Water-Yield Relationships in Deficit Irrigated Cabbage

This trial was realized in Yenisehir Vocational School between 2007 and 2008 on the purpose of study out the influence of lack of water in four growth periods of cabbage. In this trial, fourteen irrigation treatments was formed considering the growth periods (establishment, vegetative, yield formation and ripening) of cabbage (Brassicaceae Oleracea var. capitata L. Grandslam F1) and the results obtained from these treatments were evaluated. According to the content of the treatments, the water amount to the plants varied between 0 and 524 mm in the 2007 year, and between 0 and 536 mm in the 2008 year. Water consumption of cabbage in the 2007 year ranged between 200 and 795 mm and in the 2008 year ranged between 190 and 802 mm. Yield, head weight, diameter, height and dry matter ratio were determined statistically important. In 2007 and 2008 years, the maximal yield were found as 74.2 t ha and 72.4 t ha in the E100V100Y100R100 treatments, while the minimal yield were found as 2.0 t ha -1 and 4.0 ha 1 in the E0V0Y0R0 treatments, respectively. Wateryield relationship factor (ky) in 2007 and 2008 years were found as 0.96 and 0.97, respectively.


Introduction
Van Straten et al., (2010) stated that the greenhousing is worldwide the fastest growing sector of all agricultural production activities.There are two essential causes for this.First, the plant grows in greenhouse differently from the external environment, in this way supplying some way of abri from the direct effect of the external environment.This allows the production of crops at that specific place.Second, the greenhouse allows to be produced of many crops.This situation permits the grower to direct the farming in a preferable aspect.It causes to more crop yield, extended production period, less use of chemicals, better quality.The value added per decare in greenhouse crops is much more than that in field agriculture.The world's the biggest cabbage producers are China, India and Russia with 33 400 000, 9 000 000 and 3 500 000 tons, respectively (FAOSTAT, 2014).Russia is the largest cabbage consuming country.Turkey is one of the significant cabbage producer with 785 791 tons in the world (FAOSTAT, 2016).The cabbage is considered to be of European origin and grows along the North Sea, the English Channel and Northern Mediterranean.Lahana is prefered because of its various advantages such as the growth of the various climate and soil conditions, its easy of production and storage and its high food value.The cabbage is eaten up as cuisine dish in our country along with salad, raw, wrap and pickle (Vural et al., 2000).Sezen, (2005) found that surface irrigation doesn't suggest because of the low of irrigation efficiency result from drainage and salinity in plantations.Irrigation with less amount of water is important such as sprinkler and drip irrigations.There is a need for more efficient irrigation systems support to improve agricultural targets and irrigation efficiency.Moreover, irrigation water by drip irrigation is used more effective and over-irrigation causes yield losses.Thus, irrigation method is really crucial with regard to irrigation planning (Anonymous, 2005).
Irrigation planning aims of the soil water deficit to not falling below the critical level for a specific soil and crop condition.This may enable to avoid the harmful effect of water stress by means of estimating the earliest date (Ritchie and Johnson, 1990).Irrigation water is used effectively thanks to drip irrigation system.Extreme irrigation lowers yield, while insufficient irrigation reduces production and brings about water stress.
Irrigation planning with drip irrigation relies on approaches related to evapotranspiration estimations (Bar-Yosef and Sagiv, 1982;McNeeish et al., 1985;Clough et al., 1990;Hartz, 1993) and permissible soil-water consumption (Bogle et al., 1989).K values usually difficult to create accurately.Because regional conditions, soil properties, crop physiology and cultural practices affects to K values.A suggested K value for irrigation planning must be high enough to avoid the water stress caused by the needs and specific local situations.It remains low enough for effictive water management (Yuan et al., 2003) Some studies have been made to research the effect of deficit irrigation on cabbage.The purposes of this trial were to obtain a prospectus for cabbage growers and to determine drip irrigated cabbage response to deficit irrigation modes in Bursa conditions.As a result, drip irrigation method preferred in the study.

