The Impacts of Irrigation Amount on Physiological Characteristics and Yield of Spring Maize

【Background】Maize production in Jilin province of China needs irrigation because precipitation and antecedent soil water in its growth season cannot meet its demand. Although the impact of water stress in maize growth has been well documented, how its physiological characteristics respond to irrigation amount is an issue remaining obscure for maize production in Jilin province. 【Objective】This paper aims to elucidate irrigation-water use efficiency of the maize under different irrigation amounts, with a view to improve water use efficiency without compromising yield in the semi-arid areas in the west of the province. 【Method】A two-year field experiment was conducted with the variety Huanong 887 as the model plant. We compared four irrigation amounts: 500 (CK), 900 (Q1), 1 700 (Q2) and 2 500 m3/hm2 (Q3), and in each treatment we measured the accumulation of nitrogen, grain filling, activities of nitrogen metabolizing enzymes in leaves, as well as root injury level. 【Result】①The average grain-filling rate, 100-grain weight and root injury level all increased with the irrigation amount, but their values in Q2 and Q3 were significantly higher than those in Q1 and CK. ②Compared to Q1 and CK, Q2 and Q3 significantly increased nitrogen content in grains, stems and leaves. ③With the increase in irrigation amount, the activities of glutamine synthetase (GS) in the leaves increased, while the activities of glutamate dehydrogenase (GDH) in the leaves decreased. ④The yield increased with irrigation amount, especially in Q2 and Q3. ⑤No significant difference in yield and physiological traits was found between Q2 and Q3. 【Conclusion】Soil moisture is an important factor limiting growth and development of maize in the semi-arid areas in the western Jilin province. With the increase in irrigation amount, the yield, average grain-filling rate, 100-grain weight, root injury level, nitrogen accumulation and GS activity in the leaves all increased, while the activity of GDH in the leaves decreased. The physiological traits were significantly correlated with the yield. When the irrigation amount was 1 700 m3/hm2, the grain-filling rate, root injury level, nitrogen accumulation, nitrogen metabolizing enzyme activity in the leaves were optimal, giving the highest yield. It thus can be used as the reference irrigation strategy for maize production for the studied areas.