Bermudagrass Yield Research Articles

Estimating Bermudagrass Aboveground Biomass Using Stereovision and Vegetation Coverage

Accurate information about the amount of standing biomass is important in pasture management for monitoring forage growth patterns, minimizing the risk of overgrazing, and ensuring the necessary feed requirements of livestock. The morphological features of plants, like crop height and density, have been proven to be prominent predictors of crop yield. The objective of this study was to evaluate the effectiveness of stereovision-based crop height and vegetation coverage measurements in predicting the aboveground biomass yield of bermudagrass (Cynodon dactylon) in a pasture. Data were collected from 136 experimental plots within a 0.81 ha bermudagrass pasture using an RGB-depth camera mounted on a ground rover. The crop height was determined based on the disparity between images captured by two stereo cameras of the depth camera. The vegetation coverage was extracted from the RGB images using a machine learning algorithm by segmenting vegetative and non-vegetative pixels. After camera measurements, the plots were harvested and sub-sampled to measure the wet and dry biomass yields for each plot. The wet biomass yield prediction function based on crop height and vegetation coverage was generated using a linear regression analysis. The results indicated that the combination of crop height and vegetation coverage showed a promising correlation with aboveground wet biomass yield. However, the prediction function based only on the crop height showed less residuals at the extremes compared to the combined prediction function (crop height and vegetation coverage) and was thus declared the recommended approach (R2 = 0.91; SeY= 1824 kg-wet/ha). The crop height-based prediction function was used to estimate the dry biomass yield using the mean dry matter fraction.

Determination of Feed Yield and Quality Parameters of Bermudagrass (Cynodon dactylon L. (Pers.)) Populations Collected from Natural Flora

A two-year study (2020–2021) was conducted in the Erzurum province to investigate the feed quality parameters of 102 genotypes of Bermudagrass (Cynodon dactylon) collected from different locations in natural flora. Two control cultivars were also examined in this study, namely Coastal and Survivor. Parameters such as the fresh herbage weight, dry herbage weight, crude protein (CP) ratio, acid detergent fiber (ADF) ratio, neutral detergent fiber (NDF) ratio, and relative feed values (RFVs) were analyzed. In the first year of this study, Bermudagrass populations collected from natural flora were rooted in pots under greenhouse conditions. In the second year, the rooted plants were transplanted into experimental fields at the Atatürk University Plant Production Implementation and Research Center. The present genotypes generally had superior crude protein, ADF, NDF ratios, and relative feed values (RFVs) than the control cultivar. The fresh herbage weights ranged from 9.20 to 95.37 g per plant, while the dry herbage weights varied from 5.22 to 45.24 g per plant. The findings of this study showed that most of the genotypes collected from natural flora had superior feed quality parameters to the control genotypes.

Different mowing frequencies affect nutritive value and recovery potential of forage bermudagrass

Mowing is one of the most effective methods of pasture management, and frequency plays a critical role in management strategies. Bermudagrass (Cynodon dactylon (L.) Pers.) is a highly valuable forage grass due to its exceptionally high mowing recovery rate and its high potential to be used as a forage crop. In China, bermudagrass is increasingly becoming a crucial forage crop because of the growing demand from the livestock industry. The objective of the present study was to determine the effect of mowing frequencies on forage bermudagrass (‘Wrangler’) yields and nutritive value. Four treatments with different mowing frequencies (2, 4, 6 and 12 weeks) were evaluated. Harvested grasses were assessed for yield and nutritive value. The shoot dry weight, crude fibre and N content did not exhibit any difference at various mowing frequencies. The highest content of crude protein was attained at the 2-weeks mowing frequency, although the 4-weeks mowing frequency resulted in a relatively higher shoot fresh weight, crude fat content, water content, P concentration and plant height. A persistently high upregulation of NRT1, PHT1, PHT2, AOC, AOS, MYC2 and NCED1 genes were observed at 4-weeks frequency. Yield was highest at 4- and 6-weeks mowing frequencies. Consequently, the 4-weeks frequency was considered to be the optimal mowing frequency in view of the forage quality and regrowth capacity.

