Club of bologna proceedings

 
A. Mahmoud El HOSSARY 
Egypt 
I think Prof. Heege paper is very valuable, 
especially in that the tackled the straw effects 
in the seedbed. I would to ask hi,: what is the 
effect of chopped straw placement on sand 
with a high infiltration rate? Does it reduce 
the infiltration rate? My question is in 
connection with a huge project that is now 
being implemented in Egypt, which aims to 
create a new delta starting from upstream of 
the Nile, in Aswan, to the Western desert. The 
sand in that area is very coarse, and we are 
facing this problem. 
 
Hermann HEEGE 
If you put straw on the surface, this affects 
the moisture and the temperature fluctuations 
- it affects both. The moisture fluctuation is 
reduced, and the temperature fluctuation is 
also reduced. The average may remain the 
same, it depends on what is happening. So the 
average may not be affected, but the 
fluctuation is affected, and whether this is an 
advantage or a disadvantage is hard to see. I 
feel it’s more of an advantage. You get rid of 
the extremes.
 
Gajendra SINGH 
AIT 
In the developing countries, farmers have 
been cultivating farms for centuries using 
animal power. And then we introduced the 
smaller tractors. So far we have been very 
lucky because the tractor size is small, so we 
have not introduced the compaction problem 
very seriously. Also, we have found a very 
good form of co-operation between engineers 
and politicians: the reason being that 
politicians asked “can we do something for 
the small farmer?” and we as engineers said 
“OK, you can help us promote mechanical 
technology for the smaller farmers, meaning 

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85
in smaller size”. So the subsidies were 
provided for the smaller size equipment, not 
for large size, and that was true in many 
countries: for example, even in Thailand the 
tax for 2200 cm
3
 was much higher. India has 
continued that policy up to the present, but 
now we are confronted with the same 
problem that you are facing. With 
globalisation, the size, the economies of scale, 
all these things are coming into play, and that 
approach of helping the smaller farmers with 
smaller sized technology is not able to 
compete with the custom-operated large size 
equipment. Can a group like this come up 
with a strategy that for field operations, for 
soil manipulation, sets some guidelines or 
some limits on the soil pressure? I don’t think 
you can implement such guidelines, but 
issuing them would go a long way. We have 
been trying to do this in India, through the 
discussions I initiated over the last three 
years, and we said: “if we can limit to around 
30 kW operation for field operations - for 
tillage - we don’t see much problem with 
compaction”. But now we’ve also looked at 
the way the tractor industry is going, and all 
the custom work where they are interested in 
rate of work, more work per unit time, 
reducing the labour cost... they’re interested 
more in area, getting more income. It seems 
to work perfectly well when you are using 
tractors for stationary operations like 
threshing; in that case it does not matter, you 
can use any size because it’s stationary. 
Likewise, in pumping it does not matter. But 
for anything to do with traffic in the field, if 
some kind of policy can be developed based 
on the research, providing guidelines for 
limiting the soil pressure of tillage field 
equipment, I think this kind of thing will help 
the groups in various countries. Pointing out 
what have been the consequences of large size 
equipment in Europe or the USA, and why 
you first put in more energy to do the 
operation, and then put in even more energy 
to undo the compaction.