Physicochemical Properties of Silt Loamy Soil and Diversity of Diatom Species Under Winter Wheat and Oats

The aim of the research was to investigate the soil properties and the species diversity of diatoms growing in different agricultural fields with silt loamy soil. The field experiment was conducted in 2014 in Kosina, near Łańcut (SE Poland), at three sites (indicated as fields K1, K2, K3) with different soil environmental conditions and plants. The growth of winter wheat Triticum aestivum (cv. Bogatka) in fields K1 and K2 and oats Avena Sativa (cv. Haker) in field K3 under different soil management were studied. The soil samples were collected from the top layers (0–5 cm depth) each month, from April to December. Certain physical and chemical parameters of soil were measured. The pH of soil was acidic and slightly acidic in fields K1 (5.0–5.4), K2 (4.9–5.9) and K3 (4.5–5.1). The soil in field K3 had a significantly greater content of organic matter (1.06–1.30%) and water content (12.9–33.8%, v/v) than fields K1 and K2. A total of 91 diatom taxa were found. The diversity was greatest in field K2 (71 taxa), lower in K1 (54 taxa) and K3 (24 taxa). In K1, the most numerous species were Luticola D.G. Mann cf. mutica, Mayamaea atomus var. permitis (Hust.) Lange-Bertalot, and Stauroneis thermicola (Petersen) Lund, with more than a 20% share in the assemblage. In K2, very abundant assemblages were formed by Mayamaea atomus (Kütz.) Lange Bertalot, Mayamaea atomus var. permitis (Hust.) Lange-Bertalot, and Stauroneis thermicola (Petersen) Lund with a 25 to 50% share in the total diatom community. In K3, with oat cultivation, a different diatom species structure was found. Here, the most abundant were Halamphora montana (Krasske) Levkov, Hantzchia amphioxys (Ehrenb.) Grunow, Mayamaea atomus (Kütz.) Lange-Bertalot, and Nitzschia pusilla Grunow, which attained a share in the assemblage exceeding than 20%. The effects of different soil management regimes under different plants on the physical and chemical properties of the soil, and on the diversity of diatoms, were significant (P<0.05). Soil water and organic matter content affects the yield of winter wheat and oats. Significant effects of water content and pH of silt loamy soil on the growth and the diversity of species of diatoms were found.