28 Three-year evaluation of yield and nutritive value of tifton-85 bermudagrass and tifton-85 bermudagrass-alfalfa mixtures produced as baleage in the southeast

Abstract Interseeding a legume, such as alfalfa (Medicago sativa), into bermudagrass (Cynodon dactylon) for baleage production can improve forage quality, reduce supplementation needs, and minimize production losses. The objective of this research was to compare the nutritive value and yield of bermudagrass with and without interseeded alfalfa when produced as baleage. This study was conducted at the University of Georgia Coastal Plain Experiment Station in Tifton, GA, on an established field of ‘Tifton 85’ (T85) bermudagrass. Ten 0.2-ha plots were randomly assigned to either T85+N or T85 interseeded with ‘Bulldog 805’ alfalfa (T85+Alf). T85+N received N fertilization (84 kg N/ ha) four times each growing season. Plots were harvested at early bloom stage every 28 to 35 days from 2016 to 2018, baled at 40–60% moisture, and individually wrapped. At each harvest, plots were evaluated for botanical composition and forage yield, and bales were sampled prior to wrapping for nutritive value analysis. Plots were also evaluated for botanical composition using the point-transect method 10 days post-harvest. Data were analyzed using mixed models and least significant differences at α = 0.05. Although seasonal yields were greater in the T85+N during year 1, alfalfa-bermudagrass plots produced at least one additional harvest each season of the study, and on average 8 cuttings per season each year following establishment. Ultimately this contributed to greater (P < 0.0001) cumulative yield in the alfalfa-bermudagrass treatment (34,783 vs. 25,608 kg/ha, respectively). Analyses of nutritive value through near-infrared spectroscopy (NIR) show that CP and in-vitro true digestibility (IVTD) were greater (P = 0.005 and P = 0.034, respectively) in the alfalfa-bermudagrass treatment than the bermudagrass-only treatment (14.0 vs 11.4% CP and 66.7 vs. 60.2% IVTD, respectively). Improvements in seasonal yield and nutritive value makes bermudagrass interseeded with alfalfa a viable option for baleage producers in the Southeast.

102 Three-year evaluation of yield and nutritive value of Tifton-85 bermudagrass and Tifton-85 bermudagrass-alfalfa mixtures produced as baleage in the Southeast

Abstract Interseeding a legume, such as alfalfa (Medicago sativa), into bermudagrass (Cynodon dactylon) for baleage production can improve forage quality, reduce supplementation needs, and minimize production losses. The objective of this research was to compare the nutritive value and yield of bermudagrass with and without interseeded alfalfa when produced as baleage. This study was conducted at the University of Georgia Coastal Plain Experiment Station in Tifton, GA, on an established field of ‘Tifton 85’ (T85) bermudagrass. Ten 0.2-ha plots were randomly assigned to either T85+N or T85 interseeded with ‘Bulldog 805’ alfalfa (T85+Alf). T85+N received N fertilization (84 kg N/ ha) four times each growing season. Plots were harvested at early bloom stage every 28 to 35 days from 2016 to 2018, baled at 40–60% moisture, and individually wrapped. At each harvest, plots were evaluated for botanical composition and forage yield, and bales were sampled prior to wrapping for nutritive value analysis. Plots were also evaluated for botanical composition using the point-transect method 10 days post-harvest. Data were analyzed using mixed models and least significant differences at α = 0.05. Although seasonal yields were greater in the T85+N during year 1, alfalfa-bermudagrass plots produced at least one additional harvest each season of the study, and on average 8 cuttings per season each year following establishment. Ultimately this contributed to greater (P < 0.0001) cumulative yield in the alfalfa-bermudagrass treatment (34,783 vs. 25,608 kg/ha, respectively). Analyses of nutritive value through near-infrared spectroscopy (NIR) show that CP and in-vitro true digestibility (IVTD) were greater (P = 0.005 and P = 0.034, respectively) in the alfalfa-bermudagrass treatment than the bermudagrass-only treatment (14.0 vs 11.4% CP and 66.7 vs. 60.2% IVTD, respectively). Improvements in seasonal yield and nutritive value makes bermudagrass interseeded with alfalfa a viable option for baleage producers in the Southeast.

