Killi Tı n ve Organik Toprakta Toprak Su içeri ğ inin Zaman Etkili Yans ı ma Ölçer TDR Kullan ı larak izlenmesi

Öz

Bu çal ış mada, zaman etkili yans ı ma ölçer TDR ve tansiyometreler, killi t ı n ve organik toprakla doldurulmu ş toprak kolonlar ı nda, toprak su içeri ğinde ve toprak su potansiyelindeki de ğ iş iklikleri zamana bağ l ı olarak izlemek için kullan ı lm ış lard ı r. Toprak kolonlar ı içerisindeki bu de ğ işiklikleri belirlemek için üç çubuklu TDR problar ı ve tansiyometreler 5, 15, 25, 35 ve 45 cm derinliklerine yerle ştirilmi şlerdir. Bu denemede, toprak su içeri ğ indeki ve toprak su potansiyelindeki değ işiklikler 20 mm h-1sabit h ı zla uygulanan 15 litre saf suyun ya ğ murlamas ı süresince ve sonras ı nda belirlenmi ştir. Killi t ı n toprakta su hareketi ba şlang ı çta h ı zl ı olmuş ve 15 cm derinli ğ inde ilk de ğ işiklik ilk yar ı m saat içerisinde belirlenmi ş , fakat sonra su hareketin yava şlad ığı gözlemlenmiştir. Organik toprakta ise derinli ğ e bağl ı olarak toprak su içeri ğ indeki de ğ işiklikler killi t ı n topraktaki ile kar şı laşt ı r ı ld ığı nda yava ş olmuştur. 15 cm derinli ğ indeki su içeri ğ indeki ilk de ğ işiklik ancak yağ murlaman ı n başlamas ı ndan 1 saat sonra gözlemlenmi ştir. 5 cm derinli ğ indeki en yüksek su içeriği % 48,6 ancak ya ğ murlaman ı n başlamas ı ndan yaklaşı k 2,5 saat sonra belirlenmiştir.

Anahtar Kelimeler

• aman etkili yans ı ma ölçer
• su hareketi
• toprak kolonu tansiyometre

Monitoring the Soil Water Content Using Time Domain Reflectometry in a Clay Loam and an Organic Soil

Abstract

n the present study, Time Domain Reflectometry TDR and tensiometers were used to follow changes in soil water content and soil water pressure head over time in soil containers filled with a clay loam soil and an organic soil. The moisture content changes throughout the soil columns were determined by three-rod TDR probes and tensiometers inserted at the depths of 5, 15, 25, 35 and 45 cm. In the experiment, changes in soil water content and soil water pressure head were determined during and after the simulation of 15 L demineralized water applied at a constant rate of 20 mm hr-1 . The water movement through the clay loam soil was initially fast and the first moisture content change at the depth of 15 cm was detected during the first half an hour but later slow water movement was observed. For the organic soil, change in the moisture content with depth was slow compared with that of the clay loam soil. The first change in moisture content at the depth of 15 cm was observed after only 1 hour from the simulation of water. The highest moisture level, 48.6%, at the depth of 5 cm was determined only after approximately 2.5 hours later from the beginning of simulated rainfall.

Keywords

• time domain refloctemetry
• water movement
• soil column
• tensiometer

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