Soil sampling depth impact on phosphorus yield response prediction in winter wheat

Abstract

Nutrient stratification of no-till managed soil can affect soil test analysis levels of plant-available phosphorus (P). Research has suggested sampling to different depths due to soil acidity, but little work has been conducted to investigate any change to sampling recommendations for immobile nutrients. The objective of this study was to determine the soil sampling depth that had the greatest relationship with yield response to fertilizer-P. The depths sampled in this study were 0-5, 0-10, 0-15, 10-30, 5-10, 5-15, 10-15, and 15-30 cm. The results indicated that the top 15 cm of a soil profile had the greatest amount of Mehlich 3 extractable P (M3P) available and that the 5-to-10 and 5-to-15-cm depths had the highest correlation with relative yield. Soil depths outside of the proposed root zone of winter wheat (Triticum aestivum L.) (15-30 cm) had the lowest correlation with yield response. INTRODUCTIONNutrient stratification can affect soil test analysis levels of plant-available phosphorus (P). Increased nutrient stratification occurs in areas where no-till managed soils are not constantly being inverted by tillage practices. Stratification of nutrients has been well documented in notill scenarios (Hansel et al., 2017;Howard et al., 1999;Souza, 2020;Wright et al., 2007). This begs researchers to question if altering current soil sampling strategies could lead to more accurate representation of plant-available nutrients.Research has suggested different depths for sampling for soil acidity for more accurate liming recommendations. Reeves and Liebig (2016) suggested a depth of 7.6 cm for soil pH, as most acidification due to fertilizer inputs occurs Abbreviations: M3P, Mehlich 3 extractable phosphorus.

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

“…The use of isolated deeper soil layers (2-4, 2-8, 2-12, 4-8, 4-12, and 8-12 inches) did not improve the diagnosis of P availability at either site. These results contrast with those obtained by Reed et al (2022) and Bellinaso et al (2021). Bellinaso et al (2021) found that soybean yield was more related to the STP in the 4-8 and 8-12 inches layers than in the 0-4 inches layer.…”

“…In this sense, Bellinaso et al (2021) demonstrated that the STP in the 4-8 and 4-6 inches layers have a better correlation with crop productivity than the 0-4 inches layer. Similarly, Reed et al (2022) found that using the 2-4 and 2-6 inches soil layer provided the highest correlation with P yield response for wheat in Oklahoma, and the depths that did not include the 0-2 inches layer were similar or more correlated to P yield response than depths including the 0-2 inches depth. Thus, the objective of the present study was to evaluate the CSTV of P for corn and soybean in different soil layers in two long-term experiments (37 and 56 years) with increasing rates of phosphate fertilizer in North Carolina.…”

“…Similarly, Reed et al. (2022) found that using the 2–4 and 2–6 inches soil layer provided the highest correlation with P yield response for wheat in Oklahoma, and the depths that did not include the 0–2 inches layer were similar or more correlated to P yield response than depths including the 0–2 inches depth.…”