刈割次数、施肥量及混播比例对牛鞭草和白三叶混播草地牧草品质的影响

在不同刈割频率、施肥量和混播比例下,对混播草地牛鞭草Hemarthria compressa和白三叶Triflium re-pen不同种群产量、地下生物量及分蘖数进行了研究。试验表明,刈割4次牧草蛋白质的收获量与刈割5次的差异不显著(P>0.05),而酸性洗涤纤维的收获量各处理间差异极显著(P<0.01),其中以刈割4次的最高,为1 135.1 g/m2。当刈割次数适当时,牛鞭草粗蛋白的收获量随着施肥量和禾草混播比例的增加而提高。     

Desmodium: A low‐cost pasture for the eastern cape coastal region

Abstract

Desmodium intortum is well suited to the East London Coastal area for beef production under dryland conditions. Although slow to establish, satisfactory livestock production is maintained under a low fertilizer regime. Experimental results indicate stocking rates for maximum production per animal and per hectare of 0,8 and 8,2 steers (250 kg)/ha respectively.

A cost comparison between a highly fertilized Star grass pasture and a Desmodium pasture show that, while the gross margins at current beef prices favour Star grass (R2 882 and R2 052/ha/yr respectively), the returns per rand capital expenditure differ significantly (R2,29 and R10,01 respectively) in favour of Desmodium.     

Establishment of stylosanthes guyanensis in marandellas sandveld

The feasibility of establishing perennial forage legumes in veld has been investigated at Grasslands Research Station, Marandellas. Of the species tested, Stylosanthes guyanensis (stylo) appeared most suitable.

Reduction of competition from veld grasses was essential for satisfactory establishment of the legume; this was best achieved by shallow discing which also produced a suitable seedbed.

The density of stylo seedlings was affected by seeding rate and degree of soil preparation. More plants established from 4,5 kg/ha of seed broadcast onto disced soil than from 18,0 kg/ha sown onto undisturbed ground. Periodic grazing during the season of establishment had no effect on seedling density. Herbage yields followed the same trends as stylo density. Yields from the plots with the greatest density of stylo plants were more than twice those from the plots with the lowest density.

Seeding stylo into disced veld raised dry matter yields 50% and crude protein yields 300%, although yields of grass were reduced by the addition of the legume. Annual applications of 112 kg superphosphate/ ha had no effect on yields.     

混播草地建植、施肥和割草利用优化模式研究

选择牧草播期、混播草地中禾本科和豆科牧草的混合比例、施氮量、施磷量和刈割次数5个试验因子,进行了产量分析,建立该草地的综合管理优化模式,确定最佳的管理因子和水平;同时对混播草地的营养成分进行了分析。结果表明:在9月播种,豆禾比例为1∶3,施氮量为0.15 t/hm2,施磷量为0.3 t/hm2,刈割4次时,其营养成分含量达15.37%,综合效果最好。     

红三叶和鸭茅混播草地综合管理优化模式的研究

选择牧草播种期、混播草地中禾本科和豆科牧草混合比例、施氮肥量、施氮肥量和刈割次数5个管理因子，建立红三叶和鸭茅混播草地参数回归模型，并由引进行产量分析和计算机仿真寻优，建立该草地综合管理优化模式，确定最佳的管理因子和水平。分析结果表明，该草地以3月份播种、禾草混播比例75％、施氮肥和磷肥量分别为0．15t/hm^2、刈害3次效果较好。     

Effect of nitrogen application,seeding rate and defoliation height on mixtures of Trifolium vesiculosum cv Amclo and Lolium multiflorum cv Midmar: I. dry matter production,crude protein content and crude protein production*

Abstract

The interaction between Trifolium vesiculosum cv Amclo and Lolium multiflorum cv Midmar was measured in a field trial, in terms of dry matter production, crude protein content and crude protein production. The treatments included in the field trials were five different seeding rates of the grass component, four rates of nitrogen application and two defoliation heights. Total DM production of the mixtures differed only slightly, and height of defoliation had, likewise, little effect on the DM production. N application tended to increase the yield of pure grass as well as the grass component of the mixtures. Crude protein content and crude protein production of the mixtures were markedly increased by nitrogen application, largely due to effective uptake of nitrogen by the grass component. However, the highest crude protein production, achieved by an application of 240 kg N/ha to both mixtures and pure grass swards, did not differ appreciably from the amount produced by pure clover receiving no nitrogen fertilizer.     

