Ammonium and nitrate in soil and upland rice yield as affected by cover crops and their desiccation time

Pesquisa Agropecuária Brasileira

Adriano Stephan Nascente²  Carlos Alexandre Costa Crusciol¹  Tarcísio Cobucci² 

[1] ,Embrapa Arroz e FeijãoSanto Antônio de Goiás GO

关键词: Oryza sativa;    Panicum maximum;    Urochloa brizantha;    Urochloa ruziziensis;    millet;    nitrogen;    Oryza sativa;    Panicum maximum;    Urochloa brizantha;    Urochloa ruziziensis;    milheto;    nitrogênio;   

DOI  :  10.1590/S0100-204X2012001200004

来源: SciELO

【 摘 要 】

The objective of this work was to evaluate the effect of cover crops and their desiccation times on upland rice yield and on the levels of nitrate and ammonium in a no-tillage soil. The experiment was carried out in a randomized blocks, with split plots and three replicates. Cover crops (plots) were sowed in the off-season (March 2009). In November 2009, at 30, 20, 10 and 0 days before rice sowing (split plots), herbicide was applied on the cover crops (fallow, Panicum maximum, Urochloa ruziziensis, U. brizantha and millet). Straw and soil were sampled (0 - 10 cm) at the sowing day, and after 7, 14, 21, 28 and 35 days. Straws from millet and fallow were degraded more rapidly and provided the lowest level of nitrate in the soil. Urochloa ruziziensis, U. brizantha and P. maximum produced higher amounts of dry matter, and provided the highest levels of nitrate in the soil. Millet provides the lowest nitrate/ammonium ratio and the highest upland rice yield. Desiccations carried out at 30 and 20 days before sowing had the largest levels of nitrate in the soil at the sowing date. Nitrogen content and forms in the soil are affected by cover crops and their desiccation times.

【 授权许可】

CC BY   
 All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License