60 Evaluating Yield, Nutritive Value, and Storage Length of Tifton-85 Bermudagrass and Tifton-85 Bermudagrass-Alfalfa Mixtures As Baleage in the Southeast.

60 Evaluating Yield, Nutritive Value, and Storage Length of Tifton-85 Bermudagrass and Tifton-85 Bermudagrass-Alfalfa Mixtures As Baleage in the Southeast.

The Effect of Vitazyme, a Liquid Bio‐Stimulant, in Combination with Nitrogen on Yield and Nutritive Value of Bermudagrass in Southern Oklahoma

Core Ideas Vitazyme did not increase bermudagrass yield at the manufacture's recommended application rate. Vitazyme did not improve nutritive value of bermudagrass when applied at the manufacturer's recommended rate. Bermudagrass response to nitrogen rate was linear but was not influenced by Vitazyme application.

Reuse of urban-treated wastewater from a pilot-scale horizontal subsurface flow system in Sicily (Italy) for irrigation of Bermudagrass (Cynodon dactylon (L.) Pers.) turf under Mediterranean climatic conditions

Constructed wetlands (CW) are one of the most important biological technology for the treatment and reuse of wastewaters. The aim of this study was to evaluate the reuse of treated wastewater (TWW) from CW for irrigation of Bermudagrass turf (Cynodon dactylon (L.) Pers.) and assess the effects of TWW on the biometric and qualitative parameters of the turfgrass and on chemical–physical soil properties. The research was carried out in Sicily (Italy) in a pilot-scale horizontal subsurface flow system which was fed with urban TWW following secondary treatment from an activate sludge wastewater treatment plant. The pilot-system included three separate parallel units. The outflow TWW flowed downhill into three storage tanks which were connected to sprinkler systems. Bermudagrass plots were irrigated with freshwater (FW) and with TWW from planted units and unplanted unit. The TWW quality did not affect the visual turf quality and colour. The above-ground biomass yield of Bermudagrass was on average 1.31 kg m−2 in the TWW-irrigated plots. There was not a significant variation of soil pH, but an increase in organic matter content and salinity were recorded in TWW-irrigated plots. The results confirm that TWW provides an additional water source and fertilisers where the supply of FW is limited.

Blending Polymer‐Coated Nitrogen Fertilizer Improved Bermudagrass Forage Production

ABSTRACTUrea‐based fertilizers have replaced ammonium nitrate (AN) as the most common N source used in forage crops. However, urea‐based fertilizers are less efficient and result in greater N loss as ammonia. Environmentally Smart Nitrogen (ESN, Agrium Advanced Technologies) is a polymer‐coated urea‐N fertilizer that controls N release through temperature‐controlled diffusion. This study assessed the effect of different proportions of ESN and untreated urea (0, 50, 75, and 100% ESN with the balance as urea) on yield and nutritive quality of bermudagrass [Cynodon dactylon (L.) Pers.], as compared with conventional applications of AN and urea. The experimental design was a randomized complete‐block design with four replications on each of two sites and 3 yr (2010–2012). Nitrogen was applied at 336 kg ha−1 season−1, but was split over the season into two equal applications for the ESN treatments and four equal applications for the AN and urea conventional treatments. As the proportion of ESN increased, the amount of N lost through volatilization decreased. Relative to conventionally applied AN, the 50 and 75% ESN blends resulted in similar yields and 16.8% lower nitrate (NO3–N) levels in the harvested forage. Relative to conventionally applied urea, the 50 and 75% blends produced 10 and 6.1% more yield and 14.4 and 19.5% greater N removal, respectively. The 50 and 75% ESN blends were also the most cost‐effective blend systems. These results support a recommendation of blending ESN at a rate of 50 and 75% with urea as a substitute for AN.

