Iğdır yöresi topraklarında kaymak sertliği (kırılma değeri) ile ilgili araştırmalar
Crust strength (Modulus of rupture of the soils of Iğdır district)
Yazar: MUSTAFA Y. CANBOLAT
Danışman: DOÇ. DR. İBRAHİM DEMİRALAY
Atatürk Üniversitesi / Fen Bilimleri Enstitüsü / Toprak Ana Bilim Dalı
Derece: Doktora, 1990
Konu: Ziraat = Agriculture
Dizin: Iğdır = Iğdır ; Kırılma değeri = Fracture degree ; Toprak = Soil

Özet:
Bu çalışmanın amacı, (1) Iğdır yöresi (Batı İğdır ovası) topraklarının mevcut kırılma değerlerini ve bazı toprak özellikleri ile kırılma değeri arasındaki ilişkileri tespit etmek, (2) kırılma değeri yönteminde iki yöntemsel faktörün (toprağın ezilme derecesi ve kırma kuvveti uygulama hızı) kırma değeri ölçümleri üzerine etkisini incelemek ve (3) Iğdır yöresi topraklarına organik materyal (ahır gübresi ve buğday samanı) ilave edilmesinin kırılma değeri üzerine etkisini ve aynı zamanda toprak agregat stabilitesi ile toprak briketi hacim ağırlığının organik materyal ilave edilmesinin kırılma değeri üzerindeki etkisini ne ölçüde belirlediğini tespit etmek, ve briket hacim ağırlığının belirlenmesinde kullanılabilen iki yöntemin (parafin ve hesaplama) karşılaştırılmasını da yapmaktır. Iğdır ovası deniz seviyesinden ortalama 850 m yükseklikte ve eğimi % 0-6 arasında değişen bir çöküntü alanıdır. Ovanın büyük bir kısmı alüviyal topraklarla kaplıdır. Ovada karasal iklim egemen olup, ortalama yıllık yağış 233.7 mm, ortalama yıllık sıcaklık 11.6°C, ortalama nispi nem % 62 ve ortalama yıllık buharlaşma 1094.9 mm'dir. Araştırmada, Batı Iğdır ovasında kaymak sorunu görülen arazilerden ondört adet toprak örneği (0-10 cm derinlikten) alınmış ve araştırmanın amacına göre kullanılmıştır. Toprak örneklerinin kil içeriği % 16 ile % 57, silt içeriği % 16 ile % 47, ince kum içeriği % 11 ile % 41, kaba kum içeriği %0 ile %16, organik madde içeriği %0.4 ile % 1.1, kireç içeriği % 3.2 ile % 8.4, toplam tuz içeriği % 0.02 ile % 0.24, pH 7.6 ile 8.9, katyon değişim kapasitesi 20.9 ile 41.7 me/100 g, değişebilir sodyum yüzdesi % 1.7 ile % 8, aşağı plastikii limit % 19 ile % 28, agregat stabilitesi % 19 ile % 70 arasında bulunmuştur. Toprak örneklerinin kırılma değeri (modulus of rupture), "kırılma değeri ölçüm" yöntemi ile saptanmıştır. Söz konusu örneklerin mevcut kırılma değerleri 388 ile 4146 mbar arasında bulunmuştur. Bu kırılma değerlerinin, ürün bitkilerinin toprak yüzeyine çıkışlarını olumsuz yönde etkiledikleri hem toprak örneklerinin alındığı yerlerde gözlemle hem de kaynak bilgilerle tespit edilmiştir. Toprak özellikleri ile kırılma değeri arasındaki ilişkiler araştırılmıştır. Örneklerin silt içeriği ve değişebilir sodyum yüzdesi ile kırılma değeri arasında önemli (P<0.05) pozitif ilişkiler, agregat stabilitesi (11 toprak örneğinde) ile kırılma değeri arasında önemli (p<0.01) negatif bir ilişki tespit edilmiştir. Kil, organik madde, kireç içerikleri ve katyon değişim kapasitesi ile kırılma değeri arasındaki ilişkilerin önemli olmadığı saptanmıştır. Kırılma değeri yönteminde, toprağın ezilme derecesinin kırılma değeri üzerine etkisini incelemek amacıyla ondört toprak örneğine üç farklı ezilme derecesi uygulanmış (normal, fazla, çok fazla) ve şans blokları deneme planına göre yürütülmüştür. Toprak örneklerinin ezilme derecesi arttıkça ölçülen kırılma değeri artmış ve bu etki önemli (P<0.01) olmuştur. Buradan, kırılma değerinin ölçülmesinde toprak örneklerine standart bir ezme prosedürünün uygulanması gerektiği sonucu çıkarılmıştır. Ayrıca, arazi koşullarında da toprak agregatlarmın en az parçalanmasını sağlayacak niteliklere sahip tarım alet ve makinalarının kullanılmasına ve toprağın tav neminde işlenmesine özen gösterilmesinin gerektiği, bunun özellikle kaymak sorunu olan topraklarda bir zorunluluk olduğu ortaya çıkmaktadır.İÜ Kırılma değeri yönteminde, kullanılan kırma kuvveti uygulama hızının kırılma değeri üzerine etkisini incelemek amacıyla dört toprak örneğine yedi farklı kırma kuvveti uygulama hızı (250, 500, 1000, 1500, 2000, 2500 ve 3000 ml/dak.) uygulanmış ve şans blokları deneme planına göre yürütülmüştür. Kırma küveti uygulama hızının yaklaşık 500 ile 3500 mbar arasında briket kırılma değerini etkilemediği tespit edilmiştir. Toprağa organik materyal ilave edilmesinin kırılma değeri, agregat stabilitesi ve briket hacim ağırlığı üzerine etkilerini incelemek amacıyla dört toprağa ahır gübresi (<2mm) ve öğütülmüş buğday samanı (

Abstract:
The aims of this study were (1) to determine present modulus of rupture of the soils of İğdır district, and the relations between modulus of rupture and some soil properties, (2) to study the effects of soil crushing and the application rate of the breaking force (the rate of water flow) on the measurement of modulus of rupture of the soil, and (3) to determine the effects of addition of organic materials (manure and wheat straw) on the modulus of rupture, aggregate stability of the soils, and the bulk density of the soil briquets and also to compare the two methods (paraffin and calculation) for determining bulk density of the soil briquets. The work was conducted on the furteen surface (0-10 cm) soil samples taken from the İğdır district. İğdır plain is 850 m high from the sea-level, and most of the soils are alluvial. A continental cilamte is prevailing in the region with an average annual precipitation of 233.7 mm, an average annual temperature of 11.6°C, and an average annual relative hummidity of 62 % and an average annual evaporation of 1094.9 mm. The clay content of the soil samples varies from 16 % to 57 %, silt content from 16% to 47%, fine sand content from 11% to 41%, coarse sand content from 0% to 16%, organic matter content from 0.4% to 1.1% lime content from 3.2% to 8.4%, total salt content from 0.02% to 0.24%, pH between 7.6 and 8.9, cation exchange