| In Table 1 are presented some climatological
data for some selected locations in northern Iraq (Mosul, Krikuk, Sulaimaniya,
and Salahdhin) as also for one of central Iraq (Baghdad). It will be seen
from these data how the predisposing elements for a frosty weather prevail
in the northern parts. It is possible that in the past there have been fortuitous
frosty events in this region, but of so localised a nature as to escape
notice, or of serious consequence. The present report of wide spread damage
indicates the potential nature of the threat to the winter cereals of this
area. In the wheat growing regions of the world damage by frost is not unknown. For instance, heavy losses caused by frost to the wheat crop has been reported in Australia during the 1959 season (ANONYMOUS 1959) and during the 1970-71 season (GROSS 1971). The main characteristics of this damage is that it is infrequent, unpredictable, but can be severe if wide-spread. It is the spring season frost that causes the most damage, since the crop is at its active reproductive or grain filling stage, which are the most susceptible stages in the wheat plant growth. It has been noticed that early season frost could be tolerated by varieties having cold tolerance, like the winter wheats, but late season or spring frost damages all varieties alike (SINGLE 1968). In this regard winter and spring wheat varieties do not differ appreciably since cold tolerance in the early vegetative stage is not linked with cold tolerance in the reproductive stages (MARTINIC 1974). From the above observations arises considerations for possible protective measures that can be undertaken. From the view point of varietal manipulation, there are no spring wheat varieties specifically bred for resistance to late frost and are also suitable for Iraqi conditions. The only possible step, in this regard, is to recommend late maturing varities, which might escape frost injury or recover from it. Even this step is of limited scope for Iraq due to the rapid increase in the summer temperatures during the months of May and June is not very favourable for grain filling. An operational protective measure is to irrigate the crop, if frosty weather could be forecast 2-3 days in advance (LANDRES & WITTE 1967). Sprinkler irrigation rather than flood or gravity irrigation is recommended. But in northern Iraq where the cereals are raised as rainfed crops scope for protective irrigation is very limited. Even if available, it would perhaps be more economical to protect plantation or vegetable crops thus than the cereals. Low lying areas are more prone to frost damage by the influx of air mass. Consequently, avoiding planting of low lying areas with wheat or barley will minimize the loss. Likewise, planted areas in neighbourhood of timbers or tall trees are more affected by frost and are to be avoided. Good seed bed preparation also helps in reducing frost damage on account of the good moisture holding capacity of the soil. Thus, the pre-planting protective measures to be taken in frost-prone areas are: i. good seed bed preparation; ii. Correct time of planting: if the variety planted is of the early maturing type avoid very early planting, or alternatively, plant late maturing types; both these steps facilitate recovery from frost damage, thus avoiding total failure of the crop; iii. avoid planting wheat or barley in low lying areas; iv. avoid planting in the vicinity of timber or tall trees; |
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