Yield and Quality of Irrigated Bermudagrass as a Function of Nitrogen Rate

Bermudagrass [Cynodon dactylon (L.) Pers.] is a perennial grass capable of producing a large amount of forage for either hay or grazing. Information on harvest frequency and rate of N for bermudagrass production is scarce for southwest Kansas. The objectives of this research were to determine economically and environmentally justified N rates for bermudagrass grown under supplemental irrigation (161–222 mm yr−1) and to determine annual harvest frequency. A field study was conducted from 2004 to 2007 near Rolla, KS, with five N rate treatments (0, 168, 336, 672, and 1344 kg N ha−1). On five harvest dates per year, biomass yield, feed quality, soil nutrient content, and soil pH were measured. Biomass yield was relatively high in the second, third, and fourth harvest dates out of five harvest dates within a year. In each of these five harvest dates, biomass yield increased with increasing N rates from 0 to 672 kg N ha−1. A quadratic curve explained 80% of the variation for the relationship between total annual biomass yield of bermudagrass and N rate. The maximum average total annual dry matter production of about 18.5 Mg ha−1 was possible with 900 kg N ha−1. The economic N rate that confers profit, however, varied from about 120 to 600 kg ha−1 depended on value of bermudagrass forage and variable cost of production. An increase in N rate from 0 to 672 kg N ha−1 also increased protein content and biomass feed quality without adversely affecting soil quality.

Modeling a Sustainable Salt Tolerant Grass-Livestock Production System under Saline Conditions in the Western San Joaquin Valley of California

Salinity and trace mineral accumulation threaten the sustainability of crop production in many semi-arid parts of the world, including California’s western San Joaquin Valley (WSJV). We used data from a multi-year field-scale trial in Kings County and related container trials to simulate a forage-grazing system under saline conditions. The model uses rainfall and irrigation water amounts, irrigation water quality, soil, plant, and atmospheric variables to predict Bermuda grass (Cynodon dactylon (L.) Pers.) growth, quality, and use by cattle. Simulations based on field measurements and a related container study indicate that although soil chemical composition is affected by irrigation water quality, irrigation timing and frequency can be used to mitigate salt and trace mineral accumulation. Bermuda grass yields of up to 12 Mg dry matter (DM)·ha−1 were observed at the field site and predicted by the model. Forage yield and quality supports un-supplemented cattle stocking rates of 1.0 to 1.2 animal units (AU)·ha−1. However, a balance must be achieved between stocking rate, desired average daily gain, accumulation of salts in the soil profile, and potential pollution of ground water from drainage and leaching. Using available weather data, crop-specific parameter values and field scale measurements of soil salinity and nitrogen levels, the model can be used by farmers growing forages on saline soils elsewhere, to sustain forage and livestock production under similarly marginal conditions.

Irrigation and Nitrogen Impact on Bermudagrass Yield Response in the Southeastern Coastal Plain

In the southeastern region of the U.S., the cattle industry has a critical need for sustainable hay production. Yet this production is threatened by frequent short-term regional drought. This drought threat can be mitigated by properly managed irrigation. In this study on Tifton 85 bermudagrass, irrigation management, nitrogen fertility levels, and harvest interval were evaluated for their impact on hay quality and yield. The experimental treatments were arrayed in a split-plot design with harvest interval as the main treatment; irrigation by nitrogen (N) levels were the subplots. Treatments had four replicates and were repeated for two years. The optimal irrigation rate was set to maintain soil water potentials below -30 kPa. When needed, the full irrigation treatment received a 12.5 mm irrigation application. The reduced irrigation treatments received water at rates of 0%, 33%, and 66% of the full irrigation rate. In addition, each irrigation treatment had nitrogen rates of 168, 336, and 504 kg N ha-1. The irrigation and nitrogen treatments were harvested at four-week or eight-week intervals. Total harvests per year ranged from three to six. Over both years and for all harvests, there was no irrigation-nitrogen interaction for hay yield. Over all harvests, nitrogen significantly increased bermudagrass hay yield, nutrient concentrations, and forage quality. Forage quality was higher for the four-week harvest interval. Throughout the study, forage quality was maintained within desired industry standards. When irrigation was required, it significantly increased hay yield. During these periods, the four-week and eight-week 100% irrigation treatments yielded 612 and 1600 kg ha-1 greater, respectively, than the non-irrigated treatments. The four-week harvest interval was more sensitive to irrigation. Additionally, we observed a linear relationship between non-irrigated bermudagrass hay yields and average soil water potential. As soil water was depleted, non-irrigated hay yields decreased 31 kg ha-1 per kPa. Timely supplemental irrigation to maintain soil water potentials above -30 kPa can increase bermudagrass yields. Thus, irrigation management should be critically assessed for its potential role in sustaining hay production in the southeastern Coastal Plain.