capasity between 20.9 and 41.7 me/100 g, exchangeable sodium percent from 1.7% to 8%, lower plastic limit between 19% and 28%, aggregate stability between 19% and 70%, and modulus of rupture between 388 mbar and 414 6 mbar. It was found significant (P<0.05) positive relations betweenV11X silt content and modulus of rupture, between exchangeable sodium percent and modulus of rupture, negative relation (P<0.01) between aggregate stability and modulus of rupture and nonsignificant relations between clay content and modulus of rupture, between organic matter content and modulus of rupture, between lime content and modulus of rupture, and between cation exchange capasity and modulus of rupture. It was found that soil crushing affected modulus of rupture significantly (P<0.01). As the degree of soil crushing increased the modulus of rupture values measured increased. Here, it was concluded that a standart soil crushing procedure must be used in the method of modulus of rupture. Furthermore, in the field conditions agricultural machines and tools having minimum crushing effects on the soil must be used and the soil must be cultuvated in its tilth conditions. It is r a necessity particulary in the soils having crusting problem. To study, the effect of the application rate of the breaking force (the rate of water flow) used in the modulus of rupture measurement on the modulus of rupture value, seven different application rates (250, 500, 1000, 1500, 2000, 2500 and 3000 ml/minute) were applied, and four different the soil samples were used. It was found that the application rate of breaking force did not affected modulus of ruptures of the soil samples having approximately between 500 mbar and 3500 mbar of modulus of rupture values. To study, the effects of addition of organic material on modulus of rupture, aggregate stability and bulk density of the soil briquet manure (<2 mm) and wheat straw (<1 mm) at five levels of 0; 0.5; 1; 2; and 4 % on the basis of owen dryIX soil weight were added into four soil samples, in factorial design with three replications, and incubated for six weeks in the laboratory conditions. At the end of the incubation period modulus of rupture, aggregate stability of the experimental soils, and bulk density of the soil briquets were determined. For determining of bulk density of the soil briquet two different methods (paraffin and calculation from the size of the briquet) were used. It was found that as the level of organic material addition increased the modulus of rupture values of the soil were decreased. The treatment class effects and the interactions except one interaction of three factors were significant (P<0.01). The effect of the wheat straw was significantly more than that at the manure. In the experimental soils, it was found significant (P<0.01) negative relations between modulus of rupture and the level of organic material additions except two soils with wheat straw addition showed significant (P<0.05) relations. Although, it is desirable to recommend for the amount of organic material additions to prevent crust formation in the field conditions, it was not attemted to evaluate the subject economically since it is not known precisely the critical modulus of rupture values of the crop plants and the stuation could be very different under the field conditions. As the organic material additions increased the aggregate stability of the soils increased. The teratment class effects and the interactions except one interaction of three factors were significant (P<0.01). The effect of the wheat straw was significantly more than that of the manure.From these results, it was found that addition of organic matter affected aggregate stability adversely with modulus of rupture but at the same degree of significantly. Significant (P<0.01) positive relations were found between aggregate stability and the level organic material additions significant (P<0.01) negative relations were found between modulus of rupture and aggregate stability except two soils added wheat straw. Here, it was concluded that as the organic material addition increased the aggregate stability increased and as the result of which the modulus of rupture decreased. The two methods used for the measurement of bulk density of the soil briquet were compared by using "coupling method" and the difference between them found significant (P<0.01)r but in this thesis the bulk density values determined by paraffin method were used, as assumed more reliable than the calculation method. As the organic material additions increased the bulk density of the soil briquet decreased. The treatment class effects and the interaction of bulk density of the soil briquet x organic material level were significant. (P<0.01) and the other interactions were nonsignificant. Significant (P<0.01) negative relations were found between bulk density of the soil briquet and organic material additon levels, and between bulk density of the soil briquet and aggregate stability. These results indicate that as the organic material addition increased aggregate stability increased and as a result of which bulk density of the soil briquet decreased. Significant (P<0.01) positive relation were found between modulus of rupture and bulk density of the soil except two theXI soils added wheat straw (P<0.05). From these, it was concluded that as the organic material addition into the soil increased aggregate stability increased, as a result of which bulk density of the soil briquet decreased and finally modulus of rupture decreased. It was also concluded that in the favour of increation of aggregate stability by addition of organic material to the soil in the field condition a crusting layer having lesser resistance forms on wetting by irrigation and subsequent drying.