Cropping System, Landscape Position, and Topsoil Depth Affect Soil Fertility and Nutrient Buffering
2018
Conway, Lance S. | Yost, Matt A. | Kitchen, Newell R. | Sudduth, Kenneth A. | Veum, Kristen S.
Core Ideas Depth to claypan, landscape position, and cropping system influence soil fertility and nutrient buffering. Accounting for landscape‐variable depth to claypan could improve P and K management. Cover crops can help increase soil organic matter content. Cover crops may help reduce P requirements on claypan soils. Precise nutrient management across claypan soil landscapes requires an understanding of how diversity in management practices impacts soil properties and nutrient buffering. Therefore, a study was performed at the Central Mississippi River Basin site of the USDA Long‐Term Agroecosystem Network from 2010 to 2016 to determine how depth to claypan (DTC), cropping system (CS), and landscape position (LP) affect soil properties, and whether accounting for these factors could improve fertility management. Treatments consisted of five CS {MTCS, mulch till corn (Zea mays L.)–soybean [Glycine max (L.) Merr.]; NTCS, no‐till corn–soybean; NTCSW, no‐till corn–soybean–wheat (Triticum aestivum L.)–cover crop; CCRP, cool season conservation reserve program; and HAY, cool and warm‐season hay} and three LP (summit, backslope, and footslope), each with a distinct DTC. Soil test P (STP) was 9 kg P ha–¹ greater on footslopes than summits. Soil test K (STK) and soil organic matter content (SOM) were greatest on backslopes and averaged 384 kg K ha–¹ and 20 g kg–¹, respectively, Soil test P was ≥49% and STK was ≥10% lower in NTCSW than in MTCS or NTCS. However, crop diversity in NTCSW maintained STP and increased SOM 2 g kg–¹ over MTCS. Soil test P, pHₛ, and SOM were similar between CCRP and HAY, while STK in CCRP was greater at all LP. Lastly, deeper DTC caused greater P buffering and less K buffering than shallower DTC. These results indicate that eroded sideslopes with shallow DTC likely need more or more frequent P and less K than other LP.
显示更多 [+] 显示较少 [-]