Profiles of tetracycline resistance genes in paddy soils with three different organic fertilizer applications.

The rapid expansion of organic rice cultivation areas have been accompanied by increased application of organic fertilizers. The high prevalence of soil antibiotic resistance caused by organic fertilizer application poses a severe threat to the agricultural and soil ecosystems. To date, research efforts and understanding of the effects and mechanism of action of the various organic fertilizers on antibiotic resistance in paddy soils remain poorly investigated.

[Effects of wheat-straw returning into paddy soil on dissolved organic carbon contents and rice grain yield].

A tank experiment using conventional rice cultivar Nanjing 44 as experimental material was conducted at the Experimental Farm of Yangzhou University to investigate the dynamics of wheat straw decomposition rate and the amount of carbon release in clay and sandy soils, as well as its effects on the content of dissolved organic carbon (DOC) and rice yield. The two rates of wheat straw returning were 0 and 6000 kg · hm(-2), and three N application levels were 0, 225, 300 kg · hm(-2). The results showed that, the rate of wheat straw decomposition and the amount of carbon release in clay and sandy soils were highest during the initial 30 days after wheat straw returning, and then slowed down after, which could be promoted by a higher level of nitrogen application.