Among the natural catastrophes, drought and flooding caused by over-abundant rainfall cause the greatest problems in field crop production in Hungary. The droughts experienced in the early eighties and the floods suffered over the last few years have drawn renewed attention to the analysis of this problem. The period between 1991 and 2000 was characterised by frequent extremes of climate. Only three years had average rainfall, while five years were very dry and in two years the quantity of precipitation was at least 30% higher than the many years' mean. The effect of climatic factors (especially rainfall) on certain crop production factors (physical soil status, maize yield) was studied in long-term soil cultivation experiments set up in 1991 and 1994. The highest values of soil resistance were measured after disking in droughty years, while the lowest values were recorded in ploughing treatments and in disking or ploughing treatments combined with loosening. Under the given site conditions the differences arising due to the type of soil cultivation were more moderate in wet years; from the point of view of soil resistance the quantity of rainfall was the most decisive factor. The effect of soil cultivation in reducing moisture loss was most perceptible in average and dry years. The lowest moisture contents were observed after disking (13.4% in average years, 7.7% in dry years) and direct drilling (16.3% in average years, 8.9% in dry years). In wet years the soil moisture content was much more uniform, ranging from 21.7-24.3%. The differences between the treatments were not significant at the 5% probability level. The unfavourable effects of climate anomalies (drought, over-abundance of water in the topsoil) on the yield formation and yield quantity of maize depended decisively on the time of year when they were experienced and the period for which they lasted. With the exception of direct drilling, all the cultivation treatments led to approximately the yields expected under the given growing site conditions. It was also concluded that economic yields could not be achieved with direct drilling even with a normal quantity and distribution of rainfall. All in all, droughts in the winter or summer half-year had much the same effect on yields. Precipitation deficiency in the winter could not be counterbalanced by average rainfall during the vegetation period, and its effect on the yield was similar to that of summer drought. With the help of regression analysis it was found that a direct correlation between rainfall and yield could only be observed in the case of ploughing and satisfactory nutrient supplies. In the direct drilling treatment the maize yield was determined not so much by the quantity of rainfall during the vegetation period as by unfavourable changes in soil status (e.g. settling) and intense weed growth.
|Number of pages||15|
|Publication status||Published - Dec 2000|
ASJC Scopus subject areas
- Agronomy and Crop Science