Agricultural Science Commons^™

An Ecological Approach To Forage Management, J L. Brock, R.J M. Hay

IGC Proceedings (1977-2023)

The principles of defoliation management for maximum production of quality herbage are well researched, namely the manipulation of frequency and severity of defoliation, but their impact on the various levels of ecological organisation in pastures is nol fully understood or their interpretation appreciated. Using grazed ryegrass-white clover pasture as; example, detailed sward studies have suggested the following model. Defoliation frequency and severity interact lo produce varying levels of physiological stress and morphological adaptation which affecl the survival rate and size of individual growth units, the lowest level of organisation. Increasing frequency of defoliation reduces organ size but increases survival rate …

Land Use In Non-Affluent Countries As Determined By Social Infrastructure And Population Patterns, Bore Motsamai

IGC Proceedings (1977-2023)

Tenure of land in most developing countries is predominantly communal, with a mixture of introduced systems of individual ownership. Since nations attained independence structural- changes have been made in order to introduce land reform. Countries are caught up in a dilemma of having to provide social justice and greater equity through land reform, but face increasing population and landlessness. For example, Lesotho's landless rural people increased from 7.2% in 1950 to 38.5% in 1987, and 17.2% are without land and livestock. Employment opportunities fall short of satisfying the labour mBrket. With limited land resources and high population pressure, rational and …

The Future Of Sustainable Agriculture In The United States, Dennis R. Keeney

IGC Proceedings (1977-2023)

In the United States, sustainable agriculture remains complicated and controversial as a concept, particularly to define and apply in terms of practices and policies to achieve sustainability. Many consider current agricultural practices to be sustainable in the near term with regard to the dependable, affordable supply of food and fibre, but unsustainable in terms of environmental quality and social costs. Production agriculture hos been linked to soil erosion and water pollution, and the emphasis on efficiency has contributed to the loss of many farmers and increasing instability in rural communities. Many of agriculture's dilemmas can be linked to policies of …

Livestock Production Systems In The Cameroon Sahelo-Sudanian Region, E Tedonkeng Pamo, R D. Pieper

IGC Proceedings (1977-2023)

The Sahelo-Sudanian region of Cameroon extends from 7° to 13° N. The region receives 400-1000 mm rainfall and is covered by a complex mosaic of. vegelation and plant communities. Animal production has always been a cornerstone of the economy of this region. The range use system of the region is extensive. The major problem faced by pastoralists has been a compression of their range not only by the northward-moving cultivation, but also by the southward moving desertification. Various grazing melhods have been suggested but none have yet been implemented, and nomadism and transhumance remain the major production systems. Analysis of …

Runoff Studies In Different Cropping Systems And Preliminary Results For Nitrogen Leaching, Ragnar Eltun

IGC Proceedings (1977-2023)

A cropping system project was started at Apelsvoll Research Station in 1990, with the aim of developing cropping systems to minimise nutrient leaching and maximise food quality and economy. The experiment involves cash crop and forage crop systems with conventional, integrated and organic farming. This paper presents the experimental layout and preliminary measurements of nitrogen leaching. Both drainage water concentrations and runoff results shows that nitrogen leaching is less from cropping systems dominated by forages than from cash crop systems with cereals and potatoes.

Land Subdivision In The Falkland Islands, O W. Summers, W.J R. Haydock, A Kerr

IGC Proceedings (1977-2023)

The Falkland Islands agricultural industry depends mainly on wool production. This paper reviews the structure of an induslry which has changed radically in the last 10 years. Lord Shackleton completed his economic survey of the Falkland Islands in 1976 when there where only 36 fanns, most of which were owned by companies based mainly in the UK, and an absentee-landlord system prevailed. Shackleton advocated that the Falkland Islands Government should purchase large fanns and split them into smaller family units for sale to local people. Presently (1991-92) there are 92 farms and most of the Islands is in local ownership. …

Disparities In The Utilization Of Nambia's Grassland: A Need For Adjustments In The Beef Industry, Helmke Sartorius Von Bach, Johan Van Zyl

IGC Proceedings (1977-2023)

Extensive beef production, Namibia's life-line in agriculture, depends entirely on natural pastures. Socioeconomic and environmental disparities, namely (a) the· traditional smallholder communal sector versus the commercial sector and (b) areas in the vicinity versus distant from centralised abattoirs, are analysed by' using econometric analysis of time-series data on the regional influence of prices and· access to markets on beef numbers. This is particulary relevant because Namibia is in a process of structural adjustment, and in view of the beef sector's importance in the Namibian economy. The results accentuate the role of access to markets and productive opportunities for beef production …

