Evaluation of Crop Water Stress Index (CWSI) for High Tunnel Greenhouse Tomatoes under Different Irrigation Levels

Abstract

An experiment was conducted to determine the effect of water stress on yield and various physiological parameters, including the crop water stress index for tomatoes in the Central Anatolian region of Turkey. For this purpose, the irrigation schedule used in this study includes 120%, 100%, 80%, and 60% (I120, I100, I80, I60) of evaporation from the gravimetrically. Water deficit was found to cause a stress effect in tomato plants, which was reflected in changes in plants’ morphological and pomological function (such as stem diameter, fruit weight, pH, titratable acidity, and total soluble solids). Irrigation levels had a significant effect on the total yield of tomatoes. The lowest water use efficiency (WUE) was obtained from the I60, while the highest WUE was found in the I100 irrigation level. The CWSI was calculated using an empirical approach from measurements of infrared canopy temperatures, ambient air temperatures, and vapor pressure deficit values for four irrigation levels. The crop water stress index (CWSI) values ranged from −0.63 to a maximum value of 0.53 in I120, from −0.27 to 0.63 in I100, from 0.06 to 0.80 in I80, and from 0.37 to 0.97 in I60. There was a significant relation between yield and CWSI. The yield was correlated with mean CWSI values, and the linear equation Total yield = −2398.9CWSI + 1240.4 can be used for yield prediction. The results revealed that the CWSI value was useful for evaluating crop water stress in tomatoes and predicting yield.

Determination of the Effects of Different Irrigation Levels and Vermicompost Doses on Water Consumption and Yield of Greenhouse-Grown Tomato

“…The pH of tomato juice is an important quality parameter that determines taste. In previous research, Lovelli et al [53] and Boyaci et al [46] reported that the difference between different irrigation levels and pH values was statistically significant (p < 0.01). Gutiérrez-Miceli et al [44] found that vermicompost applications statistically affected pH values in tomato cultivation compared to the control group without VC (p < 0.05).…”

“…Colimba-Limaico et al [31] found that the values for stem diameter increased with increasing irrigation levels (80%, 100%, 120% and 140%). Boyacı et al [46] found that the difference in plant stem diameter between different irrigation levels (60%, 80%, 100% and 120%) was significant (p < 0.01). In this study, increasing irrigation levels and VC doses increased plant stem diameter.…”

“…The effect of irrigation level × VC interaction on fruit length was insignificant (p > 0.05). Boyacı et al [46] found that the difference between tomato fruit width and fruit length values between different irrigation levels (60%, 80%, 100% and 120%) was statistically significant (p < 0.01). Similarly, increased irrigation levels increased fertilizer intake and contributed positively to fruit width and height values.…”

“…Siingh et al [45] found the difference between tomato fruit weight values to be insignificant (p > 0.05) in their study, in which VC was not applied and 5 t/ha VC was applied. Boyacı et al [46] noticed that the difference in fruit weight values between different irrigation levels (60%, 80%, 100% and 120%) was significant (p < 0.01). In their experiment, since mineral matter intake decreased at decreasing irrigation levels, fruit weight values increased at increasing irrigation levels.…”

“…According to fruit flesh hardness values, the effect of irrigation level, VC doses, and the interaction of irrigation level × VC doses on fruit flesh hardness was significant (p < 0.01). Boyaci et al [46] determined that fruit flesh firmness values between irrigation levels increased by 120% and decreased by 60%. Accordingly, water stress was found to reduce fruit flesh firmness significantly.…”