Deep and Shallow Banding of Phosphorus and Potassium as Alternatives to Broadcast Fertilization for No‐Till Corn

Abstract

propriate soil sampling techniques (e.g., in terms of sampling depth and location relative to crop rows or Proper P and K management for no-till crops is uncertain. Potential fertilizer bands), and inefficient fertilizer placement. problems include inappropriate extrapolation of soil test interpretations and fertilizer recommendations from conventional tillage, inap-These problems could arise because of changes in nutripropriate soil sampling techniques, and inefficient fertilizer placement. ent availability at different soil depths, soil temperature This study compared broadcast, deep-band, and planter-band P and and water relations, and root growth and distribution, K placements for no-till corn (Zea mays L.). Long-term P and K among other factors. trials were established in 1994 at five Iowa research centers and were No-till management usually leads to P and K stratifievaluated for 3 yr. Eleven short-term P-K trials were established in cation in soils. Both nutrients accumulate in the soil farmers' fields during the same period. Treatments were various P surface as a result of minimal mixing of surface-applied (0 to 56 kg P ha Ϫ1 ) and K (0 to 132 kg K ha Ϫ1 ) rates broadcast, banded fertilizers and crop residues with soil, limited vertical with the planter 5 cm beside and below the seeds, and deep-banded movement of P and K in most soils, and cycling of at the 15-to 20-cm depth before planting. Soil samples were collected nutrients from deep soil layers to shallow layers through from the 0-to 7.5-cm and 7.5-to 15-cm depths prior to planting. Soiltest P (P ST ) at the 0-to 15-cm depth ranged from very low to very nutrient uptake by roots (Shear and Moschler, 1969;high across sites; soil-test K (K ST ) ranged from optimum to very high. Griffith et al., 1977;Ketchenson, 1980;Mackay et al., There were grain yield responses to fertilization at several sites, but 1987; Karathanasis and Wells, 1990;Karlen et al., 1991). no significant differences between the P or K rates and no interactionsFurthermore, reduced P sorption and K retention by between rates and placements. Phosphorus increased yields only in soil constituents in surface layers of no-till soils (Karasoils testing very low or low, and there was no response to P placement thanasis and Wells, 1990; Guertal et al., 1991) may conat any site. Potassium increased yields in several soils that tested tribute to higher soil test values in this zone. A relative optimum or higher in K ST , and yields were higher when K was deepaccumulation of P and K near the soil surface may banded. High rates of broadcast or planter-banded K did not offset decrease nutrient availability to plants because of the the advantage of deep-banded K. Responses were better related with increased likelihood of dry conditions in this zone. High deficient rainfall in late spring and early summer than with K ST . Current soil-test P interpretations and P fertilizer recommendations based J.M. Bordoli, Fac. de Agronomía, Univ. de la Repú blica, Av. Garzó n attributed to P (Randall and Hoeft,

Yield response to fertilization strategies in no-tillage soybean, corn and common bean crops

“…Working with a clayey oxisol with high P content under no-tillage and in the same region of actual work, Sá (2004) obtained increases between 8 and 19% in the accumulated yield of two corn crops in rotation with wheat and soybean when applying P in furrows. This yield increment was far below than near 70% observed in this work (Table 8) what reinforced the possibility of larger effects of N. Nevertheless, considering other comparisons among the treatments, one could infer that the starter fertilization in the corn crop could be performed with furrowing devices, period and application ways, in agreement with Bordoli and Mallarino (1998) who studied P and with Pavinato and Ceretta (2004) who studied the ways and periods of P and K application in a succession of wheat/corn. Similarity of response between P sources evaluated could be related to extractable P level since high P contents in soil generally favor equality between the soluble sources and natural phosphates (Sousa and Lobato, 2004).…”

“…The corn dry mass at the beginning of the crop development was influenced significantly by the treatments (Table 7), with lower values occurring in the treatment without fertilizer (Table 10). But the contrast analysis, therefore, was not significant (data not shown), which disagreed with several studies that although did not find differences in corn yield, obtained significant biomass accumulation in the initial phases of the crop development when the fertilizer was applied locally (Anghinoni, 1992;Model and Anghinoni, 1992;Silva et al, 1993;Bordoli and Mallarino, 1998;Mallarino et al, 1999;Kaiser et al, 2005). The high P and medium K contents in the soil and the superficial concentrations of these nutrients, associated to the high initial moisture due to regular rainfalls occurred in the beginning of the crop development (Table 2-year 2004 and 2005), could justify the difference of this study compared to the others.…”

“…There is high root concentration (Yibirin et al, 1993) and hyphae and mycorrhiza spores (Kabir et al, 1998) in the first centimeters in the superficial layer in no-tillage systems which increases the possibility of absorption of nutrients applied or accumulated in this layer. In no-tillage, the superficial nutrient application has propitiated similar yields to the furrow application in several crops (Oliveira et al, 1992, Kochhann et al, 1998Bordoli and Mallarino, 1998;Borges and Mallarino 2000;Heckman and Kamprath, 1992;Sguario Jr., 2000, Howard et al, 2002 or even superior (Buah et al, 2000), but can vary acording to crop (Pöttker, 1999). This long period study aimed to evaluate the effect of strategies in the starter fertilizer application on grain yield and its components in corn, soybeans and common beans in rotation and no-tillage system.…”

Phosphorus and root distribution and corn growth as related to long-term tillage systems and fertilizer placement

“…It is also expected that when the fertilizer is mixed with an intermediate soil volume (between that of row-application and broadcast treatment methods), and when the fertilizer is incorporated into the soil, the resulting corn grain yields are higher (Barber, 1995;Brown, 1996). However, fertilizer treatment can be less important when a soil already contains adequate P levels for crop growth and production (Bordoli & Mallarino, 1998). An evaluation of the root system is therefore an important characteristic, since root distribution reveals the effects of tillage on the soil physical and chemical conditions.…”

Speciation of Phosphorus in a Fertilized, Reduced‐Till Soil System: In‐Field Treatment Incubation Study

“…Phosphorus stratified at the soil surface may support plant root growth under moist conditions at initial stages of plant growth; however, roots explore deep soil layers for nutrients and moisture as surface soil dries in summer, so plants may suffer from low nutrient availability. Bordoli and Mallarino (1998) suggested that deep placement of nutrients (below the first 5-10 cm of the soil) may be superior to other placements such as broadcast when nutrient stratification and topsoil moisture deficits reduce nutrient uptake from shallow soil layers, but inconsistent results have been obtained from research conducted to study the effects of tillage and deeper placement of P fertilizers on grain yields of crops grown in Kansas soil with P stratification (Schwab et al, 2006). We hypothesized that in a reduced-tillage system, P placement-broadcast vs. deepbanding-can have significant influence on P fertilizer reaction products.…”