化肥减量配施微生物菌剂对桑叶产量和主要活性成分含量的影响

通过田间试验,研究化肥减量配施不同微生物菌剂(枯草芽孢杆菌、绿色木霉菌、解淀粉芽孢杆菌和胶质芽孢杆菌)对桑叶产量及桑叶多酚、1-脱氧野尻霉素(DNJ)含量的影响.结果 显示:与化肥减量相比,增施4种微生物菌剂可以提高桑叶产量,但差异不显著(P＞0.05).施用枯草芽孢杆菌和绿色木霉菌,可以提高桑叶DNJ含量;施用解淀粉芽孢杆菌会降低桑叶多酚和DNJ含量;施用胶质芽孢杆菌菌剂,可以提高桑叶中多酚含量,降低桑叶中DNJ含量.     

桑树叶面喷施有机螯合多效液施肥肥效比较试验报告

本试验采用叶面施肥的方式,通过田间试验比较了施用有机螯合多效液肥和喷施宝对桑叶生长的影响以及在桑叶育蚕和茧丝质方面的差异,结果表明:与清水作对照相比,施用螯合肥及喷施宝对桑叶生长都有良好的促进作用,表现为叶色嫩绿,叶片大而厚,老化叶少等.对桑树枝条伸长及叶片增加的影响以施用螯合肥较明显,但螯合肥及喷施宝均表现为促进叶片生长比促进枝条伸长更明显,对桑叶产量的影响两种肥料均表现出显著的促进作用,施用螯合肥比对照增加58.33%,施用喷施宝增加39.29%;对百克鲜叶干物重的影响与不施肥相比极为明显,对桑叶育蚕效果基本无差异,对蚕茧产量、质量以及蚕丝质量的影响以施用螯合肥为优,但与施用喷施宝差异不特别明显.     

施肥对桑叶品质的影响

在大田条件下研究了施肥对桑叶品质的影响 ,多年多点的试验结果表明 ,在土壤养分缺乏的桑园施用相应的缺素养分总体上有改善桑叶品质的作用。N、P、K、S、Mg、B等 6种养分的施用均明显提高桑叶必需氨基酸含量和氨基酸总量 ;N、K、S、B肥有提高桑叶蛋白质的作用 ,Mg对蛋白质的影响作用很小 ;N、Mg、B肥有提高桑叶全糖含量的作用 ,P、K肥则会降低全糖含量 ,S对桑叶全糖含量的影响不大 ;N、P、K肥施用有提高桑叶中脂肪含量的作用 ,而S、Mg、B肥的作用则相反。结果还显示 ,同一种养分在不同试验中对桑叶某一具体品质参数的影响大小及影响方向不尽相同 ,表明施肥对桑叶品质的作用还受其他因素影响。     

桑树专用有机无机复混肥试验示范

为了解桑树专用有机无机复混肥的应用效果,连续多年在8个基地开展了试验示范,调查桑树专用有机无机复混肥对桑叶产量及蚕茧产量的影响。结果表明,桑树专用有机无机复混肥施用后,桑叶增产幅度达9.57%~31.34%,平均增幅为16.55%,且有利于提高蚕茧产量,改善蚕种质量。此外,桑园施用桑树专用有机无机复混肥后,桑叶叶色浓绿,叶肉厚,桑树抗旱性增强。     

易健生物肥在桑树上施用试验初报

通过选择农桑12、农桑14两个桑树品种,施用易健生物肥,观察桑树长势、桑叶品质及增产效果,试验结果表明施用易健生物肥的桑树长势好,桑叶色较浓绿,桑木虱危害显著减少,桑树增产效果明显。现将试验结果报告如下：     

外源硒对桑叶中硒及若干化学成分含量的影响

改善桑叶茶的品质,有望促进桑树资源的综合利用,为此研究了外源硒对桑叶中硒及若干化学成分含量的影响分别对3组桑苗施用0．25、0．5、1．0mg/L Na_2seO_3溶液,并以蒸馏水作为对照,培养1个月后的调查测定结果表明：施用亚硒酸钠的浓度与桑叶中的硒含量成正相关,其中1．0mg/L Na_2seO_3处理组桑叶中的硒含量最高,与对照相比差异达显著水平,桑叶鲜物质中硒的含量由0．39μg/g上升到5．36μg/g;0．25、0．5mg/L Na_2SeO_3处理组桑叶中的氨基酸、可溶性蛋白、可溶性多糖以及桑叶黄酮类成分含量均高于对照组和1．0ng/L处理组。     

