Annual DM Yield Research Articles

Positive effects of plant diversity on dry matter yield while maintaining a high level of forage digestibility in intensively managed grasslands across two contrasting environments

AbstractThe local abiotic and environmental conditions of a grass‐based farming system may influence the agricultural benefits of mixtures in comparison to pure stands. We investigated the effects of species identities and interactions between grass, legume, and herb species on dry matter yield and sward digestibility and explored how contrasting environments may affect these relationships. We established experimental plots across 11 mixtures and 4 monocultures of perennial ryegrass (Lolium perenne L.), chicory (Cichorium intybus L.), white clover (Trifolium repens L.), and red clover (Trifolium pratense L.) established at two seeding densities in two sites Brody and Szelejewo (Poland) and managed them over a 3‐year period. The two sites were close geographically and had similar climates, but differed in soil types (Luvisols and Cambisols, respectively). We confirmed that the annual DM yields were generally higher on Cambisols soil as compared to Luvisols soil; both individual species effects and species interaction strengths differed across the two contrasting environments. The predicted annual DM yield for the 4‐species mixtures in general gave comparable or higher yields compared to monocultures across the 3 years, with the mixtures giving around 10%–30% higher yields than the weighted average of the monocultures of the constituent species. Analysing the transgressive overyielding it turned out that there was no significant difference between the 4‐species mixtures and best performing monoculture. The benefits of species diversity in our study was greater on less productive site because we found larger overyielding of the 4‐species sward on the Luvisols soil than on the Cambisols soil. Additionally, the effect of mixtures composed by 4‐species increased the yield stability compared to monocultures in the 3‐year period of our study, particularly on Cambisols soil. Sward digestibility applied to average values did not differ much between sites with mixtures performing similarly to monocultures. The reason for that could have been the dynamics of sward botanical composition during study years shifted towards increased perennial ryegrass and decreased proportions of chicory in the sward as well as the observed phenomenon that the species in mixed swards progressed to successive growth stages more slowly than in pure sowing.

Does the "high sugar" trait of perennial ryegrass cultivars express under temperate climate conditions?

The objective was to evaluate water‐soluble carbohydrate (WSC) and crude protein (CP) concentration of perennial ryegrass (PRG) cultivars with different genetic potential for producing WSC under two contrasting agronomic managements in temperate climate (southern Chile). A 4 × 2 factorial design was randomly allocated to 24 plots (31 m2 each, three blocks): four PRG cultivars (diploid standard cultivar, “2nSt”; tetraploid standard cultivar, “4nSt”; diploid high sugar cultivar developed in New Zealand, “2nHSNZ”; and tetraploid high sugar cultivar developed in Europe, “4nHSEU”) and two agronomic managements (“favourable,” defoliations at three leaves per tiller and nitrogen (N) fertilization rate of 83.3 kg N ha−1 year−1; “unfavourable,” defoliations at two leaves per tiller and N fertilization rate of 250 kg N ha−1 year−1). Herbage samples were collected in early spring, spring, summer and autumn. Concentration of WSC did not differ among cultivars in spring and summer, averaging 194 and 251 g/kg DM, respectively. The cultivar 4nHSEU had the greatest WSC concentration in early spring and autumn (187 and 266 g/kg DM, respectively) and the greatest CP concentration across samplings (average 230 g/kg DM). Favourable management improved WSC concentrations in early spring and summer and decreased CP in spring, summer and autumn. Annual DM yield did not vary with cultivar or management, averaging 8.43 t/ha. Within a 12‐month study at one site in a temperate environment in southern Chile, PRG cultivars have not shown a consistent expression of the “high sugar” trait, where a genetic × environment interaction might be operating.

PastureBase Ireland: A grassland decision support system and national database

PastureBase Ireland (PBI) is a web-based grassland management application incorporating a dual function of grassland decision support and a centralized national database to collate commercial farm grassland data. This database facilitates the collection and storage of vast quantities of grassland data from grassland farmers. The database spans across ruminant grassland enterprises – dairy, beef and sheep. To help farmers determine appropriate actions around grassland management, we have developed this data informed decision support tool to function at the paddock level. Individual farmers enter data through the completion of regular pasture cover estimations across the farm, allowing the performance of individual paddocks to be evaluated within and across years. To evaluate the PBI system, we compared actual pasture cut experimental data (Etesia cuts) to PBI calculated outputs. We examined three comparisons, comparing PBI outputs to actual pasture cut data, for individual DM yields at defoliation (Comparison 1), for cumulative annual DM yields including silage data (Comparison 2) and, for cumulative annual DM yields excluding silage data (Comparison 3). We found an acceptable accuracy between PBI outputs and pasture cut data when statistically analyzed using relative prediction error and concordance correlation coefficients for the measurement of total annual DM yield (Comparison 2), with a relative prediction error of 15.4% and a concordance correlation coefficient of 0.85. We demonstrated an application of the PBI system through analysis of commercial farm data across two years (2014–2015) for 75 commercial farms who actively use the system. The analysis showed there was a significant increase in DM yield from 2014 to 2015. The results indicated a greater variation in pasture growth across paddocks within farms than across farms.

