Response of Potato to Water Stress in Southern Serbia

PejiÄ‡ B¹*, AksiÄ‡ M², MaÄkiÄ‡ K¹ and Å ekularac G³

¹Department of Field and Vegetable Crops, Faculty of Agriculture, University of Novi Sad, Serbia

²Faculty of Agriculture, LeÅ¡ak, University of Kosovska Mitrovica, Serbia

³Faculty of Agriculture, ÄŒaÄak, University of Kragujevac, Serbia

*Corresponding author: PejiÄ‡ B, Department of Field and Vegetable Crops, Faculty of Agriculture, University of Novi Sad, Dositej Obradovic Square 8, Serbia

Received: July 28, 2015; Accepted: October 06, 2015; Published: October 23, 2015

Abstract

An investigation was carried out on alluvium soil type in the river valley of Southern Morava, Southern Serbia during the seasons of 2008 and 2009, aiming to determine the response of potato to soil water deficit, using yield response factor. The values of yield response factor were derived from the linear relationship between relative seasonal evapotranspiration deficits and relative yield loss. Values of seasonal crop response factor of 1.14 indicate that potato is moderately sensitive to soil water stress in the climatic conditions of the Southern Serbia. Seasonal evapotranspiration was 495.0 mm and 291.2 mm in irrigated and rain-fed conditions respectively. A linear relationship was found between seasonal evapotranspiration and tuber yield. Potato yield in the variant with irrigation was 48.31 t ha-1 or 88.3% higher than in the variant without irrigation.

Keywords: Irrigation; Potato; Yield Response Factor

Introduction

Production of potato (Solanum tuberosum L.) takes a very important place in world agriculture, with a production potential of about 368 million t harvested and 19.3 million ha planted area with an average yield of 19.1 t ha-1 [1]. Potato production ranks fourth in the world after rice, wheat and maize [2]. In Serbia potato is grown at about 77,000 ha with an average yield of 10.2 t ha-1, and total production of 786,000 tones. In southern Serbia potato crop land is 55,000 ha with an average yield of 9.2 t ha-1, and total production of 55,000 tones [3]. The yield of potato in Serbia is fourth times lower than this achieved in the leading potato growing countries (Germany 45 t ha-1, France 45 t ha-1, Belgium 44 t ha-1 [1]). The low yields are the consequence of inadequate management practices, insufficient amount and unfavorable arrangement of precipitation in the growing season and inappropriate irrigation scheduling applied. In Serbia potato is cultivated under both irrigated and non-irrigated conditions. Portable sprinkler irrigation systems are commonly used. Due to the unpredicted amount and distribution of precipitation in the growing season, irrigation in Serbia is mainly supplemental. It is used primarily to supplement infrequent or irregular precipitation during drought periods [4].

Profitable management of irrigated potato requires skill and the best known management practices [5-9]. If shortage of readily available water in the soil, in the growing season, is eliminated by irrigation it is possible to achieve high and stable yields of potatoes, at the level of 40-50 t ha-1 or higher [9-11].

Several authors and research groups reported results of experiments aimed at determining optimum soil moisture under different environmental and technical conditions. BoÅ¡njak and PejiÄ‡, MiliÄ‡ et al., PejiÄ‡ et al. [8, 9, 12], found that the lower limit of optimum soil moisture for potatoes is 70% of field water capacity when this crop is grown in a soil with medium texture. Wright and Stark, King and Stark, Costa et al. [13-15] indicated that maximum yield of high quality potato tubers could only be achieved if the soilâ€™s available water in the maximum active root zone would not drop below the 50% limit.

A preliminary step to a more intensive exploitation of the available agro-ecological conditions or to the development of irrigation schedules for any crop implies a study of crop requirements for water, that is, the evapotranspiration (ET) for any particular crop. To fully utilize the genetic yield potentials of potato and achieve high and stable yields, it is necessary to gain knowledge of the cropâ€™s capabilities under conditions of dry farming and irrigation. Many factors can affect the amount of ET occurring in any particular crop. These include plant, soil, cultural and environmental factors [16]. The applied irrigation system can also affect the ET of a crop under specific conditions [10, 17]. Under no limiting irrigated conditions, daily ET rates for individual vegetable crops are directly related to the meteorological processes affecting evaporative demand and to the existing stage of growth development or percent crop coverage [18]. Any estimation of ET requirements for growing crops must be accompanied by a description of the associated conditions. The duration of the total growing season and the time of the year during which crops are grown have an enormous influence on the seasonal crop water need. According to FAO [19] to get high yield of potato, with the total growing season of 120-150 days, 500-700 mm of water used on evapotranspiration is needed. Kiziloglu et al. [7] recorded seasonal evapotranspiration of potato 445.2 mm for the yield of 26.43 t ha-1 in semiarid climatic conditions of eastern Turkey. A seasonal ET of 470 mm for potato, irrigated with portable sprinklers, in the Vojvodina region, the northern part of Serbia was reported by [9].

