Maize is a vegetal specie with a big potential due  a large utilisation like food sources for people and animals and for industry. Optimizing of the water regime assures the integral use of the yield potential of the maize hybrids. In the same time, natural resources of the water are more and more used as consequence decrease continously and the increase of the water use efficiency in maize. The researches were made during 2006-2008 in a long term trial placed in 1990 on the preluvosoil from Agricultural Research and Development Station Oradea. characterized by the presence of the horizons Bt 1 (34-54 cm depth) and Bt 2 (54-78 cm depth); the colloid clay eluviation determined to appear the El horizon with 31.6% colloid clay. On 0-20 cm depth, the soil has a big percentage of macroagregates (Φ > 0.25 mm), 47.5% bulk density is of 1.41 g/cm 3 and total porosity is median one, hydraulic conductivity is of 21.0 mm/h. The values of the pH indicates a low acid soil, humus, total nitrogen, phosphorus and potassium content are low.  The source of irrigation water was a drill of 15 m depth. The chemical parameters of the irrigation water were the following: fixed mineral residue 0.5 g/l; SAR index 0.52; CSR index= -1.7%; N. Florea class = II; there are not some problemes regarding the use of irrigation use.  Two factors were studied: crop rotation (maize-monocrop; maize-wheat; maize-soybean-wheat) and water regime (unirrigated and irrigated). In comparison with unirrigated and irrigated monocrop, in the maize-wheat crop and especially in the maize-soybean-wheat very significant yield gains were obtained: 15.7% and 17.8% in the maize-wheat crop rotation and 44% and 28.3% in the maize-soybean-wheat crop rotation. In the all three crop rotation variants and in the all years studied the irrigatin determined the yield gains very significant statistically. The experiences gives the possibility of a study of crop rotation that has become a need in maize crops because of the Diabrotica virgifera, virgifera attacks, compared to older than previous literature that recommended monocrop or repeated crops. The researches were carried out in the project: PN-II-ID-PCE-2008; 1103/2009 ”Study of the relationships in the soil-water-plant-atmosphere system on the land affected succesivelly by excess and deficit of moisture from North Western Romania regarding the improve of the yield quantity and quality”.

crop rotation; maize; yield; protein content; irrigation

Presentation: oral