Abstract. Soil compaction is a common problem of mineral soils under conventional tillage practices. Organic matter addition is an efficient way of reducing the effects of field traffic in soil compaction. The aim of this study was to investigate the effects of number of tractor passes (one, three, and five) on depth-dependent (0-10 and 10-20 cm) penetration resistance, bulk density, and porosity of clay-textured soil (Typic Xerofluvent) under organic vegetable cultivation practices in the 2010-2013 growing seasons. Fields were treated with farmyard manure (FYM, 35 t ha −1 ), green manure (GM; common vetch, Vicia sativa L.), and conventional tillage (CT). The number of tractor passes resulted in increases in bulk density and penetration resistance (CT > GM > FYM), whereas the volume of total and macropores decreased. The maximum penetration resistance (3.60 MPa) was recorded in the CT treatment with five passes at 0-10 cm depth, whereas the minimum (1.64 MPa) was observed for the FYM treatment with one pass at 10-20 cm depth. The highest bulk density was determined as 1.61 g cm −3 for the CT treatment with five passes at 10-20 cm depth; the smallest value was 1.25 g cm −3 in the FYM treatment with only one pass at 0-10 cm depth. The highest total and macropore volumes were determined as 0.53 and 0.16 cm 3 cm −3 respectively at 0-10 cm depth for the FYM treatment with one pass. The volume of micropores (0.38 cm 3 cm −3 ) was higher at 0-10 cm depth for the FYM treatment with three passes. It can be concluded that organic pre-composted organic amendment rather than green manure is likely to be more efficient in mitigating compaction problems in soil.

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Öz: Agregat oluşumu ve stabilitesi; toprak yönetimine ilişkin kültivasyon uygulamaları ve bitkisel üretim farklılıklarından güçlü bir şekilde etkilenmektedir. Bu çalışmada; farklı bitki örtüsü koşullarının (elma bahçesi ve bağ) toprakların agregasyon yüzdelerinde nasıl bir değişim gösterdiği araştırılmıştır. Elma bahçesi ve bağdan (0-10, 10-20 cm) alınan toprak örnekleri farklı agregat boyutlarına (8-4, 4-2, 2-1, <1 mm) ayrılarak söz konusu toprakların agregasyon yüzdeleri belirlenmiştir. Agregasyon yüzdesi her bir derinlikte bitki örtüsüne bağlı değişim göstermekte olup bu değişim istatistiksel olarak önemli bulunmuştur (P<0.01). Agregasyon yüzdesi bitki türüne bakılmaksızın en yüksek 0-10 cm derinliğinde (62.32 (elma bahçesi), 61.14 (bağ)) belirlenmiştir. Agregat boyutlarındaki agregasyon %59.44 (2-1 mm)-%63.78 (8-4 mm) arasında değişim göstermiş olup elma bahçesinin agregasyon yüzdeleri bağa göre daha yüksek bulunmuştur. Sonuç olarak, bitki türü organik madde birikimini etkilediği için toprakların agregasyonlarını değiştirebilmektedir.

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This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record.

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Pot capacity (PC) is defined as optimum moisture level of the pot-soil for irrigation in greenhouse experiments, is not same field capacity (FC) defined for field conditions. In this study, vermicompost was applied to different levels (0%, 0.75%, 1.5%, 2.25% w/w) for a sandy loam soil. Pepper was grown in greenhouse conditions. The irrigations were carried out at the levels of 80% PC and FC. Yield and some yield components were determined after 70 days from sowing. Effects of vermicompost were also, investigated on soil field capacity, wilting point and dispersion ratio. The differences found for plant height, weight, root weight, yield, leaf chlorophyll content were statistically significant. In addition, vermicompost applications provided to reduction of dispersion ratio.