Oat Stubble Research Articles

Impact of Smoke from Wheat, Oat, and Clover Stubble Burning on Cabernet Sauvignon Grapes and Wine

Background and Aims. Stubble burning is an agricultural practice employed by some grain growers to prepare farmland for sowing and/or to control weeds and pests. Grapegrowers and winemakers have questioned whether the resulting smoke can contaminate grapes in nearby vineyards. This study therefore sought to determine the potential for smoke from three different stubble burns to taint grapes and wine. Methods and Results. Excised bunches of mature Cabernet Sauvignon grapes were exposed to smoke from prescribed burning of wheat, oat, and Balansa clover stubble windrows. Environmental sensors monitored the concentration of particulate matter as a measure of smoke density, while chemical and sensory analysis established the extent to which grapes and wine were tainted by smoke. Only grapes that were positioned among the burning wheat windrows or downwind, but in close proximity (∼200 m) to the oat stubble burn, were exposed to sufficient quantities of smoke to result in a detectable concentration of volatile phenols (up to 12 µg/kg), as chemical markers of smoke taint. These grapes yielded wines with two to threefold higher volatile phenol concentrations (up to 18 µg/L) than other wines, including the control wine, and low intensity, but perceptible smoke-related sensory attributes, indicative of low-level smoke taint. Conclusions. Chemical and sensory analyses suggest the risk of smoke taint from stubble burning is low, except where vineyards are immediately downwind and/or prolonged or repeated smoke exposure occurs. However, stubble moisture content and prevailing weather conditions affect smoke density and dispersion, and will therefore affect the potential for smoke contamination by grapes. Significance of the Study. This study will assist colocated grain growers and grape and wine producers to undertake commercial operations, without negatively impacting one another.

Self‐regenerating black medic cover crop provides agronomic benefits at low nitrogen

AbstractA black medic (Medicago lupulina L.) cover crop is able to regenerate from seed annually and produce biomass at the end of each growing season, but its long‐term effectiveness on crop productivity, water use efficiency (WUE), and soil nutrient status within a no‐till cropping system is unclear. A field experiment was established in 2003 in Saskatchewan in a 3‐yr crop rotation [flax (Linum usitatissimum L.)–oat (Avena sativa L.)–wheat (Triticum aestivum L.)]. Treatments included cover crop (black medic or no medic), and N fertilizer (20, 60, and 100% of recommended N) arranged in a split‐split plot design. Over 10 yr, medic aboveground fall biomass averaged 625 kg ha–1 (range 0–1,868 kg ha–1) and was greatest at the lowest N rate, 879 kg ha–1. Medic increased grain yield at 20% N fertilizer; no effect was observed at higher N rates. Medic increased tiller density and kernel weight at 20% N, indicating that medic positively influenced the crop throughout the entire life cycle. Medic presence did not affect grain N or P status. Medic did not affect level of available soil N in fall but consistently increased level of soil available P. This extended to the 30–60 cm soil depth in the 100% vs. lower N rates, suggesting medic roots may have influenced P cycling. In oat stubble, medic increased spring soil water and WUE. In conclusion, black medic improved crop productivity at the low N rate but improved available soil P at all N rates, warranting further research.

Comparison between incorporation and stubble burning in an Humic Haploxerands Soil, Central Southern, Chile

Stubble burning in Chile is a common practice used for the farmers but it causes nutrient losses, erosion and environmental pollution. An alternative to change this situation is the incorporation of crop residue to improve the soil quality. The objective of this research was to compare the effects of the incorporation of oat stubble and stubble burning on the chemical and physical properties in an Humic Haploxerands soil with crop rotation oat-wheat. A completely randomized experimental design was used by two treatments of incorporation and stubble burning with soil sampling at depths of 0-5, 5-10 and 10-20cm, with three replicates. The results showed that stubble incorporation represents an sustainable management alternative for the ash volcanic soils, that improve the soil pH, organic matter , potassium exchangeable , aggregates stability and soil porosity.

