Harvesting Grass Research Articles

Pumpkin Yield and Weed Populations Following Annual Ryegrass

ABSTRACT Sustainable production can sometimes be achieved with diversification of cropping patterns and by the use of disparate crops in rotation. Following a forage grass harvest for feed it may be possible to produce a cucurbit crop before it is time to reseed an overwintering grass cover crop. Pumpkins may be a crop that can be grown in rotation with grasses. Five annual Italian ryegrass varieties of varying maturity [“Shiwasuaoba” (early); “Miniamioba” and “Waseyutaka” (medium); “Marshall” and “Zorro” (late)] were established in the fall. In early summer of the following year the grasses were harvested, their yield determined, and the stubble left in place. The control was composed of winter wheat which was harvested in the spring and the stubble turned under and the soil maintained without cover. Seed of pumpkin, cv. ProGold 300, were sown into strips tilled in the ryegrass stubble or bare soil. Number and weight of pumpkins were determined. Weed cover in plots following pumpkin harvest was determined. Plots were seeded with the ryegrasses or wheat, with the procedures repeated over two years. Marketable number and yield of pumpkin were not affected by cover or year of planting and averaged 1,755 fruit/ha and 5.9 Mg·ha−1, respectively, over both years. The percent of pumpkin fruit of the expected size for this cultivar, >7.25 kg, was 41% in the first year and 26% in the second year. Approximately 68% of fruit from plants on bare soil, and 27% from plants on soil covered with ryegrass stubble, were >7.25 kg. Total weed cover was not different on bare soil between years (avg. 86%), and dicot weeds were greater in 2002 than 2003. Total weed cover in ryegrass plots averaged about 36% in 2002 and 93% in 2003. Dicot weed cover in ryegrass stubble plots were not different between years or ryegrass variety and averaged 32%. Monocot weed cover was significantly lower in 2002, 5%, than in 2003, 57%, regardless of cover. There is a need for additional studies in ryegrass-pumpkin rotation before recommendations can be made for its implementation in southeastern Oklahoma.

An Analysis of Beef Cattle Production and Contract of Grass Harvest in Okinawa

An Analysis of Beef Cattle Production and Contract of Grass Harvest in Okinawa

Switchgrass and Big Bluestem Hay, Biomass, and Seed Yield Response to Fire and Glyphosate Treatment

Timing of spring fire and glyphosate [N‐(phosphonomethyl)glycine] treatments is critical to control weeds without compromising production of warm‐season grasses. To determine the forage and seed yield response we burned or applied glyphosate to switchgrass (Panicum virgatum L.) and big bluestem (Andropogon gerardii Vitman) in mid‐April, early May, and late May in 1998 and 1999 at Rock Springs, PA. Compared with fire in mid‐April or early May, a late May burn in 1998 reduced July dry matter yields (simulating a hay harvest) by 40 to 48% but did not affect dry matter yields in September (simulating a biomass feedstock harvest) of either grass. In switchgrass, glyphosate applied in late May reduced July yields by 70% and September yields by 30%. In bluestem, late May application of glyphosate reduced July yields by 90% and September yields by 40%. In both grasses, fire in late May reduced yields less than a late May application of glyphosate. Late May glyphosate treatments reduced seed yield compared with the mid‐April date. We conclude that in central Pennsylvania switchgrass or bluestem can be burned through the first week of May (10–15 cm growth) with little effect on hay or biomass yield. Glyphosate should be applied (i) before mid‐ to late April (just before green‐up) if switchgrass or big bluestem is to be harvested as hay in July or for seed in September, or (ii) by the first week of May if the cumulative growth is to be harvested once in autumn.

