Influence of Nitrogen and Saline Water on the Growth and Partitioning of Mineral Content in Maize

ABSTRACT

Saline irrigation water has a tremendous impact on the yield potential of crops. Distribution of mineral elements in the parts of maize plant in response to saline water and nitrogen (N) nutrition was studied in a pot experiment for six weeks. Plants were irrigated either with tap water or saline water (ECw: 3.2 dSm⁻¹). Nitrogen was applied at the rate of 0, 50, 100 and 200-kg ha⁻¹ denoted as N0, N1, N2, and N3, respectively. Plants were separated into leaf, stem and root and analyzed for N, calcium (Ca), magnesium (Mg), sodium (Na), and potassium (K) concentrations. Dry matter production of leaf, stem and root was significantly reduced with saline water. The partitioning of elements in plants was the function of nitrogen and saline water. The N concentration of plant parts varied in the order of leaf > stem > root. A significant decrease in the N content was noted in plants under saline water. The root contained the highest Na content, Ca and Mg were higher in the leaf, whereas K was highest in the stem under saline water. Sodium was highest in the root and the remainder elements were greatest in the stem under tap water. Potassium and Cl were significantly reduced by N level whereas the reverse was true for Ca, Mg and Na content. The Na/K, Na/Ca, and Na/Mg ratios were also higher in salt stressed plant parts due to higher accumulation of Na ion. Among N-fertilizer treatments the Na/Ca and Na/Mg ratios were highest in control whereas Na/K increased with the addition of N. This study indicated that interaction of saline water and nitrogen has mixed effects on the partitioning of mineral elements in maize.

Keywords:

• saline water
• nitrogen nutrition
• maize growth
• mineral partitioning

ACKNOWLEDGMENT

The authors gratefully acknowledge the financial assistance provided by the Japanese Ministry of Education, Culture, Sports, Science and Technology to the first author to conduct research for two years as a visiting Associate Professor at the Arid Land Research Center of Tottori University, Japan.