جستجوی مقالات مرتبط با کلیدواژه « دماسنج مادون قرمز » در نشریات گروه « آب و خاک »

One of the important factors that reduce plant growth is the short-term water stress applied to the plant in the period of two irrigations. This research aims to investigate the relationship between crop water stress index (CWSI) of sugarcane and soil moisture under two systems of closed-end furrow irrigation (CI) and subsurface drip irrigation (SDI) at research station number one of sugarcane development research and training institute was done from July to September 2022. For this purpose, a field including ratoon 3, of the variety CP69-1062, with four replications for both irrigation systems was selected. First, the upper and lower baselines were determined for CI. Then, using these baselines, the average CWSI for SDI and CI systems was estimated for each month, separately. The highest value of CWSI for CI in September was 0.54 and for SDI in August was 0.49. Results showed that there is a high correlation between CSWI and soil moisture only in CI method for the depths of 0-30, 30-60 and 60-90 cm. The correlation between CWSI and soil moisture for CI was determined in the range of 0.60-0.70, and for SDI, in the range of 0.46-0.12. It seems that in addition to water stress, other stresses such as salinity stress caused by irrigation water and farm soil are also applied to the plant.

The use of green cover temperature for plant irrigation planning is one of the methods that has been considered by researchers. For this purpose, several indicators have been presented, among which we can mention the water stress index of the plant by Idso method. In order to plan summer corn irrigation in climatic conditions of Ahvaz using green cover temperature, in 2018 research in the research farm of Shahid Chamran University of Ahvaz Faculty of Water Engineering under four types of irrigation regime including I0, I1, I2 and I3 respectively 120 , 100, 80 and 60% of the plant's water requirement was done in a completely randomized design in three replications. Based on the results, the equation of the upper and lower base line for the corn plant, treatment I1 (100% water requirement) for the development stage is 2.89 and (Tc-Ta) ll = 1.984-0.0946VPD, for the middle stage is 3.4 and (Tc-Ta) ll = 3.217-0.1669VPD and for the final stage of growth was equal to 1.2 and (Tc-Ta) ll = 1.147-0.160VPD was obtained in degrees Celsius. The results also showed that the total water stress index for the growth period for the 120, 100, 80 and 60 treatments was 0.17, 0.22, 0.35 and 0.52, respectively. The relationship between plant water stress index and soil moisture level for different irrigation treatments was highly correlated and the equation of soil stress index with soil moisture for I1 treatment for the next day and before irrigation was equal to CWSI = 1.8296-0.0586ɵv and CWSI = 1.038 0.0281ɵv was obtained. The results showed that with decreasing water consumption, the plant's water stress index increased and with increasing water stress, the correlation between CWSI index and soil water depth decreased so that the highest R2 (0.97) in I0 treatment and the lowest R2 (0.88) was in I2 and I3 treatments. As the results of this study confirm, the plant's water stress index is a good tool for irrigation planning and optimal management in the field.

The aim of this study was to assess the crop water stress index (CWSI), derived from leaf temperature using infrared thermometer measurements, to investigate the water stress status and irrigation timing of olive trees. Fpr this purpose a regression function was determined between crop water stress index and relative water content of leaf (RWC) and soil water content (SWC). The experimental treatments involved two olive cultivars (Koroneiki and T2) and four water regimes (irrigation of 100, 85, 70 and 55% of crop water requirement). The results showed that the non-water stressed baseline is varied throughout the study period as well as during the day. The daily variations of non-water stressed baseline were mainly due to variations in the intercept of the non-water stressed baseline that can be explained by variations in zenith solar angle. After investigating the relationship between vapor pressure deficit (VPD) and the difference between crop and air temperature (), the equation of Tc-Ta = -0.45 VPD+1.06, r2 = 0.99 was determined for the non-water stressed baseline of the olive trees at 12:30 pm. The effect of irrigation regime on water stress index of Kroneiki and  olive trees was not significant in none of the measurements during the study period. However, crop water stress index was significantly correlated with relative water content (Kroneiki: r2=0.67**, : r2=0.88**) and soil water content (Kroneiki: r2=0.74**, : r2=0.78**). Therefore, the crop water stress index is a good indicator of the water stress status of the Koroneiki and T2 olive trees.