Aboveground and belowground biomass, productivity and nutrient accumulation in tree improved fallows in the dry tropics of Cameroon

The accumulation of biomass and nutrients by three tree fallows planted in a previously cultivated ferruginous soil in the Sudanian zone of Cameroon were compared with that of a natural grazed herbaceous fallow and a natural ungrazed herbaceous fallow. The planted tree fallows, that were protected against fire and grazing, included: Acacia polyacantha, Senna siamea, and Eucalyptus camaldulensis. After 5 years of fallow, mean aerial woody biomass production rates ranged from 5.30 t ha −1 per year for Acacia and 5.73 t ha −1 per year for Eucalyptus to 3.81 t ha −1 per year for Senna; furthermore, the total dry matter (DM) accumulation (root, shoot and litter) of tree fallows represented 2.5–4 times that of the herbaceous fallows. Regarding root mass, these proportions are increased to 5–7 times for the three tree species studied. Acacia had higher N and Mg contents in total DM than the other treatments while Eucalyptus had the greatest accumulation of Ca. Acacia and Eucalyptus had similar accumulation of total DM, P and K. Senna was not so productive as the other tree species but it accumulated a large quantity of K. Over a 7-year period, Acacia, a N-fixing species, accumulated in its total DM, 340 and 412 kg N ha −1 more than Eucalyptus and Senna (non-N-fixing species) did, respectively. In the context of intensive harvest of aerial biomass, the accumulation of nutrients in the belowground components is a process of high importance. The N accumulation in the Acacia root mass (342 kg ha −1) represented roughly the total N accumulation in Eucalyptus or Senna stands. In Eucalyptus the root system accounted for only 18–27% of the accumulation of total DM and nutrients, while much greater proportions were found under Senna (39–52%) and Acacia (32–47%). Thus, the harvesting methods of the aerial biomass will play an important part in the conservation of the nutrients of the system, especially in the case of Eucalyptus. Nutrient removal by harvesting under different logging scenarios was evaluated. For Eucalyptus, the technique of de-barking on-site reduced the removal of Ca and Mg by 70 and 43%, respectively. Furthermore, the results show that in the long term, in comparison to removal of timber at the end of the rotation, annual harvesting of grass for fodder in tree fallows in the Sudanian zone of Africa, would be an equally important or even a more serious risk to site fertility.

Cutters, carriers and transport chains: Distance-dependent foraging strategies in the grass-cutting ant Atta vollenweideri

Most studies on leaf-cutting ant foraging examined forest species that harvest dicot leaves. We investigated division of labor and task partitioning during foraging in the grass-cutting ant Atta vollenweideri. Workers of this species harvest grass fragments and transport them to the nest for distances up to 150 m along well-established trunk trails. We recorded the behavior of foraging ants while cutting and monitored the transport of individually-marked fragments from the cutting site until they reached the nest. A. vollenweideri foragers showed division of labor between cutting and carrying, with larger workers cutting the fragments, and smaller ones transporting them. This division was less marked when plants were located very close to the nest and no physical trail was present, i.e., the cutter often transported its own fragment back to the nest. On long foraging trails, the transport of fragments was a partitioned task, i.e., workers formed transport chains composed of 2 to 5 carriers. This sequential load transport occurred more often on long than on short trails. The first carriers in a transport chain covered only short distances before dropping their fragments, and they were observed to turn back and revisit the patch. The last carriers covered the longest distance. The probability of dropping the carried fragment on the trail was independent of both worker and fragment size, and there was no particular location on the trail for dropping, i.e., fragments were not cached. Transport time of fragments transported by a chain was longer than for those transported by single workers all the way to the nest, i.e., sequential transport did not save foraging time. Two hypotheses concerning the possible adaptive value of transport chains are discussed. The first one argues that sequential transport may lead to an increased material transport rate compared to individual transport. The second one considers sequential transport as a way to enhance the information flow among foragers, thus leading to a quicker build-up of workers at particular harvesting places. It is suggested that rather than increasing the gross transport rate of material, transport via chains may favor the transfer of information about the kind of resource being actually harvested.

