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A field experiment was conducted to study the effects of shading on tassel and ear development and yield formation of three summer maize hybrids Zhenjie 2 (ZJ2), Denghai 605 (DH605), and Zhengdan 958 (ZD958). The ambient sunlight treatment was used as control (CK) and shading treatments (40 % of ambient sunlight) were applied at different growth stages from silking stage (R1) to physiological maturity stage (R6) (treatment S1), from the sixth extended leaf stage (V6) to R1 (treatment S2) and from seeding to R6 (treatment S3). Shading had no significant effect on the time from seeding to shoot emergence (VE); however, subsequent growth and development were delayed with shading beyond this point. The differentiation time of both tassel and ear delayed, and female spike (tassel) floret differentiation, sexual organ formation time, and anthesis-silking interval (ASI) were lengthened. After shading, the total number of floret, silk, and fertilization floret reduced significantly; the number of abortive seeds increased, and the total setting percentage among different treatments showed that CK>S2>S1>S3; and the total setting percentages in S1, S2, and S3 of ZD958 were 44, 72, and 15 % respectively. The total floret number of tassel primordium differentiation, fertility rate, and seed setting rate of florets in S3 treatment was the minimum; kernels per ear decreased seriously and single ear setting percentage was only 16 %; although floret degeneration number of S2 during ear differentiation stages increased and floret fertility rate reduced than that of CK, fertilization flower seed production increased and abortive seed decreased after canceling shading. Aborted kernel of S1 increased and kernel dry weight reduced, resulting in a significant decrease of kernel number per ear and kernel weight, and the grain abortive rate of 40-62 %. In conclusion, shading changed the growth and development process and caused infertility of tassel and ear; tassel branches decreased, reducing pollen vitality and silks differentiation cut down; and grain dry matter accumulation and setting percentage decreased, causing yield reduction. Grain yield and biomass reduced 66, 36, and 93 % compared to the control by shading treatments of S1, S2, and S3, respectively. [ABSTRACT FROM AUTHOR]

• Controlled-release urea with irrigation affects maize biomass and N accumulation. • Optimum controlled-release urea improved photosynthetic capacity for each irrigation level. • The interaction of irrigation and controlled-release urea on maize yield was significant. Effective irrigation and nitrogen (N) management is crucial for sustainable agricultural development. Controlled-release fertilizer has been widely used to improve N use efficiency and save labor in one-off application. A specially designed soil column and field trial were conducted to investigate the effect of the interaction of irrigation management and nitrogen on yield, N uptake, and photosynthetic characteristics of summer maize. In the soil column experiment, severe water stress (W1) significantly decreased the leaf area index, relative chlorophyll content, and net photosynthesis and delayed maize growth, resulting in significant yield loss. Under mild water stress (W2), increased controlled-release urea (CRN) application counteracted the inhibition of maize growth. Under adequate water condition (W3), the yield and maize growth exhibited no significant difference between CRN 210 and 315 kg N ha–1. In the field experiment, CRN 210 and 315 kg N ha–1 also exhibited similar yield and were significantly higher than common urea 315 kg N ha–1 under conventional irrigation (CI). Under half-reduced conventional irrigation (RI), yields of CRN 315 kg N ha–1 increased by 10.5% and 7.5% compared with that of CRN 210 kg N ha–1 in 2014 and 2015. The interaction between irrigation and CRN could effectively alleviate the adverse effects of mild drought on summer maize by delaying leaf senescence, increasing chlorophyll content, and improving photosynthetic performance during the grain-filling period. These characteristics allowed more water and nutrients for maize plant and ultimately increased the yield. In areas with adequate irrigation conditions, CRN reduced to 210 kg N ha–1 could satisfy maize growth. In mild water stress and half-reduced conventional irrigation area, the CRN rate of 315 kg N ha–1 used by traditional farmers showed superior benefits. [ABSTRACT FROM AUTHOR]