Comparison Between Fodder Cropping Rotations Carried With Or Without Meadow In The Intensive Farming System Of The Po Valley Plain (Italy), Mario Onofrii, Cesare Tomasoni, Lamberto Borrelli

IGC Proceedings (1977-2023)

Pour fodder cropping rotations were compared at different degrees of crop intensification: (RI) a I-year continuous monoculture of Italian ryegrass (Loll111n multij/orum Lam.) +silage maize (Zea mays L.); (R3) a 3-year rotation of Italian ryegrass+silage maize - barley (Hordeum vulgare L.)+silage mai1:e - grain maize; (R6) a 6-year rotation of Italian ryegrass+silage maize for 3 years followed by meadow for 3 years (Trifolium repe11s L. + Festuca ari111di11acea Schreb,): (PM) a monoculture of permanent meadow. The most efficient rotation for dairy cattle feeding, on sandy-loam soils, was the I-year rotation of Italian ryegrass, followed by silage maize, with 22 9S0 …

Cadmium In Soil, Pasture And Grazing Ruminants, J Lee, N D. Grace, A D. Mackay, M J. Hedley, J R. Rouce

IGC Proceedings (1977-2023)

Cadmium, present in New Zealand hill country pastures rrom Cd­amended phosphatic fertiliser use, is assimilated by grazing ruminants. Concentrations of Cd in plasma from sheep grazing pastures containing low (0.1-0.2µglg dry weight) or high (0.8-1.4 µgig dry weight) levels of Cd were 0.15±0.04 nglg and 0,35:1:0.15 ng/g, respectively (P<0.08). Cadmium in pasture was highly correlated (P<0,001) with soil O.IM HCl-extractable Cd (log10 Soiled= -0.98+0.26 Plantcd).

Nitrogen Dynamics In Three Contrasting Grassland Systems: Implications For Pasture Productivity And The Potential For Environmental Pollution, B E. Ruz-Jerez, R E. White, P Roger Ball

IGC Proceedings (1977-2023)

Nitrogen (N) dynamics were compared in 3 contrasting grassland systems (2 legume-based and I receiving fertiliser N) in a cool temperate region of New Zealand. The study was concentrated on the various N transfers that occurred during and after grazing. Critical periods for N loss by different processes have been identified, allowing a more comprehensive understanding of the role of N in the productivity of different types of pasture, and the potential for environmental pollution, Calculation of N inputs and outputs for the three pastures indicated that the two legume-based systems were more or less in balance, but in the …

Reduction Of Nutrient Losses For Dairy Farms, With Emphasis On Nitrogen, W Luten, D J. Den Boer

IGC Proceedings (1977-2023)

Recently the Dutch government presented several policy papers in which standards are given for maximum allowed emissions to air, groundwater and surface water. Depending on the farm situation an optimum combination of measures in relation to housing, slurry storage, slurry and fertiliser application, and composition of the ration can be taken. In general a better use of nutrients from animal manure by applying slurry with low emission techniques in the growing season and a reduction of the stocking rate by a higher milk production per cow are the most effective and cheapest measures to reach these targets. There is a …

Use Of Pasture As A Receivers For Swine Lagoon Effluent, J P. Mueller, J C. Barker, J P. Zublena, M H. Poore, R W. Harvey, J T. Green

IGC Proceedings (1977-2023)

Swine waste management-cattle grazing systems were monitored on 2 North Carolina farms from 1990-1992, Farmers co-operated directly in the project by furnishing land, labour, equipment and cattle and by maintaining records of grazing and waste applications. Local county agricultural extension agents helped with management decisions, record­keeping and co-ordinating activities among project participants. On a fann where waste was applied to pastures for 5 years, soil N in the upper l m averaged from 230-500 kg/ha, NO3 -N in the forage remained above 10 g/kg for the grazing season and 2 of 4 test wells recorded NO3 levels above 10 mg/I. …

Pastoral Systems Of Central Himalaya: How Long Will They Survive?, K S. Rao, K G. Saxena

IGC Proceedings (1977-2023)

Pastoral systems of Central Himalaya are very old and until recent time were in balance with environment, Recent changes in socio­political setup have drastically altered the status of these systems. The change of political power in trans-Himalayan Tibetean plateau has resulted in closure of international boarders, thus taking away the mercantile aspects of pastoralists and reducing pastoral area. Increased human disturbances on fragile Himalayan marginal lands and excessive onslaught on forests for fuel and fodder by the sedentary population has resulted in degradation and non-productive grasslands which do not help pastoralists sustain existing systems. Changes in relations between migratory pastoralists …

A Preliminary Discussion Of The Management And Administration Of Yunwu Mountain Natural Grassland Reserve In China, Zhao Zhiyi, Yang Ailian

IGC Proceedings (1977-2023)

The advantages and problems encountered in the establishment of a grassland reserve are described. The conflicts between local farmers' requirement to feed and water livestock and the conservation strategy of natural grassland are discussed.

