刈割时间对青贮玉米秸秆饲料营养成分的影响

国外较多的研究是从整株玉米青贮的角度研究不同品种和收获成熟期对青贮饲料营养价值的影响，而国内对青玉米秸秆青贮的研究报道多涉及提高青贮饲料的品质，为此试验选用收刈时间（生长期）为92、94、96、98、100、102和104d的高油115玉米青秸秆调制青贮饲料，研究玉米秸秆收刈时间对青贮饲料营养成分的影响，结果表明收刈时间明显影响青贮饲料的氨态氮、CP和NDF含量，尤其是明显影响青贮饲料的有机物体外降解率，收刈时间对青玉米秸秆青贮饲料的乳酸、丁酸含量和ADF含量没有明显的影响(p>0.05)。     

Hybrid and N Fertilization Affect Corn Silage Yield and Quality

We determined the effect of N fertilization on dry matter (DM) yield, predicted milk yield, and forage quality of fresh (green chopped) and ensiled forage of two brown midrib (BMR) hybrids, a leafy hybrid, and a conventional silage hybrid. Increasing N rates from 0 to 200 kg ha^?1 increased corn grain, stover and whole plant DM yield and milk yield. The forage yield and quality response to N was similar for all hybrids. Nitrogen fertilization increased forage crude protein (CP) concentration but had little effect on other forage quality components. BMR hybrids, F377 and F657, had the lowest grain, stover and whole plant yield but had the highest digestibility and predicted milk yield Mg^?1 of forage. Predicted milk yield ha^?1 was similar for the BMR, leafy and conventional hybrids. Ensiling reduced starch concentration compared with green chopped forage, but effects on other forage quality variables were less consistent. Hybrid and N fertilization affects were similar for green chopped and ensiled corn forage.     

Effect of High Lucerne (Medicago sativa L.) Sowing Rates on Establishment Year Yield, Stand Persistence and Forage Quality

The effect of very high sowing rates on establishment year dry matter (DM) yield and stand persistence of irrigated lucerne ( Medicago sativa L.) was studied. Two cultivars ('Peace' and 'Apollo II') were sown in 1986 at two row spacings and six sowing rates from 5.6 to 50.4 kg ha⁻¹. Established seedling density (S_d) increased linearly with sowing rate (R):S_d= 24.1R. Establishment year DM yield increased at sowing rates from 5.6 to 16.8 kg ha⁻¹, levelled off as sowing rate increased to 33.6 ka ha⁻¹, and then decreased as sowing rate increased further. Thus, there was a broad optimum sowing rate that gave a maximum sowing year DM yield. Percent plant survival to the third year (1988) decreased with increasing sowing rate so that plant densities became similar for sowing rates greater than 16.8 kg ha⁻¹. Within the range 5.6 to 16.8 kg ha⁻¹, increasing sowing rate increased stand persistence measured as 1988 plant density; however, a corresponding increase in DM yield was not obtained. For all full-production years, DM yield was independent of sowing rate. Sowing rate did not affect three chemical measures of forage quality.     

Gaseous Loss of Nitrogen in Paddy Soils

Irrigation practices for rice ( Oryza sativa ) that are common in South Asia were simulated under greenhouse conditions, and the resulting range of gaseous N losses was determined. The interaction of water and fertilizer management for growing paddy rice was quantitatively evaluated at several rates of N fertilization. Continuous flooding, alternate flooding and drying, and dry periods before, after, and during flowering were combined with 3 rates of N, i.e., 0, 50, and 100 mg kg⁻¹ by uniform incorporation and by mud ball placement.
Gaseous loss of native soil N was small (10 mg kg⁻¹) when no fertilizer was applied and the crop stand was adequate. Loss increased to 32 mg kg⁻¹ when stands were halved. Gaseous loss of 41 to 58% were found when fertilizer was applied. Alternate flooding and drying was the least desirable irrigation practice with losses of 40 to 87 mg N kg⁻¹. Placement of N in mud balls reduced gaseous N loss under all irrigation procedures by 14 to 32% compared to uniform application at the low N application rate. Under continuous flooding only 28% of a second increment of 50 mg kg⁻¹ of applied N was lost compared to 82% loss with alternate flooding and drying.     