Field-scale monitoring of the long-term impact and sustainability of drainage water reuse on the west side of California's San Joaquin Valley

Diminishing freshwater resources have brought attention to the reuse of degraded water as a water resource rather than a disposal problem. Drainage water from tile-drained, irrigated agricultural land is degraded water that is often in large supply, but the long-term impact and sustainability of its reuse on soil is unknown. Similarly, nothing is known of the ramifications of terminating drainage water reuse. The objective of this study is (i) to monitor the long-term impact on soil chemical properties and thereby the sustainability of drainage water reuse on a marginally productive, saline-sodic, 32.4 ha field located on the west side of California's productive San Joaquin Valley and (ii) to assess spatially what happens to soil when drainage water reuse is terminated. The monitoring and assessment were based on spatial chemical data for soil collected during 10 years of irrigation with drainage water followed by 2 years of no applied irrigation water (only rainfall). Geo-referenced measurements of apparent soil electrical conductivity (EC(a)) were used to direct the soil sampling design to characterize spatial variability of impacted soil properties. Chemical analyses of soil samples were used (i) to characterize the spatial variability of salinity, Na, B, and Mo, which were previously identified as critical to the yield and quality of Bermuda grass (Cynodon dactylon (l.) Pers.) grown for livestock consumption and (ii) to monitor their change during the 12 year study. Soil samples were taken at 0.3 m increments to a depth of 1.2 m at each of 40 sample sites on five occasions: August 1999, April 2002, November 2004, August 2009, and May 2011. Drainage water varying in salinity (1.8-16.3 dS m(-1)), SAR (5.2-52.4), Mo (80-400 μg L(-1)), and B (0.4-15.1 mg L(-1)) was applied from July 2000 to June 2009. Results indicate that salts, Na, Mo, and B were leached from the root zone causing a significant improvement in soil quality from 1999 to 2009. Salinity and SAR returned to original levels or higher in less than two years after termination of irrigation. Boron and Mo showed significant increases. Long-term sustainability of drainage water reuse was supported by the results, but once application of irrigation water was terminated, the field quickly returned to its original saline-sodic condition.

Potassium Influences Forage Bermudagrass Yield and Fungal Leaf Disease Severity in Mississippi

Fungal diseases in bermudagrass [Cynodon dactylon (L.) Pers.] and numerous other crops have been associated with K deficiency. This study evaluated how levels of K in potash fertilizer (0-0-60) and broiler litter influenced forage yields and severity of disease symptoms caused by a natural complex of fungal pathogens in ‘Tifton 44’ bermudagrass in Mississippi. The relative incidence at different K levels of six species of Bipolaris, Curvularia, and Exserohilum in the complex was also investigated. Disease symptoms were universal and strong in all plots in 2010, but weak and transient in 2011. Forage dry matter (DM) yields increased linearly and significantly (P < 0.05) as K-fertilizer rate increased from 0 to 167 kg K/ha. Disease severity in whole plots decreased as K levels increased in 2010, and severity of symptoms on individual leaves in 2011 was lower at 167 kg K/ha than 0 kg K/ha. The incidence of individual fungal pathogens on symptomatic leaves in 2010 ranged from 3 to 100% (E. rostratum and B. hawaiiensis were universal pathogens) and levels observed for four variable, non-universal pathogens did not differ between K-fertilizer rates. These results indicated that the reduced disease severity observed at the highest K levels was not caused by changes in the incidence of four fungal pathogens within the disease complex.

