Evaluation of the cumulative effect of drip irrigation and fertigation on productivity in a poplar plantation

Abstract

& Key message Combined drip irrigation and fertigation significantly increased stem volume and biomass production in a poplar plantation, and showed a cumulative effect over years. The promoting effects were mainly attributable to increased nitrogen and water availability in the surface soil through the combined management. & Context Fast-growing and high-yielding poplar plantations have been identified as major commercial forests in China. Intensive management of irrigation and fertilization can greatly increase productivity of plantations. Quantitative investigations on the cumulative effect of drip irrigation and fertigation over years are quite infrequent. & Aims We aimed to quantitatively evaluate the effects of drip irrigation and fertigation plans on tree growth and productivity in a poplar plantation, and to analyze their possible cumulative promoting effect over multiple years. & Methods Treatments including nine drip irrigation and fertigation combinations, and single furrow irrigation in spring as control, were conducted in a poplar plantation for three successive years. The combined treatments consist of three irrigation levels (WP −75 , WP −50 , and WP −25 , in ascending order) and three levels of nitrogen addition (N 60 , N 120 , and N 180 , in ascending order). Soil nitrogen and water content were measured throughout the 3 years. Based on tree surveys, tree growth, volume, and biomass production were evaluated each year. & Results Nitrogen and water availability in the surface soil increased in the drip irrigation-and fertigation-treated plots. Drip irrigation and fertigation treatments resulted in significant higher growth, stem volume, and biomass productions compared to control. Biomass increments in drip irrigation-and fertigation-treated plots were 4. 8-50.0, 5.3-26.5, and 4.3-52.2% higher than control in the three experimental years, respectively, with WP −25 N 180 and WP −50 N 180 recording the highest increments. Fertigation showed cumulative effects over multiple years and the positive effects increased with the dosage. However, irrigation showed little cumulative effect and the greatest effect was obtained under medium level. & Conclusion Combined drip irrigation and fertigation greatly promoted the plantation productivity. The combined management effect varied with application plans and plantation ages, and showed a cumulative effect over years.

Fine root morphology and growth in response to nitrogen addition through drip fertigation in a Populus × euramericana “Guariento” plantation over multiple years

“…The soil is a sandy loam, and the total nitrogen, available N, available phosphorus, and potassium contents at the beginning of the experiment were 0.58 g kg −1 , 12.79 mg kg −1 , 4.89 mg kg −1 , and 195.31 mg kg −1 , respectively. Detailed information of soil physical properties has been presented in Yan et al (2018).…”

“…The datasets generated and/or analyzed during the current study are available in the Dryad repository (Yan et al 2018 Compliance with ethical standards…”

“…Further investigation is thus needed to clarify how fine roots change their growth and morphological traits in response to N addition in forest plantations, especially to the recent highly increasing anthropogenic N deposition (Galloway et al 2008;Kou et al 2016). Previous studies on nitrogen management have been performed either on pot-grown specimens or on field-grown trees with conventional fertilization techniques (Coleman 2007;Yan et al 2018). Long-term field experiments with high-efficiency fertilization techniques should be of great significance to our limited understanding of the effects of nitrogen addition on fine roots within a soil profile.…”

“…Poplar plantations are one of the most widely planted commercial forests, and China has the largest area in the world (Dickmann 2006;Perry et al 2001;Yan et al 2018). Highefficiency fertilization techniques such as fertigation have been increasingly applied to the cultivation of plantations to meet their high nutrient requirements around the world (O'Neill et al 2014;Rennenberg et al 2010;Wang et al 2015).…”

“…Highefficiency fertilization techniques such as fertigation have been increasingly applied to the cultivation of plantations to meet their high nutrient requirements around the world (O'Neill et al 2014;Rennenberg et al 2010;Wang et al 2015). Although previous studies have shown that fertigation can significantly promote the growth and production of polar plantations Yan et al 2018;Yan et al 2016), the responses of root systems were not reported. Several studies investigated fine root characteristics in poplar (Alafas et al 2008;Dickmann et al 1996;Douglas et al 2010;Heilman et al 1994;Mulia and Dupraz 2006;Pregitzer et al 2000), but those on root morphological traits in response to N addition through long-term field experiments were relatively few (but see Coleman 2007;Dickmann et al 1996).…”