Effects of Plant Density and Nitrogen Fertilizer on Nitrogen Uptake from Soil and Nitrate Pollution in Potato Tuber
In order to investigate plant density and nitrogen fertilizer
on nitrogen uptake from soil and nitrate pollution in potato tuber cu.
Agria, a factorial experiment based on randomized complete block design
with three replications was carried out in Ardabil, Iran, in 2006. Factors
were nitrogen levels (0, 80, 160 and 200 kg ha-1 net nitrogen)
and plant densities (5.5, 7.5 and 11 plant m-2). Results showed
that the most nitrogen uptake by plant aerial parts and the most nitrate
concentration in dry and fresh tuber weight were observed at 200 kg ha-1
nitrogen, 11 plant m-2 and 200 kg ha-1 nitrogen,
5.5 plant m-2, respectively. At 160 kg ha-1 nitrogen
(as equal to 80 kg ha-1 nitrogen) and 11 plant m-2,
the most tuber and yield of tuber were gained. With increasing nitrogen
application up to 160 kg ha-1, nitrogen uptake by tuber, number
of tuber, tuber dry weight and mean tuber weight was increased. 160 and
80 kg ha-1 nitrogen jointly with density of 5.5 plant m-2,
caused the most mean tuber weight per plant. So, utilization of 80 kg
ha-1 nitrogen to reach highest yield and less nitrate pollution,
density of 11 plant m-2 to gain seed tuber (because of reduction
in tuber weight and size) and density of 7.5 plant m-2 for
eating usages, are recommended.
to cite this article:
Sh. Jamaati-e-Somarin, A. Tobeh, M. Hassanzadeh, S. Hokmalipour and R. Zabihi-e-Mahmoodabad, 2009. Effects of Plant Density and Nitrogen Fertilizer on Nitrogen Uptake from Soil and Nitrate Pollution in Potato Tuber. Research Journal of Environmental Sciences, 3: 122-126.
Potato (Solanum tuberosum) is grown and eaten in more countries than
any other crop and in the global economy it is the fourth most important crop
after the three cereals including maize, rice and wheat (Stephen,
1999). The fate of nitrogen fertilizers used in potato production is an
important environmental concern (Meyer, 2002). Nitrogen
is an essential element for plant growth and is a main part of proteins. When
plant grows up in unfavorable environmental conditions, protein production is
reduced and nitrogen accumulates as non-protein compounds. Belanger
et al. (2000) reported that estimation of optimum fertilizer rates
is of interest because of growing economic and environmental concerns. Usually,
there is a close relationship between light intensity and nitrate reduction
in green leaves. Also, Nutrient elements deficit has important effect on nitrate
pollution. With increasing nitrogen application and plant density, potato yield
increases (Arsenault et al., 2001). Plant density
in potato affects some of important plant traits such as total yield, tuber
size distribution and tuber quality (Samuel et al.,
2004). Haase et al. (2007) found that tuber
N uptake and nitrate concentration were significantly influenced by amounts
of nitrogen fertilizer. Also, nitrogen uptake increases number of tuber, tuber
weight, qualitative and quantitative aspects of tuber. But, over-usage of nitrogen
delays tuber growth and reduces its qualitative and quantities aspects. Maher
(1998) reported that with increasing plant density, mean tuber weight decreased
and in low densities, number of harvested tubers, was decreased. Increasing
plant density led to mean tuber weight decrease and number of tuber and yield
per unit area, increase (Osaki et al., 1995).
