内蒙古高原紫花苜蓿土壤氮素丰缺指标和推荐施氮量

为了给内蒙古高原紫花苜蓿（Medicago sativa L.）测土施氮奠定科学基础，本研究采用“零散实验数据整合法”和“养分平衡-地力差减法”新应用公式，开展了该自然区域紫花苜蓿土壤氮素丰缺指标和推荐施氮量研究。结果表明：内蒙古高原生长第1年紫花苜蓿土壤碱解氮第1~6级丰缺指标为≥48，20~48，8~20，4~8，2~4和<2 mg·kg^-1，土壤全氮第1~5级丰缺指标为≥1.4，0.8~1.4，0.4~0.8，0.2~0.4和<0.2 g·kg^-1，土壤有机质第1~6级丰缺指标为≥17，10~17，6~10，3~6，2~3和<2 g·kg^-1。当紫花苜蓿目标产量9~18 t·hm^-2、氮肥利用率40%时，内蒙古高原紫花苜蓿第1~6级土壤推荐施氮量分别为0，68~135，135~270，203~405，270~540和338~675 kg·hm^-2。     

应用多重PCR检测人工感染鸡呼吸道疾病的研究

本文报道了IBV，NDV，ILTV，MG人工感染4周龄SPF鸡和非免疫鸡后，用多重PCR检测试验鸡的咽喉棉拭子和器官组织样品，并与传统的病原分离鉴定，血清学方法进行比较，多重PCR无论是对单一感染病原，还是对两种以上混合感染病原，其敏感性和检测速度都优于传统的鉴别诊断方法，具有较高的实用价值，可以直接应用于临床检测，服务于生产。     

Rapid [14C]heptachlor clearance from body stores of ovines: ingested mineral oil and parenteral trans-stilbene oxide lack effects

Recently we reported elimination of radioactivity from [14C]heptachlor from body stores of lactating ovines, mainly into excreta rather than milk, contrasting sharply with bovines. To further assess heptachlor metabolism and clearance by ovines, 12 fine-wool wether lambs (41 +/- 3 kg) housed in metabolism stalls were fed pelleted alfalfa hay (96%) plus molasses (3%) ad libitum and were dosed i.p. once with [14C]heptachlor (1.643 mg/kg body wt; sp. act. = .89 microCi/mg). Feces and urine were collected separately and quantitatively. Light mineral oil was mixed with feed (5 g/100 g) of six lambs and trans-stilbene oxide, an inducer of biotransformational enzymes, was administered i.p. (4 g/hd initially; 2 g/hd daily thereafter) through 20 d to three lambs given each mineral oil treatment, in 2 x 2 factorial arrangement. Feces, urine, blood, bile and body tissues were assayed for total 14C activity. Radioactivity (heptachlor and [or] metabolites) eliminated into excreta during 21 d amounted to 34 to 36% of dose administered, of which 67% appeared in urine and 33% in feces. Biological half-time for elimination into excreta was 11.3 d [Kel = -.061/d], similar to 11.7 d we reported for lactating ewes. Clearance from blood had T1/2 = 14 d. Neither mineral oil nor trans-stilbene oxide altered rate or route of 14C activity excreted or concentrations of 14C activity in blood. Results confirmed that ovines eliminate heptachlor much more rapidly than bovines.     

Response of Mustard to Ethrel Spray and Basal and Foliar Application of Nitrogen

In a field trial conducted during 1992–93 and 1993–94, the effect of basal (B) nitrogen (N) (45 and 60 kg N ha⁻¹) and foliar application (F) of water (W) or 10 kg N ha⁻¹ and 400 or 600 ppm ethrel (E) (2-Chloro ethyl phosphonic acid) at 70 days after sowing was studied on leaf area index and dry mass at 90 days and pod number per plant, seeds per pod, 1000 seed weight, seed yield, oil content and oil vield at harvest of mustard ( Brassica juncea L. Czern & Coss.) cv. T-59. Recommended basal (B) application of 90 kg N ha (BN₉₀) was used as control. On the basis of 2 year data it was found that basal application of 60 kg N and foliar spray of 10 kg N ha ⁻¹ and 600 ppm ethrel gave higher values for growth and yield characteristics and enhanced seed yield and oil yield by 12.5 and 14.8%, respectively over control BN_90.     