In order to evaluate the Crop Water Stress Index (CWSI) of potato crop, a split- plot design was carried out in a randomized complete block design in Shahrekord Agricultural and Natural Resources Research Center in the growing season of 2018. This experiment consists of two methods of irrigation (surface and subsurface drip irrigation) in the main plots and four irrigation levels (Full Iirrigation, FI; Regulated Deficit Irrigation, RDI-80; Regulated Deficit Irrigation, RDI-65; and Partial Root-zone Drying PRD-75) in subplots, in three replications for potato (Bourren cultivar) with a period of growth of 120 days. Based on the results, the trend of changes in the CWSI of the crop in irrigation treatments for surface and subsurface drip irrigation was between 0.16 and 0.56 and 0.15-0.49, respectively.The relationship between CWSI and yield (Y) for surface and subsurface drip irrigation was Y = -122.28 CWSI + 82.38 and Y = -101.61 CWSI + 70.97, respectively. The yield of crop for treatments FI، RDI_80، PRD_75 and RDI_65 in surface drip irrigation was 52.1, 48, 31.6, and 23.4 Ton.ha-1, respectively and for subsurface drip irrigation 48.6, 44.3, 29.6 and 21.8 Ton.ha-1, respectively.The maximum amount of water consumed for treatment FI was 4590.2 m3.ha-1. The results showed that in order to achieve the highest yield in subsurface drip irrigation, the potato crop should be irrigated in the range of 0.16 to 0.2 of the CWSI.

One of the important factors which has led to reduction of the sugarcane yield is short-term water stress either in growing season or in the meantime of two sequence irrigation events. Therefore, studying and monitoring of crucial parameters of sugarcane water content (canopy temperature, soil moisture and vegetation moisture) is essential. The main objectives of present study are monitoring the effective parameters of sugarcane water content, and consequently determining the correlation between two different methods for determining irrigation schedule which are based on the canopy temperature and the leaf sheath moisture measurement, in order to have an efficient irrigation scheduling as well as determining the time and the amount of irrigation, accurately.

One of the important factors that reduce of sugarcane yield is short-term water stress between irrigation rounds. So that, the goal of this research is monitoring effectiveness parameters that determine water status of plant for irrigation scheduling and detection irrigation time.
This research monitored CWSI at sugarcane fields from May-September 2015 in Salman Farsi agro industry unit. Four different ages of sugarcane fields (plant, Ratoon1, Ratoon2, Ratoon3) at CP69-102 variety were investigated. For detection CWSI, sugarcane canopy temperature using infrared thermometer at three directions was measurement. Second step of this research in places that canopy temperature was measured, the percentage of soil moisture at two depths (0-30 cm & 30-60 cm) were measured and relationship of Soil moisture with CWSI was investigated. Each round, eight fields that have same age and various irrigation days for monitoring has been selected (totally 32 fields). With a round of measurement at different ages to calibration the relationship between soil moisture and CWSI was done. At the second round of measurement validation was conducted. Relationship between soil moisture and CWSI was assessment.
Lower baseline equation for CP69-1062 in all of the growth period , with R2=87% was estimated. Also upper baseline equation is horizontal line that vicinity 4°c varied. Results shown with increase of sugarcane age correlation between CWSI and Soil moisture was decreased. In other words, age of sugarcane is effectiveness parameter on absorb water to sugarcane. The results shown that the optimal amount of water stress index in all of sugarcane ages to start of irrigation is 0.5. Calibration equation shown RMSE=0.15 between observation and calculated CWSI. As so correlation between CWSI & soil moisture was low, so that the affection of irrigation water salinity is significant and salinity stress is important.
Generally, the results have shown that CWSI that was calculated from canopy temperature is good index to varied of plant water, so that utilize it for determine irrigation time and soil moister because of irrigation water salinity is not reasonable.

Irrigation scheduling with salinity and stresses, is much more difficult than Full irrigation. Using canopy temperature for plants irrigation scheduling is one of the methods that have been attention by many researchers. On of the usual method is presented by Idso. This research intends to investigate irrigation scheduling of summer maize using crop canopy temperature in Ahvaz climate (2013-2014) using surface irrigation with two levels of salinity irrigation water( S1=2.5 ds/m ,S5=5 ds/m).Crop water stress index(CWSI) is calculated for the two treatments. The experiment had three replications. With due to the obtained results, The CWSI for the two treatments S1 (minimum salinity) and S5 (maximum salinity) in September 14 and October 15 were 0.26 and 0.22. Upper baseline for the S1, in September and October are 5.05 C0 and 4.975 C0 respectively. For the S5 treatment the upper baselines in September and October were 2.85 C0 and 2.60 C0 respectively. Lower baseline also were calculated for the treatments. That was represented It is found that the S1 lower baseline is lower than the S5 treatment. This is due to the S5 treatment was effected By tension more than the S1 treatment. By using of measured data for scheduling irrigation maize in October and September with surface irrigation methods, some equations were determined. By using of the equations and comparing measured with the calculated canopy and air temperature, time of irrigation can be detected.

