discussion of these issues, practitioners will be better equipped to provide informed education and support. 相似文献
16.
Fertilization increases paddy soil organic carbon density 总被引：5，自引：0，他引：5
Shao-xian Wang Xin-qiang Liang Qi-xiang Luo Fang Fan Ying-xu Chen Zu-zhang Li Huo-xi Sun Tian-fang Dai Jun-nan Wan Xiao-jun Li 《Journal of Zhejiang University. Science. B》2012,13(4):274-282
Field experiments provide an opportunity to study the effects of fertilization on soil organic carbon (SOC) sequestration.
We sampled soils from a long-term (25 years) paddy experiment in subtropical China. The experiment included eight treatments:
(1) check, (2) PK, (3) NP, (4) NK, (5) NPK, (6) 7F:3M (N, P, K inorganic fertilizers+30% organic N), (7) 5F:5M (N, P, K inorganic
fertilizers+50% organic N), (8) 3F:7M (N, P, K inorganic fertilizers+70% organic N). Fertilization increased SOC content in
the plow layers compared to the non-fertilized check treatment. The SOC density in the top 100 cm of soil ranged from 73.12
to 91.36 Mg/ha. The SOC densities of all fertilizer treatments were greater than that of the check. Those treatments that
combined inorganic fertilizers and organic amendments had greater SOC densities than those receiving only inorganic fertilizers.
The SOC density was closely correlated to the sum of the soil carbon converted from organic amendments and rice residues.
Carbon sequestration in paddy soils could be achieved by balanced and combined fertilization. Fertilization combining both
inorganic fertilizers and organic amendments is an effective sustainable practice to sequestrate SOC. 相似文献
17.
通过测坑定位试验,研究了3种施肥处理下稻田土壤微生物多样性变化。试验结果表明,有机肥能提高土壤微生物的丰富度和多样性。施肥后,稻田上层土壤的土壤微生物群落结构发生了明显的改变。有机肥处理的土壤DNA丰富度最大,为19;无机肥处理的最小,为14。3种施肥处理的DNA序列Shannon-Weaver指数分别为:混施肥处理1.85,有机肥处理2.30和无机肥处理1.60,均匀度指数分别为:混施肥处理0.73,有机肥处理0.82和无机肥处理0.64。上层土壤中,无机肥处理和混施肥处理的微生物多样性相似系数为79%,而施用有机肥的处理与混施肥处理、无机肥处理的相似系数为62%,这表明施用有机肥能明显改变稻田土壤微生物的种群结构。下层土壤各处理仍然具有较高的相似性。 相似文献
18.
近50年来，发育生物学和生殖生物学领域出现了两大突出进展，震撼了生物学界和整个世界。一是哺乳动物精子获能的发现而创建了试管动物和试管婴儿技术，它标志着人们对生殖生理和生殖控制的完善；二是以卵子为受体的克隆动物的诞生，使哺乳动物体细胞克隆成为可能，这标志着人类对生殖和发育机制的发挥和创新，并为人类干预生殖和发育开拓了广阔前景。虽然受精生物学与动物克隆是研究生命启动奥秘的一门学科，已成为生命科学研究的核心之一，但是还有诸多问题亟待发掘并需要深入研究。本文主要从以下两方面介绍20年来在该领域研究中取得的进展与成果：（1） 动物有性生殖研究方面侧重介绍受精机理和显微受精的研究成果；（2） 动物无性生殖研究方面重点介绍克隆牛及其基础研究的进展。 相似文献
19.
论新疆可持续农业中化肥的发展方向 总被引：1，自引：0，他引：1
农业的持续发展离不开肥料的增产作用 ,有资料表明 ,新疆 195 5— 1997年的化肥施用量与粮食总产量之间的相关系数r=0 .96 1.目前 ,新疆土壤中钾的含量出现明显的入不敷出 ,部分农田出现亏缺。在新疆农业的持续发展中 ,应加强农田养分投入的宏观调控 ,积极发展作物专用复混肥的生产和应用 ,加快新疆对先进技术的引进和研究应用 ,促进新疆农业的可持续发展。 相似文献
20.
研究不同磷肥处理农田黑土基本理化性质、磷脂脂肪酸、酸（碱）性磷酸酶、微生物量碳或氮等变化规律。结果表明,有机肥-化肥配施明显提高土壤有机质、总氮以及速效氮、磷、钾等养分含量,进而促进微生物量碳、微生物量碳/有机质比值、磷酸酶活力以及各菌群磷脂脂肪酸含量显著增加。长期氮磷钾配施土壤有机质活性严重退化、不利于土壤微生物生长,而单施磷肥或氮磷肥配施对微生物活力与结构影响较小。有机肥处理中单烯不饱和/饱和脂肪酸比值>1,远高于其他化肥处理,可用来指示有机质质量与可用性;而支链/单烯不饱和脂肪酸与单烯不饱和/饱和脂肪酸比值呈极显著负相关,表明G+菌对养分胁迫抗性强于G-菌。磷脂脂肪酸PCA表明,有机肥与化肥处理微生物群落结构显著不同。个别脂肪酸载荷值分析表明,真菌受无机肥施用影响显著;而G+菌更易受有机肥影响。 相似文献