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Journals / Artvin Çoruh Üniversitesi Orman Fakültesi Dergisi / 2026 / Cilt: 27 Sayı: 4

Estimating Soil Moisture Constants in Transition-Zone Ecosystems: Calabrian Pine (Pinus brutia Ten.) Afforestation Sites in the Niksar Region

Geçiş Zonu Ekosistemlerinde Toprak Nem Sabitelerinin Tahmini: Niksar Yöresi Kızılçam Ağaçlandırmaları Örneği

Ergün Kahveci(TOKAT GAZİOSMANPAŞA ÜNİVERSİTESİ, NİKSAR MESLEK YÜKSEKOKULU)0000-0003-2178-4302
Salih Malkoçoğlu(MUĞLA SITKI KOÇMAN ÜNİVERSİTESİ, KÖYCEĞİZ MESLEK YÜKSEKOKULU)0000-0002-9599-628X
Pages
1–12
Publication Date
2026-10-05
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AI Summary & Key Takeaways

AI Insight
⚡ TL;DR(Too Long; Didn't Read)

These regional PTFs can provide preliminary estimates for comparable calcareous, fine-textured Calabrian pine afforestation soils, but independent external validation is required before broader application.

📌 3 Key Takeaways

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Objective & Hypothesis:This study aimed to estimate field capacity (FC) and permanent wilting point (PWP) in Calabrian pine (Pinus brutia Ten.) afforestation sites in the Niksar region of Türkiye.
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Key Findings & Data:The primary dataset comprised 132 mineral-soil samples from 46 profiles selected using a 300 × 300 m systematic grid as the primary framework and, where field conditions permitted, supplementary intermediate points placed at approximately 150 m intervals to increase sampling density within the Calabrian pine afforestation area (0-10 cm: 46; 10-30 cm: 46; 30-50 cm: 40).
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Conclusion & Impact:These regional PTFs can provide preliminary estimates for comparable calcareous, fine-textured Calabrian pine afforestation soils, but independent external validation is required before broader application.
🔬Design:Modeling & Simulation
📍Scope:120 samples
⚙️Variables:Pedotransfer fonksiyonları · Çoklu doğrusal regresyon · Çoklu doğrulama

Abstract

This study aimed to estimate field capacity (FC) and permanent wilting point (PWP) in Calabrian pine (Pinus brutia Ten.) afforestation sites in the Niksar region of Türkiye. FC and PWP were determined as gravimetric water contents on an oven-dry soil mass basis. The primary dataset comprised 132 mineral-soil samples from 46 profiles selected using a 300 × 300 m systematic grid as the primary framework and, where field conditions permitted, supplementary intermediate points placed at approximately 150 m intervals to increase sampling density within the Calabrian pine afforestation area (0-10 cm: 46; 10-30 cm: 46; 30-50 cm: 40). Soil properties were summarized descriptively, bivariate associations were evaluated using Spearman rank correlations, and multiple linear regression (MLR)-based pedotransfer functions (PTFs) were developed. Prediction performance was evaluated using profile-based cross-validation, in which one profile was left out in each iteration (LOPO-CV). Northness was available for 42 profiles (120 samples), which formed the final model dataset. The FC model included pH, northness, organic matter, and clay (R2 = 0.631; adjusted R2 = 0.618). The PWP model included CaCO3, organic matter, clay, northness, and pH (R2 = 0.857; adjusted R2 = 0.851). LOPO-CV yielded R2 values of 0.563 and 0.828 and RMSE values of 4.10 and 2.99 percentage points for FC and PWP, respectively. These regional PTFs can provide preliminary estimates for comparable calcareous, fine-textured Calabrian pine afforestation soils, but independent external validation is required before broader application.

Özet

Bu çalışmada, Kelkit Havzası’nda geçiş özellikleri gösteren Niksar yöresindeki kızılçam (Pinus brutia Ten.) ağaçlandırma sahalarında tarla kapasitesi (TK) ve daimi solma noktasının (DSN) tahmin edilmesi amaçlanmıştır. TK ve DSN fırın-kuru toprak kütlesine göre gravimetrik su içeriği olarak belirlenmiştir. Ana veri seti, 300 × 300 m sistematik ağın ana çerçeve olarak kullanıldığı ve arazi koşullarının elverdiği kesimlerde örnekleme yoğunluğunu artırmak amacıyla yaklaşık 150 m aralıklı tamamlayıcı ara noktaların eklendiği 46 toprak profilinden alınan 132 mineral toprak örneğinden oluşmuştur (0-10 cm: 46; 10-30 cm: 46; 30-50 cm: 40). Toprak özellikleri tanımlayıcı istatistikler ve Spearman sıra korelasyonu ile değerlendirilmiş, TK ve DSN için çoklu doğrusal regresyon (MLR) tabanlı pedotransfer fonksiyonları geliştirilmiştir. Tahmin performansı her yinelemede bir profilin dışarıda bırakıldığı profil bazlı çapraz doğrulama (LOPO-CV) ile değerlendirilmiştir. Kuzeylik verisi bulunan 42 profil ve 120 örnek üzerinden geliştirilen TK modeli pH, kuzeylik, organik madde ve kil değişkenlerini içermiştir (R2 = 0.631; düzeltilmiş R2 = 0.618). DSN modeli CaCO3, organik madde, kil, kuzeylik ve pH değişkenlerini içermiştir (R2 = 0.857; düzeltilmiş R2 = 0.851). LOPO-CV’de TK ve DSN için R2 sırasıyla 0.563 ve 0.828, RMSE ise 4.10 ve 2.99 yüzde puanı olmuştur. Modeller, benzer kireçli ve ince tekstürlü kızılçam ağaçlandırma toprakları için bölgesel ön tahmin araçlarıdır; daha geniş kullanım için bağımsız dış doğrulama gereklidir.

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Cite This Article

Kahveci, E., Malkoçoğlu, S. (2026). Estimating Soil Moisture Constants in Transition-Zone Ecosystems: Calabrian Pine (Pinus brutia Ten.) Afforestation Sites in the Niksar Region. Artvin Çoruh Üniversitesi Orman Fakültesi Dergisi, Cilt: 27 Sayı: 4, 1–12. https://doi.org/10.17474/artvinofd.1970830

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