农机液压技术的应用与发展

液压技术的应用已成为现代化农业机械的典型标志。为此,介绍了农机液压技术的应用现状;并根据科学技术的发展,简要分析了农机液压技术的发展趋势。     

Metabolic fate of [14C]endrin in bluegill fish

Bluegill absorbed 85% of 1 ppb of endrin from water within 48 hr under static exposure conditions. The absorbed radiocarbon was eliminated linearly with a half-life of about 4 weeks. Analyses of eliminated radioactivity revealed only conjugated metabolites. 12-anti-Hydroxyendrin and 12-syn-hydroxyendrin were tentatively identified by cochromatography using thin-layer chromatography/autoradiography and gas chromatography. These metabolites were also present as conjugates in the fish organs. Seventy-three percent of the absorbed radioactivity recovered from fish extracts was in the form of unchanged endrin.     

苇状羊茅种子生产技术研究进展

苇状羊茅是一种抗逆性较强的牧草,具有广泛的适应性和较高的经济价值及饲用价值,已在我国南方亚热带地区广泛应用,从苇状羊茅的生物学特性、苇状羊茅牧草种子需求现状、苇状羊茅牧草种子生产技术现状、研究进展等方面进行综述,以期为苇状羊茅牧草种子生产技术的进一步研究和利用提供参考。     

Hypernatremia secondary to homemade play dough ingestion in dogs: a review of 14 cases from 1998 to 2001

Objective: To correlate the sodium chloride dosage and the serum sodium concentration to clinical signs, to determine if the dosage of homemade play dough (and, therefore, sodium chloride) is the most reliable way to predict clinical signs and prognosis, and to review previously reported treatment options. Design: Retrospective case series. Animals: Fourteen dogs with a history of homemade play dough ingestion. Procedure: Cases were examined for each animal's signalment including body weight, age, approximate amount of play dough ingested, the estimated sodium chloride dosage, clinical signs, serum sodium concentration, and outcome when available. The literature was reviewed to determine pathophysiology and treatment regimens. Results: Twelve of 14 dogs (86%) that ingested homemade play dough showed clinical signs. Vomiting (9 of 14, 64%), polydipsia, and seizures (4 of 14 each, 29%) were the most common signs followed by polyuria, tremors (3 of 14 each, 21%), and hyperthermia (2 of 14, 14%). The lowest calculated dosage associated with objective clinical signs was 1.9 g/kg. Seizures were reported in all animals with serum sodium levels greater than 180 mEq/L. Conclusions and clinical relevance: Homemade play dough ingestion can be a serious and life‐threatening problem. Many factors can contribute to the toxicity of homemade play dough. This study indicates that the serum sodium concentration is a more reliable indicator of the clinical course of the toxicity rather than the amount of play dough and, therefore, the dosage of sodium chloride ingested. Treatment should be based on a clinical evaluation of the patient and laboratory results, and consists of controlling seizures, reducing serum sodium concentrations slowly, and supportive care.     

新疆干旱地区紫花苜蓿种植技术要点

近年来新疆干旱区紫花苜蓿种植面积基本呈逐年上升趋势,苜蓿在各地区的种植业结构调整中已占据重要位置,成为农牧结合的纽带.作者在新疆喀什地区对紫花苜蓿新品种进行多年的种植试验示范,积累了干旱区苜蓿种植的实践经验.本文力图从重新认识和重视苜蓿生产的作用出发,强化农艺实用技术的示范推广和对其生产者的指导与服务,切实提高苜蓿生产的经济效益.     

盐胁迫对菘蓝幼苗生长和抗性生理的影响

以“定蓝1号”为试验材料,采用不同浓度NaCl溶液(0,30,60,90,120和150 mmol·L^-1)对菘蓝幼苗进行处理,胁迫14 d后测定了其生长指标、生物量积累、叶片相对含水量、根系活力、根质膜透性、渗透调节物质含量以及抗氧化酶活性等指标,分析不同程度盐胁迫对菘蓝幼苗生长和抗性生理的影响。结果表明:NaCl胁迫对菘蓝幼苗株高和根长都有抑制作用,对根和叶的物质积累也有显著影响,并随浓度的递增呈降低的趋势;菘蓝幼苗叶片相对含水量和根系活力均随NaCl浓度的增加呈现下降趋势,而根质膜透性、叶片脯氨酸含量则呈升高趋势;丙二醛(MDA)含量、组织自动氧化速率(RAD)、过氧化物酶(POD)活性和超氧化物歧化酶(SOD)活性都随NaCl浓度的增加呈先升高后降低的趋势。但当NaCl浓度低于90 mmol·L^-1时,菘蓝幼苗的生长没有受到盐胁迫的明显抑制,根系活力降低不明显,脯氨酸、丙二醛含量和保护酶活性也未显著升高,说明菘蓝幼苗对低浓度盐环境具有一定的耐受性。