Estimation of soil nitrogen supply in potato fields using a plant bioassay approach

Abstract

G. 2005. Estimation of soil nitrogen supply in potato fields using a plant bioassay approach. Can. J. Soil Sci. 85: [377][378][379][380][381][382][383][384][385][386]. Soil N supply is an important contributor of N to crop production; however, there is a lack of practical methods for routine estimation of soil N supply under field conditions. This study evaluated sampling just prior to topkill of whole potato plants that received no fertilizer N as a field bioassay of soil N supply. Three experiments were performed. In exp. 1, field trials were conducted to test if P and K fertilization, with no N fertilization, influenced plant biomass and N accumulation at topkill. In exp. 2, plant N accumulation at topkill in unfertilized plots was compared with mineral N accumulation in vegetation-free plots. In exp. 3, estimates of soil N supply were obtained from 56 sites from 1999 to 2003 using a survey approach where plant N accumulation at topkill, and soil mineral N content to 30-cm depth at planting and at tuber harvest were measured. Application of P and K fertilizer had no significant effect on plant N accumulation in two trials, and resulted in a small increase in plant N accumulation in a third trial. Zero fertilizer plots, which can be more readily established in commercial potato fields, can therefore be used instead of zero fertilizer N plots to estimate soil N supply. In exp. 2, estimates of soil N supply were generally comparable between plant N accumulation at topkill and maximum soil NO 3 -N accumulation in vegetation-free plots; therefore, the plant bioassay approach is a valid means of estimation of plant available soil N supply. Plant N accumulation at topkill in exp. 3 averaged 86 kg N ha -1 , and ranged from 26 to 162 kg N ha -1 . Plant N accumulation was higher for sites with a preceding forage crop compared with a preceding cereal or potato crop. Plant N accumulation was generally higher in years with warmer growing season temperatures. Soil NO 3 -N content at harvest in exp. 3 was less than 20 kg N ha -1 , indicating that residual soil mineral N content was low at the time of plant N accumulation measurement. Soil NO 3 -N content at planting was generally small relative to plant N accumulation, indicating that soil N supply in this region is controlled primarily by growing season soil N mineralization. Use of a plant bioassay approach provides a practical means to quantify climate, soil and management effects on plant available soil N supply in potato production. 377-386. La quantité de N présente dans le sol apporte beaucoup au N dont les cultures ont besoin pour croître. Cependant, on manque de méthodes pratiques pour estimer couramment les réserves de N dans les champs. La présente étude devait établir si l'échantillonnage de plants de pomme de terre entiers n'ayant pas reçu d'engrais azoté juste avant le défanage donnerait une idée de la concentration de N dans le sol. Les auteurs ont effectué trois expériences à cette fin. Dans la première, des essais sur le terrain ont permis de vérifier si l...

N2O emissions from spring barley production as influenced by fertilizer nitrogen rate

“…Previous studies in this region also measured generally low soil mineral N contents in spring, particularly for a preceding cereal crop (Be´langer et al 1998;Zebarth et al 2005a). Soil N supply in this study ranged from 34 to 66 kg N ha (1 .…”

“…( Above-ground plant N accumulation with no fertilizer N application was used as a measure of soil N supply (Zebarth et al 2005a). All above-ground plant tissue was harvested by hand in a 0.89-m 2 area within each plot for the 0-kg N ha…”

Rate and time of fertilizer nitrogen application on yield, protein and apparent efficiency of fertilizer nitrogen use of spring wheat

“…Soil mineral N content has also been shown to be useful in optimizing fertilizer N recommendations for cereal crops in humid environments (Harrison 1995;Bundy and Andraski 2004). However, in some humid regions such as Atlantic Canada, soil mineral N content is generally low in spring, and soil N supply is determined primarily by soil N mineralization (Bélanger et al 1998;Zebarth et al 2005). There is currently no practical method of predicting soil N mineralization prior to seeding a cereal crop.…”

Nitrogen apparent recovery can be used as the indicator of soil nitrogen supply

“…Of course, this is possible only having a good knowledge about the local farming conditions. Similar approach is supported also by other researchers (Schepers, Meisinger, 1994;Sanderson et al, 1999;Bélanger et al, 2000;Olfs et al, 2005;Zebarth et al, 2005). Soil nitrogen supply should be taken into consideration when making fertiliser nitrogen recommendations, but there is a lack of practical methods for routine estimation (analysing) of soil nitrogen supply under field conditions.…”

“…However, some authors point out that close agreement between these experiments and field measurements is mostly lacking (Hofman et al, 1985;Sharifi et al, 2007;Ros, 2011). For example, research done with potatoes showed that nitrogen recommendations based on soil analysis were no better than those based on the information of previous cropping and soil type (Zebarth et al, 2005). Therefore the authors of the United Kingdom fertiliser recommendation guide suggest that, since research has not yet identified a preferred laboratory method that is suitable for routine use, measurement of the topsoil organic matter content and computer modelling could give more useful indications (Fertiliser Manual, 2010).…”