Effects of soil drought during the generative development phase on seed yield and nutrient uptake of faba bean (Vicia faba)

Abstract

The effects of periods of drought during different phases of reproductive growth of faba bean (Vicia faba L.) cv. Xichang Dabai were investigated in a pot experiment at Xichang Agricultural College, China. Parameters were total dry matter; seed yield; yield components; concentrations of nitrogen, phosphorus, and potassium; and total uptake in different organs. All drought treatments decreased total dry matter production and seed yield per plant. Plants subjected to drought from initiation of pod-set to full pod-set (stage D4) produced 32% less total dry matter and 45% less seed yield than the irrigated control. Mean seed weight was a relatively stable yield component. Statistical analysis indicated that only plants subjected to drought at stages D4 and D5 (drought from full pod-set to maturity) had a significantly (P < 0·05) lower mean seed weight than the control.

The nutrient concentration was generally high in the younger or more active organs of faba bean, and comparing the nutrients, the N concentration in leaves, stems, flowers, pods, and grain was greatest, followed by K concentration, and P concentration was least. All soil drought treatments decreased the nutrient concentration in various organs after 17–19 days of drought. However, the decreases at maturity were less clear, except the nutrient concentrations in stems and leaves. Water deficit significantly decreased total grain nutrients per plant, the decreases being 34–45% for N uptake, 34–47% for P uptake, and 33–46% for K uptake. Simple linear correlations with the P and K concentration in leaves at maturity and number of pods and seeds per plant gave a correlation coefficient (r) of 0·804–0·874.