Substrates for mushroom, enzyme and metabolites production: A review

The agri-food industry produces a large quantity and variety of foods that are the basis of diet for humans in the world, generating waste with a high content of compounds such as lignin, cellulose and hemicellulose that are difficult to degrade. There are chemical methodologies for the partial degradation of agro-industrial waste, but it carries a possibly greater risk of environmental contamination by the chemicals used for such purposes, so natural alternatives are sought for its degradation and obtain an economic and sustainable benefit for its use through mushroom cultivation. Mushroom production can be carried out using macrofungi that are edible, have medicine value also enzyme or metabolite-producing. Waste such as sunflower seed husk, peanut husk, corn husks, potato husk, coffee husk, cocoa husk, bean shell, pea shell, sawdust from different woods, cob and stubble of corn, oat stubble, tomato stubble, sorghum stubble, straw from various cereals, wheat bran, rice bran, cotton stalks, sugarcane bagasse, tequila agave waste, quinoa waste, coconut and banana wastes, dehydrated jicama, almond leaves, among others, are used as a substrate for the cultivation of mushrooms, which have been used alone or in mixtures, seeking to increase the production of carpophores or their metabolites and enzymes.

Soil Nitrate Nitrogen Content and Grain Yields of Organically Grown Cereals as Affected by a Strip Tillage and Forage Legume Intercropping.

Reducing tillage intensity and increasing crop diversity by including perennial legumes is an agrotechnical practice that strongly affects the soil environment. Strip tillage may be beneficial in the forage legume–cereals intercropping system due to more efficient utilization of biological nitrogen. Field experiments were conducted on a clay loam Cambisol to determine the effect of forage legume–winter wheat strip tillage intercropping on soil nitrate nitrogen (N-NO3) content and cereal productivity in various sequences of rotation in organic production systems. Forage legumes (Medicago lupulina L., Trifolium repens L., T. alexandrinum L.) grown in pure and forage legume–winter wheat (Triticum aestivum L.) strip tillage intercrops were studied. Conventional deep inversion tillage was compared to strip tillage. Nitrogen supply to winter wheat was assessed by the change in soil nitrate nitrogen content (N-NO3) and total N accumulation in yield (grain and straw). Conventional tillage was found to significantly increase N-NO3 content while cultivating winter wheat after forage legumes in late autumn (0–30 cm layer), after growth resumption in spring (30–60 cm), and in autumn after harvesting (30–60 cm). Soil N-NO3 content did not differ significantly between winter wheat strip sown in perennial legumes or oat stubble. Winter wheat grain yields increased with increasing N-NO3 content in soil. The grain yield was not significantly different when comparing winter wheat–forage legume strip intercropping (without mulching) to strip sowing in oat stubble. In forage legume–winter wheat strip intercropping, N release from legumes was weak and did not meet wheat nitrogen requirements.

Temporal variation of mechanical strength and moisture content of a Eutric Fulvudands after incorporation of oat (Avena sativa) stubble, a case study

Temporal variation of mechanical strength and moisture content of a Eutric Fulvudands after incorporation of oat (Avena sativa) stubble, a case study

Formas de preparo de solo e controle de plantas daninhas nos fatores agronômicos e de produção da mandioca

The study was conducted to evaluate ways of soil tillage and weed control on the production of cassava. Prior to planting the experiment, an area was left fallow, with a predominance of Brachiaria brizantha , and another area cultivated oat in the conventional tillage system. At the end of the cycle of oats the area was used for the experiment with cassava (cv IAC15). The experimental design was a randomized complete block with three treatments and six repetitions. The treatments corresponding to the types of tillage systems and crop driving were: T1-conventional tillage in the fallow and weed control (CT), T2 – No-till on the oat stubble without control of invasive plants (NTwwc) and T3 – No-till oat straw on the control of invasive plants (NTwc). For the treatment corresponding to conventional tillage (CT) of the experimental plots were prepared with a plow and a harrow leveling. The tillage was performed using mechanized planter. The harvest was performed 14 months after planting. The highest values for plant height and fresh weight of shoots were observed in treatments corresponding to the no-tillage system (NTwc and NTwwc). The greatest number of roots ha-1 was observed in NTwwc treatment differing only from the CT. No significant differences were observed for the fresh mass production of roots among the treatments. The highest value from starch content of roots obtained was in the NTwc treatment.