Material and Methods
The trial was realized in Yenisehir Vocational School, Bursa in 2007 and 2008 years.For practical purposes, plastic greenhouse (8 m x 40 m) was used.In the study place, winters are cold and summers are hot.The average annual rainfall and temperature values for the region where the greenhouse experiments were made in 2007 and 2008 were 482,9-630,7 mm and 13,6-12,9 o C respectively.While the average minimum temperature for 2007 and 2008 were -6,6 -(-5,9) o C between January and December, the average maximum temperature in August was measured as 32,9 and 34,6 °C (Anonymous, 2010).The soil of study place was sandy clay and pH value of soil ranged between 7.86 and 8.05.The specific features of the soil are given in Table 1.
A suitable well for irrigation was used as the water source in the trial area and the quality of irrigation water was determined as C1S1.3x15 NPK manure was utilized to trial plots while the cabbages were being planted, and 75 kg of 3x15 NPK manure per decares were utilized.The urea form of the nitrogen was applied to the plots together with water.25 kg manure (% 46 N) per decare in vegetative period was applied as the first manure application, while 25 kg manure (% 46 N) per decare was applied along with irrigation water during the yield formation period.Furthermore, during the vegetative and yield formation periods the generative growth of plant was supported by using 25 kg of magnesium nitrate manure per decares (11 -0 -0 + 16 MgO -Nitrogen % 11 and MgO % 16).The cabbage seedlings were transplanted into the trial pots on August 03, 2007 and on August 01 2008 years, respectively.Seedlings were planted on the same line and at a distance of 60 cm between the plant lines.The specific parameters of cabbage are yield, head weight, diameter, height and dry matter ratio.The four heads harvested from the middle of the plots were weighed and head weight were determined by the averages of these values.Head diameter and height were calculated by measuring with a scale/ruler.The dry matter ratio of the cabbage was calculated by drying the leaves of the fruit in a drying oven for 48 hours and at 65ºC.The trial design was formed by randomly distributing fourteen different treatments on three different blocks.The size of trial plots was 4 m 2 (2.0 m x 2.0 m) and the intervals between blocks and plots were 2.0 m and 0.75 m, respectively.Each plot had 9 plants and 0.60 m apart between the rows with 0.60 m spacing in each row.The detail of one of the trial plot is shown in Figure 1.
In growth periods of the cabbage (establish, vegetative, yield formation and ripening) were formed fourteen deficit irrigation treatments based on full or deficit irrigation applications, 0.75-50-0.25% of the deficit irrigations were applied in different growth periods of the plant (establishment, vegetative, yield formation and ripening), while in the fully irrigated treatments, all of this water was applied.In line with this planning, irrigation treatments were planned like this: E100V100Y100R100, E75VYR, E50VYR, E25VYR, EV75YR, EV50YR, EV25YR, EVY75R, EVY50R, EVY25R, EVYR75, EVYR50, EVYR25, E0V0Y0R0 (Table 2.).
In the trial, the plants were irrigated drip irrigation method and water was provided from an irrigation well.The specific features of the irrigation water utilized in the study are given in Table 3.The water has low-sodium risk, has a medium EC and is in C2S1 class.In growth periods of plant, the damp contains of the soil was followed before and after irrigation with a gravimetric method in every 30 cm till 120 cm depth.
ET, was calculated by means of water balance equation (Eq. 1) 11 .
ET= I + P -Rf -Dp ± S Where, ET represents the evapotranspiration, I shows the irrigation water (mm), P is the precipitation, Rf is the surface flow (mm), Dp is deep drainage (mm) and S is the between two soil water changing in effective root depth (mm/90 cm).Before planting seedlings, water was used to the tomato with the drip irrigation method.Total precipitation (P) and surface flow (Rf) was omitted and the soil moisture between the depths of 90 to 120 cm of the soil is accepted as the deep drainage (Dp).However, during the growing period, soil moisture changes between 90 and 120 cm were not followed and the deep drainage was accepted as "0".In this trial, the relationships between yield and ET is defined by the Steward Model (Eq.2) (Stewart et al., 1975;Doorenbos and Kassam, 1979).The equation can be showed as Where Ym (t/ha) and Ya (t/ha) are maximal and real yield, respectively, ETm (mm) and ETa (mm) are maximal and real evapotranspiration, respectively.The yield response factor is shown as ky.WUE values were determined to assess irrigation efficiency in treatments.WUE and IWUE terms refer to contribution of irrigation water to effective use of plant production stages (Bos, 1980).The ratio of yield (YLD) to ETa expressed as WUE and it is demonstrated as WUE=YLD/ETa (kg/m 3 ).IWUE was predicted by the following equation; ( ) Where YLD is yield and YLDrainfed is the yield found from the rainfed treatment, IRGA is the seasonal water amount (mm).The damp content of the soil till 90 cm depth was calculated before the seedlings were planted into the soil.All treatments were completed in the level of field capacity.In 2007 year, irrigation was started on August 10, 2007 and in 2008 year was started on August 08 and irrigation was done every 7 days.The irrigation water for the four growth stages are given in Table 4. Crop evapotranspiration for the different growth stages are given in Table 5.
Product efficiency and quality parameters are evaluated.Variance analysis was done with the values of product productivity and productivity components by using MSTAT-C and MINITAB software (Steel and Torrie, 1980).

