Spring Nitrogen Fertilization of Ryegrass–Bermudagrass for Phytoremediation of Phosphorus‐Enriched Soils

Abstract

Because annual ryegrass (Lolium multifl orum L.) exhibits increases in herbage P with increasing soil P, biomass response to N should infl uence phytoremediation of P-enriched soils. Field plot (each 2 by 5 m) studies were conducted to determine the eff ect of six N schemes that provided 112 or 168 kg N ha -1 on uptake of P and soil test P (STP, 0-15-cm depth) of double-cropped bermudagrass [Cynodon dactylon L. (Pers.)] and ryegrass. Bermudagrass was previously fertilized with 9 and 18 Mg broiler litter ha -1 in 2004-2007, no litter was applied aft er 2007. At past litter rate of 9 Mg ha -1 , total uptake of P averaged 48.5 kg ha -1 in 2008 and 51.7 kg ha -1 in 2009. Based on initial STP levels in 2007, results in 2009 indicated STP levels decreased by approximately 50 kg ha -1 yr -1 , with reductions of 44% at 9 Mg litter ha -1 (104-58 mg kg -1 ) and 38% at 18 Mg litter ha -1 (173-108 mg kg -1 ). Averaged across years and litter rates, uptake of P in ryegrass was greater at 168 than 112 kg N ha -1 (35.4 vs. 29.4 kg ha -1 , P < 0.01) and ranged from 35.8 kg ha -1 in scheme N5 to 26.7 kg ha -1 in scheme N1. Schemes N5 and N6, with a total rate of 168 kg N ha -1 in March and May, stimulated uptake of P in ryegrass and ryegrass-bermudagrass, but STP levels in 2009 were not lower than a single application of 112 kg N ha -1 in January and March.

Leaf nitrogen and phosphorus stoichiometry of plant communities in geochemically phosphorus-enriched soils in a subtropical mountainous region, SW China

“…Our results showed that soil in the GPES region had extremely high total P (6.57 9 10 3 mg/kg) and available P content (381.54 mg/ kg), which were significantly higher than the results obtained by Hou et al (2010) from non-GPES regions in Central Yunnan. The soil P level in GPES in Central Yunnan was significantly higher than the P-enriched threshold identified by Delorme et al (2000), where GPES had higher soil P content and variability, and was very different from other P-enriched regions identified in earlier studies, e.g., pasture and farmland (Delorme et al 2000;Read 2012;Sharma and Sahi 2005). P forms in leaves were relatively variable, as plants could store not only P o but also P i in leaves.…”

Current re-vegetation patterns and restoration issues in degraded geological phosphorus-rich mountain areas: A synthetic analysis of Central Yunnan, SW China

“…Vegetation restoration is one potential solution to these problems. However, recent research has mostly focused on farmland and pasture ( Sharma et al., 2007 , Read, 2012 , Volis, 2016 ). In the GPR region of Florida in the United States, research has concentrated on wetland and marsh areas but neglected mountain regions ( Brown, 2005 , Andrews and Broome, 2006 , Jayakumar et al., 2010 , Beavers et al., 2013 ).…”