ASPECTOS AGRONÔMICOS E PRODUTIVOS DOS HÍBRIDOS DE GIRASSOL (Helianthus annus L.) HELIO 251 E HELIO 360

This study had as objective to quantify achenes, leaves, stem and capitulum production and participation, as well as green and dry matter production of two sunflower hybrids for silage production. Two sunflower hybrids, Helio 251 (H251) and Helio 360 (H360), were used and implanted under oat stubble. The counting of twelve points with five linear meters/hectare of each hybrid was carried out to evaluate hybrid production and five samples were taken to evaluate plant composition. A complete randomized experimental design was used and the averages were analyzed by Tukey test. H251 hybrid presented higher plants per linear meter and per hectare (3.99 vs. 3.12 plants/m; 49,953.95 vs. 38,342.10 plants/ha, for H251 and H360, respectively). H360 capitulum were heavier than the ones from H251, when expressed in green (303.79 g/plant) or dry (56.88 g/plant) matter basis, consequently, it showed heavier achenes (151.09 and 100.12 g/plant, respectively, for green and dry matter). H360 presented higher stem weight, when expressed in green (120.95 vs. 61.27 g/plant) or dry (48.58 vs. 29.01 g/plant) matter basis. The higher weights of capitulum, achene and stem presented by H360 resulted in heavier plants and superiority on dry matter production per hectare. KEYWORDS: achenes, capitulum; dry matter; green matter; leaves; stem.

Ovarian Development and Ovipositional Preference of the Western Corn Rootworm (Coleoptera: Chrysomelidae) Variant in East Central Illinois

The rotation of maize, Zea mays L., and soybean, Glycine max (L.) Merr., has been the traditional cultural tactic to manage the western corn rootworm, Diabrotica virgifera virgifera LeConte, in the Corn Belt. The reduced effectiveness of this rotation as a pest management tool in east central Illinois, northern Indiana, and southern Michigan can be explained by the shift in the ovipositional behavior of the new variant of western corn rootworm. The objective of this study was to evaluate the influence of maize, soybean, oat, Avena sativa L., stubble, and alfalfa, Medicago sativa L., on the ovarian development and ovipositional preferences of the variant western corn rootworm. Field research was conducted near Urbana, IL, during 1998–2000. Gravid females were present throughout the season in all crops, and due to the prolonged period in which western corn rootworm females can lay eggs, none of the crops were immune from oviposition. Results indicated that the western corn rootworm variant oviposits in maize, soybean, oat stubble, and alfalfa. In 1998 and 1999, maize was the preferred oviposition site among crops; however, in 2000, maize, soybean, and oat stubble treatments had similar densities of western corn rootworm eggs. Lack of oviposition preference of the western corn rootworm variant demonstrated in this experiment represents a reasonable explanation of why the effectiveness of the rotation strategy to control western corn rootworm has diminished.

Ovarian development and ovipositional preference of the western corn rootworm (Coleoptera: Chrysomelidae) variant in east central Illinois.

The rotation of maize, Zea mays L., and soybean, Glycine max (L.) Merr., has been the traditional cultural tactic to manage the western corn rootworm, Diabrotica virgifera virgifera LeConte, in the Corn Belt. The reduced effectiveness of this rotation as a pest management tool in east central Illinois, northern Indiana, and southern Michigan can be explained by the shift in the ovipositional behavior of the new variant of western corn rootworm. The objective of this study was to evaluate the influence of maize, soybean, oat, Avena sativa L., stubble, and alfalfa, Medicago sativa L., on the ovarian development and ovipositional preferences of the variant western corn rootworm. Field research was conducted near Urbana, IL, during 1998-2000. Gravid females were present throughout the season in all crops, and due to the prolonged period in which western corn rootworm females can lay eggs, none of the crops were immune from oviposition. Results indicated that the western corn rootworm variant oviposits in maize, soybean, oat stubble, and alfalfa In 1998 and 1999, maize was the preferred oviposition site among crops; however, in 2000, maize, soybean, and oat stubble treatments had similar densities of western corn rootworm eggs. Lack of oviposition preference of the western corn rootworm variant demonstrated in this experiment represents a reasonable explanation of why the effectiveness of the rotation strategy to control western corn rootworm has diminished.

