Water and Nitrogen Effects on the Growth and Yield of Spring Wheat.

Abstract

To study the combined effects of controlled water and nitrogen supplies on growth and yield of spring wheat (Triticum aestivum L.), plants were grown in a controlled environment chamber during the entire growth period.When the 3rd leaf was visible, three levels each of water and nitrogen supply, for a total of nine treatments, were applied using the system to accurately control soil water and nitrogen levels. There was a significant interaction of water and nitrogen levels on growth and yield of wheat. Under low water conditions few tillers were produced and the biomass production and grain yield were suppressed, whereas nitrogen supply level had little impact on the plants. With increasing water supply, on the other hand, the production of tillers, biomass and yield increased significantly. Furthermore, the nitrogen supply level had significant effects on growth and yield as the water stress decreased. Water and nitrogen shortages caused increases in phyllochron values. However, heading of the main stem was almost unchanged because of the compensation by a decreased number of leaves on main stem. The impact of water and nitrogen stresses on growth and yield was reflected primarily by the strong response of tillering at the individual plant level.

Effects of Water Supply and Light Intensity on the Growth of Spring Wheat.

“…The PPFD effects on LWP were accelerated under severe water stress and water supply effects on them were also accelerated under higher PPFDs. Tamaki et al (1999) also showed that water deficiency lowered LWP in the other study.…”

“…Roy and Gallagher (1985) and Davidson and Chevalier (1987) observed that drought delayed tiller emergence. Krenzer et al (1991) and Tamaki et al (1999) also found lower leaf emergence rates at low water supply.…”

“…Allard et al (1991) reported that few tillers survived under low PPFD. Roy and Gallagher (1985) and Tamaki et al (1999) reported that, under water stress, few tillers were initiated and survived. From this experiment, we found that the water supply rate affected the tiller initiation and survival significantly over I300.…”

“…The water control system (Tamaki et al, 1999) consists of a sleeve in which plants are grown in a rooting medium which fits into a device containing a column of floral foam through which the water flow passes toward the rooting medium . The height differential between the rooting medium and the water table , and the hydraulic conductivity of the pathway through the floral foam are controlled.…”

“…The objective of this experiment was to study the interaction of water supply and light intensity on the growth of spring wheat under carefully controlled water conditions . To accurately and reproduceably control the water supply to individual plants , we used a water control system (Tamaki et al, 1999) suggested by Wookey et al . (1991) of originally described by Snow and Tingey (1985).…”