Laboratory Measurement of Mowing Machine Material Feed Rate

The main objective of this research was to evaluate two possibilities of material feed rate measurement of modern mowing machines equipped with conditioner. The machines are commonly used for harvest of grasses (Lolium multiflorum, Dactylus glomerata, Phleum pratense, etc.), clover (Trifolium pratense, etc.), alfalfa (Medicago sativa) etc. A mowing machine with finger conditioner was equipped with an electronic measuring unit for the purpose of our measurements. The mowing machine's conditioner shaft was supplied with strain gauges placed on a torque-meter and with a RPM optical sensor counter. Together with torque-meter the mowing machine was equipped with a curved impact plate mounted on the machine's material output. It was decided to arrange a laboratory measurement to obtain information about the dependence of conditioner power input and signals from the impact plate on material mass flow. A mixture of grass and alfalfa was used for our measurement. The measurements carried out proved that a very good linear relationship existed between the conditioner's power input, output frequency of the apparatus measuring impact force by means of the impact plate, and material feed rate through the mowing machine. The calculated coefficients of correlation were about 0.95. It is possible to differentiate a material feed rate difference of 0.5kg s−1 using both methods. This accuracy should be sufficient for practical utilisation such as creating yield maps.

Effluent polishing via pasture irrigation in Harare, Zimbabwe

Harare, the capital city of Zimbabwe, is experiencing eutrophication-related problems in its downstream potable water supply source of Lake Chivero. This is due mainly to poorly treated sewage effluent encroachment into upstream rivers, especially Marimba River. Crowborough Pasture Irrigation farm is in the Marimba sub-catchment area and has 305 hectares of irrigated pastures. Studies started from July 2000 to August 2001 focusing on the pasture's management of nutrients (nitrogen and phosphorus) and their impact on Marimba River. Water and nutrient balances were developed. Reduction efficiencies for this pasture were found to be 84% for TN and 54% for TP. Both the Crowborough sewage treatment works and the pastures are overloaded. It was therefore concluded that the current system is no longer sustainable economically and environmentally. From the results of our study we recommend that additional treatment units be constructed at Crowborough sewage treatment works to meet current flows. Moreover, pasture management needs substantial improvement. Nutrient recovery should be enhanced by regular harvesting of pasture grass and converting cow dung into an economic commodity as manure for neighbouring residents. Maize cultivation is also recommended to replace pasture grass as it is a local staple crop and has high nutrient uptake rates.

Food Waste Compost Effects on Fertilizer Nitrogen Efficiency, Available Nitrogen, and Tall Fescue Yield

Composting of food waste is increasing as composting technologies improve and as social and environmental pressures demand alternatives to disposal in landfills. Few agronomic studies are available to document N availability following food waste compost application. The objectives of this study were (i) to determine food waste compost effects on N fertilizer uptake efficiency across a range of N fertilizer rates, (ii) evaluate the effect of food waste composts on grass yield and N uptake by tall fescue (Festuca arundinacea Schreb. ‘A.U. Triumph’), and (iii) estimate the residual effects of compost application on N fertilizer requirements. We used a split‐plot design with two compost treatments and a no‐compost control as main plots, and NH4NO3 (34‐0‐0) applied at rates of 0, 17, 34, 50, and 67 kg ha−1 per grass harvest as subplots. A food waste + yard trimmings + paper (FYP) compost and a food waste + wood waste + sawdust (FW) compost were applied at rates of approximately 78 Mg ha−1 (870–1000 kg N ha−1) before seeding tall fescue. Compost did not affect grass yield or N uptake in the first year of the study. Compost increased grass yield during the second and third seasons after application. Grass N uptake increased linearly with fertilizer N application rate in all years. Compost did not affect fertilizer N uptake efficiency (the linear slope describing grass N uptake vs. fertilizer N application). Nitrogen fertilizer requirements during the midseason growth period were reduced by 0.22 to 0.37 kg N ha−1 d−1 during the second season after compost application and by 0.13 to 0.26 kg ha−1 d−1 during the third season after compost application. Results of this study suggest that N mineralized from compost and N provided by fertilizer can be considered as additive components of N supply for crop growth.