Dry Matter Yield Potentials of Some Gamba Grass (<i>Andropogon gayanus</i> Kunth.) Accessions in the Southern Guinea Savanna of Benue State, Nigeria

Benue state of Nigeria has a high potential for ruminant livestock production with its extensive grass cover of the southern guinea savanna, dominate by gamba grass (<i>Andropogon gayanus</i> kunth). However, this and other grasses have not been evaluated for forage utilization in the state. Investigations were therefore conducted to identify suitable genotypes among the local and introduced grasses. Forage dry matter yields of 20 accessions of <i>A. gayanus,</i> from Benue and neighbouring Kogi states were evaluated at three locations in Benue state: Makurdi (7°43’N, 8°32’E). Otupka (7°04’N, 7°39’E) and Yandev (7°22’N, 9°02’E). forage was harvested every six weeks during the rainy season over two years in a completely randomized design with three replicates. There are significant differences in annual rainy season DM yields of the 20 <i>A. gayanus</i> accessions. At Makurdi, DM yields in t/ha varied from 4.7 (Acc.9) to 14.4 (Acc.2), while at Otukpa yields ranged from 7.7 (Acc.4) to 22.3 (Acc.12) and 5.7 (Acc.9) to 14.9 (Acc.18) at Yandev. Average DM yields over the three sites varied from 1.9 (Acc.3 and Acc.6) to 13.4 (Acc.10). based on the DM production, accessions 10, 11 and 18 may be considered for exploitation in Benue state.

Yield and herbage quality from organic grass clover leys—a meta-analysis of Norwegian field trials

A meta-analysis based on experiments in organically cultivated grasslands in Norway was conducted to quantify the effects of management factors on herbage yield and feed quality. A dataset was collected that included 496 treatment means from experiments in five studies carried out at eight locations with the latitude range of 58.8 to 69.6 N between 1993 and 2010. We tested the effect of harvesting system (two vs. three cuts annually), plant developmental stage at the first cut, growth period (temperature sum) and the herbage clover proportion. Plant maturity at the first cut and herbage clover proportion explained to a large extent herbage yield and quality of the first cut and annual yield. The timing of the first cut influenced also the yield and herbage quality of the second cut. The analysis confirmed the importance of legumes performance for herbage yield and quality from grasslands in organic production. Estimated annual herbage DM yield harvested at standardized plant development stage and at average clover proportion was 9 % higher in the two—compared to the three-cut system. The crude protein concentration and in vitro dry matter digestibility was 17 and 3 % higher and the NDF concentration 7 % lower in the annual herbage from the three-cut than from the two-cut system, respectively. The empirical equations developed in this study may be applied to explore different options for grassland management as basis for ration and production planning and in scenario analysis of economic performance of individual and model farms. The equations do also reveal in numeric terms the trade-offs in management practice between high yields, yield digestibility, NDF and crude protein content in organic forage production relying on red clover N2 fixation as the engine in the system.

Seasonal dry matter production, botanical composition and forage quality of kikuyu over-sown with annual or perennial ryegrass

The seasonal growth and low forage quality of kikuyu restrict milk production. The aim of this study was to determine the yield and nutritional value of irrigated kikuyu over-sown with perennial, Italian or Westerwolds ryegrass grazed by dairy cows. The three pasture systems reached optimum growth during different months and seasons. Lowest growth rates occurred during winter. Peak growth rates occurred during spring for the Italian ryegrass–kikuyu, summer for the Westerwolds ryegrass–kikuyu, and late spring and early summer for perennial ryegrass–kikuyu pasture. All three pasture systems had similar total annual dry matter yields (kilograms dry matter [DM] per hectare) during year 1, but the perennial ryegrass–kikuyu pasture achieved a higher annual DM yield during year 2. As kikuyu density increased in kikuyu–ryegrass pastures from winter to summer, the DM and neutral detergent fibre content increased, whereas the metabolisable energy content decreased. All three treatments were deficient in calcium during all seasons and in phosphorus during summer and autumn as a pasture for high-producing dairy cows.

