Predicting nitrogen fertilizer requirements of potatoes in Atlantic Canada with soil nitrate determinations

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...

Section: Discussionsupporting

confidence: 93%

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

Zebarth¹,

Leclerc²,

Moreau³

et al. 2005

“…MacLean and McRae (1987) found nitrification to be very sensitive to temperature, with nitrification of urea fertilizer N essentially complete after 48-68 d at 18°C, and 90% complete after 92 d at 9 and 13°C. The persistence of elevated NH 4 + -N concentrations for much of the growing season suggests that in-season sampling for soil inorganic N concentration, for example as suggested by Bélanger et al (2001), should be done for both NO 3 --N and NH 4 + -N. There was limited evidence of nitrate leaching during the growing season in this experiment. The only exception was evidence of downward movement of soil NO 3 --N within the hill observed at topkill in 1999 in response to the substantially above-average rainfall in September of 1999.…”

Section: Discussionmentioning

confidence: 78%

“…Milburn et al 1997) or soil inorganic N concentrations in potato fields at specific times (e.g. Bélanger et al 2001). However, no studies of soil N dynamics have been done in this region.…”

Section: Mots Clés: Solanum Tuberosum Nitrification Lixiviation Desmentioning

confidence: 99%

Spatial and temporal distribution of soil inorganic nitrogen concentration in potato hills

Zebarth¹,

Milburn²

2003

Self Cite

Zebarth, B. J. and Milburn P. H. 2003. Spatial and temporal distribution of soil inorganic nitrogen concentration in potato hills. Can. J. Soil Sci. 83: [183][184][185][186][187][188][189][190][191][192][193][194][195]. The purpose of this study was to determine the spatial and temporal variation in soil inorganic N concentration in the potato hill, and to discuss the implications of this variation on soil sampling strategies. The experiment was conducted in 1999 and 2000 using four treatments: bare soil with no N fertilizer applied, and a potato crop with no fertilizer N added, with 180 kg N ha -1 applied at planting, or with 120 kg N ha -1 applied at planting plus 60 kg N ha -1 applied at hilling. Elevated (above background) soil NH 4 + -N concentrations were measured for 40 or more days after planting, therefore in-season sampling should be done for both soil NO 3 --N and NH 4 + -N. There was a period of up to 50 days between planting and rapid crop N uptake during which loss of NO 3 --N from the root zone could occur. Split fertilizer application reduced the risk of NO 3 --N loss during this time, but resulted in reduced tuber yield in 1999. Strong vertical variation in soil inorganic N concentration was measured in the potato hill as a result of fertilizer banding and soil N mineralization at shallow depths. Soil inorganic N concentrations were elevated in the hill, but not in the furrow, resulting in strong horizontal variation in soil inorganic N concentrations in the potato hill. Despite this variation, a systematic sampling strategy where soil was sampled in the centre of the hill, the centre of the furrow, and mid-way between the hill and furrow, done in combination with elevation control of soil sampling, resulted in an unbiased estimate of soil inorganic N concentration in the potato hill. --N et de NH 4 + -N pendant la période de croissance. La zone racinaire pourrait perdre du NO 3 --N pendant un maximum de 50 jours entre la plantation et le moment où la culture absorbe rapidement l'azote. L'application d'engrais en deux temps atténue les pertes éventuelles de NO 3 --N durant cette période, mais a diminué le rendement en tubercules en 1999. La concentration de N inorganique varie beaucoup verticalement dans les buttes après application de l'engrais en bandes et il y a minéralisation du N à faible profondeur. Le sol des buttes renferme une grande quantité de N inorganique, mais pas celui du sillon, ce qui se traduit par une importante variation horizontale de la concentration de cet élément dans la butte. Malgré cela, les auteurs ont obtenu une estimation non biaisée de la concentration de N inorganique en prélevant méthodiquement des échantillons au centre de la butte, au centre du sillon et à mi-chemin entre les deux tout en vérifiant la hauteur à laquelle étaient prélevés les échantillons.

“…However, information on soil N dynamics in potato fields is limited, with most existing information coming from experimental plots (Bélanger et al 2001;Zebarth and Milburn 2003). Soil N processes are sensitive to soil and climatic conditions and to crop management practices.…”

mentioning

confidence: 99%

“…Spring soil inorganic N measurements have been used in making fertilizer N recommendations for potato in some potato production areas, for example in Germany (Wehrmann and Scharpf 1986). However, Bélanger et al (2001) concluded that preplant measurement of soil NO 3 content, or soil inorganic N content, did not adequately predict the optimal fertilizer N rate for potato in Atlantic Canada when used alone. This result is likely due in part to the greater importance of net soil N mineralization, compared to carry-over, in determining soil N supply in potato fields (Zebarth and Milburn 2003;Zebarth et al in prep.).…”

mentioning

confidence: 99%

Soil inorganic nitrogen content in commercial potato fields in New Brunswick

Zebarth¹,

Leclerc²,

Moreau³

et al. 2003

Self Cite

. 2003. Soil inorganic nitrogen content in commercial potato fields in New Brunswick. Can. J. Soil Sci. 83: 425-429. Information on inorganic N content in commercial potato fields in Atlantic Canada is limited. Soil inorganic N measurements were collected from 228 commercial potato fields from 1999 to 2001. Soil NO 3 content to 30 cm depth at planting ranged from 2 to 124 kg N ha -1 , and was generally higher for preceding potato, red clover, or hay crops compared to preceding cereal or other crops. Soil NH 4 content to 30 cm depth measured at planting ranged from 3 to 64 kg N ha -1 , indicating that both soil NO 3 and NH 4 need to be measured to assess plant-available soil N content in spring. Soil NO 3 content to 30-cm depth at tuber harvest ranged from 3 to 250 kg N ha -1 , generally increased with increasing fertilizer N application rate, and differed among different potato cultivars. Soil NO 3 content measured to 30-cm depth in spring ranged from 3 to 100% of soil NO 3 at harvest in the preceding fall, indicating that highly variable losses of soil NO 3 from the root zone occur between growing seasons. La concentration est généralement plus élevée si les terres ont précédemment servi à produire des pommes de terre, du trèfle rouge ou du foin plutôt que des céréales ou d'autres cultures. À la même profondeur, la concentration de NH 4 fluctue de 3 à 64 kg de N par hectare, égale-ment à la plantation. Il convient donc d'établir la quantité de NO 3 et de NH 4 pour évaluer la concentration de N disponible dans le sol au printemps. À la récolte, la concentration de NO 3 se situe entre 3 et 250 kg de N par hectare, toujours à la profondeur de 30 cm. Elle augmente généralement avec le taux d'application des engrais azotés et varie avec le cultivar. La quantité de NO 3 mesurée au printemps à la même profondeur s'établit entre 3 et 100 % de celle relevée à la récolte, l'automne précédent, signe que la quantité de NO 3 perdue au niveau des racines varie considérablement d'une période végétative à l'autre.