Food Waste Compost Effects on Fertilizer Nitrogen Efficiency, Available Nitrogen, and Tall Fescue Yield

Composting of food waste is increasing as composting technologies improve and as social and environmental pressures demand alternatives to disposal in landfills. Few agronomic studies are available to document N availability following food waste compost application. The objectives of this study were (i) to determine food waste compost effects on N fertilizer uptake efficiency across a range of N fertilizer rates, (ii) evaluate the effect of food waste composts on grass yield and N uptake by tall fescue (Festuca arundinacea Schreb. ‘A.U. Triumph’), and (iii) estimate the residual effects of compost application on N fertilizer requirements. We used a split-plot design with two compost treatments and a no-compost control as main plots, and NH4NO3 (34-0-0) applied at rates of 0, 17, 34, 50, and 67 kg ha−1 per grass harvest as subplots. A food waste + yard trimmings + paper (FYP) compost and a food waste + wood waste + sawdust (FW) compost were applied at rates of approximately 78 Mg ha−1 (870–1000 kg N ha−1) before seeding tall fescue. Compost did not affect grass yield or N uptake in the first year of the study. Compost increased grass yield during the second and third seasons after application. Grass N uptake increased linearly with fertilizer N application rate in all years. Compost did not affect fertilizer N uptake efficiency (the linear slope describing grass N uptake vs. fertilizer N application). Nitrogen fertilizer requirements during the midseason growth period were reduced by 0.22 to 0.37 kg N ha−1 d−1 during the second season after compost application and by 0.13 to 0.26 kg ha−1 d−1 during the third season after compost application. Results of this study suggest that N mineralized from compost and N provided by fertilizer can be considered as additive components of N supply for crop growth.

Reefscape: reflections on the Great Barrier Reef

Map Introduction Diving for Oldies Fishness Going with the Flow When the Reef Was Ours Reefscape with Sea Serpents The Tears of the Turtle Sea Grass Harvest Chick City An Island in Time Stressed-Out Reefscape The Beginning of the End of It All Saltwater Spirituality Notes Further Reading Interesting Web Pages Acknowledgements Index