Effect of Legume Management on Forage Production and Residual Effects on Upland Rice

An experiment was conducted over the period 1995–96 in a warm-temperate environment in Nepal to investigate the effect of cutting frequency on forage yields of three temperate legume species, grown during the winter season, and the residual treatment effects on a subsequent upland rice crop. The three species, Persian clover ( Trifolium resupinatum ), white clover ( Trifolium repens ) and vetch ( Vicia benghalensis ), proved to be well adapted to the winter growing conditions and produced cumulative forage yields between 6.8 t DM ha⁻¹ (vetch) and 9.2 t DM ha⁻¹ (Persian clover). Vetch grew vigorously throughout the winter months and provided reasonable forage yields between December and February, whereas the clovers provided green fodder up to July. These species may therefore make a substantial contribution to alleviating the severe shortage of quality feed during the winter months. Grain yields of the subsequent rice crop ranged from 3.6 to 7.3 t ha⁻¹. Rice yields were greatly affected by the previous legume species and forage management practices. In general, the removal of legume forage greatly reduced the residual effect, and farmers will have to seek a compromise between maximizing green fodder production and the immediate beneficial residual effect of the legume crop on rice yield.     

Intercropping of Corn with Soybean, Lupin and Forages: Silage Yield and Quality

Intercropping of corn with legumes is an alternative to corn monocropping and has a number of advantages, for example, lower levels of inputs, lower cost of production and better silage quality than monocrop systems. An experiment was carried out at two sites in 1993 and 1994 to investigate the effects of seeding soybean or lupin alone or in combination with one of three forages (annual ryegrass, Lolium multiflorum Lam.; perennial ryegrass, Lolium perenne L.; red clover, Trifolium pratense L.) on silage yield and quality. The intercrop plots received 90 kg ha⁻¹ less nitrogen fertilizer than monocrop plots, which received 180 kg ha⁻¹. Corn biomass yield had a variable response to the treatments, but showed no change at most site-years. Soybean and lupin biomass yields were decreased by intercropping (80–98 % for soybean, and 94–100 % for lupin). However, when corn growth was limited due to poor establishment at one site in 1994, soybean was able to grow well and produce yields similar to those of monocropped soybean. The three underseeded forages did not grow well during the period examined (up to silage harvest) and had no effect on the yield of any crop. Total silage yields were similar to corn monocrop biomass yields even during 1994 at the site with low corn population densities because soybean was able to compensate for reduced corn growth.     

不同玉米品种青贮饲料营养成分比较分析

【研究目的】为研究不同玉米品种间的青贮饲料营养物质的差异;【方法】选取104d收刈的青玉米秸秆和饲用玉米调制青贮以研究不同品种玉米青秸秆对青贮饲料营养成分的影响,60d后分析测定青贮饲料营养成分;【结果】结果表明,玉米品种明显影响青贮饲料的氨态氮、乳酸、CP、NDF和ADF含量,青玉米秸秆(粮食用)青贮饲料的乳酸、丁酸含量和ADF含量没有明显差异(p>0.05),饲用玉米青贮的乳酸、丁酸含量显著高于青玉米秸秆的青贮饲料(p<0.05);【结论】不同玉米品种的青贮原料对青贮发酵产物及青贮饲料营养物质含量有明显的影响。     

Uptake and partitioning of sludge-borne copper in field-grown maize (Zea mays L.)

Accumulation of sludge-borne copper (Cu) by field-grown maize and its distribution between the different plant organs was studied in detail in a long-term sewage sludge field trial. Since 1974, field plots on a coarse sandy soil have been amended each year with farmyard manure (FYM) at a rate of 10 t dry matter (DM) ha⁻¹ year⁻¹ and with sewage sludge at the two levels of 10 t DM ha⁻¹ year⁻¹ (SS 10) and 100 t DM ha⁻¹ per 2 years (SS 100). All field plots have been cropped annually with maize. In 1993, five replicate plants per treatment were examined at six different growth stages from seedling to grain maturity. Each plant was separated into at least 12 different parts and the Cu content of each was determined. Regarding growth parameters, no visible deleterious effects on plant development due to the different soil treatments could be observed, although the dry matter yield of roots and stalks of SS 100-treated plants was significantly reduced. Significantly increased Cu concentrations of up to 60 mg Cu kg⁻¹ DM in the roots of young SS 100-grown maize plants and of up to 20 mg Cu kg⁻¹ DM in the upper leaves at silage stage were found. No critical Cu amounts were reached in the grains until harvest.     