红三叶和鸭茅混播草地综合管理优化模式的研究

选择牧草播种期、混播草地中禾本科和豆科牧草的混合比例、施氮肥量、施磷肥量和刈割次数五个管理因子 ,建立红三叶和鸭茅混播草地参数回归模型 ,并由此进行产量分析和计算机仿真寻优 ,建立该草地的综合管理优化模式 ,确定最佳的管理因子和水平。分析结果表明 ,对于该草地在 3月份播种、禾草混播比例 75%、施氮肥和磷肥量分别为 0 1 5t/hm2 、刈割 3次效果较好     

Influence of grazing management on the production of an irrigated grass/legume pasture in the Rûens area of the Southern cape

Abstract

The production of an irrigated grass/legume pasture was determined using Merino ewes on rotational and continuous grazing systems. The clover content of the pasture declined, while the grass content increased under both systems. The lucerne content of the rotationally‐grazed pastures did not change, but lucerne failed to persist under continuous grazing. Rotational grazing resulted in a lower clover content and, consequently, in a lower production per individual animal at low stocking rates during two seasons, but in a higher pasture production and grazing capacity, than under continuous grazing. At high stocking rates the individual animal production was, however, highest under rotational grazing, resulting in a higher animal production per ha than under continuous grazing.     

The effect of form and level of nitrogen fertlization on the yield of Digitaria eriantha Steud*

Abstract

On dryland Digitaria eriantha ammonium sulphate and limestone ammonium nitrate were superior to potassium nitrate and urea. With reference to the level of nitrogen fertilization it was found that levels in excess of 300 kg N/ha, and up to 400 kg N/ha, could be economically justified, even on a pasture with a high basal level of fertility.     

Identification of companion legumes for midmar Italian ryegrass

Abstract

In a preliminary investigation seven legumes were planted alone and in combination with Lolium multiflorum cv. Midmar. The pure stands of legumes were harvested at either four, five or six week cutting intervals, while the pure stands of Lolium multiflorum and the ryegrass/legume mixtures received in addition to the cutting treatments 0, 200 or 400 kg N/ha in four equal applications. The ryegrass and legume components were harvested separately for dry matter yield (DM) and crude protein (CP) determinations.

Trifolium repens and T. pratense were the most suited companion legumes in terms of DM yield, CP content and the ability to extend the growing season. Ornithopus sativus and T. vesiculosum were the most suited annual legumes to grow in combination with L. multiflorum. Nitrogen had a far stronger positive effect on the DM yields and CP content than cutting interval, with the pure stands of L. multiflorum responding the most to nitrogen. The legume DM yields were adversely affected by the addition of nitrogen and by lengthening of the cutting interval. The incorporation of legumes into a ryegrass sward had the greatest positive effect on DM yields and CP content and yield when no nitrogen was applied and when harvested at six week intervals. Dry matter yields of the mixtures were only slightly reduced when half the maximum amount of nitrogen was applied.     

Effect of nitrogen application,seeding rate and defoliation height on mixtures of Trifolium vesiculosum cv Amclo and Lolium Multiflorum cv midmar: II. Yield advantage as reflected in the land equivalent ratio*

Abstract

Pure stands of Trifolium vesiculosum cv Amclo and Lolium multiflorum cv Midmar were compared with a range of mixtures of these two species in terms of dry matter production, crude protein content and crude protein production. Land equivalent ratios (LER) calculated for both dry matter and crude protein production showed that mixing of the two species was advantageous. This was more evident in terms of crude protein production than in DM production. High seeding rates of the grass (20–25 kg/ha), low levels of nitrogen (60 kgN/ha) and heavy defoliation (50 mm) gave the highest LER values. It was concluded that better utilization of land could be obtained with mixtures of the two components than with pure stands.     

Production and quality norms of certain grass species for fodder flow planning: Pretoria area

Abstract

Four subtropical (Cenchrus. Digitaria, Anthephora and Sorghum) and two temperate grass species (Festuca. Agrotricum) were grown in a replicated field experiment at three levels of N application, with adequate P and K. Species were mown at 4‐, 6‐ and 8‐weekly intervals. DM production data for 6‐ and 8‐weekly and 4‐ and 6‐weekly intervals are presented for subtropicals and temperates, respectively.

The object was to determine the seasonal accumulative DM production curves, productivity spread and quality, for use in fodder flow planning.

The subtropical grasses produced 2 to 3 times as much DM as the temperate grasses : CGR 745—1237 versus 345—440 kg/ha/wk under supplementary irrigation. The subtropicals produced ca 2^{h times as much under irrigation than under rainfed conditions.