Reports and Short Notices

Introduction This brief paper presents some preliminary results of a survey conducted among the transhumant Mon Pa pastoralists of the alpine terrain of Tawang, in Arunachal Pradesh in the eastern Indian Himalayas. The term Mon Pa is an exonym and means `the others' in Tibeto-Burmese. These primarily yak herders who are indigenous to the area also own some cattle, mules, horses and sheep and practice limited horticulture in their village lands, at around 3,000m. While Mon Pa men take their herds over long distances in search of pasture, women, children and the elderly remain throughout the year in these villages, tending some of their livestock and collecting firewood. Till quite recently, Mon Pa pastoralists, who are Mahayana Buddhists (Sarkar 1980) were polyandrous, and since herds are owned jointly by brothers, one herder can be replaced after a while by his brother. Thus, yak herds live in the forests and alpine meadows (Farooquee 1997) continuously, with the herders in charge rotating. With rapidly shrinking pastures and the breaking down of their exchange relationships with Mon Pa farmers of the Tawang region, who bartered grain for yak cheese, butter, and meat (Nanda 1981, Furer-Haimendorf 1982, Jha 1988, Duarah 1992, Farooquee 1997), the entire community is struggling against the severe impact of economic change. In order to maintain the regular barter system, Mon Pa pastoralists have had large herds of up to 145 yaks per household besides two or three heads of cattle, one or two mules and horses, and a few goats. To feed such a large stock of yaks, they have nomadised, and this environmental strategy has, in its turn, both enabled a sustainable pastoral economy and become the basis of Mon Pa pastoralist identity. The Area The Thingbu-Mukto division of Tawang district in Arunachal Pradesh where this survey was carried out, lies in the alpine zone between 3,100 and 4,000 m, well above the timberline. The mean annual temperature is below 6[degrees]C, with mean winter temperatures below -1[degrees]C (Champion and Seth 1965). The herbage of the high altitude eastern Himalaya is highly nutritious and can contain crude protein up to seventeen percent. It is very common to find the farmers here harvesting grass from the forest areas to feed their animals (Verma 1988). Some of the commonest plants found in the region are species of the genera Corydalis, Sorosis, Silens, Saussurea, Geranium, Geum, and common grasses in the alpine region are Poa, Agrostis, Calamogrostis, Yak grass, Festuca, Korbressia, Irish grass (Sundriyal 1995). Traditional Patterns of Pastoral Movement Mon Pa pastoralists rotate traditionally between a multi-pasture encampment used in mid- and late winter, spring and summer, and an encampment used in autumn and early winter. This system allows them to utilise a series of common grazing lands, while also providing an ample supply of ungrazed forage reserves for use in autumn and early winter on which the animals subsist through the long winters. They stay in each of these pastures for only as long as enough fodder is available here as calculated by them traditionally. This complex system of pasture rotation appears quite similar to that of the nomads of the Tibetan Plateau (Goldstein et al. 1990). Unlike, say, herders in non-mountainous arid zones, such as the Bedouin of Saudi Arabia who move opportunistically among very large areas of land in response to random and patchy rainfall (Perevalotsky 1987), these alpine herders have skilfully cashed-in on climatic and altitudinal variations spread across a spatio-temporal scale. They distribute their herds between different pastures in such a manner that they calve in winter when they move down closer to their villages after grazing in the alpine meadows in summer. Over the years, a certain ecological balance had been maintained and untill recently, there were no indications of overgrazing. Increasingly, however, there are indications of the degradation of these common resources. …

99/01361 Some plant species screened for energy, hydrocarbons and phytochemicals : Sekar, T. and Francis, K. Bioresour. Technol., 1998, 65, (3), 257–259

Roots help in soil water and nutrient uptake and provide carbon (C) input for soil C sequestration, but information on root biomass of bioenergy perennial grasses is lacking. Root/shoot ratios are used to estimate crop root biomass and C inputs, but the values for perennial grasses are also scanty. We examined root biomass, root/shoot ratios, and soil water contents to a depth of 120 cm after grass harvest in the fall for three bioenergy perennial grasses applied with four nitrogen (N) fertilization rates from 2011 to 2013 in the northern Great Plains, USA. Perennial grasses were intermediate wheatgrass (Thinopyrum intermedium [Host] Barkworth and Dewey), smooth bromegrass (Bromus inermis L.), and switchgrass (Panicum virgatum L.), and N fertilization rates were 0, 28, 56, and 84 kg N ha−1. Root biomass declined with depth and about 60% of the total biomass was located at 0–15 cm where intermediate wheatgrass and switchgrass had higher biomass than smooth bromegrass in 2011. Shoot biomass was greater in intermediate wheatgrass in 2011 and in switchgrass in 2013 than other grasses and increased with increased N rates. Root/shoot ratio was greater in switchgrass than other grasses at 0–120 cm in 2011, but was greater in smooth bromegrass than switchgrass at 0–60, 0–90, and 0–120 cm in 2012 and 2013. Mean root/shoot ratios across N rates and years were not different among grasses and varied from 1.54 at 0–15 cm to 2.54 at 0–120 cm, which were substantially greater than 0.15 and 0.33, respectively, observed for spring wheat (Triticum aestivum L.). Soil water content increased with depth and was greater under switchgrass than other grasses at 0–120 cm in 2011 and 2013. Water content varied with N rate at various soil depths and years. Root biomass was negatively correlated with soil water content (r = −0.56, P = 0.03, n = 15). Because of greater root and shoot biomass, intermediate wheatgrass reduced soil water content due to increased water uptake and will likely provide more C inputs for soil C sequestration from belowground biomass compared to smooth bromegrass and spring wheat.

