In conservation tillage, fertilizer placement is designed to improve nutrient availability. Our objective was to determine the effect of tillage (no-Till and strip-Till) and P and K rate and placement on the distribution of soybean [Glycine max (L.) Merr.] roots and on water, P, and K levels in soil. A 3-yr field experiment was conducted near Urbana, IL, with soybean following corn (Zea mays L.). Rates of 0-0, 36-0, 0-168, and 36-168 kg P-K ha-1 yr-1 were applied as no-Till/broadcast (NTBC), no-Till/deep band (15 cm beneath the planted row) (NTDB), and strip-Till/deep band (STDB). Roots and soil water, P, and K levels were measured periodically at in-row (IR) and betweenrows (BR) positions at 0- to 5-, 5- to 10-, 10- to 20-, and 20- to 40-cm depths. Deep banding increased P and K soil test levels beneath the row and lowered soil surface test-values compared to broadcast applications, but had no effect on root distribution. Compared to NTBC and NTDB, STDB had a 20% increase in soil water content during the seed-fi ll period at BR within the top 10 cm of soil where greatest apparent nutrient uptake (estimated by changes in soil-Test levels) occurred. Within that zone, NTBC produced and maintained a larger root system than STDB. However, STDB had 23% greater P and 30% greater K accumulation in shoots and also greater apparent nutrient uptake and greater apparent nutrient uptake rate per unit of root surface area. The results indicate that STDB provides overall better soil conditions for P and K uptake compared to the NTBC and NTDB systems.
ASJC Scopus subject areas
- Soil Science