Plant population, yield and water use of lucerne sown in autumn at four sowing rates

Successful establishment of lucerne requires an adequate plant population to maximise yield and maintain stand persistence. The impact of autumn sowing lucerne at four sowing rates was investigated in a split-plot experiment at Lincoln University, Canterbury from 2007-2012. Emerged seedlings represented about 50% of the seeds sown regardless of the 7-16 kg/ha sowing rate. Self-thinning occurred at a faster rate from the higher sowing rates with populations of 80 plants/m2 in all treatments by Year 6. These populations ensured annual DM yields were maximised and similar across sowing dates and rates, in all years. However, the 10 t DM/ha yield in Year 1 was below the 13 t/ha average from Years 2-5. This suggests Year 1 crops were still in an establishment phase in their first spring after autumn sowing. This is supported by the initial spring water use efficiency (WUE) in Year 1 crops of 15-20 kg DM/ ha/mm of water used. This was lower than the 30-40 kg DM/ha/mm in subsequent years, and is consistent with Year 1 crops partitioning a higher proportion of assimilate below ground during the establishment phase. These calculated WUE values were probably overestimated because they were based on NIWA assumptions of 150 mm of available water for pastures, which appears to be too low for lucerne. Keywords: alfalfa, Medicago sativa

Botanical composition, production and nutrient status of an originally Lolium perenne-dominant cut grass sward receiving long-term manure applications

Effects of long-term applications (50, 100 and 200 m3 ha−1y−1) of pig and cow slurries on yield, botanical composition and nutrient content of herbage of an original perennial ryegrass sward were assessed in a three-cut silage system and compared with unamended and fertilized controls in the 36th year of the experiment. Cow slurry at 50 m3 ha−1 produced similar annual herbage DM yield to 200 kg ha−1 fertilizer N in 2006, whereas about 100 m3 ha−1 pig slurry were required to produce a similar amount of DM. The highest slurry application rate significantly influenced sward botanical composition without depressing DM yield. The principal invading species were creeping bent and meadow grasses (similar to findings at a previous assessment in 1981) except in the unamended control (which were common bent and Yorkshire fog). Perennial ryegrass remained a main species in plots receiving fertilizer (31 % annual DM yield) and low slurry rates (38 %) but declined to 3 % annual DM yield at the highest slurry rate where the ability of ryegrass to utilize slurry N and P may have been affected by chemically or physically induced deficiencies of other nutrients (e.g. Ca) or direct physical effects such as smothering.

