Occasional soil tillage, liming, and nitrogen fertilization on long-term no-tillage system

Abstract

The objective of this work was to evaluate the residual effects of occasional soil tillage in a 17-year-old, no-tillage system, associated with liming and nitrogen fertilization, on the crop yields and chemical properties of a very clayey Oxisol in the South of Brazil. A randomized complete block design in split-split plots was used, with two soil managements (with or without plowing), two liming treatments (with or without the required dose to raise base saturation to 70%), five N doses applied on side-dress (0, 1, 2, 4, and 6 times the recommended amounts), and four replicates. A rotation system was used with corn and soybean in the summer, and with wheat and black oats in the winter. The residual effects of occasional soil tillage in a consolidated no-tillage system do not supplant those of liming applied on soil surface, in periods of water deficit, which subsidizes the recommendation to maintain the system consolidated. Excess N fertilization in no-tillage, with liming applied only on soil surface, may harm wheat yield, acidifying the topsoil and leaching Mg2+ to the subsurface soil layers. Without liming, soil acidification is more intense with N fertilization, which, however, favors the accumulation of organic matter on soil surface in a consolidated no-tillage system.

Short-Term Effects of Tillage Systems, Fertilization, and Cropping Patterns on Soil Chemical Properties and Maize Yields in a Loamy Sand Soil in Southern Mozambique

“…Accordingly, CA in combination with fertilization (fertilized = 5.92 and unfertilized = 5.95) increased pH levels compared to CT in combination with fertilization (fertilized = 5.46 and unfertilized = 5.44). These findings agree with other studies [29], namely a significant influence by the tillage system in combination with N fertilization on pH, where higher values were recorded under CA than CT.…”

“…The findings corroborate with those of other investigators [31,32], who reported a significant influence on OC by the interaction of the tillage system and N fertilization. A decrease in organic matter under CT and N fertilization interaction was also reported [29].…”