Sampling Layer for Soil Fertility Evaluation in Long-Term No-Tillage Systems

Abstract

ABSTRACT:In no-tillage (NT) systems, there is no plowed layer since the soil is not tilled. Thus, the soil layer for fertility evaluation can be defined as the one in which the fertility indices are affected by the surface application of lime and fertilizers and soil properties have the closest relationship with crop yields. The objective of this study was to determine the most appropriate soil layer under long-term NT for sampling for fertility evaluation in the South-Central region of Paraná, Brazil. A total of 99 field experiments of crop rotations were performed, including soybean, corn, barley, wheat, and white oat, all on Oxisols (Hapludox). Despite the surface application, lime and fertilizers increased base saturation (V) and available K to a depth of 0.20 m. The relationship with crop yields was high for V and low for available K for both soil layers (0.00-0.10 and 0.00-0.20 m); for P, however, the relationships with soybean and corn yields were strongest in the 0.00-0.20 m layer. Thus, considering the soil layer fertilized by the surface application of lime and potassium fertilizers and the highest relationship of soil P contents with the yield of the main crops of the crop rotation, the 0.00-0.20 m layer is the most appropriate for soil fertility evaluation under long-term no-tillage systems.

Soil sampling depth effect on critical soil test values of phosphorus for conservation agriculture

“…The results obtained in Piedmont show that the CSTV for corn is higher than for soybeans. Similar results were also observed by Morales et al (2023) in North Carolina, and by Vieira et al (2015;2016) in South Brazil. Moreover, the effect of crop productivity on CSTV is confirmed by Tidewater results, where there was an increase of about 25% in CSTV for the 2022 corn (103 lb ac -1 ) compared to the 2021 corn (84 lb ac −1 ).…”

“…(2023) in North Carolina, and by Vieira et al. (2015; 2016) in South Brazil. Moreover, the effect of crop productivity on CSTV is confirmed by Tidewater results, where there was an increase of about 25% in CSTV for the 2022 corn (103 lb ac ‐1 ) compared to the 2021 corn (84 lb ac −1 ).…”

“…In South Brazil, Vieira et al. (2016) found that after ∼10 years under NT there was a better prediction of CSTV using the 0–8 inches layer compared to 0–4 inches. This contrast with our results in the Piedmont where fields had been managed for more than 21 years in NT and the relationship between crop yield and STP using the 0–4 inches layer compared to the 0–8 inches layer were very similar.…”

Tillage systems and cover crops affecting soil phosphorus bioavailability in Brazilian Cerrado Oxisols

“…The 0-5 and 5-10 cm results were averaged over 10 cm as they showed similar behaviour, similar to previous studies evaluating the effects of tillage system in soils (Rodrigues et al, 2016;Vieira et al, 2016). However, other studies evaluating the effect of cover crops on P availability have reported higher P accumulation in the 0-5 cm depth, with small or no influence in deeper layers (Soltangheisi et al, 2017;Tiecher et al, 2012aTiecher et al, , 2012b.…”

Legacy phosphorus in Brazilian agriculture and cover crops contribution to enhance this nutrient bioavailability in tropical Oxisols

“…The 0-5 and 5-10 cm results were averaged over 10 cm as they showed similar behaviour, similar to previous studies evaluating the effects of tillage systems in tropical soils Vieira et al, 2016). However, other studies evaluating the effects of cover crops on P availability have reported higher P accumulation in the 0-5 cm depth, with small or no influence in deeper layers (Soltangheisi et al, 2017;Tiecher et al, , 2012b).…”