Increment of plant density decreases mean tuber size probably because of plant
nutrient elements reduction, increment of interspecies competition and large
number of tubers produced by high numbers of stems (Beraga
and Caeser, 1990). Marguerite et al. (2006)
showed that the mean maximum increase in total tuber yield, generated by N fertilization
against the zero-N treatment, was 34.3% and ranged from 10.5 to 54.7% and in
regard to potato, the improvement of N efficiency should be also achieved by
splitting N fertilizer applications and by monitoring the crop N needs to match
crop N requirements and mineral N supply throughout the growing season. Joern
and Vitosh (1995) indicated that increasing nitrogen values resulted in
increase of tuber nitrate concentration. Georgakis et
al. (1997) concluded that by increasing plant density, the tuber yield
was increased. Karafyllidis et al. (1997) reported that plant density
strongly affected yield, both by number and by weight and more tubers and yield
per square meter were expected in higher plant densities. Wadas
et al. (2005) reported that, with increasing the level of nitrogen
fertilization, the nitrate content of tuber was increased and higher applications
of nitrogen, caused higher nitrate content in tubers, too.
The aim of this study was investigation of different plant density and
nitrogen level on nitrogen uptake by plant from soil, tuber nitrate pollution,
yield and yield components in order to definition of the best nitrogen
level and plant density in which the highest tuber yield with the lowest
environmental pollution were gained in year 2006 in Ardabil region, Iran.
MATERIALS AND METHODS
In order to evaluation of plant density and nitrogen fertilizer on nitrogen
uptake from soil and nitrate pollution of potato tuber Agria cultivar,
a factorial experiment based on randomized complete block design was carried
out with three replications in Ardabil, Iran, in 2006. First factor was
nitrogen level (0, 80, 160 and 200 kg ha-1 net nitrogen) and
second was plant density (5.5, 7.5 and 11 plant m-2). Nitrogen
was of urea source and applied in two stages, planting date and earthling
up stage. Based on soil test pH depth of 0-30 cm, Total Saturated Electrical
Conductivity (TSEC) was 3.68 mmhos cm-1, soil pH was 8.09,
total nitrogen was 0.56 % and soil texture was loamy sand. Rows were spaced
60 cm. Plots were included six rows each three meters. In order to preventing
nitrogen effects in adjacent plots, they were placed 1.5 meters distance.
Tubers of 60-70 g were sown in 13 May 2006. Sowing depth was 12-13 cm.
Last harvest was assigned for yield. Promoting storage capability, 10
days before harvest, aerial parts were removed (Khajehpour, 2004). Sampling
was done from 2 m2 plot area, then, tubers were transferred
to the laboratory.
Before measurements, tubers were washed along with roots and stolons. Different
plant tissues were dried separately for 48 h in 75Â°C and weighed. Tuber nitrate
pollution was calculated by sulfosalicylic acid method using spectrophotometer
device (Cecile, France). Calculation of nitrogen uptake rate was made according
to the Hashemidezfooli et al. (1998):
||Nutrient element uptake
Results were analyzed by SAS software, mean comparisons were done via
Duncan`s multiple range test and graphs were drawn by Excel software.
RESULTS AND DISCUSSION
Results showed that simple effects of plant density and nitrogen level on
nitrogen uptake by aerial parts and tubers (p<0.01) and interaction effects
of plant densityxHnitrogen level (p<0.05) only for nitrogen uptake by aerial
parts, were significant. Since, increasing nitrogen application led to over-growth
of aerial parts and consequently, increase of leaves and stems dry weight, so,
it increased nitrogen uptake. The most nitrogen was uptaken at 200 kg ha-1
nitrogen and the less at control level, for all aerial parts. But in tuber,
it was increased up to 160 kg ha-1 and then, decreased (Table
1). Increment of density increased dry matter of aerial parts per unit area.
This led to more nitrogen uptake in aerial parts and tubers so, the most and
the less uptake was observed in 11 and 5.5 plant m-2 (Table
1). With increasing plant density and constant rate of available nitrogen,
competition for nitrogen, increased. In 200 kg ha-1 nitrogen and
11 plant m-2 treatments, the most uptake and in 80 kg ha-1
nitrogen and 5.5 plant m-2, the less uptake was observed (Table
2). Haase et al. (2007) reported that with
increasing N application, nitrogen uptake in tuber was increased and it is in
accordance with present study. Also, they revealed more nitrogen uptake by tuber
in case of increased nitrogen. Since, nitrogen uptake in tuber per unit area
increased as a result of plant density and nitrogen level increment, so this
increase, has affected positively tuber yield and yield components and probably,
the best reason to yield increment.
