EXPLORING OPTIMIZATION OF WATER AND NITROGEN FERTILIZER MANAGEMENT FOR POTTED MAIZE BASED ON PCA

Deficit irrigation has been widely used in crop production, but there is not enough information about how and whether water stress and nitrogen (N) fertilizer interact with maize (Zea mays L.) growth and nitrogen uptake in pot experiments. In this study, the effects of deficit irrigation and N fertilizer application rate at different growth stages on physiological and morphological parameters of potted maize were studied to determine whether the jointing stage was the key period of maize water demand. The experiment was arranged in a randomized complete block design with two factors (5 irrifation levels x 4 N fertilizer application rates) and replicatesd three times. Leaf area, plant height, root length, root activity, dry matter accumulation, and N uptake decreased with the increase of N fertilizer application rates. The plant height in deficit irrigation at mature stage (D-m) was the highest, which was 9.4% similar to 20.5% higher than that of deficit irrigation at other growth stages. Deficit irrigation at filling stage (D-f) had the highest chlorophyll content, which was 3.6% similar to 9.4% higher than that of other irrigation treatments on averaging N fertilizer application rates. The root number increases first and then decreases with the increase of N fertilizer application rate on averaging irrigation treatments. The mean water use efficiency (WUE) order from high to low was D-s (deficit irrigation at seedling stage) > D-m > F-i (full irrigation) > D-f > D-j (deficit irrigation at jointing stage) on averaging N fertilizer application rates. WUE was only significant correlated with plant height. The NUE was significantly correlated with leaf area, chlorophyll content, root activity, dry matter accumulation and nitrogen uptake. The results showed that the jointing stage was sensitive to water and nitrogen requirements. The F1N1 (full irrigation, and 0.1 g N kg(-1) soil) treatment ranked first after analyses in the combinational evaluation, which provides a reference for evaluating and selecting better field crop management methods.