Management of Italian and Perennial Ryegrasses for Seed and Forage Production in Crop Rotations

Italian ryegrass (Lolium multiflorum Lam.) and perennial ryegrass (L. perenne L.) can be grown for seed and forage in cold winter regions provided the stand persists well over winter. Seed yield and plant characteristics during primary growth, and forage yield during regrowth, were determined for two Italian and one perennial ryegrass cultivars in Atlantic Canada. Establishment methods and dates included sowing ryegrass in cultivated soil alone or with barley in mid‐May and, after harvesting the barley crop, by sowing ryegrass following conventional or reduced cultivation and by no‐till drilling into barley stubble in mid‐August and early September. Despite some winterkill, particularly in Italian ryegrass, seed and forage yields were adequate in post‐establishment growing seasons. Seed yield for Italian ryegrass was greatest (1270 kg ha^?1) when it was sown into cultivated soil in mid‐August and least (890 kg ha^?1) when sown alone in May. Italian ryegrass yielded 15–17 % more seed when plots were established in mid‐August rather than in mid‐May or early September. Italian ryegrass cv. Lemtal had a greater density of fertile tillers (1030 m^?2) in the sward than cv. Ajax (860 m^?2) and its tiller density was greater when seeded into cultivated soil in September than in mid‐August. There were fewer spikelets per seed head for sowing Italian ryegrass with barley in May than for the other methods of establishment. Forage yield in regrowth was greater for Italian ryegrass cv. Ajax (2770 kg ha^?1) than for cv. Lemtal (2480 kg ha^?1). Seed yield of perennial ryegrass was greater when seeded in mid‐May than in mid‐August or early September. The seed yield of perennial ryegrass was greater when it was sown with barley in May and harvested for grain, than when it was sown alone or with barley harvested at late milk stage. The establishment methods for mid‐August and early September sowing had little effect on seed yield. However, the no‐till and reduced tillage methods resulted in a greater tiller density than sowing into the cultivated seedbed. Fertile tillers tended to be denser under reduced cultivation for sowing in August. Forage yield of perennial ryegrass regrowth was not influenced by the sowing method and timing. In conclusion, Italian and perennial ryegrasses produce adequate seed and forage regrowth under different establishment methods and timing. However, the poor persistence of Italian ryegrass may limit commercial production after the establishment year in Atlantic Canada.     

Maize-Soybean Intercropping: Effect of Different Variety and Sowing Density of the Legume on Forage Yield and Silage Quality

Two studies were carried out to evaluate the effect of different agronomic solutions on the quanti-qualitative yield of maize-soybean intercropping for silage production.
In the first year the research compared the use of two hybrids of the cereal ( Lorena and Luana ) as control and in association wirh soybean varieties of different maturity group [ Futura (I) and King (II)]. In the following growing season the two sowing densities of the soybean (20 vs 40 p/m²) were analyzed.
In both trials the intercropping gave a production similar to that obtained from the cereals control while its protein content was significantly higher.
The maturity group of soybean did not modify yield and chemical composition of the intercropping. This could have been arisen from the unfavourable climatic conditions of the first growing season. In the same trial it appeared the possibility of altering the intercropping yield and composition by choosing the maize hybrid.
The suitable water availability for the cereal recorded in the second study, increased the maize yield reducing the difference in composition between pure crop and mixed forage.
The sowing density of the soybean did not affect the productive response of the intercropping.
Maize-soybean intercropping did not show any detrimental effect during ensiling and ensiling losses were similar to those of the maize silage.     

Agronomic Factors in Evaluating Forage Crops II. Predicting Fiber Components (NDF, ADF, ADL) from Crop Leafiness

The relationship of the stage-to-stage changes in alfalfa herbage leaf percentage and the corresponding changes in fiber components represented by neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) was tested in alfalfa crop diverse in stand and canopy ages, stages of maturity harvested across seasons in two separate years. Regression analyses showed that for all fiber components, leaf percentage consistently provided highly significant linear relationships for predicting herbage fiber content; NDF (r²= 0.915), ADF (r²= 0.937) and, ADL (r²= 0.851). These were highly comparable with the application of the mean stage by weight (MSW) system for predicting NDF (r²= 0.946), ADF (r²= 0.891) and ADL (r²= 0.841) thus indicating the practical use of leaf percentage as a good alternative approach for predicting fiber content of the alfalfa crop.     