버뮤다그라스 초지에 보파한 이탈리안 라이그라스의 파종시기가 목초생산성과 식생에 미치는 영향

This study was carried out to determine the effect of seeding dates of Italian ryegrass interseeded into bermudagrass sod on the forage productivity and botanical composition of Italian ryegrass and bermudagrass. Experimental plot was located at 200 m altitude within Subtropical Animal Experiment Station, National Institute of Animal Science in Jeju from 2009 to 2010. Seeding date treatments of Italian ryegrass into bermudagrass sod were arranged in a randomized complete block design replicated three times. Italian ryegrass was drilled in row 20 cm apart after clipping the bermudagrass at a cutting height of 2~3 cm. Seeding time was on 15 September, 30 September and 15 October. The dry matter yield of Italian ryegrass was higher in 15 September seeding treatment, the dry matter yields of 30 September and 15 October seeding treatment were not different. The Italian ryegrass interseeded into bermudagrass sod didn`t affect the dry matter yield in the summer harvests of bermudagrass, and the dry matter yield of bermudagrass showed the highest in August. In botanical composition, Italian ryegrass showed to reduced growth in early seedling stage after seeding by competition with bermudagrass, but Italian ryegrass was dominant to June increasing of temperature in spring next year and bermudagrass after Italian ryegrass harvests was dominant during summer season.

Effect of Nitrogen Fertilizer Rate and Harvest Season on Forage Yield, Quality, and Macronutrient Concentrations in Midland Bermuda Grass

Bermuda grass [Cynodon dactylon (L.) Pers.] is a major forage for grazing and hay production in the southern United States. The objectives of this study were to determine effects of nitrogen (N) fertilization rate (0, 112, 224, 336, and 448 kg ha−1), split spring and summer applications of N at the 224 and 448 kg ha−1 rates, and harvest periods (spring and summer) on forage yield, crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), total digestible nutrients (TDN), and concentrations of phosphorus (P), potassium (K), magnesium (Mg), and calcium (Ca in Midland Bermuda grass. Data were collected from 2002 to 2008 as part of an ongoing, long-term soil fertility experiment in southern Oklahoma. Repeated measures analysis of these long-term data showed that forage yield responses to N rate varied with year and harvest time with up to 2.5-fold yield differences among years. Nitrogen fertilization increased CP, TDN, and macronutrient P and Mg and decreased ADF and NDF. Crude protein was increased by ≥50%, and ADF and NDF dropped by up to 25% with the greatest N rate. In general, split N applications did not affect forage yield but produced low-quality forage compared to single N application in spring. Split application of 448 kg N ha−1 gave forage with CP, TDN, ADF, and NDF similar to the Bermuda grass receiving 336 or 448 kg N ha−1 as a single application. Spring forage had better forage quality than summer harvests. While N fertilization increased forage Mg and P concentrations by more than 50% during both spring and summer, it had no effect or slight increased K and Ca concentrations. In the southern Great Plains, despite the weather-dependent variability in forage yield of Bermuda grass, N application increase forage quality.