답리작으로 호밀과 헤어리베치의 단, 혼파 재배 시 우분뇨 및 화학비료의 시용에 따른 생산성 평가

본 실험에서는 답리작으로 호밀과 헤어리 베치를 단파 혹은 혼파 재배 시 화학비료와 가축분뇨의 시용에 따른 생산성과 사료가치를 평가하여 양질의 조사료 자원을 확보하고자 실시되었는데, 그 결과를 요약하면 다음과 같다. 답리작으로 호밀 단파구와 호밀 및 헤어리 베치 혼파구의 연 평균 건물과 가소화양분총량(TDN) 수량은 각각 ha 당 7.2와 4.0 ton 및 8.0과 4.4 ton으로 헤어리 베치 단파구의 연 건물수량과 TDN 수량(4.5 및 2.7 ton/ha) 보다 유의하게 높았다(p<0.05). 또한 호밀과 헤어리 베치의 혼파재배구(7.7%)가 조단백질 함량이 호밀 단파구보다 높았으며 TDN 함량과 RFV(각각 55.8과 79.4)도 높았다. 호밀재배 시 액상우분뇨를 100% 시용한 구에서는 연 건물수량과 TDN 수량이 ha 당 각각 7.4과 4.1 ton으로 인산과 칼리만 시비한 구(7.2와 3.9 ton/ha)와 무비구(5.5와 3.1 ton/ha) 보다 높았으며 화학비료 대비 연 건물수량과 TDN 수량이 각각 75.52와 78.97%의 수준을 나타내었다. 또한 TDN 함량과 RFV도 무비구와 액상우분뇨가 다른 처리구 보다 높게 나타났다. 호밀과 헤어리 베치 혼파재배 시 액상우분뇨를 100% 시용한 구에서는 ha 당 각각 7.6과 4.5 ton을 나타내어 질소, 인산 및 칼리 시비구 대비 연 건물수량과 TDN 수량이 79.50과 86.77%의 수준을 나타내었고 조단백질 함량은 액상우분뇨 시 용구에서 8.5%로 다른 처리구 보다 유의하게 높았으며(p<0.05), TDN 함량과 RFV도 각각 58.3%와 86으로 가장 높게 나타났다. 이상의 결과를 종합해 볼 때, 호밀의 단파보다는 헤어리 베치와의 혼파가 건물수량은 감소하지만 사료가치의 개선 및 영양수량의 증가를 초래하였으며 이와 더불어 화학비료 시비구 보다 액상우분뇨 시용으로 자원의 재활용, 조사료의 품질 개선 및 사료가치의 급감을 방지하여 수확시기 연장 등을 기대할 수 있었다. This study was carried out to evaluate the effect of application of cattle manure and chemical fertilizer on dry matter productivity and nutritive values of rye and hairy vetch according to two different sowing methods such as single or mixed-sowed cultivation. Dry matter and TDN yields for rye single culture, and rye and hairy vetch mixed culture were 7.2 and 4.0 ton/ha, and 8.0 and 4.4 ton/ha, respectively. They were significantly (p<0.05) higher than that (4.5 and 2.7 ton/ha) of hairy vetch single culture. Moreover, plots produced by mixed-sowing cultivation had a higher crude protein (CP) as 7.7% than that of only rye plot, and higher TDN and RFV as 55.8 and 79.4%, respectively. Within rye alone plots, completely cattle slurry application produced significantly higher annual DM and TDN yields (7.4 and 4.1 ton/ha) than those of P+K fertilization (7.2 and 3.9 ton/ha) as a chemical fertilizer and non-fertilizer (5.5 and 3.1 ton/ha). Cattle slurry application plot revealed 75.52 and 78.97% of N+P+K fertilization plot for annual DM and TDN, respectively. Within mixed-sowing cultivation with rye and hairy vetch, completely cattle slurry application produced 7.6 ton/ha DM and 4.5 ton/ha TDN, showing 79.50 and 86.77% of N+P+K fertilization plot, respectively. Furthermore, the CP content for cattle slurry plots was 8.5%, which was significantly (p<0.05) higher than those of other plots, and it was also highest in TDN (58.3%) and RFV (86). Overall, rye mixed-sowing with hairy vetch rather than rye alone sowing reduced DM yields, but leaded to enhancement of feed value and nutritive yields. And also, it would be expected that cattle slurry application in comparison with chemical fertilizers might result in reutilization of resources, improved forage quality and, extended harvest period by preventing feed value from rapidly deteriorating.