Effect Of Sewage Sludge On The Mineral Composition Of Corn, Arthur E. Peterson, P E. Speth, P L. Schlecht

IGC Proceedings (1977-2023)

For the past 12 years, digested sewage sludge from the Milwaukee Metropolitan Sewerage District has been applied to a Plano silt loam (prairie) soil near Elkhorn, Wisconsin, and corn raised as the indicator crop. The corn has been harvested as silage and fed to dairy cnttle. The amounts of macro-, micro-, and heavy metals contained in this forage were compared with the amounts contained in the untreated areas, and in the forage produced by a sustainable agriculture study on the same experimental station. None of the heavy metals have moved out of the plough layer (lop 25 cm). The uptake …

Sustainable Direction For Resource Management An Assessment Of The Regional Council Role, Allan Lohrey

IGC Proceedings (1977-2023)

The 1980s has seen an increased world awareness of the concept of sustainability. In 1991 New Zealand enacted the Resource Management Act (RMA) which reflected society's concern for a need to consider future generations when making decisions relating to the use of natural resources. Regional councils have been allocated the role within the Act to promote sustainable management at the regional level. The short term challenge to regional councils is to manage resources in manner which strikes a pragmatic balance between the ongoing needs of society and the need to provide resources for future generations. Regional councils will know they …

Application Of Dairy Manure On Alfalfa, Stephen J. Herbert, Jayarm Daliparthy, P L.M Veneman

IGC Proceedings (1977-2023)

Applying dairy manure to alfalfa (Medicago sativa L.) as ,in alternative 10 excess application to· corn (Zea mays L.) may reduce nitrate pollution of groundwater. Field experiments were conducted at 2 sites in Massachusetts, USA, lo study the impact or dairy manure application to alfalfa on forage yield, weed infestation· and nitrate movement. Treatments were an unfertilized (no N) check.· plot, low and high manure (112 and 336 kg N/ha/year equivalerit), and low and high N fertiliser (112 and 336 kg N/ha/year from NH4NO3),'. Liquid dairy manure was applied 10 • alfalfa immediately· after 1st· cutting during spring …

Tar Vine And Its Management, Department Of Primary Industries And Regional Development, Western Australia

Biosecurity factsheets

Tar vine (Boerhavia coccinea) is a common summer weed species that depletes soil moisture and nutrients, reducing the yield potential of the subsequent crop. It also acts as a green bridge for crop pests and disease.

Bean Yellow Mosaic Virus And Its Management In Lupins, Department Of Primary Industries And Regional Development, Western Australia

Grains and other field crops factsheets

Bean yellow mosaic virus (BYMV) is an aphid-transmitted virus that commonly causes necrotic symptoms that kills lupin plants when infected early before pod set. When plants are infected after pod set, black pods develop (known as black pod syndrome).

BYMV is found predominantly in high rainfall areas of the Western Australian (WA) grainbelt. This page outlines the symptoms, diagnosis, factors favouring disease risk and spread, yield and quality impacts, and management for BYMV in lupin crops in WA

Cucumber Mosaic Virus And Its Management In Narrow Leafed Lupins, Department Of Primary Industries And Regional Development, Western Australia

Grains and other field crops factsheets

Cucumber mosaic virus (CMV) is a seed- and aphid-borne virus that infects narrow-leafed lupins. Western Australian (WA) grainbelt regions most at risk are the high rainfall zones of the northern and central agricultural region and the south coastal region.

The principal infection source for lupin crops is sowing infected lupin seed.

Ascochyta Blight Disease And Its Management In Faba Beans, Department Of Primary Industries And Regional Development, Western Australia

Grains and other field crops factsheets

This factsheet summarises the symptoms, disease risk, infection cycle and control measures for Ascochyta blight (Ascochyta fabae) in faba bean compared to the diseases, Alternaria and Cercospora.

Blackleg And Its Management In Canola, Department Of Primary Industries And Regional Development, Western Australia

Grains and other field crops factsheets

Blackleg, caused by the fungus Leptosphaeria maculans, is the most common and serious disease of canola in Western Australia (WA). Blackleg can cause significant damage by infecting the cotyledons or first leaves early in the season, leading ultimately to crown lesions or cankers later in the season.