Simple effect of plant density and nitrogen and their interaction effect
on tuber nitrate pollution based on dry weight (p<0.01) and fresh weight (p<0.05)
was significant. With increasing nitrogen level, nitrate content in tuber dry
and fresh weight significantly increased. More nitrate content in tuber, as
a result of increase nitrogen application, has been reported by Wadas
et al. (2005). Increase of density, reduced tuber nitrate pollution,
as well (Table 1). Perhaps, this is because of low fertilizer
distribution between the large number of plants and consequently, the tubers.
In 200 kg ha-1 nitrogen and 5.5 plant m-2, the most nitrate
pollution in fresh and dry weight, was observed (Table 2).
In all nitrogen levels, Agria Cu. has accumulated the less nitrate rate in both
fresh and dry tuber weight. Also, it could be found that nitrogen usage over
the favorite range either caused to yield reduction or, increased nitrate accumulation
Yield and Yield Components
Effects of plant density, nitrogen level (p<0.01) and their interaction
effect (p<0.05) on tuber yield, were significant. Also, effects of plant density
and nitrogen level (p<0.01) on tuber dry weight and tuber yield per unit area,
were significant. Effects of plant density and nitrogen level (p<0.05) on mean
tuber weight and number of tuber per unit area, were significant, as well. With
increasing plant density, tuber yield was decreased per plant and increased
per unit area (Table 1). This result has been reported by
many of other researchers (Osaki et al., 1995;
Georgakis et al., 1997; Karafyllidis et al.,
1997). In 160 and 80 kg ha-1 nitrogen and density of 5.5 plant m-2,
the most tuber yield per plant was observed (Table 2). Increment
of nitrogen application up to 160 kg ha-1, led to increase of number,
dry weight, tuber yield per unit area and mean tuber weight and then decreased.
This is because of high growth of aerial parts as a result of over-usage of
nitrogen (more than 160 kg ha-1) and consequently, increases of intra
competition to reach water, mineral elements and light that significantly reduced
yield and yield components at 200 kg ha-1 nitrogen. In density of
5.5 plant m-2, the most mean tuber weight was gained. Increase of
plant density, decreased mean tuber size probably as a result of lack of available
nutrient elements, intra competition or great number of produced tubers per
plant (Beraga and Caeser, 1990).
||Effect of plant density and nitrogen levels on measured
|Numbers with same words in each column, have no significant
differences to each other
||Effect of plant density and nitrogen levels on measured
|Numbers with same words in each column, have no significant
differences to each other
In general, the most amount of nitrate in dry and fresh weight of tuber
was observed in 200 kg ha-1 nitrogen, 5.5 plant m-2
treatments and the most tuber yield per plant was gained in jointly 80
and 160 kg ha-1 nitrogen, 5.5 plant m-2 treatments.
Nitrate pollution at 80 and 160 kg ha-1 net nitrogen was 170.52
and 214.47 mg kg-1 tuber dry weight and 38.88 and 50.82 mg
kg-1 tuber fresh weight, respectively. At these nitrogen levels
especially 80 kg ha-1, nitrate accumulated was lower than critical
range so, application of 80 kg ha-1 nitrogen to gain most tuber
yield with less nitrate pollution in tuber, is recommended for Agria Cu
in Ardabil region. Noticing mean tuber yield in Ardabil region of 28.7
t ha-1 and its comparison with yield of 80 and 160 kg ha-1
nitrogen treatment (29.44 and 31.74 t ha-1, respectively),
it seems that can be recommended for this region. Also, density of 11
plant m-2 is suitable to obtain planting seed (according to
reduction of tuber weight and size). But, density of 7.5 plant m-2
is recommended for eating usages.