유휴 논 토양에서 액상 우분뇨의 시용이 톨 페스큐의 건물수량과 사료가치에 미치는 영향

본 실험은 유휴 논토양에 톨 페스큐를 재배하였을 때, 액상우분뇨를 물로 희석하거나 희석하지 않고 시기를 다르게 시용하여 계절별 및 연간 건물수량과 사료가치를 조사하고 화학비료 시비에 따른 건물수량과 사료가치도 비교하여 액상우분뇨의 적정 시용 시기와 희석수준을 결정하고자 실시되었으며, 그 결과를 요약하면 다음과 같다. 1) 액상우분뇨를 물로 희석하지 않거나 희석하여 시용하였을 때 연간 건물수량이 ha당 각각 <TEX>$10.57{\sim}12.51$</TEX> 톤(평균 11.50 ton DM/ha)과 <TEX>$11.31{\sim}14.81$</TEX> 톤 (평균 13.13 ton DM/ha)으로 무시비구의 ha당 9.21톤 보다 높은 건물수량을 나타내었는데(Table 2), 액상우분뇨를 이른봄과 여름철 시용한 구(SA구)와 이른 봄, 늦봄 및 여름철 분할 시용한 구(SUA구) 그리고 액상우분뇨를 물로 희석하여 봄철에 전량 시용한 구(DS구), 이른봄과 여름철에 시용한 구(DSA 구) 및 이른 봄, 늦봄 및 여름철에 분할 시용한 구(DSUA구) 등에서 무시비구 보다 유의하게 높은 건물수량을 나타내었다(p<0.05). 2) 질소와 인산 및 칼리를 시비한 구에서는 ha당 15.38 톤의 연간 건물수량을 나타내어 무시비구와 인산과 칼리 시비한 구(10.68 톤/ha) 보다도 유의하게 높은 건물수량을 나타내었다(p<0.05). 또한 인산과 칼리 시용구의 연간 건물수량은 액상우분뇨 시용구의 평균 연간 건물 수량보다도 낮았다. 3) 화학비료구에서 무기태 질소의 건물생산 효율은 연 평균 31.3kg DM/kg N이었으며, 예취 시기별로 보면 2번초>1번초>3번초 순으로 낮아졌지만 액상우분뇨 질소의 연간 건물생산 효율은 무 희석구와 희석구가 각각 15.3과 26.1kg DM/kg N을 나타내었고 2번초에서 가장 높았다. 한편 무기태 질소 대비 액상우분뇨 질소의 건물생산효율은 무희석구와 희석구가 각각 48.9와 83.4%에 도달하였다. 4) 톨 페스큐의 연간 평균 조단백질 함량은 액상우분뇨 시용구에서 <TEX>$9.9{\sim}11.6%$</TEX>로 무시비구의 9.5%와 화학비료 구의 <TEX>$9.0{\sim}9.8%$</TEX> 보다 유의하게 높았지만(p<0.05), 연간 평균 NDF와 ADF 함량은 무시비구가 가장 낮았고 무시비구의 상대 사료가치(RFV)와 TDN 함량은 모든 처리구보다 유의하게 높았다(p<0.05). 5) 액상우분뇨 시용과 희석시용으로 톨 페스큐의 연간 조단백질 수량과 가소화 양분수량은 무시비구 및 인산과 칼리를 시용한 구 보다 유의하게 높았는데(p<0.05), 이러한 경향은 액상우분뇨를 희석하여 이른 봄, 늦봄 및 여름철에 분할 시용한 구(DSUA구)에서 더욱 뚜렷하였다. This experiment was conducted to investigate effects of application of diluted and undiluted cattle slurry with water on seasonal and annual dry matter yields and feed values of tall fescue in the uncultivated rice paddy and it was compared with chemical fertilizer in order to determine optimal application season and dilution level of cattle slurry. When diluted or undiluted cattle slurry with water was applied to uncultivated rice paddy, annual dry matter yields showed 11.31 to 14.81 ton DM/ha (average 13.13 ton DM/ha) for diluted and 10.57 to 12.51 ton DM/ha (average 11.50 ton DM/ha) for undiluted cattle slurries, these had a higher dry matter yield than those of no fertilizer (9.21 ton DM/ha). Furthermore, separate application of early spring and summer (SA plots), separate application of early and late spring, and summer (SUA plots) fur undiluted cattle slurries, and whole application of spring (DS plots), separate application of early spring and summer (DSA plots), separate application of early and late spring, and summer (DSUA plots) for diluted cattle slurries were significantly (P<0.05) higher for annual dry matter yield than no fertilizer plots. Plots applied chemical fertilizer with nitrogen (N), phorphorus (P) and potassium (K) had 15.38 ton DM/ha annually, resulted in significantly (P<0.05) higher DM yield than chemical fertilizer containing P and K, and no fertilizer plots. Moreover, average annual DM yield for the chemical fertilizer with P and K was lower than that of cattle slurry applications. The efinciency of DM production for mineral nitrogen of chemical fertilizers was annually average 31.3 kg DM/kg N. In terms of cutting time of tall fescue, it was lowered in the order of 2nd growth followed by 1st and 3rd growth. However, efficiencies of annual DM production of nitrogen for diluted and undiluted cattle slurries were 26.1 and 15.3 kg DM/kg N, respectively, especially, highest in 2nd growth. While, efficiencies of DM production for cattle slurry versus for mineral nitrogen were 48.9 (undiluted) and 83.4% (diluted), respectively. For annual crude protein (CP) contents of tall fescue, aqueous cattle slurry applications showed 9,9 to 11.6%, which were significantly (P<0.05) higher than no fertilization (9.5%) and chemical fertilizer (9.0 to 9.8%), but annual average NDF and ADF contents were lowest in no fertilization. On the contrary, relative feed value (RFV) and total digestible nutrients (TDN) of no fertilizer plots were significantly (P<0.05) higher than the other plots. The application of cattle slurry and their dilution significantly increased yields of crude protein and total digestible nutrients compared with no and/or P and K fertilizers (P<0.05). These trends were much conspicuous in water-diluted cattle slurries applied in the early and late spring and summer, separately (DSUA plots).