Results
In 2007 and 2008 years, maximal irrigation water was found in E100V100Y100R100 treatment as 524 -536 mm and minimal irrigation water was found in E0V0Y0R0 treatment as 0 -0 mm, respectively.Plant water consumption of the cabbage (ETc) went up with the increment in the water amount.In E100V100Y100R100 and E0V0Y0R0 treatments, it was found as 200-795 mm in 2007 year and as 190 -802 mm in 2008 year, respectively.The irrigation water and yield values are given in Table 6.
Linear relationships between ETc with Ya, and IW with Ya were observed for 2007 year.As for that the trial results, irrigation applications considerably influenced the yield (Fig. 2 and Fig. 3), and when they were assessed as the values of 2007 and 2008, the maximal values of yield were found as 74.2 t ha -1 and 72.4 t ha -1 in E100V100Y100R100 treatment (Table 8 and Table 9).
While a positive straight line relationship was obtained between the water amount and the yield, head weight, diameter, height; a negative straight line relationship was obtained between the irrigation amount and dry matter ratio.As for that the relationship, these results were determined: head weight ( 2007

Crop yield response factor (ky)
Crop yield response facto (ky) is defined as the linear relationship between relative crop evapotranspiration and relative yield decrease.This is accepted to be the response of the yield to the relative crop evapotranspiration.In another saying, it indicates the decrease in the yield corresponding to each level of deficit in water consumption.Seasonal crop yield factors (ky) were determined as 0.96 (2007 year) and 0.97 (2008 year) (fig.5).The increase in ky value is due to the increase in the water deficiency.This result shows that the seasonal crop yield factors are a bit low in the period of cabbage but it is accordant with the crop yield factors in the every growth periods given in literature.The difference of results may refer to the differences between the empirical, soil conditions, climatic.

Water use efficiencies
WUE and IWUE values of the 2007 and 2008 years, when the trial was performed, were obtained different allied to the treatments (Table 10).The maximal WUE values for 2007-2008 years were found as 0.09, 0.10, 0.10 -0.09, 0.09, 0.10 and 0.09, 0.09, 0.10 -0.09, 0.09, 0.09 kg mm -1 from E75VYR, E50VFYR, E25VYR and EV75FYR, EV50FYR, EV25FYR treatments, respectively.IWUE values for 2007-2008 years were found as 0.14, 0.14, 0.14 -0.14, 0.15, 0.16 kg.mm -1 and 0.14, 0.14, 0.15 -0.14, 0.15, 0.14 kg kg.mm -1 respectively.When WUE and IWUE values were taken into consideration, the maximal WUE and IWUE values were obtained from establishment and vegetative periods and the lowest value was obtained from yield formation and ripening periods.In another saying, the maximal yield was found and the most water was saved with deficit irrigation only in the establishment and early vegetative periods of the cabbage.

