Search

Nitrogen (N) use efficiency (NUE) of fertilizer N can be accurately estimated by tracing the fate of soil applied labelled fertilizer, but the quantity of N remobilization from non‐kernel components into kernels in maize (Zea mays L.) plants is difficult to determine. A field experiment involving stem infusion with labelled 15N solution was conducted at Ottawa, Ontario (45°22'N, 75°43'W) for two years to determine whether stem infused 15N could be used to quantify N remobilization and the contribution of remobilized N to the grain. A current stay‐green commercial hybrid was grown at three fertilizer N rates and infused with 30 mL 15N solution [35.7 mmol N as 15NH4 15NO3 at 99.2 15N% atom enrichment (a.e.)] into the internode below the primary cob at anthesis. The control plants were infused with distilled water. Sampling occurred at 3 d, 2 wk and 5 wk after anthesis and at physiological maturity. Each plant was subdivided into ten components. Dry weight, total N concentration and 15N% a.e. were d...

Field experiments were conducted in summer 1992 on the Central Experimental Farm, Ottawa (45°22'N, 75°43'W) to determine whether a stem infusion technique developed for maize under controlled conditions was applicable to field‐grown maize and to evaluate whether providing sucrose in solution at silking via stem infusion altered plant source‐sink relationships sufficiently to increase kernel set. The higher and more variable evaporative demand and more difficult installation under field conditions dictated modifications to the stem infusion apparatus to prevent leakage and to facilitate assembly prior to field set‐up. A range of several field parameters were tested to identify conditions that would maximize infusion of sucrose solution: raising the syringe barrel height increased the volume of solution uptake; the largest amount of sucrose was taken up using a concentration of 150 g sucrose L‐1, and consecutive multiple infusions of the same plant increased solution uptake. Solution uptake was fou...