Yield, persistence, and nutritive value of autumn harvested tall fescue

Tall fescue, harvested or grazed in autumn, may be a potential source of forage but little is known of the effect of a fall harvest or grazing on yield and nutritive value of tall fescue in the mid-north of eastern Canada (˜ 1400 growing degree-days). Three tall fescue cultivars (Courtenay, Kokanee, and Montebello) were submitted to 10 harvest management treatments (two dates of second harvest and five dates of third harvest) over 3 production years in the Saguenay-Lac-St-Jean region (QC). The cultivars Courtenay and Kokanee were more productive and persistent than Montebello. The annual DM yield decreased by an average of 15% between the first and the second production year and by an average of 35% between the first and the third production year; these decreases were greater (22 and 41%, respectively) when the third harvest was taken in early October. Increasing from 28 to 35 d the interval between the first and second harvests increased DM yield of the second harvest by more than 0.5 Mg ha-1, but caused a greater reduction in DM yield of the third harvest, primarily during the first 2 production years. Third-harvest DM yields of more than 4.0 Mg ha-1 were obtained in the first and second production years, while third-harvest DM yields varied from 2.5 to 3.0 Mg ha-1 in the third production year. With the delay of the third harvest in autumn, the concentration of crude protein decreased to 120 g kg-1 DM, the concentration of water-soluble carbohydrates increased to 150 g kg-1 DM, while that of acid detergent fibre changed very little. Tall fescue has a significant yield potential in late summer and early autumn in the mid-north of eastern Canada, primarily in the first 2 production years. However, harvesting or grazing tall fescue in the week preceding or following the first killing frost will reduce persistence and spring regrowth the following year. Key words: Lolium arundinaceum (Schreb.) S. J. Darbyshire, cutting management, cultivars, water-soluble carbohydrates

The performance of a white clover based dairy system in comparison with a grass/fertiliser-N system. I. Botanical composition and sward utilisation

The performance of a white clover based dairy system in comparison with a grass/fertiliser-N system was studied during three years. Mixed swards of perennial ryegrass and white clover were established successfully through reseeding or sodseeding. Both systems had 59 dairy cows and a milk quota of 450 tonnes per year. The allocated areas of 41 ha for the grass/clover system and 34 ha for the grass/fertiliser-N system were based on an expected yield difference of 15 to 20% in favour of the grass/fertiliser-N swards. The grassland management consisted of a rotational grazing system with one to three silage cuts per paddock, depending on herbage growth. The average white clover ground cover was 31, 30 and 26% in the three subsequent years, but with a large variation between seasons and paddocks. Season, clover variety and sward age × clover variety explained 28% of the variance in clover cover, but 72% remained unexplained. Grass/clover and grass/fertiliser-N swards received 69 and 275 kg N ha −1 year −1, respectively, including the inorganic N from applied cattle slurry, but excluding animal excreta during grazing. The average annual net DM yield from grass/fertiliser-N swards was 10.8 t ha −1 and from grass/clover swards 10.1 t ha −1. The yield difference occurred mainly in spring, but was smaller than expected, causing a relative silage surplus for the grass/clover system. The OMD of grass/clover was slightly, but consistently, higher than that of grass-only, while the CP concentration of grass/clover was consistently higher from July onwards. It is concluded that mixed swards of perennial ryegrass and white clover can function as a sound basis to produce good quality herbage for a dairy system.

Produção de forrageiras anuais de estação fria no litoral sul do Rio Grande do Sul

Forrageiras anuais de estação fria, Avena strigosa Schreb cv. IAPAR-61 Ibiporã, Lolium multiflorum Lam cv. Comum, Lotus subbiflorus Lag. cv. El Rincón, Avena sativa L. cv. UPF-16, Trifolium subterraneum L. cv. Woogenellup, Trifolium resupinatum L. var. resupinatum cv. Kyambro, Secale cereale L. cv. BR-1, Trifolium vesiculosum Savi cv. EMBRAPA-28 Santa Tecla e Vicia angustifolia L. foram avaliadas usando um delineamento experimental de blocos ao acaso com três repetições, no período de 1994 a 1996, na Estação Experimental Terras Baixas da EMBRAPA - Clima Temperado, Pelotas, RS, em Planossolo, unidade de mapeamento Pelotas. A área recebeu preparo convencional e adubação conforme análise do solo. Os cortes foram efetuados a cada 28 dias, sendo o primeiro 60 dias após a emergência. Os rendimentos médios anuais de MS (kg/ha•ano) e os teores médios de PB e FDN foram determinados. Houve efeito da interação entre anos e espécies. Avena strigosa IAPAR-61, L.multiflorum Comum e L.subbiflorus Rincón foram destaque, pelo alto potencial de produção de forragem, assim como pelo crecimento nos períodos outono/inverno, inverno/primavera e primavera, respectivamente. Todas as espécies avaliadas produziram forragem de alto valor nutricional, em termos dos teores de PB e FDN. Vicia angustifolia teve sempre o mais alto teor de PB e a maior produção relativa de inverno. Trifolium subterraneum Woogenellup foi a única espécie que produziu sementes viáveis suficientes para assegurar adequada regeneração natural da planta no início do segundo ano.