Discussion
In our trial, irrigation treatments considerably influenced yield, head height, diameter, weight and dry matter.Total water amounts range from 380 to 500 mm subject to the length of growing season and climate (Doorenbos and Kassam, 1979).Kumar and Sahu (2013) reported that the total depth of water for cabbage applied were 107 and 268 mm, respectively.The cabbage yield for 2007 and 2008 years ranged between 74.2-2.0 and 72.4-4.0 t ha - 1 , respectively.The results of our study shows that the influence of deficit irrigation on yield was quite important.According to the yield results, all treatments were ranked as the different statistical groups.It is concluded that the amount of irrigation water applied to different phenological periods of the plant was important on the yield value of the plant.This result is in agreement with those of (Doorenbos and Kassam, 1979 At all of treatments except for E100V100Y100R100, yield was significantly lowered as irrigation water amount decreased.As determined in yield, the quality values of the cabbage (head weight, diameter, height and dry matter) have given a similar response to deficit irrigation.As expected, the non-irrigated (E0V0Y0R0) treatment had lower values than all irrigation treatments.Head weight, diameter ve height values were not included in different statistical groups.This situation is that the amount of irrigation water had a good few effect on head weight, diameter and height.However, the amount of irrigation water had no significant effect on head weight, diameter and height.This situation can be attributed to the fact that plant water consumption wasn't high during plant growing period.These values are similar to those of previous studies (Janes, 1950 Since all treatments in the trial had lower than E100V100Y100R100 treatments.The minimal dry matters were found at E100V100Y100R100 treatments while the minimal dry values were observed at E0V0Y0R0 treatments in 2007 and 2008 years of the study.We may infer that important increments in dry matter may be provided by the rising level of irrigation water deficiency.The results obtained from the trial are in conformance with those of (Janes, 1950;Abdel et al., 1994;Bogoescu, 2000;Wahome et al., 2009).
The maximal WUE and IWUE values for 2007 and 2008 years found as 0.16-0.15and 0.15-0.15,respectively.The maximal WUE and IWUE values were found in establishment and vegetative periods and the lowest value was obtained from yield formation and ripening periods.When the findings of several researchers compared with the results of our study, the findings were found to be same to (Doorenbos and Kassam, 1979;Sammis et al., 1988;Himanshu et al., 2012;Kushwah and Dwivedi, 2013;Agrawal et al., 2018).These values were influenced climate, variety and soil structure.As explained by Davis et al. ( 2008), it may be attributed to the variety and applied cultural practices handling under different climate and geographical conditions.Crop yield response factor (ky) for 2007 and 2008 year were calculated as 0.96 and 0.97 for cabbage, respectively.The specified values of ky (0.96-0.97) which is lesser than 1.00 shows that cabbage is susceptible to the water.Research values who studied on similar issues also matches up with ky factor (Doorenbos and Kassam, 1979;Sammis et al., 1988;Himanshu et al., 2012;Kushwah and Dwivedi, 2013;Agrawal et al., 2018).