The effect of stage of grass maturity at harvesting and restricting fermentation on the intake of grass silage by beef cattle

In recent years there has been an improvement in the genetic potential of dairy cattle through intensive breeding programs and of beef cattle through a shift from native beef breeds to Continental breeds. These potential improvements can only be realised if increased intakes can be achieved. If conserved forages are to meet these higher nutrient requirements then the intake of conserved forages should be maximised. Two potential methods by which silage intake can be increased are by increasing silage digestibility through more frequent harvesting of grass (Gordon, 1989) or by restricting fermentation of the resulting silage (Doherty and Mayne, 1996). The objective of the current study was to examine the relative effects of digestibility and restricting fermentation on the intake of silage with the aim of establishing the optimum approach to achieving higher nutrient intakes from ensiled forages.

The effect of stage of grass maturity at harvesting and restricting fermentation on the intake of grass silage by beef cattle

In recent years there has been an improvement in the genetic potential of dairy cattle through intensive breeding programs and of beef cattle through a shift from native beef breeds to Continental breeds. These potential improvements can only be realised if increased intakes can be achieved. If conserved forages are to meet these higher nutrient requirements then the intake of conserved forages should be maximised. Two potential methods by which silage intake can be increased are by increasing silage digestibility through more frequent harvesting of grass (Gordon, 1989) or by restricting fermentation of the resulting silage (Doherty and Mayne, 1996). The objective of the current study was to examine the relative effects of digestibility and restricting fermentation on the intake of silage with the aim of establishing the optimum approach to achieving higher nutrient intakes from ensiled forages.

97/04746 Harvest of grass for combustion in late summer and in spring: Hadders, G. and Olsson, R. Biomass and Bioenergy, 1997, 12, (3), 171–175

97/04746 Harvest of grass for combustion in late summer and in spring: Hadders, G. and Olsson, R. Biomass and Bioenergy, 1997, 12, (3), 171–175

Biosolids and Dairy Manure as Nitrogen Sources for Prairiegrass on a Poorly Drained Soil

Accurate prediction of plant-available N release from municipal and agricultural byproducts is needed to optimize crop yields and minimize nitrate leached to groundwater. We conducted a 4-yr study to determine plant-available N release from two byproducts: dewatered biosolids (stabilized solids from municipal wastewater treatment) and dairy manure. The Buckley loam soil (fine-loamy, mixed, nonacid, mesic Typic Humaquepts) at our study site had a perched water table 0 to 24 in. below the surface from mid-November through mid-May. Biosolids and manure were surface-applied to established prairiegrass [Bromus unioloides (Willd.) H.B.K. cv. Grasslands Matua; syn. B. willildnowii Kunth] for 2 yr (1991-1992). Plant-available N released from biosolids or manure was measured for two additional years (1993-1994) after we terminated application. Cumulative apparent N recovered by grass harvest for 1991, 1992, and 1993 was 77, 74, and 65% for urea; 27, 29, and 38% for biosolids; and 17, 28, and 36% for manure. Biosolids or manure applied in 1991-1992 increased soil nitrate recovered after a summer of chemical fallow in 1994. The additional nitrate recovered in 1994 represented approximately 6% of the biosolids or manure N applied in 1991-1992. Our study demonstrated increased soil N mineralization rates following 2 yr of biosolids or manure application. Farm management plans for biosolids and manure use must account for the residual effects of previous applications.