Captures of Western Corn Rootworm (Coleoptera: Chrysomelidae) Adults with Pherocon AM and Vial Traps in Four Crops in East Central Illinois

It is hypothesized that the long-term rotation of maize (Zea mays L.) and soybean (Glycine max L.) in east central Illinois has caused a significant change in the ovipositional behavior of the western corn rootworm, Diabrotica virgifera virgifera LeConte. Since the mid 1990s in east central Illinois, western corn rootworm adults have been observed feeding on soybean foliage and also now use soybean fields as egg laying sites. This behavioral adaptation has greatly decreased the effectiveness of rotation as a pest management tactic. By using Pherocon AM and vial traps, we evaluated the influence of maize, soybean, oat stubble (Avena sativa L.), and alfalfa (Medicago sativa L.) on male and female adult western corn rootworm densities from April 1998 through September 2000 near Urbana, IL. Our results indicated that western corn rootworm adults are common inhabitants of maize, soybean, oat stubble, and alfalfa. Trapping efforts with both Pherocon AM (attractive) and vial traps (passive) revealed that initial densities of both male and female western corn rootworm adults were greater in maize. Soon after emergence, densities of females began to decline within maize and increase in other crops (soybean, oat stubble, and alfalfa). Results from this experiment support the hypothesis that variant western corn rootworm females in east central Illinois are colonizing crops other than maize at densities of potential economic importance. Those producers who choose to rotate maize with soybean or alfalfa may remain at risk to economic larval injury to maize roots. Potentially, oat stubble also may support levels of western corn rootworm females resulting in sufficient oviposition to cause economic losses to rotated maize the following season.

Forages resources in "dehesa" system: fertilization, tillage and forage sowing. I. Influence to the environment (soil and vegetation)

This work studies the ecological impact to the environment (soil, vegetation) produced by the application of differenttreatments, such as phosphoric fertilization, superficial tillage on the pasture, or deep ploughing and sowing fodder, ontwo types of soil, slate and granite over the period 1994-1997. The evolution of the chemical and granulometric compositionof the soil and also the covering and floral composition of the vegetation was monitored. The duration of the residualeffect was also considered, in order to determine the best possible time to carry out these practices. The evolution ofthe pH and the levels of organic matter, carbon, nitrogen, calcium, phosphorus, potassium, clay, lime and humidity werethe main factors surveyed on the soil. For each type of treatment, the floral abundance and density of the vegetation wasrecorded and catalogued. One of the conclusions obtained was that both the content in organic matter of the soil and thefloral cover decreases with sowing of fodder. The recovery of the soil organic matter usually takes more than four years,whereas the vegetation cover reaches its initial levels after three years. By the end of the experimental period these coverlevels are even higher than the original ones. In three year old oat stubble, pastures that can be related to syntaxonomicunits (Koelerio Corynephoretea y Molinio-Arrhenateretea) were seen. The plots of fertilized pasture showed higher levelsof legumes whereas the plots that had been fertilized and ploughed showed increased values of both legumes and grasses.The oat stubble showed higher levels of Composites after the first year, but their presence decreased with time.

Forages resources in "dehesa" systems: fertilization, tillage, and forage sowing. 2. Productivity and use of rain water

In two «dehesa» grasslands with different soils, one over slate and the other over granite, studies were carried out toinvestigate the influence that phosphoric fertilization, surface tillage of pastures and oat sowing have on the primaryproduction and its nutritive value, on the index of utilization of raining water, and on the evolution of oat stubble withtime. Additionally, economic studies of the previous results have been carried out. Phosphoric fertilization and superficialtilling of pastures did not have a relevant influence on the primary production. Additionally, in the successive regrowthover oat stubble there was no response to phosphoric fertilization. The production increments with respect tocontrols are related to the preparatory tillage for sowing the oats, and the changes that the vegetation experimented.This effect decreased with time. The dry matter production in the oat treatments was higher than in the pastures, bothin slate and granite soils. In dehesa systems the use of raining water for the production of 1 kg dry matter ha-1 was verylow, and, on the average, 0.278 and 0.588 l m-2 were needed in pastures, but this amount decreased significantly in theoats: 0.059 and 0.110 l m-2 in slates and granites, respectively; with better use of the water in the more fertile soils. Theeconomic response to the oat sowing was about 252 and of 160 euros ha-1 year-1 in slates and granites, but there was noeconomic response to the fertilization and superficial tilling of pastures during the period of the experiment.