桑树喷施维氨微APW螯合肥试验

<正> 目前,在农作物上施用叶面肥,特别是施用微量元素肥,已成为夺取农业丰收,提高产量,改善品质,大幅度提高效益的有效手段之一,为提高桑叶的产量和质量,增加桑园的经济效益,今年春季进行了使用维氨微APW(桑叶专用)螯合肥对桑树进行根外施肥试验,取得了良好的经济效益,现将试验结果报告于后:     

桑叶叶面微量元素复合肥料

<正> 这是一种新型的专用桑叶叶面喷洒的微量元素复合流体肥料,含有多种微量元素和适量的氮、磷、钾。施用该液肥能增加桑叶产量,提高蚕茧的产量和质量。经过在江苏吴江、上海金山、安徽合肥等地三年试验,能增加桑叶产量10％以上。     

中国农技推广网重点推荐技术 种桑养蚕想增产奇农技术帮您忙

经多年实践证明，重庆圣农素系列——蚕桑（柞）多功能专用产品，在桑树或桑叶上施用，桑叶肥大硕厚，产量高，防治桑叶各种病虫害，消除桑树或桑叶的肥料、农药和除草剂的残毒，不易引起蚕发病和农药中毒，提高茧丝量和产量，蚕茧洁白，质量高，一般可增蚕茧30％左右。特别在条件差，经常发生农药中毒或空气污染的地方及蚕病的毒病、     

利用植物生长调节剂乙烯利省力化收获桑叶的试验

将植物生长调节剂乙烯利用于诱发桑叶的脱落,实现桑叶的省力化收获。于不同养蚕季节的桑叶采收高峰期(5龄蚕用叶高峰期)到来之前,将植物生长调节剂乙烯利、脱落酸和TDZ分别配制成一系列浓度的溶液,对桑树进行喷施处理,调查其诱导桑叶的脱落效果。3种浓度的乙烯利溶液在春蚕期用叶高峰时段(5月末至6月初)前施用,均没有促进成熟桑叶脱落的效果;在中秋蚕期用叶高峰时段(9月13日左右)施用1 000 mg/L乙烯利溶液,4 d后人为摇动处理的植株枝条,成熟桑叶脱落率达到50%~60%;在晚秋蚕期用叶高峰时段(10月22日左右),以1 000或2 000 mg/L乙烯利溶液处理后4 d,桑叶的自然脱落率可达35%以上,摇动枝条可使桑叶脱落率达到90%以上,仅残留上部幼嫩叶片,与传统的片叶收获方式相比较,工效提高6倍以上。脱落酸和TDZ在试验浓度范围内没有观察到促进桑叶脱落的效果。对家蚕的安全性试验结果显示,家蚕幼虫5龄期饲喂1 000或2 000 mg/L乙烯利溶液喷施桑叶,其结茧率和虫蛹率与对照组均没有显著差异。试验结果提示:乙烯利可以作为脱叶剂促进桑叶脱落,适于在北方蚕区中、晚秋蚕期的养蚕用叶高峰时段使用。     

Dietary magnesium and urolithiasis in growing calves

The effect of high levels of dietary magnesium (1.4%) alone or in combination with elevated calcium (1.8%) or phosphorus (1.6%) on growth and health of male calves was evaluated during a nine week feeding trial after weaning. Twenty calves were randomly divided into 4 feeding groups consisting of controls, high magnesium, high magnesium and calcium or high magnesium and phosphorus. Elevated dietary minerals caused decreased feed intake and growth rate. Blood urea nitrogen and serum creatinine levels were greatly elevated in calves fed high magnesium or magnesium and phosphorus and serum urea nitrogen was moderately elevated in calves fed high magnesium and calcium. These elevations suggested the occurrence of renal damage as a result of microcrystalline obstruction of renal tubules. Serum magnesium levels were three times normal in calves fed high magnesium or magnesium and phosphorus, but only twice normal in calves fed high magnesium and calcium. High dietary magnesium resulted in a significant depression in blood calcium level. This effect was somewhat overcome by additional dietary calcium Three calves fed the high magnesium diet and two calves fed the high magnesium and phosphorus diet developed urinary tract obstruction. The chemical composition of uroliths recovered from these calves was calcium apatite. Elevated dietary magnesium has been shown to be a cause of urolithiasis in growing male calves. Additional dietary calcium, but not phosphorus, appears to protect calves against urolithiasis induced by elevated dietary magnesium.     

