Yield yield components and nutrient content of corn zea mays grain as influenced by post silking moisture stress
Harder, H.J.; Carlson, R.E.; Shaw, R.H.
Agronomy Journal 74(2): 275-278
ISSN/ISBN: 0002-1962 Accession: 006925083
The effect of successive, repetitive moisture-stress treatments on yield and yield components was determined. Experiments were conducted in the movable rain shelter facility at Ames, Iowa [USA], during the summers of 1976 and 1977. With this facility, different soil moisture conditions were imposed simultaneously with plants growing under similar conditions of atmospheric demand. Corn plants were grown in containers with 100 l of a Nicollet loam soil (an Aquic Hapludoll, fine-loamy mixed mesic). Single and multiple periods of moisture stress were imposed after silking in 1, 2 or 3 successive stress cycles to study their effect on grain yield and yield components (kernels per plant and mass per kernel). Successive respective stress treatments on the same plants were included to observe plant response to moisture stress after sink size (kernel number) was altered because of previous stress. Grain yield reductions of up to 33% depended primarily upon severity and duration of soil moisture stress. Additional stress cycles did not always cause an additive reduction in grain yield. Moisture stress that occurred within 2 wk after silking reduced the number of kernels per plant by .apprx. 15% with little influence on final mass per kernel. Additional stress cycles had only minor effects on kernel number. Plants that were stressed shortly after silking and suffered reduction in kernels per plant had shorter, but uniformly filled ears, suggesting that stress-inhibited development of kernels at the tip of the ear. Moisture stress influenced mass per kernel in a complex fashion. Decreases up to 20% were observed. The observed pattern for mass per kernel depended on the timing of stress in relation to silking date and previous moisture-stress history of the plant. Moisture stress increased the percentage of N in the grain from 1.7% in controls to 1.8 and 1.9% in 1 and 2 repeated stress cycles, respectively, but did not significantly influence percentage of P or percentage of K in the grain at harvest.