Differences between Maize Cultivars in Yield Formation, Nitrogen Uptake and associated Depletion of Soil Nitrate

In a 3-year field experiment conducted on a Gleyic Luvisol in Stuttgart-Hohenheim, ten maize cultivars (nine commercial and one experimental hybrid) were compared in their ability to utilize a high soil nitrogen (N) supply. Total N content of the shoots at about silage maturity ranged from 213 to 328 kg N ha⁻¹ (1986), from 177 to 223 kg N ha⁻¹ (1987) and from 185 to 226 kg N ha⁻¹ (1988). In all three experimental years, total shoot N uptake was significantly positively correlated to stover yield, and also to N concentrations in the ears and in the total plant dry matter. In contrast, a negative correlation between ear yields of the cultivars and total N uptake was indicated. Differences between the cultivars in N uptake were reflected in a corresponding soil nitrate depletion. At harvest, residual nitrate-N in the 0–90 cm soil layer ranged from 34–63 kg N ha⁻¹ m 1987 and 32–71 kg N ha⁻¹ in 1988. The results indicate, that growing of cultivars selected for high N uptake-capactiy of the shoots may contribute to an increased utilization of a high soil N supply and thus to a reduction of nitrate leaching.     

Nitrogen Nutrition of Potato Cultivars Differing in Maturity

In potato, dry matter (DM) production and partitioning between plant organs and N accumulation are affected by N application; however, since cultivars differ in these processes, N fertilization must be adjusted to each cultivar. This paper studies the response of potato cultivars differing in maturity to N fertilization in the south-east of the Buenos Aires Province (37°45'S, 58°18'W) in two growing seasons. Treatments combined four N doses (0–180 kg ha⁻¹) and four cultivars: Jaerla (early), Spunta (mid-early), Mailén INTA (medium late) and Huinkul MAG (late). DM and N content were measured in leaves, stems and tubers throughout the growing season and intercepted photosynthetically active radiation was regularly assessed. There was an increase in tuber yield up to intermediate N doses (60 kg ha⁻¹ in 1990 and 120 kg ha⁻¹ in 1991). Tuber yield was similar for Spunta and Huinkul MAG. There was no interaction between cultivar and N fertilization for tuber dry matter yield. DM partitioning to leaves and tubers during the growing season differed among cultivars, but N availability affected partitioning similarly for all cultivars. Jaerla had a high and Huinkul MAG had a low radiation use efficiency between plant emergence and the beginning of tuber formation. Jaerla, Spunta and Mailén INTA reached maximum N content in foliage at ≈60 days after emergence and Huinkul MAG 20 days later. Total N content at maturity varied between 120 and 250 kg ha⁻¹ and was affected by cultivar and N dose. The results will help to improve N fertilization recommendations and management practices as related to each cultivar under the environmental conditions of this region.     

多花黑麦草在生长兔上的营养价值评定

为评定多花黑麦草在生长兔上的营养价值,研究以福建黄兔为对象,对2 个多花黑麦草品种采用全粪收集法进行消化试验。结果表明：福建黄兔生长兔对多花黑麦草‘美克斯’和‘海里克斯’干物质（DM）、粗蛋白质（CP）、粗纤维（CF）、中性洗涤纤维（NDF）、酸性洗涤纤维（ADF）、粗脂肪（EE）、粗灰分（ash）、钙（Ca）、磷（P）和无氮浸出物（NFE）的表观消化率分别为：52.67%、82.68%、21.70%、26.58%、28.59%、68.37%、57.69%、71.64%、70.82%、64.38%和50.45%、79.53%、24.69%、30.45%、32.69%、69.84%、59.38%、70.48%、69.31%、69.30%。其中生长兔对多花黑麦草DM、CP、EE、Ca 和P 的表观消化率较高,对CF的表观消化率较低。     

Forage Yield and Sucrose Response of Rhodes and Ruzi Grass to Cutting Height and Cutting Frequency Under Irrigation