Effects of white clover (Trifolium repens L.) on plant and soil nitrogen and soil organic matter in mixtures with perennial ryegrass (Lolium perenne L.).

To increase our insight into the above- and belowground N flows in grass and grass-clover swards relations between crop and soil parameters were studied in a cutting trial with perennial ryegrass (Lolium perenne) monocultures and ryegrass-white clover (Trifolium repens) mixtures. The effects of clover cultivar on herbage yield, the amount of clover-derived nitrogen, apparent N transfer to companion grass, dynamics of N and organic matter in the soil were estimated. The grass monocultures had very low DM yields (<2.1 t ha[-1]) and a low N concentration in the harvested herbage. During 1992-1995 the annual herbage DM yield in the mixtures ranged from 7.0 to 14.3 t ha[-1], the white clover DM yield from 2.4 to 11.2 t ha[-1] and the mean annual clover content in the herbage DM harvested from 34 to 78%. Mixtures with the large-leaved clover cv. Alice yielded significantly more herbage and clover DM and had a higher clover content than mixtures with small/medium-leaved cvs. Gwenda and Retor. Grass cultivar did not consistently affect yield, botanical composition or soil characteristics. The apparent N[2] fixation was very high, ranging from 150 to 545 kg N ha[-1] in the different mixtures. For each tonne of clover DM in the harvested herbage 49 to 63 kg N was harvested, while the apparent N transfer from clover to grass varied between 55 and 113 kg N ha[-1] year[-1]. The net N mineralization rate was lower under monocultures than under mixtures. The C mineralization and the amounts of C and N in active soil organic matter fractions were similar for monocultures and mixtures, but the C:N ratio of the active soil organic matter fractions were higher under grass than under mixtures. This explains the lower N mineralization under grass.

Productivity and composition of bromegrass alfalfa mixtures for hay in the Aspen Parklands of western Canada

Dry matter yield of smooth bromegrass (Bromus inermis Leyss.) - alfalfa (Medicago sativa L.) mixtures is restricted by short growing seasons and poor legume persistence in the Aspen Parklands of western Canada. Meadow bromegrass (Bromus riparius Rehm.) has recently gained acceptance, but comparative information on smooth and meadow bromegrass in grass-alfalfa mixtures is unavailable. We examined DM yield of binary grass-legume mixtures containing either Carlton or Manchar smooth bromegrass or Regar meadow bromegrass with Peace or Beaver alfalfa under a two-cut hay-management system at four sites in central Alberta for 3 yr. Annual DM yield was 40% greater (P ≤ 0.0001) at sites near Lacombe (7570 kg ha−1) than at Bluffton and Vegreville (5420 kg ha−1). Dry matter yield of smooth bromegrass mixtures (8020 kg ha−1) was 20% higher (P ≤ 0.01) than that of meadow bromegrass mixtures (6690 kg ha−1) near Lacombe. Alfalfa DM yield was 2.1 times higher at Bluffton and Vegreville (2770 kg ha−1) than near Lacombe (1300 kg ha−1). Near Lacombe, alfalfa regrowth was suppressed (P ≤ 0.0001) by smooth bromegrass, which had 2.3 times larger (P &lt; 0.001) tillers than meadow bromegrass at first cut. At Bluffton and Vegreville, DM yield of meadow bromegrass mixtures equalled or exceeded (P ≤ 0.05) that of smooth bromegrass mixtures. Although first-cut tiller weight of smooth bromegrass was 73% more (P ≤ 0.0001) than that of meadow bromegrass at Bluffton and Vegreville, tiller density of meadow bromegrass was 1.7 times greater (P ≤ 0.0001) than that of smooth bromegrass. Results indicate that smooth bromegrass mixtures were superior to meadow bromegrass mixtures for hay production at moist fertile locations, despite reduced alfalfa persistence. At drier or less fertile sites, however, DM yield of meadow bromegrass mixtures was higher than that of smooth bromegrass mixtures when weather conditions for regrowth were favourable. Key words: Bromegrass-alfalfa mixtures, hay, parklands

Effects of harvesting systems on yield, persistence, and nutritive value of alfalfa

