Ahmet Ertek

Effects of different drip irrigation programs on the boll number and shedding percentage and yield of cotton

This study investigated the effects of different drip irrigation programs on boll number, shedding percentage, and yield of cotton. The amount of water used was based on free surface evaporation from a screened class-A pan. Irrigation treatments consisted of two different irrigation intervals (I1: 5 days; I2: 10 days), three plant-pan coefficients (Kcp1: 0.75; Kcp2: 0.90; Kcp3: 1.05) and two different wetting factors (P1: 0.70 (constant) and P2: based on cover percentage of the crop). The first irrigation was carried out when the available water in the 120 cm of the soil profile was at the 40% level. The results revealed significant linear relationships between cotton yield-irrigation water and boll number-shedding percentage. On the other hand, the shedding was decreased by increasing the amount of applied irrigation and irrigation interval. Therefore, the yield increased by increasing the boll number. Furthermore, it was found that there was a significant (P<0.01) inverse linear relationship between the shedding rate and boll number. Author Keywords: Cotton; Boll number; Shedding percentage; Drip irrigation; Yield

Effects of different irrigation programs and nitrogen levels on nitrogen concentration, uptake and utilisation in processing tomatoes (Lycopersicum esculentum)

A study was conducted to investigate the effect of different irrigation programs and nitrogen (N) levels on N concentration, uptake and utilisation by the processing tomato (Lycopersicum esculentum). The amount of water used was determined based on a screened class-A pan. Irrigation treatments consisted of 2 different irrigation intervals (I5, 5 days; I10, 10 days) and 3 plant-pan coefficients (Kcp0.50, 0.50; Kcp0.75, 0.75; Kcp1.00, 1.00). Nitrogen treatments consisted of 3 N levels (N0, 0 kg/ha; N80, 80 kg/ha; N160, 160 kg/ha). The irrigation interval, plant-pan coefficient and N fertiliser rate affected all parameters examined; however, the N fertiliser rate had the greatest impact. Nitrogen applications increased N concentrations in the leaf, tomato and vegetative biomass. Plant total N uptake and benefit rate from fertiliser was highest with the N160, I10 and Kcp0.75 and Kcp1.00 treatments. Results show that the N160, I10 and Kcp0.75 treatments can be used for increasing plant N uptake and the benefit rate from fertiliser.

Importance of pan evaporation for irrigation scheduling and proper use of crop-pan coefficient ( Kcp), crop coefficient ( Kc) and pan coefficient ( Kp)

The objectives of this study were: (1) to submit co mprehensive information about the distinctions among pan coefficient ( Kp), crop coefficient ( Kc), and crop-pan coefficient ( Kcp); (2) to reveal the importance of using pan evaporation for irrigation scheduling. The amount of water allocated for agricultural production has been decreasing due to rapid population growth, industrialization and contamination. Therefore, to obtain maximum yield a nd avoid excessive water application, the water requirements of the cultivated plants should be acc urately determined, and irrigation water should be applied according to the needs of the plants. Crop water consumption ( ETc) varies from region to region depending on crop type, stage of growth, soi l, and climate conditions. Different evapotranspiration rates may be observed even in di fferent parts of the same region. Considering global warming and climate change in recent years, it is clear that the predicted ET values of a year can not be used safely for upcoming years. Research stu dies have revealed a linear correlation between crop water consumption and the amount of water evap orated from open water surface. Therefore, irrigation scheduling through using the combination of proper crop-pan coefficient and pan evaporation (Class-A pan) is very important due to both ease of adjustment to the climate changes and ease of application. Even though many studies have been conducted on this issue, there is still need to collective and detailed information about use of evaporation p an for irrigation scheduling and above mentioned coefficients.

Growth and Yield of Pepper (Capsicum Annuum L.) Under Root Zone Restriction

The world production of green pepper is about 24 million tons from 1.66 million ha while its production in Turkey is about 1.79 million tons from 88.000 ha Ertek et al. [1]. Pepper is included in the Capsicum genus of the Solanaceae family; perennial in warm climates, and multi-year in tropical climates it is a cultivar. Pepper plants grow best at temperatures in the range of 20 to 25 °C. Pepper plants are damaged at temperatures above 32 °C and below 5 °C. Soil moisture should be at 65-70% of field capacity. Pepper plants require a large amount of water for optimal vegetative and reproductive processes. The pepper roots are very sensitive to excess water. Therefore, irrigation water required for pepper must be given adequately and without delay Koc F [2]& GAP [3].