Effects of nitrogen supply methods on fate of nitrogen in maize under alternate partial root-zone irrigation

Dongliang Qi,Tiantian Hu,Xue Song

doi:10.25165/j.ijabe.20201303.5287

Abstract

Partial root-zone irrigation (PRI) has been practiced worldwide, but little information is available on nitrogen (N) supply methods influence on fate of applied N fertilizer for crop production under PRI. A field experiment was conducted to investigate effect of N supply methods on the uptake, residual, and loss of applied N fertilizer in maize (Zea mays L.) under alternate PRI at Wuwei, northwest China in 2014. 15N-labeled urea was used as N fertilizer. Two irrigation methods included alternate furrow irrigation (AI) and conventional furrow irrigation (CI). Two N fertilizer supply methods included conventional N supply (CN) and alternate N supply (AN), were applied in combination with each irrigation method. Grain yield, root length density (RLD), N uptake by maize at the maturity stage, and atom % of 15N excess, residual 15N and residual NO3-N in the 0-100 cm soil layer after maize harvest were determined. Results shown that compared to CI coupled with CN, AI coupled with AN or CN significantly increased the grain yield, harvest index, RLD, N uptake by maize, 15N accumulation in grain, atom % of 15N excess in the 0-60 cm soil layer, the residual 15N and 15N uptake rates; but significantly decreased the residual NO3-N in the 0-100 cm soil layers and 15N loss rate. Moreover, the synchronized rather than separation supply of N fertilizer and water enhanced the most above parameters under AI. 15N uptake rate was positively correlated with RLD in the 0-40 cm soil layer, suggesting that the enhanced RLD contributed to the improved 15N uptake rate. Therefore, alternate furrow irrigation coupled with conventional or alternate nitrogen supply (synchronized supply of N fertilizer and water) could help improve 15N uptake rate and reduce the 15N loss rate. Keywords: 15N-labeled technology, root length density, nitrogen fertilizer fate, nitrogen management, residual nitrogen DOI: 10.25165/j.ijabe.20201303.5287 Citation: Qi D L, Hu T T, Song X. Effects of nitrogen supply methods on fate of nitrogen in maize under alternate partial root-zone irrigation. Int J Agric & Biol Eng, 2020; 13(3): 129–135.

Highlights

The increasing freshwater consumption has encouraged more research into developing novel irrigation strategies to improve crop water use efficiency (WUE)[1]
3.1 Grain yield, harvest index and the total N uptake As shown in Table 3, AIANS, AIAND and AICN significantly increased harvest index and grain yield compared to CICN
AIANS 56.28a 28.14a 88.91b 44.46b 54.81b 27.41b AIAND 53.14a 26.57a 95.31a 47.66a 51.55b 25.78b AICN 58.02a 29.01a 89.34b 44.67b 52.64b 26.32b CIAN 47.56b 23.78b 83.70c 41.85c 68.74a 34.37a CICN 45.86b 22.93b 84.38c 42.19c 69.76a 34.88a Note: Values followed by different letters within each column are significantly different at the probability level of 0.05

Summary

Introduction

The increasing freshwater consumption has encouraged more research into developing novel irrigation strategies to improve crop water use efficiency (WUE)[1]. Partial root-zone irrigation (PRI) and deficit irrigation (DI) are water-saving irrigation techniques which have been intensively studied in many regions of the world. In PRI, half of the root zone is irrigated, while the other half is left dry[3]. It has been shown that PRI can allow the induction of the abscisic acid-based root-to-shoot chemical signaling to regulate growth and water use[4]. Given a same amount of irrigation water, APRI was superior to DI and FPRI in terms of yield maintenance and increase in WUE[5,6,7,8,9]. The sustainable use of water and N fertilizer has become a priority for agriculture, especially in water deficit regions

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