The number of annual harvests and the interval between harvests affect DM yield, persistence, and nutritive value of alfalfa (Medicago sativa L.). The effects of harvesting alfalfa three times annually, with the intervals between harvests varied and with the third harvest taken prior to, during, or after the critical fall rest period, were investigated from 1985 to 1988 on a field of alfalfa established in 1984. Seven harvesting systems, comprising three harvests with varied regrowth intervals and a two-harvest system, were studied along with two rates of potassium fertilization. Harvesting alfalfa three times a year, with the third harvest taken during or after the critical fall rest period, produced the largest yields of DM, digestible DM, and crude protein. Dry matter yield was not reduced in three-harvest systems when the third harvest was taken during the critical fall rest period, provided there was an interval of approximately 500 growing degree-days between second and third harvests. Taking the first harvest at the early bud stage of development instead of the early bloom stage reduced annual DM yields. Increasing annual potassium fertilization from 200 to 400 kg K ha−1 did not affect DM yield or persistence under any harvesting system. Harvesting management of alfalfa in the fall should be based on the duration of the growth period between the second and third harvests instead of a critical fall rest period based on calendar dates.Key words: Medicago sativa L., yield, nutritive value, persistence, harvest management, K fertilization

The effect of fertilizer sulphur on grass production for silage

AbstractThe effects of rate and pattern of fertilizer S application on herbage production from Perennial ryegrass‐dominant swards at six potentially S‐deficient sites in south‐west Scotland were measured under a silage cutting regime (3 cuts year‐1) with high fertilizer N application (300 kg ha−1 year‐1). Fertilizer S (as gypsum) was applied at annual rates from 0 to 48 kg ha−1 as single spring applications before the first cut or split before each of the three cuts. The residual effect of S in the year following its application was assessed at one site.Applied S increased total DM production at four of the six sites. These increases were restricted to the second and/or third cuts and were generally in the range 10‐30% greater than where no S was applied. Timing of S application was not important in influencing annual DM yield. The residual effect of gypsum in the year following application was small.The supply of available soil S is limiting herbage production in certain areas and soil types of south‐west Scotland. Areas of S deficiency are likely to increase in the future and need to be identified more precisely than they are at present.

Dry matter production and nitrogen utilization in cropping systems with grass, lucerne and maize. 1. Comparison of crop characteristics, growth and production.

DM production and crop characteristics of Medicago sativa were studied in comparison with Lolium perenne and maize under temperate conditions and various N applications. Annual DM yields of M. sativa ranged from 13.4 to 18.1 t/ha and were comparable to those of L. perenne and maize. However, the digestibility of M. sativa was lower than that of L. perenne cut for silage and that of maize. Despite significant differences in leaf:stem ratio, specific leaf area and LAI, full light interception was achieved with the same amount of DM for L. perenne and M. sativa. After defoliation by cutting, the time taken to regenerate a closed crop canopy did not differ. DM losses of M. sativa by root and shoot senescence were measured. The decline in tap root number was compensated for by the number of shoots per tap root. It was concluded that the yield potential of M. sativa could be improved by breeding for earlier cv. with a good persistence of roots and shoots. (Abstract retrieved from CAB Abstracts by CABI’s permission)

An assessment of insidious pest damage to 26 varieties of seven species of herbage legumes

During 1977–79 the dry-matter yield of 26 herbage legume varieties receiving frequent applications of the organophosphorous pesticide phorate was compared with that of untreated plots. The total annual DM yield of sainfoin and lucerne was not affected by pesticide treatment. White clover yield was affected: pesticide application increased the DM production of the nine varieties studied by, on average, 9% in 1978 and 13% in 1979. The proportion of white clover present in white clover/ryegrass plots was enhanced by pesticide treatment. No attempt was made to establish the identity of the pest group(s) that may have been responsible for these effects. In a second experiment there was no significant effect on seedling establishment from phorate treatment applied to six legume varieties at the time of sowing.

The effects of nitrogen fertilizer applied in spring on swards of ryegrass sown with four cultivars of white clover

AbstractNitrogen fertilizer was applied at 0, 30,60 and 90 kg N ha‐1 in March 1976, 1977 and 1978 to plots containing perennial ryegrass cv. Barlenna sown either alone or with white clover cv. Blanca, Sabeda, Olwen and S100 in four replicated blocks.Dry matter (DM) yield of all swards responded positively to N with the response being highest in the no‐clover swards in two of the three years. Annual DM yields were lower in the no‐clover than in the mixed swards at any given N level. The higher levels of N reduced DM yield in mixed swards at some harvests in midsummer.Swards of S100 were consistently among the lower yielding mixed swards, whereas the other three clover cultivars varied in their relative yields. There were no N x cultivar interactions for white clover yields; irrespective of cultivar, N application reduced annual white clover yield by similar amounts.It is concluded that it is beneficial to apply moderate amounts of N fertilizer to mixed swards in spring and that under these conditions the yield differences between swards including medium‐large and smaller leaved white clover cultivars are similar to differences between the inherent yield potential of these cultivars in mixed swards receiving no N.