Impact of forest conversion to agriculture on carbon and nitrogen mineralization in subarctic Alaska

Land-use change is likely to be a major component of global change at high latitudes, poten- tially causing significant alterations in soil C and N cycling. We addressed the biogeochemical impacts of land-use change in fully replicated black spruce forests and agricultural fields of different ages (fol- lowing deforestation) and under different management regimes in interior Alaska. Change from forests to cultivated fields increased summer temperatures in surface soil layers by 4-5 °C, and lengthened the season of biological activity by two to three weeks. Decomposition of a common substrate (oat stubble) was enhanced by 25% in fields compared to forests after litter bags were buried for one year. In-situ net N mineralization rates in site-specific soil were similar in forests and fields during summer, but during winter, forests were the only sites where net N immobilization occurred. Field age and management had a significant impact on C and N mineralization. Rates of annual decomposition, soil respiration and summer net N mineralization tended to be lower in young than in old fields and higher in fallow than in planted young fields. To identify the major environmental factors controlling C and N mineralization, soil temperature, moisture and N availability were studied. Decomposition and net N mineralization seemed to be mainly driven by availability of inorganic N. Soil temperature played a role only when comparing forests and fields, but not in field-to-field differences. Results from soil respiration measure- ments in fields confirmed low sensitivity of heterotrophic respiration, and thus decomposition to tem- perature. In addition, both soil respiration and net N mineralization were limited by low soil water con- tents. Our study showed that (1) C and N mineralization are enhanced by forest clearing in subarctic soils, and (2) N availability is more important than soil temperature in controling C and N mineraliza- tion following forest clearing. Projecting the biogeochemical impacts of land-use change at high lati- tudes requires an improved understanding of its interactions with other factors of global change, such as changing climate and N deposition.

Intake and production of ewes grazing oat stubble supplemented with sweet lupin ( Lupinus albus) seed

Oat stubble was grazed continuously during the summer and autumn (December–April) for 154 days by reproducing ewes ( n = 48) and rumen fistulated wethers ( n = 12) at a stocking rate of 2.4 sheep ha −1. The stubble was supplemented with 0, 200, 400 and 600 g sweet lupin seed per sheep day −1 during the last 6 weeks of pregnancy and the first 5–6 weeks of lactation. An average of 1787 kg DM ha −1 with a mean CP content of 71 g kg −1 and DOM content of 501 g kg −1 was available during the experimental period. A deficiency in CP content of the pasture was indicated by low rumen ammonia-N levels of wethers (3.7–3.9 mg per 100 ml), which progressively increased ( P < 0.05) by 3.2 mg per 100 ml (SE b = 0.6; R 2 = 0.94) for each 100 g of supplement provided (OM basis). Organic matter intake of ewes from pasture per se during late pregnancy (1063 ± 86 g per ewe day −1) and during lactation (1015 ± 150 g per ewe day −1) declined ( P < 0.05) by 42 g day −1 for each 100 g of supplement provided on an OM basis. Sweet lupin supplementation at 400 g day −1 fulfilled requirements for DOM and CP during late pregnancy. During lactation a deficiency in DOM and CP still occurred at a supplementation level of 600 g day −1. The BW loss of ewes during the first 6 weeks of lactation was reduced ( P < 0.05) by 2.0% (SE b = 0.5; R 2 = 0.91) for each 100 g increase in supplementary feed per day provided on an OM basis. No significant differences between supplementary groups were observed in terms of lamb birth weight, the lamb growth rate up to 42 days of age or in ewe wool growth rate. This was probably due to the high degradability of lupin seed.