Festuca and Agrotricum, Digitaria. Athephora and Sorghum, Cenchrus, gave peak CGR's after 9, 15, 16 and 18 weeks after end of August, respectively. Irrigation resulted in peak CGR being reached earlier in the growing season than under rainfed conditions and in subtropicals maintaining a high CGR for 1½ — 2½ months longer.

Various implications of the results for pasture management, and the fact that quality and DM yield generally are antagonistic in subtropical grasses, were discussed.     

播种量和品种对紫花苜蓿植株动态变化、产量及品质的影响

本研究在河南农业大学科教试验园区进行,采用裂区设计,以播量(15.0,22.5,30.0kg/hm2)为主区,8个不同秋眠级苜蓿品种为副区,研究其对植株数量动态、干物质产量、营养品质的影响,旨在为苜蓿生产确定最佳播量和适宜品种,发展精准苜蓿产业提供科学依据。结果表明,(1)3种播量的越冬率无显著性变化(P0.01);但不同苜蓿品种的越冬率有差异,在85.53%~98.24%之间,其中秋眠和半秋眠苜蓿品种的越冬率都显著高于非秋眠品种,从安全越冬考虑,在河南省宜栽培秋眠和半秋眠品种。(2)播种量对植株数量动态变化有极显著影响(P0.01),随着播种量的增加,植株数量不断增加,这种变化趋势在第一生长年非常明显,但随着生长年限的延长,3种播种量的植株数量均呈现出第一生长年急剧下降、第二生长年缓慢下降、第三生长年趋于平稳一致的变化态势;植株数量随生长时间的延长尤其是在年际间变化的规律不因品种而改变。(3)播种量对年干物质产量无显著影响(P0.01),但干物质产量有随播种量增加不断提高的趋势;播种量对营养品质有一定影响,随着播种量的增加,其粗蛋白质(crude protein,CP)和粗脂肪(ether extract,EE)含量、相对饲喂价值(relative feed value,RFV)有上升的趋势,中性洗涤纤维(neutral detergent fiber,NDF)、酸性洗涤纤维(acid detergent fiber,ADF)含量有下降趋势。(4)不同品种对干物质产量和营养品质有一定的影响,从高产和品质综合考虑,以先行者最适合在郑州地区种植;播量在22.5~30.0kg/hm2情况下,有利于提高苜蓿的产量和品质。综上,在河南以种植半秋眠品种为宜,不同播量的苜蓿品种其植株数都有随生长期的延长而减少最后恒定的趋势,在适宜播量范围内,有利于提高苜蓿的产量和品质;在生产实践中,可根据生产目的和播种量选择适宜的品种。     

Herbage yields of thirty grasses fertilized heavily with nitrogen

Prior to 1962 it was thought that 90 to 135 kg N per ha annually gave satisfactory yields of grass herbage. Grasses were consequently selected for their productivity with this amount of applied nitrogen.

It was subsequently shown that the yield response of grasses was linear with up to 450 kg N per ha. Thus it became necessary to test again many commonly‐grown grasses with this high rate of nitrogen.

Thirty grasses were fertilized annually with 450 kg N, 90 kg P₂O₅ and 65 kg K₂O per ha. Herbage yields were determined each time the grasses reached early anthesis . Mean herbage yields over four years varied from 1 700 to 17 900 kg dry matter per ha.

Results showed clearly that stoloniferous grasses were more productive than tufted grasses. The significance of high yielding stoloniferous grasses in relation to beef production in Rhodesia is briefly discussed.     

Influence of nitrogen fertilisation on forage and animal production of a continuously grazed irrigated grass/clover pasture in the Rûens area of the southern Cape

Abstract

The production of an irrigated grass/clover pasture was evaluated under continuous grazing at a range of stocking rates (20.6 to 35.9 Merino ewe units ha^‐1 and two nitrogen fertiliser treatments (0 and 300 kg N ha^‐1 a^‐1) over a period of four years. The clover content of the pastures declined, while the grass component increased with increased pasture age on both nitrogen treatments, leading to grass domination by the end of the trial period. The clover content (%) of the green dry matter (DM) was higher and the grass content (%) lower on the zero‐nitrogen than the nitrogen‐fertilised pastures, with the average daily gain of the sheep and wool production per ewe unit highest at low stocking rates on the zero‐nitrogen treatment. However, the total amount of green DM was higher on the nitrogen‐fertilised than on the unfertilized treatment, resulting in higher stocking rates for maximum wool and meat production per hectare. A higher profit margin was realised at lower stocking rates on the zero‐nitrogen treatment when compared with the fertilised treatment. The low weaning mass of the lambs at high stocking rates on the fertilised pastures questions the profitability of using nitrogen fertiliser on irrigated grass/clover pastures.     

