Effects of deficit irrigation on yield and yield components of maize grown under Bursa conditions

Thesis Type: Doctorate

Institution Of The Thesis: Uludağ Üniversitesi, Turkey

Approval Date: 2010

Thesis Language: Turkish




Irrigation is needed to obtain economic maize yields in Turkey. Many farmers in Bursa province have limited irrigation water supplies, and need to produce crops with less water. This research aimed at determining of the effects on vegetative growth, yield and other yield components of irrigation and water stress imposed under drip irrigation method at different development stages in maize (Zea mays L.) grown in the conditions of Bursa-Mustafakemalpaúa Valley located in a sub–humid region has been carried out in the trial area of the Mustafakemalpaúa Vocational School, Uludag University, during the years of 2008 and 2009. The field trials were conducted on a clay loam soil, with Pioneer 31P41 corn hybrid. A randomized complete block design with three replications was used. The growth stages of the plant (vegetative (V), flowering (F) and grain formation and ripening (T)) were considered and a rainfed (non-irrigated) treatment (K) and 16 irrigation treatments with full (VFT) and 15 different deficit irrigations (V, F, T, VF, VT, FT, V25FT, V50FT, V75FT, VF25T, VF50T, VF75T, VFT25, VFT50 and VFT75) were applied. The effect of irrigation or water stress at any stage of development on grain yield, fresh forage yield, dry matter yield, leaf area index, plant height, leaf number/plant, stem diameter, harvest moisture, ear weight, percentage of separate into grains, harvest index, ear height, ear diameter, first ear height, row number/ear, kernel number/row, 1000 kernel weight and hectoliter weight were evaluated. The seasonal water applied ranged from 371 to 1018 mm. Treatments resulted in seasonal evapotranspiration of 277–1102 mm and 332–1164 mm in 2008 and 2009, respectively. Evapotranspiration increased with increased amounts of irrigation water supplied. The highest seasonal evapotranspiration (average of 1133 mm) was estimated at the VFT (full irrigation at three stages) treatment. Grain yield and the other yield components increased with irrigation water amount, and the highest grain yields (2052 and 2045 kg/da) were obtained from the VFT and VFT75 treatments; average 62% an increase compared to the non-irrigation treatment. Also, grain yields increased linearly with seasonal evapotranspiration. The yield response factor, which indicates the relative reduction in yield to relative reduction in evapotranspiration, was separately calculated for each, two and total growth stages, and it was found 0.54, 1.14, 0.34 and 0.90 for the vegetative, flowering, grain formation and ripening growth stages and the total growing season. On the other hand, the highest values of irrigation water use efficiency were determined to be 1.62 kg/m3 in the VF treatment. The highest values for water use efficiency were found to be 2.05, 2.02 and 2.01 kg/m3 in the FT, V and VF treatments, respectively. As a result, it was found that maize was rather sensitive to soil water deficit. The most sensitive growth period was flowering, following vegetative and grain formation and ripening periods, respectively. It is concluded that VFT irrigation is the best choice for maximum yield under the local conditions, but these irrigation schemes must be reconsidered in areas where water resources are more limited. In the case of more restricted irrigation, the limitation of irrigation water at the flowering and vegetative periods should be avoided.