Reduced growth and yield of wheat with conservation cropping. I. Field studies in the first year of the cropping phase

An experiment was conducted on a red earth at Harden, N.S.W., to investigate the effects of tillage and stubble management on the growth and yield of wheat in the first year of conservation cropping. Treatments involved stubble-management systems of incorporation, burning or retention combined with tillage systems of either direct drilling or minimum tillage. The experiment was conducted on an oat stubble of 3.9 t ha-1. Direct drilling and stubble retention both reduced seedling growth by 15%, compared to cultivated and stubble burnt treatments, but had no effect on plant density or tillering. The effects on shoot growth were additive and persisted until maturity, leading to grain yields which varied from 2.16 t ha-1 for the stubble-mulched, direct-drilled treatment to 3.20 t ha-1 for the burned-stubble, minimum-till treatment. Direct drilling reduced the total root length in the profile (0-160 cm) at anthesis by 40%, but there was no effect of stubble retention. Reduced shoot growth and rooting depth on direct-drilled and stubble-retained treatments reduced the recovery of water and mineral N by the crop and increased the leaching of mineral N below the root zone. Early shoot growth reductions on direct-drilled plots were not related to levels of soil water, mineral nitrogen (N) or soil temperature. Reduced shoot growth was associated with increased severity of Rhizoctonia in some direct drilled plots, but growth reductions often occurred in the absence of obvious symptoms. High soil strength (&gt;2 MPa) in the top 10 cm of soil may have contributed to reduced growth, although the exact mechanism remains unclear. Reduced growth associated with the presence of stubble was not caused by immobilization of N or increased leaf disease, although reduced soil temperatures may have been partly responsible.

Habitat and Food Preferences of Allonemobius allardi (Orthoptera: Gryllidae) and Potential Damage to Alfalfa in Conservation-Tillage Systems

Population estimates of the cricket Allonemobius allardi (Alexander & Thomas) in orchardgrass, Dactylis glomerata L.; alfalfa, Medicago sativa L.; and weedy fields revealed significantly lower cricket densities for alfalfa compared with orchardgrass and weed fields. However, densities were not significantly different between orchardgrass and weed fields despite a considerable dissimilarity in vegetative composition. Laboratory feeding studies suggest that crickets preferred to forage on the substrate and had difficulty recognizing preferred food plants that were elevated above the substrate. Crickets preferred alfalfa to bluegrass, thatch, or oats, but preferred bluegrass to thatch. No significant difference in feeding was observed between whole alfalfa leaves and alfalfa leaf disks when poth were placed horizontally on the testing arena substrate. The contents of crops from field-collected crickets showed Alternaria , rust spores, and fungi occur relatively frequently but do not account for a substantial percentage of cricket crop contents. Legumes and dandelion also occur with a moderately high frequency and are a major component of cror contents. Cage tests in glasshouse and field showed one to two cricket adults per 0.09 m2 reduced alfalfa seedling numbers by 1–20% in the 2 wk from seedling emergence to formation of the first trifoliate in conservation-tillage systems when alfalfa was planted in oat stubble.

Effects of Weed and Invertebrate Control on Alfalfa Establishment in Oat Stubble

Crop residues in conservation tillage can provide excellent habitats for invertebrates that feed on alfalfa seedlings. The impact of invertebrate feeding on seedlings has been assessed for alfalfa no-till seeded into wheat (Triticum aestivum L.) stubble and grass sods, but not oat stubble. Thus, our objective was to determine the influence of weed and invertebrate control on alfalfa (Medicago sativa L.) establishment in oat (Avena sauva L.) stubble. Alfalfa was drilled into a plowed seedbed or into oat stubble. Postplant weed control (none or sethoxydim) and slug and insect control (plowing, methiocarb bait [3,5-dimethyl-4-(methylthio)phenol methylcarbamate], carbofuran [2,3-dihy-dro-2,2-dimethyl-7-benzofuranyl methylcarbamate], methiocarb plus carbofuran, and none) treatments were evaluated during the establishment of alfalfa at the Rock Springs Agricultural Research Center in Centre County, PA, on a silt loam (Typic Hapludalf; fine, mixed, mesic) soil. Slug numbers were measured 1,3, and 6 wk after planting. Seedling frequency and invertebrate feeding were measured 3 and 6 wk after planting. Morphological development was measured 6 wk after planting. Yields were taken the spring following planting. Reducing weed populations increased seedling shoot weight, trifoliolate leaves per plant, and production year first-cut yields. Invertebrate management decreased gray field slug (Derocerus reticulatum) populations and increased seedling frequency during initial seedling growth. Controlling volunteer oat was the major factor affecting establishment and yield of alfalfa no-till seeded into oat stubble.

