Cover Crops and Nitrogen Fertilization Effects on Nitrogen Soil Fractions under Corn Cultivation in a No-Tillage System

Abstract

ABSTRACT:The use of cover crops has recently increased and represents an essential practice for the sustainability of no-tillage systems in the Cerrado region. However, there is little information on the effects of nitrogen fertilization and cover crop use on nitrogen soil fractions. This study assessed changes in the N forms in soil cropped to cover crops prior to corn growing. The experiment consisted of a randomized complete block design arranged in split-plots with three replications. Cover crops were tested in the plots, and the N topdressing fertilization was assessed in the subplots. The following cover species were planted in succession to corn for eight years: Urochloa ruziziensis, Canavalia brasiliensis M. ex Benth, Cajanus cajan (L.) Millsp, and Sorghum bicolor (L.) Moench. After corn harvesting, the soil was sampled at depths of 0.00-0.10 and 0.10-0.20 m. The cover crops showed different effects at different soil depths. The soil cultivated with U. ruziziensis showed higher contents of total-N and particulate-N than the soil cultivated with C. cajan. Particulate-N was the most sensitive to changes in the soil management among the fractions of N assessed. The soil under N topdressing showed a lower content of available-N in the 0.10-0.20 m layer, which may be caused by the season in which the sampling was conducted or the greater uptake of the available-N by corn.

Cover Crops from Winter Wheat, Triticale and Peas Cultivated in Pure Stands and Mixtures - Soil and Weed Suppression Benefits

“…The studies of Romdhane et al ( 2019) have sown that total nitrogen and soil organic carbon were higher when cover crops were naturally (by frost) and/or mechanical eliminated compared to rolling and glyphosate termination treatments, while cover crop biomass was positively correlated to soil carbon and C:N ratio. Other studies shown that cover crop species showed, in general, different abilities to accumulate nitrogen fractions in the soil as a result of their chemical characteristics and the C/N ratio was the main characteristic that differentiated the abilities of cover crops to accumulate N in the soil (Veras et al, 2016).…”

Combinations of Plant Species for Rotation With Onion Crops: Effects on the Light Fraction, Carbon, and Nitrogen Contents in Granulometric Fractions of the Soil Organic Matter

“…The higher PON contents in the bulk soil of the 0-5 cm layer in T2, T4, T6, and T8 were mainly due to the decomposition of vetch and oilseed radish (T2) and velvet bean (T4, T6, T8) plants, which provided nitrogen-rich residues. Contrastingly, the higher PON contents found in the bulk soil of 0-5 cm layer in T3 and T5 may be due to the immobilization of N by the grass species used, which contain more C in their tissues, decreasing the decomposition rate of plant residues and increasing PON contents due to their slower mineralization (Veras et al, 2016;Fu et al, 2019).…”

GRAIN SORGHUM GROWN AS SECOND CROP AND INOCULATED WITH Azospirillum brasilense ASSOCIATED WITH NITROGEN FERTILIZATION

“…In this sense, many farmers do not fertilize crops and only sow on residues from previous crops (usually soybeans). This practice is based on the promotion of atmospheric N fixation by legumes, relatively speeding up N cycling given fast decomposition and mineralization of low C/N ratio residues (Veras et al, 2016). Mineralization is rapid due to the high N rates and low lignin and polyphenol contents in the residue (Abera et al, 2012).…”