Determination of the appropriate time to irrigation is an important decision that farm planners are faced to it. Using canopy temperature for plants irrigation scheduling is one of the methods that have been attention by many researchers. In this way, several indicators have been proposed among which can be noted Idso Crop Water Stress Index (CWSI) method. This research intends to investigate irrigation scheduling of summer maize using crop canopy temperature in Ahvaz climatic condition in farming years 2013-2014 under sprinkler irrigation (fixed irrigation system) with two levels of salinity irrigation water ( S1=2.5 dS/m ,S5=5 dS/m) in three replications. Accordingly, the amount of crop water stress index in September was estimated for two treatments S1 (minimum salinity) and S5 (maximum salinity), respectively, 0.14 and 0.29 and in October, 0.18 and 0.27, respectively. Upper baseline equations for the S1 treatment, in September and October was calculated (Tc – Ta)u.l= 5.75 ºC and (Tc – Ta)u.l= 4.70 ºC, respectively. For the S5 treatment the upper baselines equations in September and October were (Tc – Ta)u.l= 2.94 and (Tc – Ta)u.l= 2.85 ºC, respectively. Lower baseline equations were calculated in S1 and S5 treatments and showed that the water stress in S1 treatment was lower than to S5 treatment due to the lower baseline. By using of measured data, for scheduling irrigation of maize in October and September with sprinkler irrigation method, some equations were determined. By using of the equations and comparing difference between leaf and air temperature measured by leaf and air temperature calculated (calculated allowable amount) can be detect time of irrigation in both treatments.

Use of canopy temperature for plants irrigation scheduling is one of the methods that have been attention by researchers. Several indexes have been provided for this method and one of them is Idso index . This research intends to investigate irrigation scheduling of summer maize using canopy temperature in Ahvaz climate in farming years 2013-2014 (summer cultivation) under sprinkler (fixed irrigation system) and surface irrigation with five levels of salinity irrigation water (S1, S2, S3, S4 ,S5). The experiment had three replications. Based on the obtained results, The CWSI for sprinkler irrigation in september and october estimated 0. 14 and 0.18 respectively. Also for surface irrigation in september and october estimated 0.14 and 0.15. Calculated equation for lower base in sprinkler and surface irrigation present less water stress in surface irrigation than sprinkler irrigation. of course, this does not mean that sprinkler irrigation has been stressed, but in these two types of irrigation CWSI values ​​indicate non-stress conditions for both irrigation. By using of measured data for scheduling irrigation maize in octobar and september with sprinkler and surface irrigation methods, some equations was determind.Than by using of the equations and comparing difference between leaf and air temperature measured by leaf and air temperature calculated can detect time of irrigation.

This study was conducted to determine the possibility of a crop water stress index (CWSI) to schedule irrigation for Pistachio tree under subsurface drip irrigation. The effects of two irrigation intervals consisting 3 (I3) and 14 (I14) days based on measuring soil water content were investigated on the CWSI. From 22 May (DOY 143) to 22 September (DOY 266), the evapotranspiration in I3 and I14 treatments varied from 795.45 to 490.79 mm, respectively. The CWSI was calculated using the empirical approach from measurements of infrared canopy temperatures, air temperatures and vapor pressure deficit values for the two irrigation levels. The lower baseline (non-water stressed baseline) was calculated as (Tc – Ta)LL = -1.642 VPD + 1.432 with R2 = 0.49. This equation had a correlation coefficient equal to 0.77 (P<0.01). An average threshold CWSI value of about 0.5 and 0.49 was calculated for I3and I14 treatments, respectively. Duncan test showed the effect of irrigation levels on CWSI was significant at P<0.05. Linear relationship between evapotranspiration and monthly CWSI calculated as ET = -804.7 CWSI + 680.1 with determination coefficient equal to 0.6 (P<0.05). The CWSI can be employed as a useful tool for assessing crop water stress for Pistachio.