Feeding areas and local movement patterns of post-breeding Greylag Geese Anser anser in South Sweden

Greylag Geese Anser anser mostly selected one field type, neglecting all other available types. After the breeding season they started to feed on grasslands, turned to peas during the end of July or the middle of August, and then shifted to wheat stubble in the first half of September. Only two other field types, barley stubble and newly-sown cereals, were occasionally selected. Most of the time they never showed any interest in oat stubble, newly-sown cereals and newly-sown rape. Rape stubble and ploughed fields were never used. Fields with high-energy food accounted for about 95% of all goosedays each autumn. The exploitation rate of large fields (&gt;17 ha) with peas or wheat stubble was much higher than that of smaller fields with the same crop. Distances between roosts and feeding areas were normally less than 5 km. In October the activity pattern, characterized by two daily feeding periods, began to weaken, with some geese staying on the feeding grounds all day. In November all geese spent the whole day on the feeding grounds. The length of time spent on the feeding grounds per day increased from about 200 min. in mid-August to more than 400 min. in early October. The marked families not only stayed in the study area the whole autumn but moreover, they rarely moved between different gathering areas. There were no significant differences between families and pairs without young with respect to the time they were present and the number of times they moved between different gathering areas. Subadults moved between gathering areas significantly more often than did mature birds.

Utilization of urea and molasses supplements by cattle grazing cereal stubbles

Responses of cattle to urea and molasses supplements while grazing cereal crop stubbles were studied in two experiments.In experiment 1,2.5-year-old Friesian cows in early pregnancy grazed an oat stubble (6800 kg DM ha-1) for 12 weeks at a stocking rate of 3.8 cows ha-1. In addition, some were offered liquid supplements of molasses, or urea-molasses. Liveweight gain (mean 18 kg) was not significantly different between treatments during the first 6 weeks. Thereafter, unsupplemented cows lost weight at 1.6 kg day-1 compared with 0.5 kg day-1 for supplemented cows (P(0.05).In experiment 2, 1.5-year-old Angus X Friesian cows in early pregnancy, and rumen-fistulated Friesian steers, were grazed on wheat stubble for 15 weeks and were unsupplemented, or offered supplements of a urea-mineral block, a molasses lick, or a urea-molasses lick. The stubble initially contained c. 6000 kg DM ha-1 of crop residues, and at all times at least 100 kg DM ha-1 of mainly green stemmy weeds of digestibility (0.45. The diet selected contained &gt;50% dead plant material except during the final week, and ranged in digestibility from 0.53 initially to 0.31 in the 12th week.Intakes of all supplements were highly variable among individuals with coefficients of variation usually &gt;50%. Mean intakes of digestible organic matter (DOM) were generally increased by supplementation.During the first 11 weeks, mean liveweight gains ranged from 3.5 to 27 kg for the unsupplemented and urea-mineral block fed cattle. respectively, but thereafter all cattle lost weight rapidly (mean 1.33 kg day-1).Mean concentrations of rumen volatile fatty acids (VFA) fell during the experiment from 80.3 to 47.4, and from 90.9 to 56.4 mmol l-1 in the unsupplemented and supplemented steers, respectively. Rumen VFA levels were not related to molasses or urea intakes, and overall there was no relationship between liveweight change and levels of VFA in the rumen. Mean rumen ammonia levels, which were generally &lt; 100 mg N l-1 in unsupplemented and molasses-fed steers, were increased by both urea supplements, particularly in the second half of the experiment.Although various parameters indicated likely deficiencies of energy and N in the diet, these supplements were generally of little benefit to cattle grazing cereal stubbles.