Soil and crop response to phosphorus and potassium management under conservation tillage

Abstract

In conservation tillage systems, proper fertilizer phosphorus (P) and potassium (K) management is critical to optimize yield and minimize negative environmental impacts. The objective of this study was to assess the responses of crop yield, nutrient use efficiencies, root growth, and soil test P and K levels to tillage, fertilizer placement, and fertilizer rates in a corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] rotation.Experiments were conducted for 8 yr in Illinois with tillage/fertilizer placement as the main plot (no-till/broadcast [NTBC], strip-till/broadcast [STBC], and strip-till/deep band [STDB]) and PK fertilizer rates as the subplot. The NTBC treatment consistently reduced yields in corn by 6.2 and 4.5% and in soybean by 3.1 and 6.1% relative to STBC and STDB, respectively. Also, NTBC had greater root length density at inrow and between-row positions relative to STBC and STDB. Nutrient use efficiency indices (partial nutrient balance, agronomic efficiency, and partial factor productivity) declined with increasing P and K rates but were not affected by tillage/fertilizer placement treatments. Deep banding significantly reduced soil P and K concentrations in surface layers while increasing them at the depth of application. These results underscore the reported potential for deep banding combined with strip-till to improve conditions for nutrient uptake while reducing the risk for nutrient losses to the environment. Critical soil test P and K levels (21 mg P kg −1 and 217 mg K kg −1 ) were similar for P and greater for K than the current university recommendations, which highlights the need for continuous refinement of soil fertility recommendations to keep pace with changes in production technologies and yield levels.

Soil Properties after Eight Years of the Use of Strip-Till One-Pass Technology

“…Additionally, the content of available nutrients in soil increased: phosphorus by 17.4% and 12.0%, potassium by 10.4% and 8.5%, magnesium by 10.8% and 3.3%, respectively. Yuan et al [54] stress that strip-tilling with a deep strip application of fertilizers, technology similar to that applied in our research, increases the use and effectiveness of nutrients, decreases losses, and limits the risk of environmental pollution.…”

Can Banding Reduce Phosphorus Rates and Environmental Losses?

“…Fabian Fernández, University of Minnesota associate professor of soil, water, and climate, also recently studied P banding in depth. His recent central Illinois study also found no agronomic efficiencies to deep‐banding P (Yuan et al., 2020). His eight‐year research used three farmers’ fields with six replications of each tillage × fertilizer rate × fertilizer placement treatment.…”

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

“…For this reason, it is common to find reports where P applied by in-furrow, deep banding, or incorporation resulted in greater crop yields when compared to P applied on the soil surface (broadcast) (Yuan et al, 2020). The opposite, i.e., higher crop yields with broadcast application compared to other P application methods (e.g., banded, incorporated by plowing), is not as common and only occurs in very specific conditions (Oliveira et al, 2022).…”