Harvest of grass for combustion in late summer and in spring

Swedish studies concerning the production of grass for combustion during the 1980s demonstrated that it was impossible to produce fuel guaranteed to be of acceptable hygienic quality at a reasonable cost. In those studies, the grass was harvested during summer using conventional haymaking methods. To avoid the problems involved with a summer harvest, it was proposed in 1989 that the grass be harvested during the winter or spring following the growing season. Since then, a system based on this delayed-harvest concept has been evaluated with regard to biological yield, losses during winter, harvesting technology, losses during harvesting and fuel characteristics. The crop used has been reed canary grass ( Phaláris arundinácea L.). In contrast to harvest in late summer, a spring harvest was found to be of practical value. It provides a usable fuel of higher quality than that of grass from summer harvesting. The delay in the harvest leads to reduced concentrations of most elements that are undesirable in combustion, e.g. nitrogen, sulphur, chlorine or potassium. An exception is silica, the concentration of which increases during winter. A valuable effect of spring harvesting is that the initial ash deformation temperature is increased. Furthermore, the need for fertilizer with delayed harvest is low owing to the low content of nutrients in the harvested material. The main disadvantage is that there are major losses of material during the autumn and winter.

Fall Harvest Management Effects on ‘Grasslands Matua’ Prairie Grass Quality

AbstractForage production of ‘Grasslands Matua’ prairie grass [Bromus catharticus M. Vahl; syn. B. unioloides Kunth, B. willdenowii Kunth] (Matua, for short) during the fall months is excellent, but highly management dependent. Unfortunately, fall harvest management effects on the quality of this grass are relatively unknown. Our objectives were to determine the effects of fall harvest management on forage quality of Matua prairie grass during the fall and following spring. Two field experiments were conducted on Hagerstown silt loam soil (fine, mixed, mesic Typic Hapludalfs). Experiment 1 addressed date of fall harvest and residual stubble height; Experiment 2 addressed frequency of fall harvest and residual stubble height effects on forage quality in the fall and spring. Delaying fall harvest of Matua prairie grass caused forage crude protein (CP) content to decline by about 30%; however, delaying fall harvest had no or little effect on acid‐detergent fiber (ADF), neutral‐detergent fiber (NDF), or in vitro dry matter digestibility (IVDMD). Grasslands Matua quality in the spring was unaffected or inconsistently affected by fall harvest management. Delaying harvest of Matua prairie grass in the spring reduced forage quality but not to the extent reported for other cool‐season forage grasses. Our findings indicate that Matua offers considerable latitude in fall and spring harvest management with regards to obtaining quality forage; however, these finding should be considered along with previous findings that fall harvest management has a large effect on winter survival of Matua.

Effects of Single Season and Rotation Harvesting on Cool-and Warm-Season Grasses of a Mountain Grassland

A mountain bunchgrass community with cool-season Parry oatgrass (Danthonia parryi) and warm-season slimstem muhly (Muhlenbergia filiculmis) as major grasses was treated with early partial harvest of cool-season grasses and late partial harvest of warm-season grasses. Warm-season grasses in these communities were greatly reduced by repeated late harvest, slightly reduced by late harvest in alternate years, and slightly promoted by early harvest of cool-season grasses. The dominant cool-season grasses responded less to repeated early harvests than did the less abundant warm-season grasses to repeated late harvests. The hypothesis that different harvest schedules may lead to alternative equilibria is supported, and rest alone may not cause a shift from a cool-season dominated equilibrium toward a greater warm-season presence in the plant community.

Effects of Harvest Time and Grass Hay Addition on Composition and Digestion of High- and Low-Glucosinolate Rapeseed Forage

(...) Three experiments were conducted to evaluate the nutritive value of high (HG) and low (LG) glucosinolate rapeseed forage (RSF) varieties. An in vitro trial evaluated forage from an HG and an LG variety sampled before (BF) and after (AF) fall frost, and before (BI) and after (AI) inflorescence. Rapeseed forage dry matter (DM) was extremely fermentable, averaging 76.3, 73.8. 59.9 (P<0.01), and 55.2% (P<0.05) disappearance after 24 h of incubation for BI, AF, BF, and AI samples, respectively. (...)