Changes in variety choice, crop rotation, earlier sowing times, and stubble retention have extended the risk of blackleg disease. Because of early emergence, later stages of crop growth are more likely to be exposed and infection can occur on all parts of the plant above ground, including canola flowers, stems, and branches (this …

Root Lesion And Burrowing Nematodes And Their Management, Department Of Primary Industries And Regional Development, Western Australia

Grains and other field crops factsheets

Nematodes are common soil pests that feed on the roots of a wide range of crops in all agricultural areas of Western Australia, resulting in significant crop yield loss. Root lesion nematode can be managed but not eradicated.

This factsheet summarises the biology of the root lesion nematode (RLN, Pratylenchus spp.) and burrowing nematode (Radopholus spp.) species that damage Western Australian (WA) crops, and their diagnosis and management.

Roly Poly And Its Management, Department Of Primary Industries And Regional Development, Western Australia

Grains and other field crops factsheets

Roly poly, also known as prickly saltwort or tumbleweed (Salsola australis), is a native species found throughout Australia. The dead plants can break off at ground level, forming the ‘tumbleweeds’ seen in movies.

Like most summer weeds, roly poly uses soil moisture and nutrients that would otherwise be available to the following crop. The time taken to clear uncontrolled plants can delay seeding.

Livestock will graze the young plants; however, they will not eat the mature plants and are injured by the prickly leaves.

Net Form Net Blotch And Its Management In Barley, Department Of Primary Industries And Regional Development, Western Australia

Grains and other field crops factsheets

Net form net blotch is a fungal disease that can reduce yield and grain quality of barley crops. It can vary in appearance depending on the pathogen, variety of barley, and stage of infection. This factsheet describes the symptoms, and how this disease is managed.

Claying To Ameliorate Soil Water Repellence, Department Of Primary Industries And Regional Development, Western Australia

Natural resources factsheets

Claying involves adding and incorporating clay-rich subsoil into water repellent topsoil to overcome the repellence. Adding clay-rich soil provides a long-term solution to soil water repellence, and increases soil water holding capacity, reduces wind erosion risk, and may reduce frost risk.

Claying is best suited to medium to high rainfall environments in Western Australia, with higher crop and pasture yield potential.

Growing Oaten Hay On Frost Prone Paddocks, Department Of Primary Industries And Regional Development, Western Australia

Grains and other field crops factsheets

Growing oaten hay on frost-prone paddocks minimises the frost risk because it is cut soon after flowering, avoiding the frost sensitive period. If severe frost damage occurs to other crops, baling them for hay may reduce economic loss.

Oats are much more tolerant than other cereals to frost events that occur during vegetative growth and flowering.

Yellow Spot And Septoria Nodorum Blotch And Their Management In Wheat, Department Of Primary Industries And Regional Development, Western Australia

Grains and other field crops factsheets

Leaf spot diseases affecting wheat in Western Australia (WA) are yellow spot (Pyrenophora tritici-repentis), septoria nodorum blotch (Parastagonospora nodorum), and septoria tritici blotch (Zymoseptoria tritici). They are caused by 3 different fungal pathogens but the disease symptoms and biologies are similar.

Impact from leaf spot diseases vary greatly from season to season and between locations. They are a problem in continuous wheat crops in stubble retention (no-till) farming systems. For the most effective control, an integrated disease management (IDM) approach is required.

This page outlines the symptoms, diseases spread and risk factors, yield and quality losses, and management options for …

Wheat Streak Mosaic Virus And Wheat Curl Mite And Their Management, Department Of Primary Industries And Regional Development, Western Australia

Grains and other field crops factsheets

Wheat streak mosaic virus (WSMV) is a seed and mite-borne virus that infects wheat, causing severe leaf symptoms and reduced yields. The symptoms and damage are more severe in wheat than other hosts, in which infection is symptomless.

Wheat streak mosaic virus can cause crop failure when widespread infection occurs in seedling wheat, particularly when a heavily WSMV-infected green bridge is not controlled before sowing an early crop, and warm temperatures favour mites.

Wheat curl mite (Aceria tosichella) is the only known vector of WSMV. It can transmit the virus in its nymph and adult stages.

Doublegee And Its Management, Department Of Primary Industries And Regional Development, Western Australia

Grains and other field crops factsheets

Doublegee is a significant weed of agriculture and causes a loss of $20 million annually over an estimated one million hectares of crops and one million hectares of pastures, in Western Australia (WA) alone.