Magnesium metabolism in the laying fowl

Laying fowls were fed on synthetic diets containing 49, 118, 486, 655, 1242 and 2176 mg/kg magnesium. Magnesium intake and plasma concentration were significantly correlated: 49% of the plasma Mg was diffusible. The hens fed on magnesium‐deficient diets (49 to 118 mg/kg magnesium) were hypomagnesaemic while those receiving 2176 mg/kg were hypermagnesaemic. In the deficient hens the liver showed magnesium depletion, increased calcium content and decreased fresh weight. Skeletal muscle was unaffected by the dietary variations in Mg. The magnesium concentration in the femur was positively correlated with the plasma magnesium concentration. Femurs showed a loss of magnesium and increased mineralisation (especially of the medullary bone) in deficient hens, and a net gain of magnesium in the birds receiving 2176 mg/kg magnesium. The magnesium concentrations in egg shells, albumen and yolk were also positively correlated with the plasma magnesium concentration. The shells of eggs laid by magnesium‐deficient hens were thin, a reflection, apparently, of the reduced plasma calcium levels associated with the decreased bone mobilisation.     

Influence of magnesium gluconate on stress reactions in rats

During the tests carried out with rats the organic complex magnesium gluconate was examined for its bioavailability and its stress-reducing properties after oral application. The increase of magnesium concentration in serum achieved by means of magnesium gluconate turned out to be higher than the increase of concentration due to the administration of magnesium chloride. Just like other organic magnesium complexes, magnesium gluconate, administered for three days via feed to rats under stress conditions of immobilization, the substance causes a significant reduction in the increase in catecholamine and corticosterone concentration in serum. Regarding the reduction of stress in rats, the optimal concentration in feed is between 500 and 1000 mg of magnesium as magnesium gluconate per kg.     

Intracellular free magnesium concentration in healthy horses

Equine metabolic syndrome (EMS) is a worldwide disease in horses that parallels human diabetes mellitus type 2. In both diseases, patients show an altered peripheral insulin sensitivity as a key feature. In humans, multiple studies have demonstrated the beneficial effect of magnesium supplementation on insulin sensitivity. However, serum magnesium levels vary and are therefore not a reliable indicator of the patients’ magnesium status. Determining the intracellular free magnesium concentration appears to be a more sensitive diagnostic indicator. In this study, the free intracellular magnesium concentration was measured using mag‐fura 2 spectrophotometry in blood lymphocytes in 12 healthy, non‐obese horses at 9 a.m., 12 a.m. and 4 p.m. to establish reference ranges according to a protocol designed for human blood lymphocytes. Additionally, the serum magnesium concentration was measured. In all horses, the total serum magnesium concentration was within the reference range. The mean free magnesium concentration in blood lymphocytes of all horses was 0.291 ± 0.067 mmol/L with no significant difference between the time points. The reference range for the free intracellular magnesium concentration in equine lymphocytes was set at 0.16–0.42 mmol/L. The established values are slightly lower than those in healthy humans. The designed protocol for the measurement of the intracellular free magnesium concentration might be an excellent research tool to assess the cellular magnesium status and to reliably diagnose an altered magnesium homeostasis in EMS. Further studies shall elucidate possible alterations in cellular magnesium status in horses with EMS.     

1,25 dihydroxyvitamin D3 increases plasma magnesium and calcium in sheep fed liquid diets low in calcium and magnesium

Sheep given a liquid diet low in calcium and magnesium by infusion directly into the abomasum developed concurrent hypocalcaemia and hypomagnesaemia, with plasma concentrations of calcium and magnesium decreasing to 2.0 and 0.4 mmol/l respectively. Treatment of these hypomagnesaemic sheep with 1,25 dihydroxyvitamin D3 (1,25(OH)2 D3) increased the plasma calcium, magnesium and phosphorus concentrations with plasma calcium increasing to 2.5 mmol/l and plasma magnesium to 0.6 mmol/l. Plasma magnesium increased despite a small but significant increase in the daily excretion of magnesium in the urine, and the amount of magnesium derived from either bone and/or intestine must have been greater than the amount lost in the urine. Since in other experiments we have demonstrated that plasma calcium remains within the normal range when a liquid diet adequate in magnesium but low in calcium is infused, these results imply that either synthesis of and/or end organ response to 1,25(OH2) D3 is impaired in magnesium deficient sheep.     

Hypomagnesaemia in beef cows wintered in Ontario.

