Influence of drip irrigation, nitrogen fertigation, and precipitation on soil water and nitrogen distribution, tree seasonal growth and nitrogen uptake in young triploid poplar (Populus tomentosa) plantations

Abstract

Abstract The patterns of soil water and mineral nitrogen (Nmin) distribution, stand growth, and N uptake in a triploid Populus tomentosa plantation under two-year drip irrigation and N fertigation (DIF) treatments were investigated. There was a positive relationship between stand growth and the amount of precipitation and irrigation. Precipitation and irrigation affected the content of Nmin in top 0−20 cm soil layer after fertigation and the redistribution of Nmin in the soil. There was no significant difference in N uptake in poplar plantation among DIF treatments, and the high-fertigation in the rainy seasons didn’t enhance stand growth. Thus, high-level irrigation with lower N fertigation was recommended in the study area. The long-term effects of fertigation on tree stand growth and Nmin distribution in deep soil layers and underground water remain to be studied further.