Nitrogen and winter cover crop effects on spring and summer nutrient uptake

AbstractOverseeded winter annuals in bermudagrass [Cynodon dactylon (L.) Pers.] improve annual dry‐matter (DM) yield and capture nutrients in fields receiving manure application. This study determined the DM and nutrient uptake responses of annual ryegrass (Lolium multiflorum L.), cereal rye (Secale cereale), berseem clover (Trifolium alexandrinum L.) and bermudagrass‐winter fallow to 0, 50, 100 and 150 kg N ha−1 applied approximately 2 months before a single spring harvest, and in addition to swine‐effluent N (258 and 533 kg ha−1 in summer 2000 and 2001, respectively). Under drought conditions in 2000, DM yield at the spring harvest was highest in ryegrass, and summer DM yield of bermudagrass was greater at 100 and 150 kg N ha−1 than 50 kg N ha−1(P &lt; 0·05). The concentration and uptake of N at the spring harvest increased linearly across N rates in both years (P &lt; 0.05). Cover crops differed in N uptake in 2000 (P &lt; 0.01) and values ranged from approximately 141 kg N ha−1 in berseem clover to 86 kg N ha−1 in rye. Per unit of N applied, uptake of N increased by approximately 0·409 kg ha−1 in 2000 and 0·267 kg ha−1 in 2001; uptake of P increased by 0·029 and 0·014 kg ha−1 respectively. In 2000, uptake of P was responsive to N rate and this relationship was significant (P &lt; 0·01) in winter fallow (slope = 0·032) and ryegrass (slope = 0·057). Increased uptake of N and P at the single spring harvest was due mainly to higher concentrations in herbage and not higher DM yield.

Dairy Manure Compost Application Rate and Timing Influence Bermudagrass Yield and Nutrient Concentration

ABSTRACTManagement strategies for applying composted dairy manures on perennial forages are not well defined. We researched compost application timing and rate with and without supplemental inorganic nitrogen on ‘Coastal’ bermudagrass [Cynodon dactylon (L.) Pers.]. Treatments were 18, 36, and 72 Mg ha−1 dry dairy compost rates (supplying 112, 224, and 448 kg N ha−1) applied in November, January, or March and supplemented with 0 or 112 kg ha−1 inorganic N fertilizer as ammonium nitrate after each harvest. The addition of compost increased (P &lt; 0.05) yield compared with no‐compost plots the first year, but the benefits were only measureable at the 72 Mg rate by the second year. Waiting to apply compost until March resulted in 26% greater (P &lt; 0.05) yields the first year at the 72 Mg compost rate, 15% at the 36 Mg rate, and 17% at the 18 Mg rate compared with the January applications at the same rates. November compost application resulted in greater uptake of compost‐phosphorus by plants, March dates improved compost‐potassium uptake, while grass N uptake was independent of application date. On composted plots, plant N and K concentration increases were discernable in early harvests, while P increases were apparent in subsequent harvests compared with no compost. Supplemental N increased dry matter (DM) and P yields. Results indicated that compost application dates and amounts change P uptake rates or inorganic fertilizer N efficiency.