The development of irrigated pastures in the Sudan is still at its infancy. The present study determined the influence of 2 cutting heights (2.5 and 5.0 cm) and 4 cutting frequencies (4-, 6-, 8-, and 10-week) on forage yield as dry matter and forage sucrose of Rhodes grass ( Chloris gayana Kunth. cv. Massaba ) and Ruzi grass ( Brachiaria ruziziensis Germain et Everard cv. Congo Signal ) under irrigated conditions. Forage yield interactions involving species X cutting height X cutting frequency were significant. These yield interactions were attributed to differences in growth period and growth rhythm of the two species. On average, Rhodes exhibited a short growth period (13 months) compared to Ruzi grass (20 months). Forage yield and forage sucrose were, on average, superior in Ruzi compared to Rhodes grass. Forage yield and forage sucrose averaged 5.2 t ha⁻¹ and 7.2 % fw sucrose in Ruzi compared to 2.8 t ha⁻¹ and 6.9 % fw sucrose in Rhodes grass. Forage yield and forage sucrose of both species were negatively correlated with cutting frequency. The highest forage yield may be obtained at an 8-week cutting frequency in Rhodes (45.6 t ha⁻¹ yr⁻¹) compared to a 10-week cutting frequency in Ruzi grass (88 t ha⁻¹ yr⁻¹). Results suggest that very high forage yields as dry matter and forage sucrose of Rhodes and Ruzi grass may be possible under irrigated conditions in the Sudan at a cutting frequency of between 8 to 10 weeks.     

Spring Barley Responses to Nitrogen Fertilizer and Ethephon in Regions with a Short Crop Growing Season

Aspects of intensive management practices such as high N fertilization inputs and plant growth regulator use could potentially increase cereal yields in regions with a short crop-growing season and occasionally dry and hot weather. A field experiment was carried out for four years (1987 to 1990) at Agronomy Research Centre of McGill University, Canada to evaluate the response of spring barley ( Hordeum vulgare L.) cv. Cadette, Laurier and Leger to N rates (0, 70 and 140 kg N ha⁻¹) and ethephon (2-chloroethyl phosphonic acid) growth regulator treatment. The application of higher than conventional N level (70 kg N ha⁻¹) did not increase barley yields under dry weather conditions and when the soil N resources were high. The high levels of N did increase the grain crude protein concentration by 2 to 10 g kg⁻¹, as did ethephon treatment. The feed quality of spring barley was improved. Ethephon treatment reduced grain yield due to a severe reduction in the number of grains spike⁻¹, and/or 1000-grain weight, although the number of spikes m⁻² was increased. Thus, the overall effect of ethephon treatment on yield was inconsistent and was influenced to a large extent by the prevailing weather conditions.     

凋萎时间对青玉米秸秆青贮饲料营养成分的影响

【研究目的】青贮饲料调制是一项短时间内的突击性工作，刈割青玉米秸秆未能尽快调制青贮致使青贮饲料质量受影响；【方法】为此本试验选用农大108玉米秸秆收获后凋萎的1d、3d、5d、7d调制青贮，以研究刈割后凋萎时间对青贮饲料营养成分的影响；【结果】在本试验的凋萎条件下，试验期内玉米秸秆中干基水溶性碳水化合物含量、水分含量逐渐下降，凋萎7d的水溶性碳水化合物、水分含量显著低于其它处理组，在凋萎的1d、3d、5d、7d调制青贮，凋萎7d的青贮pH和氨态氮比例显著高于凋萎1d(pH,4.82比5.27；氨态氮/总氮,5.90%比8.56%)，但青贮饲料中乳酸、粗蛋白、中性洗涤纤维和酸性洗涤纤维含量没有显著差异。【结论】结果表明收刈后青玉米秸秆5d之内可以调制青贮     

Effects of elevated CO2 and cutting frequency on the productivity and herbage quality of a semi-natural grassland