Drought tolerance is defined as the ability of plants to live, grows, and yields satisfactorily with limited soil water supply or under periodic water deficiencies [20]. The actual evaluation of stress related to the yield due to soil water deficit during the potato growing season can be obtained by the estimation of the yield response factor (Ky) that represents the relationship between a relative yield decrease (1â€“ Ya/Ym) and a relative evaporation deficit (1â€“ETa/ETm) [21]. For Ky â‰¤ 1 the plant is tolerant, for Ky â‰¥ 1, the plant is sensitive to water stress. Doorenbos and Kassam [22] estimate that the average value of Ky is 0.7 during the potato growing season. Vaux and Pruitt [23] suggest that it is highly important to know not only the Ky values from the literature but also those determined for a particular crop species under specific climatic and soil conditions. This is because Ky may be affected by other factors besides soil water deficiency, namely soil properties, climate (environmental requirements in terms of evapotranspiration), growing season length and inappropriate growing technology, applied irrigation method. Water deficit effect on crops yield can be presented in two ways, for individual growth periods or for the total growing season. Kobossi and Kaveh [24] suggested Ky values for the total growing period instead for individual growth stages as the decrease in yield due to water stress during specific periods, such as vegetative and ripening periods, is relatively small compared with the yield formation period, which is relatively large. Potato is very sensitive to water stress particularly in the stage of tuber formation. Even the decrease of 10% in the optimum water treatment in the growing period could have caused a decrease in the yield of potato [14]. Hassan et al. [25] reported that, potato is more sensitive to water stress at the stolonization and tuberization stages than the bulking and tuber enlargement stages. For the north-east of Portugal Ferreira and Goncalves [26] reported values of Ky for potato in the range of 0.71-1.12 regardless of nitrogen dosage. Unlu et al. [10] also found out that there was no apparent effect of season or N fertilization rates on Ky values of potato (0.91-0.97) but the influence of different methods of irrigation were recorded (0.68 for trickle and 1.05 for sprinkler).

The objective of the study was to estimate the yield response factor and on the basis of it to analyze a seasonal potato response to water stress and in such a way to obtain additional information that can be useful in the improvement of potato growing practices under climate conditions of southern Serbia but also for the whole region around this areas well as neighboring countries.

Materials and Methods

The study was conducted on alluvium soil type (Table 1) in the river valley of Southern Morava (43o 19`N and 21Â°54`E, 194 m a.s.l.) during the seasons of 2008 and 2009.

During the growth period (April-September), the average seasonal temperature (oC), total seasonal precipitation (mm) and relative air humidity were 19.3oC, 222.7 mm and 65% in 2008 and 19.6oC, 231.2 mm and 65% in 2009, respectively. Total precipitation were measured from the standard pluviometer replenishment in experiment field while seasonal average air temperature and average relative air humidity values were taken from NiÅ¡ meteorological station.

In the area, summers are hot and dry, and winters are cold and wet. Average temperature and rainfall values during the growth period (April-August) were 18.4ÂºC and 22.0 mm in the first year of the research, and 20.4ÂºC and 43.9 mm in the second year of the research respectively. During the growth period of the potato, minimum and maximum temperature values were 15.5ÂºC in April and 22.3ÂºC in August in the first year and 7.5ÂºC in March and 24.3ÂºC in August in the second year respectively.

The trial was set in random complete block design with four replications. The experiment included irrigated (well-watered) and non-irrigated (rain-fed) treatment. Tensiometers installed at the depth of 20 cm were used to determine the time of irrigation. Irrigation started when 30 kPa was read on the tensiometer`s vacuummeter. Tensiometers were controlled twice a day at 8 a.m. and 18 p.m. Irrigation was carried out by drip irrigation system.

Potato planting was done in the first half of April in both years, with the cultivar Kennebec. The row spacing between and within the rows were 0.7 and 0.3 m respectively. The size of the experimental unit was 10.5 m2. All plots received a seasonal total of 200 kg N, 120 kg P2O5, 300 kg K2O and MgO 95 kg per hectare. The potato were grown using commercial weed and pest management practices typical for the region. Potato was harvested at technological maturity and yield was calculated in t ha-1.

Yield response factor (Ky), for the growing season, on potato yield was determined using the Stewartâ€™s model [21] as follows:

Response of Potato to Water Stress in Southern Serbia

Abstract

Introduction

Materials and Methods

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References