Nutrient budgeting for trace elements: Examples from Scottish organic farms

This report was presented at the UK Organic Research 2002 Conference. Farmgate nutrient budgets have been calculated for Cu, Co and Mo for six farms in NE Scotland. All five livestock farms studied had a positive balance for Co, one showed a negative balance for Cu and two showed negative balances for Mo. The stockless farm studied showed a positive balance for Cu but negative balances for Co and Mo. These balances were calculated for a one-year period only and may thus have been strongly influenced by one-off purchases e.g. calcified seaweed. Future work will calculate budgets over whole rotations to provide a clearer picture of the long-term sustainability of trace element use on organic farms

Nutrient budgets on organic farms: a review of published

This report was presented at the UK Organic Research 2002 Conference. On organic farms it is important that a balance between inputs and outputs of nutrients is achieved. This paper collates nutrient budgets collated at the farm scale for 88 farms in 9 temperate countries. The majority of budgets were compiled for dairy farms (56). All the nitrogen budgets showed an N surplus (average 83 kg N ha-1 year-1). The phosphorus (P) and potassium (K) budgets showed both surpluses and deficits (average 3.4 kg P ha-1 year-1; 13.7 kg K ha-1 year-1). For all nutrients as nutrient inputs increased the surplus increased more significantly than the nutrient outputs. Overall, the data illustrate the diversity of management systems in place on organic farms, which consequently lead to significant variability in nutrient use efficiency and potential nutrient sustainability between farms. There are opportunities for almost all organic farmers to improve the efficiency of nutrient cycling on the farm and increase short-term productivity and long-term sustainability

Nitrogen fixation and soil nitrogen in organic ley arable rotations

This report was presented at the UK Organic Research 2002 Conference. Nitrogen (N) fixation in a white clover/ryegrass mixture was measured in 1,2,3 and 4-year-old organically managed leys during 2000. N fixation varied between 73.7 in 1-year-old leys and 33.5 kg ha-1 in 4-year-old leys. Soil nitrate-N, grass N yield and N content of grass and clover were all lowest in 2-year-old leys and highest in 3-year-old leys. The proportion of clover nitrogen derived from the atmosphere (pNdfa) was significantly lower in 3-year-old leys

Nutrient cycling on organic farms

This paper examines the sustainability of nutrient cycling on organic farms. After a brief consideration of the principles of nutrient cycling in organic agriculture, data on soil P and K indices and farm nutrient budgets is used to assess the integrity of nutrient cycling, including some consideration of losses to the environment. An attempt is made to assess the wider sustainability of organic farming in the context of the limited amount of recycling possible

Carrot or stick? – Would information concerning the economic value of nutrient losses, and their impact on food quality achieve greater environmental protection than regulation?

This report was presented at the UK Organic Research 2002 Conference. Organic standards have, since their origin (Soil Association 1967) required high standards of manure management, but in reality, these have not been implemented, possibly because of perceived costs of improved handling. However, a cost/benefit analysis of intermediate steps of nutrient conservation and manure handling may provide a practical solution, optimising retention of nutrients, financial and time inputs and environmental protection. Recent research on composting with conventional manures has quantified nutrient losses from heaps with different treatments (Parkinson et al, 2001). Financial and environmental costs and benefits of different management approaches are discussed

Crop protection in organic agriculture - a simple matter?

This report was presented at the UK Organic Research 2002 Conference. Crop protection strategies in organic agriculture and horticulture aim to prevent pest, disease and weed problems through optimisation of the cropping system as a whole. Choice of crops and varieties within the rotation and use of appropriate husbandry practices are critical to the success of the system and direct curative action against pests and diseases is rarely necessary. Research is urgently needed to determine strategies for control of key pests and diseases in organic systems if UK organic agriculture is to expand to meet increasing consumer demand. This paper describes current prevention and control strategies for pests, diseases and weeds in UK organic agriculture and identifies problems that are currently limiting expansion of the industry

An investigation into the relationship between preceding break crops and weed populations in barley crops in organic ley/arable rotations

This report was presented at the UK Organic Research 2002 Conference. The relationship between weed populations and cereal crops following nine organic break crops was investigated in field trials in Warwickshire, Aberdeenshire and Ceredigion in 2001. Weed biodiversity was high on all sites and varied between sites in terms of species present. Severity of weed infestation differed significantly between sites and between cereals following different break crops. The impact of break crop species on the incidence and severity of the weed burden in the following cereal is discussed in relation to the field trials at the three sites

Observations on the post-natal development of the tiny musk shrew, Crocidura bicolor

Crocidura bicolor is the smallest of southern Africa's Crocidura shrews and little is known of its biology. A female, captured in the Kruger National Park, was observed giving birth to two young. The post-natal development of the young reported here was slower than the two previously published Incidences. Suggested reasons for the discrepancies are the differential diets of the mothers, their geographical origins and the smaller size of this female

Utilising the concept of nutrients as a currency within organic farming system

This report was presented at the UK Organic Research 2002 Conference.Within organic systems, the successful management of nutrients at the field level is crucial for maximising production and minimising the environmental impacts. This requires that the farmer makes the best possible use of nutrients excreted by the grazing or housed livestock. In addition, the farmer must successfully manage the nutrients built-up in the ley phase of the crop rotation over the whole of the arable phase period. To analyse these complex flows, a nutrient budget model has been developed that describes the spatial and temporal flows within the organic farming system. The concept is analogous to treating nutrients as a currency where the flow of nutrients represents a cashflow. A spatial nutrient budget permits the analyses of the performance of the nutrient flows to be examined for the housing, manure, livestock, rotational land and permanent pasture to be analysed separately. This analysis will allow the farmer to better understand the weaknesses in the system, and hence take preventative measures

Development of software to plan conversion to organic production (OrgPlan)

This report was presented at the UK Organic Research 2002 Conference. OrgPlan is a computer programme aimed at farmers and advisors assisting with the planning of an organic conversion. The programme is divided into technical modules, supported by a standard enterprise database, a report builder and an advisory section. Through the farm profile builder, rotation, cropping and livestock planner, conversion scenarios over several years can be developed and are evaluated for technical and financial feasibility by calculating farm gate budgets for key resources (forage energy and key nutrients) and financial reports (cash flow budget and profit and loss account). The poster illustrates the basic functioning of the software as well as the underlying rationale for the scenario evaluation