川东地区白三叶引种适应性试验研究

从2003年开始.在四川达州试验点连续5年对拉丁诺和胡依阿两品种白三叶(Trifolium repens)生长发育、根系生长情况、茎叶比、草产量以及种子产量进行观察测定.结果表明,两品种较为适应川东地区的夏季高温伏早天气,能完成整个生育周期,全年生长,无明显枯黄期,青绿期320 d以上.越夏率100%.抗病力强;具有较...     

Identification of companion small grains for midmar Italian ryegrass

Abstract

In a preliminary investigation four small grain species, oats (Avena sativa), rye (Secalae cereale), wheat (Triticum aestivum) and triticale (Triticum × secalae) were planted alone and in combination with Lolium multiflorum cv Midmar under irrigation. The dry matter (DM) yield of Midmar was also compared to that of four other annual ryegrass cultivars. All species combinations were harvested at either three‐ or six‐week cutting intervals and fertilized with either 200 or 400 kg N/ha.

As a group the pure ryegrasses had a greater yield potential than the small grain‐Midmar group which in turn out‐yielded the small grain group. Increasing cutting interval from three to six weeks had a far stronger positive influence on DM production than that of doubling the amount of nitrogen. Rye was the most successful small grain in being able to fill the winter gap in the fodderflow of Midmar ryegrass.

The small grains on average contributed about 25 % towards the total DM production in the small grain‐Midmar mixtures. Oats, although initially slow, had significantly (P≤0,05) higher yields than any of the small grains and had a longer, more evenly distributed growing season.     

刈割频度、播种比例和施肥量对牛鞭草和白三叶混播草地牧草产量的影响

在不同刈割频度、施肥量和混播比例下,对混播草地牛鞭草和白三叶不同种群年总产草量进行了研究。结果表明,刈割频度对产草量的影响最大,其差异达到极显著水平(P<0.01),其中刈割频度为5次的处理鲜草总产量最高。施肥量和播种比例的互作效应对总产草量的影响差异也达到了极显著水平(P<0.01);其中施肥水平低,牛鞭草混播比例低的处理总产草量高;施肥水平高的处理,牛鞭草混播比例高的则总产草量高,而白三叶则相反。因此,牛鞭草和白三叶的混播在合理的管理措施下是有可能的;同时为了达到高产优质,初步认为刈割间期以45d,较高的施肥量和混播比例以2:1为宜。     

施肥水平和刈割制度对鸭茅生产性能的影响

对 1997、1998两年播种量为 2 0kg/hm2 的鸭茅进行播种试验 ,氮肥水平分别是 0 ,37,74,111,148,185kg/hm2 ;刈割频率每年为 2次、3次。氮肥水平增加到 74kg/hm2 时 ,干物质 (DM )产量最高 ,首次刈割推迟 ,刈割周期延长 ,DM产量提高。提早播种对于提高产量有显著影响 ,晚秋 (10月份 )收割会使冬季营养贮备贫乏 ,从而对安全越冬造成威胁。鸭茅总含氮量 2 .5 8% 4.40 % ,在氮肥水平低于111kg/hm2 时 ,含氮量受氮肥水平的影响不大。体外干物质消化率 (IVDMD)受刈割频率的影响较大 ,氮肥水平高于 74kg/hm2 时 ,硝态氮 (NO3 N)积累量超过 0 .15 % ,可能会对家畜造成毒害作用     

Effect of cutting frequency on the yield and quality of legumes and grasses under irrigation

Abstract

Four pasture legumes and seven grasses were subjected to a range of cutting frequencies during the 1980/81 season. A wide range of responses emerged, judged by both the dry matter and TDN yield responses of the different species. Whereas two cultivars of white clover and Ruanui ryegrass were most productive with frequent harvesting (every 2 to 4 weeks), kikuyu and Sirocco Phalaris responded well to a long interharvest interval (8 to 10 weeks). A number of pasture types, including lucerne, Currie cocksfoot, K31 fescue and Ariki ryegrass produced well at intermediate harvesting frequencies (6‐weekly) while in yet others (Kenland red clover and Seedmaster Phalaris) yield was not materially different over a wide range of cutting intervals in the range 6 to 10 weeks.