Monoliths of a fertile, although N limited, C₃ grassland community were subjected (or not) to an atmospheric CO₂ enrichment (600 μmol mol⁻¹), owing to the Mini-FACE system from August 1998 to June 2001, at two contrasting cutting frequencies (3 and 6 cuts per year). The present study reports the effects of elevated CO₂ on the above-ground productivity and on the herbage quality. Elevated CO₂ did not affect the dry matter (DM) yield of the swards in 1999. In 2000, the second year, there was a positive CO₂ effect (+26%) both on the DM and on the nitrogen yields (+30%). With the frequently cut monoliths, the DM of the legume component of the sward was strongly increased by elevated CO₂. This effect became also significant in July 2000 for the low cutting frequency treatment. These results are in good agreement with the concept of an increased legume development and symbiotic N₂ fixation triggered by an increased ecosystem scale demand of N under elevated CO₂. At a low cutting frequency, the DM of the forbs was strongly increased in elevated compared with ambient CO₂. This increased development of the forbs apparently led to a competitive decline of the grasses. Therefore, the total DM yield response to CO₂ was smaller at a low (+15%) compared with a high (+36%) cutting frequency in 2000. An increase in the water soluble sugar content of the bulk forage under elevated CO₂ and a corresponding decline in cell wall contents (NDF) were observed. In June 1999, the decline in NDF was correlated with an increased in-vitro DM digestibility. The forage quality was also indirectly affected by elevated CO₂ through changes in leaf:stem ratio and in botanical composition. At a low cutting frequency, the increased forb content favoured the herbage quality because of a higher digestibility of the forb shoots and, indirectly, through the reduction in the mass of the grass stems. These results emphasise the role of species dynamics for elevated CO₂ impacts on semi-natural grassland productivity and herbage quality.     

Yield and quality components of silage maize in killed and live cover crop sods

In sloping areas with high precipitation, planting maize into live winter cover crop sods may help to alleviate the environmental problems associated with clean-tillage production systems of maize. The present study evaluates the performance of silage maize (Zea mays L.) under several cultivation methods: CC (conventional cropping system, i.e., maize was sown into the bare, autumn-ploughed soil); LGS/CK (maize was planted into a living Italian ryegrass (Lolium multiflorum Lam.) sod which was subsequently herbicidally killed); and LGS/MR (similar to LGS/CK, but the ryegrass was mechanically regulated). The research was conducted in the midlands of Switzerland on a fertile sandy loam under humid conditions during three cropping seasons. With 110 kg N ha⁻¹ (fertilizer nitrogen plus mineral nitrogen of the soil at maize planting), the CC system was much more productive than were the LGS/CK and LGS/MR systems in terms of dry matter and nitrogen yields of maize. Increasing the nitrogen supply to 250 kg N ha⁻¹ considerably reduced the yield advantage of CC over the LGS/CK and LGS/MR systems, indicating that nitrogen was the most limiting factor for maize yield in the mulch seeding systems. With 250 kg N ha⁻¹, the LGS/CK and LGS/MR systems produced greater total yields of digestible organic matter (maize plus ryegrass) than did the CC system, whereas the total nitrogen yield was similar for all cropping systems. The whole-shoot concentrations of nitrogen were highest under CC, irrespective of the level of nitrogen supply. With 110 kg N ha⁻¹, concentrations of phosphorus and magnesium were clearly higher for the mulch seeding systems. There were only minor differences among the cropping methods in the concentrations of potassium and calcium in the whole shoot. When 250 kg N ha⁻¹ were applied, there were no significant variations among the cropping systems in the concentrations of minerals. Changes in the botanical composition of the cover crop sod and in the time and method of cover crop control may help to reduce the competition for nitrogen between maize and the living mulch.     

种植密度对不同类型玉米青贮产量和营养价值的影响

为明确不同类型青贮玉米在临沂地区最佳种植密度,设置了4个密度梯度（60 000、75 000、90 000、105 000株/hm ²）,研究种植密度对专用型青贮玉米雅玉8号和粮饲兼用型玉米登海605饲用产量和营养价值的影响。结果表明：密度对不同类型青贮玉米鲜草、干草产量影响显著,密度增加,青贮玉米鲜草产量和干草产量均先增加后减少,在密度75 000株/hm ²时均获得最高鲜草、干草产量。密度对不同类型青贮玉米粗脂肪、粗灰分、酸性洗涤纤维含量和子粒产量、粗蛋白产量、粗脂肪产量、可消化干物质、相对饲喂价值、无氮浸出物含量和总能量影响显著,密度增加,雅玉8号粗蛋白、粗脂肪含量和可消化干物质、干物质采食量、相对饲喂价值和无氮浸出物含量下降,粗灰分、中性洗涤纤维和酸性洗涤纤维含量呈上升趋势,子粒产量、粗蛋白、粗脂肪产量和总能量先增加后减少,在密度75 000株/hm ²均获得最高子粒、粗蛋白、粗脂肪产量。从饲料总能量来说,专用型青贮玉米雅玉8号和粮饲兼用型玉米登海605在山东临沂地区饲用的最佳种植密度均为75 000株/hm ²。