Topsoil replacement depth and organic amendment effects on plant nutrient uptake from reclaimed natural gas wellsites

Abstract

. Topsoil replacement depth and organic amendment effects on plant nutrient uptake from reclaimed natural gas wellsites. Can. J. Soil Sci. 86: 859-869. Sustained plant nutrient availability on reclaimed wellsites is critical to the successful restoration of crop productivity. This study evaluated topsoil replacement depth (TRD) (0, 50, 100, and 150% of mandatory TRD) and organic amendment [beef cattle feedlot manure, compost derived from straw-bedded cattle feedlot manure, wheat (Triticum aestivum L.) straw, alfalfa (Medicago sativa L.) hay, and unamended control] effects on nutrient uptake by a wheat crop at three abandoned gas wellsites in south-central Alberta. Grain N uptake increased by 0.055 kg ha -1 for each percent increase in TRD, reflecting the corresponding linear increase in grain N concentration. Low carbon to nitrogen (C:N) ratio amendments, particularly compost and alfalfa, were the most effective for improving grain N concentration and uptake. Conversely, N concentration and uptake were lowest for the high C:N (53:1) wheat straw amendment. Reclamation programs should, therefore, consider incorporation of the low C:N alfalfa or compost in order to safeguard against N deficiency in the first 1-2 yr following reclamation. Our results also show that high P amendments, such as manure and compost, are better choices for improving P uptake by spring wheat. These results emphasize the importance of topsoil replacement and amendment quality (C:N ratio and P concentration) in ensuring adequate N and P supply in the 1-2 yr following reclamation. Based on this, compost appears to be the best single amendment for ensuring enhanced uptake of both N and P on reclaimed wellsites in the short term.

Organic amendment effects on crop productivity and nutrient uptake on reclaimed natural gas wellsites

“…2). These significant amendment effects are in contrast to the findings of Zvomuya et al (2006), who reported no significant differences between alfalfa hay and compost applications in a reclamation study comparing 5 amendments (applied at the 8· rate) at 4 topsoil replacement depths. On average, total P uptake at the Hussar site was higher with compost than with alfalfa hay application, reflecting the significantly higher total aboveground yields plus slightly higher straw and grain P concentrations associated with compost application.…”

“…Higher NHI is desirable in wheat because of the positive correlation between protein content and N concentration in the grain (Ehdaie and Waines 2001). However, our results from the Turin site and those from a recent study (Zvomuya et al 2006) indicate that a greater partitioning of N to the grain does not always result in higher grain N concentration. Zvomuya et al (2006) suggested that higher NHI values may merely reflect improved grain yields or greater HI.…”

“…However, our results from the Turin site and those from a recent study (Zvomuya et al 2006) indicate that a greater partitioning of N to the grain does not always result in higher grain N concentration. Zvomuya et al (2006) suggested that higher NHI values may merely reflect improved grain yields or greater HI. A significant year · amendment interaction was detected for grain P concentration at Hussar, where compost application resulted in higher grain concentration in 2003, while the concentrations were similar for the two amendments in 2004 (Fig.…”

“…However, there was a significant amendment · rate interaction for the P uptake (discussed below), with the two amendments differing only at the 8· rate. By comparison, Zvomuya et al (2006) reported superior total P uptake from compost compared with alfalfa application in one of 3 years.…”

“…Incorporation of organic amendments in reclamation schemes is also encouraged, based on the demonstrated benefits of these amendments in disturbed land restoration (Brown and Chaney 2000;Larney and Janzen 1996;Larney et al 2000a, b;2003. Recent studies in southern Alberta confirmed the efficacy of beef cattle (Bos taurus) feedlot manure compost and alfalfa (Medicago sativa L.) hay in improving soil quality (Larney et al 2005), crop [wheat (Triticum aestivum L.)] yields (Larney et al 2003), and nutrient uptake (Zvomuya et al 2006) on reclaimed wellsites. However, the single, primarily N-based amendment rate used in these studies was adapted from prevailing manure and compost recommendations for undisturbed agricultural soils (Gagnon and Simard 1999) and may not reflect amendment requirements on disturbed lands.…”