Results
According to the results of the study, irrigation water were applied 524 and 536 mm in E100V100Y100R100 treatment applied to full irrigation in 2007 and 2008 years.The plant water consumption of cabbage was determined as 795 and 802 mm in 2007 and 2008 years for E100V100Y100R100 treatment.Crop yield response factors (ky) for the different plant growth periods (Establishment, vegetative, yield formation and ripening) were found as 0.47, 0.84, 1.23, 1.28 in 2007 year and 0.49, 0.88, 1.25, 1.26 in 2008 year.Crop yield response factor (ky) for the total growth period was found as 0.96 in 2007 year and as 0.97 in 2008 year.The highest crop yield response factor values were obtained from the ripening and yield formation periods.These values for 2007 and 2008 years were calculated as 1.28-1.23 and 1.26-1.25,respectively.The highest crop yield response factors (ky) obtained from ripening and yield formation periods showed that the cabbage was susceptible to water in these periods.The highest yield decreases in all plant growth periods were in ripening and yield formation, while the lowest yield decreases were in establishment and vegetative periods.In our trial, it was studied out that irrigation treatments considerable influences yield, head diameter, weight, height and dry matter ratio.In 2007 and 2008 years, the maximal yield was 73.3 t h -1 and it was found in E100V100Y100R100 treatment.The minimal yield was found as 3.0 h -1 in E0V0Y0R0 treatment.The yield decreased significantly due to the irrigation water deficiency.The relative decreases in yield in 2007 and 2008 were %0.5, %2.6, %5.0, %8.5, %10.4,%11.2, %16.9, %18.2, %24.5, %35.4,%41.6, %%46.6,%3610.0 and %6.0, %1.4,%2.4,%6.6, %7.1, %21.7, %13.3, %19.3, %25, %25.7, %39, %43.7, %1710, respectively.WUE and IWUE values of establishment and vegetative periods were the lowest values.In water deficiency conditions, the establishment and vegetative periods of cabbage are the most suitable periods for deficit irrigation and the yield and quality value decreases was the lowest during these periods.
As a result, of a possible deficit irrigation in a semi-humid climate condition, it is necessary to plan carefully and it is possible to say that the levels and times of the deficit irrigation were significantly effective on cabbage yield.In cabbage irrigation, if the deficit irrigation treatment is obligatory, water deficiency should be planned only for establishment and vegetative periods.The water deficiency shouldn't be applied in other plant growth periods and irrigations during ripening period should be exactly applied.In addition, in the irrigation planning to be done in similar climatic conditions may be benefited from crop yield response factor (ky) values.The results used to determine the amount of reduction in yield in response to the water deficiency to be applied to the plant may be used in studies related to cabbage.
Agrawal et al. (2018) determined that water used for cabbage varied from 189 to 710 mm.Kiziloglu et al. (2007) specified that 449.4 mm irrigation amount and 932 mm evaporation were applied to the plants in whole growth period.Wahome et al. (2009) stated that water applied for cabbage varied from 420 to 491 mm in different treatments and two mulch materials.Sammis and Wu (1989) found that the irrigation amount ranged from 0.42 to 1.94 mm and plots were arranged in the form of a tree repeated gradient irrigation.Abdel et al.(1994)   reported that irrigation water was applied 3.6 and 9 mm day-1 during the growth period of cabbage (Brassica oleracea var.capitata L.) and irrigation frequencies were preferred 1 and 3 days in winter conditions of Oman in the Gulf region.Smittle et al. (1994) notified that the water applied for cabbage changed from 71 to 182 mm.In the same study, pan evaporation values varied from 131 to 270 mm.Bucks et al. (1973) indicated that the consumptive use requirement (380 mm of water) for high production of cabbage was about the same for all irrigation methods.Sammis et al. (1988) reported that the plant consumptions of lettuce and Chinese cabbage were 205 mm and 209 mm, respectively.Kiziloglu et al. (2008) specified that the total evapotranspiration for red cabbage in Turkey conditions was 937 mm.In the first year of the trial, a total of 524 mm of the amount of irrigation water was applied to the E100V100Y100R100 treatment which was applied in full water and 536 mm in the second year.In addition, the plant water consumption of cabbage was determined as 795 and 802 mm in 2007 and 2008 years for E100V100Y100R100 treatment.The results of the irrigation amounts and crop water consumption values of the trial were compatible with previous studies (Bucks et al., 1973; Doorenbos and Kassam, 1979; Sammis et al., 1988; Sammis and Wu, 1989; Smittle et al., 1994; Abdel et al., 1994; Kiziloglu et al., 2007; Kiziloglu et al., 2008; Wahome et al., 2009; Kumar and Sahu, 2013; Agrawal et al., 2018).

Figure 1 .Figure 2 .
Figure 1.The detail of a plot

Figure 4 .
Figure 4. Relationship between applied of irrigation water and head weight, head diameter, head height and dry matter ratio.
Linear relationships between ETc with (Ya), and IW with Ya were observed for 2008 year.The relationship equation is as follows; Y a = 0.1343ET c -2.0828 with R 2 =0.92 and Ya = 0.1274IW + 3.1626 with R 2 =0.93 (Fig 3 and Fig 4).
The relationship equation is as follows; Y a = 0.1166ET c -16.57 with R

Table 1 .
Some of chemical and physical properties of experimental field soil

Table 3 .
Chemical composition of irrigation water used in the experiment

Table 4 .
The amount of irrigation water applied for the different growth stages according to the treatments

Table 5 .
Crop evapotranspiration for the different growth stages according to to the treatments

Table 6 .
Relationship between the decrease in relative water use and decrease in relative yield and yield response factor for cabbage irrigated by a drip system in 2007 and 2008

Table 7 .
Crop water production functions obtained for each growth stage and total growing season in 2007 and 2008

Table 8 .
Effects of irrigation treatments on cabbage parameters in 2007** means correlation is significant at the 0.005 level.ns shows non-significant correlation.

Table 9 .
Effects of irrigation treatments on cabbage parameters in 2008** means correlation is significant at the 0.005 level.ns shows non-significant correlation.

Table 10 .
Total water use efficiency (WUE) and irrigation water use efficiency (IWUE) values for the cabbage irrigated by a drip system at different irrigation treatments.