Combining economical and ecological goals in farm
advisory work by means of simple models. |
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Greengard AB, Dösjebro, Sweden. bertilsson@greengard.se
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The main
goal for a farm manager normally is, and should be, to maximize the economic
result of the enterprise. A crucial question is the planning horizon: the
next year, two – three years ahead or even longer? Long- term considerations
are difficult. Yet they are necessary in a soil based production. A farm is
also an ecological and environmental enterprise. In increasing degree the
society poses demands in this respect. However much the farmer would like to
comply he has to consider the economic viability of environmental measures.
His planning situation has been
further complicated. Calculation
tools, “models”, spreadsheets for planning, are being used for different
parts of the agricultural production process, for instance rotations,
machinery use and animal nutrition. The aim of this work is to combine
economy and ecology, to include and quantify longterm considerations as well
as environmental consequences and involve the farmer in the process. Farming
perspectives. The
“models” are Excel spreadsheets which contain data and information as well as
tables for calculations. The process is interactive with the farmer as an
important actor. He should be in control, only he knows the local data and
can judge the situation on his own farm. And without his acceptance the
results and the advice are of little value. Components: Cropping
sequence with yields, prices and costs. Soil
carbon (humus) balance, its development and likely longterm effects. Indicators
of diversity, nitrogen leaching, pesticide use, traffic intensity and diesel
requirement. Two alternatives are considered: the present situation
(alternative 1) and an improved example (alternative 2). Focus is on changes
in alternative 2 compared to 1. This reduces the input requirement and
facilitates the work greatly. The
system is now beginning to come into practical use. The experience so far is
that in at least 7-8 cases of 10 it is possible to find solutions giving both
better economy, better longterm sustainability and better environmental
performance. True win – win situations. A key
variable: cropping sequence. The
starting point is the rotation or the normal cropping sequence. The results
of all available Swedish and some Danish rotation and pre-crop experiments
are summarized and are available as background data in the spreadsheet. It is
important that these data have been put on a common reference level (in this
case a varied cereal cropping sequence). Effort has been put in extracting
quantitative data also from more diffuse scientific descriptions. Without
figures the knowledge cannot be used effectively in the planning process. In fact
this data collecting work was very rewarding. The combined knowledge was
found to be quite consistent. It is presented for each individual report so
that both the consistency and the existing variation can be shown, discussed
and considered.. The
farmer provides his normal cropping sequence, yields (his true recorded
yields) and prices.The practical work situation can be use of a common
computer, or, more efficiently, both the farmer and the advisor works “from
home” with the same program and with telephone contact. Then
improvements are discussed. It can be to replace a barley crop with an
oilseed, legume or even green manure crop, it may be introduction of cover
crops, reduced tillage etc. This results in an Alternative 2 to consider. The first
step is to discuss changes in yields caused by the introduced “improvement”.
The word “change” is important. Concentrating on changes makes the process
easy. The next
step is to adjust the changes in production costs. Standard values are given
as background information, but the farmer has the final word. The work and
machine situation is considered. Should only direct costs be used or are also
capital costs influenced? That depends on the situation. Then this
first part is finished. We get the economic difference between the two
alternatives. It is very easy to test the sensitivity for variations in yield
effects and costs. What could happen if..? Soil
carbon. Based on
the cropping sequences the soil carbon development is calculated for the two
alternatives by means of Carbon Perspectives, Cpersp, which is presented in a
separate paper. Typical issues to consider are: leys, green manure, straw
removal, cover crops, delayed soil tillage, manure use. The
result can be used for longterm considerations of the sustainability of the
system. If the soil carbon content is low, an effect on yields is considered.
A review of existing data points to yield effects of about 3% per 0.1%
carbon, if the content is below 2%. Other
parameters. Indicators
of the diversity of the system, the proportion of nondisturbed land during
autumn – spring, the use of pesticides and the use of tractor fuel is
attained in the process. An
example of results. Starting
point: a rotation with barley, winter rape, winter wheat, sugar beets, summer
wheat. Yield level 6-8 tons for cereals. If barley is replaced by a ley for
green manure, the profitability
increases by SEK 86 per hectare and year (about $10) and all environmental
parameters are improved. For the individual barley crop the farmer looses an
income of 5800, but when cost
reductions and yield increases on other crops are summarized there is
a net profit, although modest. And soil and environment has gained. |
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References |
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