A field experiment was undertaken in northern Ontario in order to assess the magnesium status of beef cattle raised in the area. Magnesium status was assessed using several criteria including blood and urine magnesium levels, and bone biopsy samples. Eighteen groups each containing four pregnant Shorthorn beef cows were used. Each of the following three mineral feeds were offered to six groups throughout the experiment: a mineral feed without magnesium, a mineral feed containing 8% magnesium in the form of magnesium oxide and the third containing sequestered magnesium with a magnesium level of about a tenth of that in the mineral feed containing magnesium oxide. During the winter, when the cows were housed indoors, they were fed grass silage. Six groups, two of each mineral feed, remained indoors throughout the summer. The other 12 groups were turned out to pasture on May 25 and continued receiving the appropriate mineral feed. There were no differences in serum magnesium owing to magnesium-supplementation treatments observed at any time during any experiment. Serum magnesium levels fell drastically in all groups before the cows were released to pasture, implying that the hypomagnesaemic condition was attributable to the stress of yarding. The rate of recovery from hypomagnesaemia was slower in the cows released to pasture than in those kept indoors. Urine samples from cows returned to the pasture were indicative of low magnesium status. At the end of the experiment, the magnesium levels in the bones of the housed animals were higher than for those on pasture. In spite of severe cases of hypomagnesaemia, no clinical signs of this metabolic condition were observed.     

Magnesium in the 1990's: Implications for Veterinary Critical Care

Magnesium is the second most abundant intracelular cation, exceeded only by potassium. The majority of magnesium is found in bone and muscle. This cation is required for many metabolic functions, most notably as a coenzyme for the sodium-potassium ATPase pump. Magnesium functions to maintain the electrolyte gradient across all membranes. Interference with this gradient may result in changes in the resting membrane potential and disturbances in repolarization, resulting in cardiovascular and neuromuscular abnormalities.
Hypomagnesemia may be the most underdiagnosed electrolyte disorder. Incidence rates greater than 50 percent have been reported in critically ill human patients. Currently there is little or no information available regarding the incidence and significance of hypomagnesemia in hospitalized animals. Causes of magnesium deficiency can be divided into four general categories: gastrointestinal, renal, endocrine and miscellaneous. The diagnosis of magnesium depletion can be difficult since less than one percent of total body magnesium is located in serum. Alternative methods of evaluating magnesium status include determining ultrafilterable magnesium levels, mononuclear blood cell magnesium levels or by quantifying magnesium retention of an administered loading dose.     

Magnesium concentrations in the ventricular and lumbar cerebrospinal fluid of hypomagnesaemic cows

Samples of ventricular and lumbar cerebrospinal fluid (CSF) were taken at intervals from six lactating dairy cows, made hypomagnesaemic by feeding a magnesium-deficient diet. Initially the ventricular CSF had a higher magnesium concentration than lumbar CSF but as the cows became hypomagnesaemic the magnesium concentration in ventricular CSF decreased more rapidly than that in lumbar CSF. Tetany occurred when the concentration of magnesium in ventricular CSF fell below about 0.5 mmol litre-1. Intravenous infusion of magnesium into two hypomagnesaemic cows increased the concentration of magnesium in ventricular CSF before there was any change in the lumbar CSF. Newly formed CSF from the ventricles appeared to be more sensitive to changes in the concentration of magnesium in plasma than lumbar CSF which equilibrates with the diffusible magnesium of the central nervous system.     

东北农牧交错带小尾寒羊放牧系统中镁含量的分析

2 0 0 2年 5 ,7,9月 ,对东北农牧交错带内某草甸土壤、小尾寒羊主食 3种牧草、放牧小尾寒羊被毛和血液中镁含量进行了分析。结果表明 ,该交错带草甸土壤中镁的总平均含量为 0 4 1% ;小尾寒羊主食 3种牧草中镁的年平均含量分别为 0 4 6 %、0 2 2 %、0 15 % ,牧草中镁的总平均含量为 0 2 8% ;放牧小尾寒羊被毛和血液中镁的总平均含量分别为 85 8 5 1μg g和 30 38μg g。据此认为 ,该交错带放牧小尾寒羊不会发生镁缺乏症和镁中毒病 ,但其镁营养处于低水平。     

宰前短期添加镁对PIC育肥猪肉色和pH值的影响

试验研究了宰前短期添加不同剂量镁对PIC育肥猪肉质的影响。试验以PIC育肥猪为研究对象,共分4个处理,每个处理4头。分别在限饲基础日粮基础上每日补饲0、2、4、6 g镁。结果表明:每头添加镁2 g/d有提高色素含量趋势(P>0.05),添加4 g/d可极显著提高肌肉色素含量7.41%(P<0.01),添加6 g/d显著提高肌肉色素含量(P<0.05);肉色评分随添加剂量的增加而提高,2 g/d可以显著提高肉色评分(P<0.05),4、6 g/d可极显著提高肉色评分(P<0.01);随镁添加量的增加,肌肉pH值显著提高(P<0.05),6 g/d添加组与对照组相比较差异极显著(P<0.01)。宰前5 d补镁可增加肉色,显著提高肌肉pH值,改善猪肉品质。