This study was supported by the Central Laboratory of Agricultural Faculty,
University of Mohaghegh Ardabili. Valuable experimental support by Aziz
Jamaati-e-Somarin and Rogayyeh Zabihi-e-Mahmoodabad is greatly appreciated.
This work was extracted from M.S. thesis of Shahzad Jamaati-e-Somarin.
Arsenault, W.J., D.A. Leblanc, G.C.C. Tai and P. Boswall, 2001.
Effect of nitrogen application and seed piece spacing on yield and tuber size distribution in eight potato cultivars. Potato Assoc. Am., 78: 301-309.Direct Link |
Belanger, G., J.R. Walsh, J.E. Richards, P.H. Milburn and N. Ziadi, 2000.
Comparison of three statistical models describing potato yield response to nitrogen fertilizer. Agron. J., 92: 902-908.Direct Link |
Beraga, L. and K. Caeser, 1990.
Relationships between number of main stems and yield components of potato (Solanum tuberesom
L. cv. erntestolz) as influenced by different day length. Potato Res., 33: 257-267.CrossRef | Direct Link |
Georgakis, D.N., D.I. Karafyllidis, N.I. Stavropoulos, E.X. Nianiou and I.A. Vezyroglou, 1997.
Effect of planting density and size of potato seed-minitubers on the size of the produced potato seed tubers. Acta Hortic., 462: 935-942.Direct Link |
Haase, T., C. Schuler and J. Heb, 2007.
The effect of different N and K sources on tuber nutrient uptake, total and graded yield of potatoes (Solanum tuberosum
L.) for processing. Eur. J. Agron., 26: 187-197.CrossRef | Direct Link |
Hashemidezfooli, A., A. Koocheki and M. Banayanavval, 1998.
Yield increment of crop plant (Translation). 1st Edn. Jehad daneshghahi Mashad Press, Mashad. Iran, ISBN 964-6023-05-3.
Joern, B.C. and M.L. Vitosh, 1995.
Influence of applied nitrogen on potato. Part I: Yield, quality and nitrogen uptake. Am. Potato J., 72: 51-63.CrossRef | Direct Link |
Khajehpour, M., 2004.
Production of Industrial Plants. 1st Edn., Jehad-e-Daneshgahi Isfahan Press, Isfahan, Iran, ISBN: 961-6122-63-9
Maher, M.J., 1998.
The effect of planting density on the production of potato minituber under protection. Proc. Agric. Res. Forum, UCD., 4097(b): 1-13.Direct Link |
Marguerite, O., G. Jean-Pierre and L. Jean-Francois, 2006.
Threshold value for chlorophyll meter as decision tool for nitrogen management of potato. Agron. J., 98: 496-506.CrossRef | Direct Link |
Meyer, K.M., 2002.
Impact of nitrogen management strategies on yield, N-use efficiency and rhizoctonia diseases of Irish potato. M.Sc. Thesis, Faculty of North Carolina State University. A thesis submitted to the Graduate Faculty of North Carolina State University in partial fulfillment of the requirements for the Degree of Master of Science.
Osaki, M., H. Ueda, T. Shinano, H. Matsui and T. Tadano, 1995.
Accumulation of carbon and nitrogen compounds in sweet potato plants grown under deficiency of N, P, or K nutrients. Soil Sci. Plant Nutr., 41: 557-566.Direct Link |
Samuel, Y.C., D. Essah, G. Holm and J.A. Delgado, 2004.
Yield and quality of two US red potatoes: Influence of nitrogen rate and plant population. Proceedings of the 4th International Crop Science Congress Brisbane, Australia, 26 Sep-1 Oct. http://www.cropscience.org.au/icsc2004/copyright.htm.
Jackson, S.D., 1999.
Multiple signaling pathways control tuber induction in potato. Plant Physiol., 119: 1-8.Direct Link |
Wadas, W., R. Jabłońska-Ceglarek and E. Kosterna, 2005.
The nitrats content in early potato tubers depending on growing conditions. Elect. J. Polish Agric. Univ., 8: 26-26.Direct Link |