질소시비 수준 및 재생기간이 톨페스큐와 버뮤다그라스의 지방산조성에 미치는 영향

본 시험은 질소시비 수준과 재생기간이 툴페스큐와 버뮤다그라스의 지방산 조성과 버뮤다 그라스의 사초생산성에 미치는 영향을 평가하기 위하여 국립축산과학원 제주출장소 시험포장에서 2006년 6월부터 2007년 12월까지 수행되었다. 톨페스큐의 식물체내 지방산 조성은 팔미틱산(C16:0), 리놀산(C18:2)과 리놀렌산(C18:3)이 총지방산의 87(N-0), 88(N-50), 88(N-100)%를 차지하였으며 질소시비수준에 따라 뚜렷한 차이가 나타나지 않았다. 재생기간이 길어질수록 리놀렌산(C18:3)은 감소하는 경향을 보였으며 리놀산(C18:2)은 다른 지방산과 달리 증가하는 것으로 나타났다. 버뮤다그라스의 질소 시비수준에 따른 지방산 조성은 팔미틱산(C16:0)이 톨페스큐보다 높게 나타났으며 리놀산(C18:2)과 리놀렌산(C18:3)은 톨페스큐보다 낮은 것으로 나타났다. 재생기간이 길어짐에 따라 리놀산(C18:2)과 리놀렌산(C18:3)은 톨페스큐와 달리 감소하는 것으로 나타났다. 버뮤다그라스는 질소시비수준이 높고 재생기간이 증가할수록 건물수량이 증가하는 것으로 나타났으며, 질소시비수준이 높을수록 조단백질함량은 증가하였으며 재생기간이 길어질수록 사료가치는 감소하였다. 이상의 결과를 종합해보면 질소 시비수준에 따른 톨페스큐와 버뮤다그라스의 지방산 함량은 뚜렷한 차이를 보이지 않았으나 수확 후 재생기간에 따른 변화는 뚜렷하게 나타남으로서 초지를 활용한 CLA 증진축산물을 생산시 가급적 수확 후 재생기간이 짧은 어린 목초를 이용할 수 있는 초종별 적정 예취시기와 방목전략을 세워야 할 것으로 생각된다. 또한 향후 각 초종별 계절 및 생육단계가 목초 내 지방산 함량에 미치는 영향에 대한 연구가 이루어져야 할 것으로 생각된다. Two experiments were conducted to evaluate the effects of nitrogen (N) application level and regrowth period on the fatty acid (FA) concentration and forage production of tall fescue (Festuca arundinacea Schr.) and bermudagrass (Cynodon dactylon (L.) Pers.). N was applied at 0, 50 and 100 kg/ha, and swards were cut after regrowth periods (15d, 30d and 45d). Concentrations of Individual FA were determined by gas chromatography. FA composition of tall fescue contains a high proportion (<TEX>$87{\sim}88%$</TEX>) of total FA contents as palmitic (C16:0), linoleic (C18:2) and linolenic acid (C18:3). The FA composition was not affected by N application, but a longer regrowth period significantly (p<0.05) decreased the composition of linolenic acid (C18:3) and increased those of linoleic acid (C18:2). The FA composition of bermudagrass was not affected by N application, but a longer regrowth period significantly (p<0.001) decreased the composition of linoleic (C18:2) and linolenic acid (C18:3). Linoleic and linolenic acfd of tall fescue were higher than those of bermudagrass. Dry matter (DM) yield of bermudagrass was significantly (P<0.05) affected by N application level and regrowth period. DM yield was higher at high N application and was higher at longer regrowth period. The crude protein concentration was higher at high N application and was low at longer regrowth period. Application of nitrogen fertilizer Increases dry matter (DM) yield and crude protein (CP) content of bermudagrass. These studies demonstrate opportunities to affect the FA concentration and composition of FA in forage through management strategies, which could affect milk FA composition.

Dual‐Function Growth Medium and Structural Soil for Use as Porous Pavement

Permeable grass-covered surfaces can reduce the quantity of storm water runoff and filter out potentially harmful chemicals. The objective of this study was to develop permeable structural soils that sustained healthy turf growth and filtered heavy metals from contaminated pavement runoff. The basic soil medium was a 50:50 mixture (v/v) of expanded shale (ExSh) and quartz sand (QS). The ExSh component consisted of (i) large-diameter particles (3-6 mm), (ii) small-diameter particles (1-3 mm), or (iii) a 50:50 mixture (v/v) of the two. The basic blends were mixed with 0, 10, and 20% sphagnum peat moss (v/v) and 0, 10, and 20% natural zeolites (v/v) and placed in 15-cm-diameter pots in a greenhouse. Bermudagrass plugs were planted in each pot. The addition of sphagnum peat moss to the basic ExSh/QS blend increased bermudagrass growth and improved plant response to added fertilizer. Zeolites had no significant effect on plant growth in the absence of sphagnum peat moss. Growing mediums that contained 10 to 20% sphagnum peat moss and 10 to 20% zeolites consistently produced more bermudagrass biomass than the unamended ExSh/QS mixture. Changing the ratio of small- to large-diameter ExSh in the basic medium did not affect bermudagrass yield. Very low amounts of Cd, Cu, Pb, and Zn were recovered in leachate after the addition of 10 mg metal per pot, suggesting that most heavy metals (>99%) were retained in the growing mediums. Zeolites reduced the amount of Cd and Pb in leachate water, but not Cu or Zn.