Published in Scientific Papers. Series A. Agonomy., Vol. LVI
Written by Gigel ŞTEFAN, Claudia ŞTEFAN, Georgeta BELENIUC
Agricultural year 2012 was characterized, in terms of climate, by high temperatures in all cultivated areas of the country and small amounts of precipitation. According to official data it was estimated that, among the spring crops, the most affected by prolonged drought at national level was maize crop, on more than its half cultivation area. Climatic drought was completed by pedological drought, which led to installation of severe drought respectively, a soil moisture whose values were more below the values appreciated as optimum for field crops, according to specialized institutions. In this context, drought effects have also been strongly manifested in Moldavian Tableland and Plain region, especially in certain counties where, in the absence of irrigation systems, caused severe disturbances in spring crops development. Based on these considerations, the present work-paper highlights a few aspects regarding the soil moisture regime, during the vegetation period of maize crop, within a non-irrigated agricultural farm, specialized on plant production and located in north of Moldova (respectively Mitoc, Botosani county). In order to get information on soil humidity and water reserve, determinations were made on soil momentary moisture in the field, at intervals corresponding to different development stages of maize. For establishing the range of soil water availability for maize plants, soil moisture was estimated in correlation with active humidity interval, using soil active moisture index (Iua). Active moisture index showed that, in the first stage of vegetation, soil water was very easily accessible to plants. Thus, maize plants benefit of a proper start in vegetation, covering the emergence - 8 leaves stage under very favourable conditions. At the end of June - early July, the active moisture index showed the tendency of soil moisture to decrease significantly, approaching - in terms of value - the wilting coefficient. Decreased soil moisture coincided with the beginning of maize critical period for water. In the period between panicle emergence - maturity, due to lack of rainfall, associated with pronounced increased temperatures, a drastic decrease of soil moisture could be registered; in this case, active moisture index showed a very low water accessibility for plant, the values being almost equal to the wilting coefficient. It can be state that, in year 2012, maize production in the investigated farm began to be influenced, in the sense of its diminution, since panicle emergence stage, drought manifesting until the end of the vegetation period. Thus, maize had not properly covered all its vegetation stages, reaching maturity much earlier. The 3.5t/ha average yield obtained was estimated as significant under the productive potential of the used hybrid, soil fertility and inputs applied.
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active moisture index
