Illinois
Fertilizer Conference Proceedings
January 29-31, 1996
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Kevin L. Barber1
Concern over soil and water conservation has resulted in many producers shifting from traditional methods of tillage to the no-tillage system. The common practice of applying phosphorus (P) and potassium (K) fertilizer to the surface of soils under no-till management causes stratification of P and K in the topsoil. Also, adoption of the no-tillage system results in the accumulation of crop residues on the soil surface. A modification of the no-tillage system may involve residue removal from the row area alone or in combination with cultivation of a narrow strip of the row area. The cultivation of the row area is known as strip or zone tillage.
Residue serves as an insulating barrier thereby affecting soil temperature and water. In South Africa, soil temperature increased and soil water content decreased as residue-free bands were increased from 0 to 12 inches (Berry and Mallett, 1989). Fortin (1993) observed that soil temperature in a 12 inch residue-free band was similar to that in conventionally tilled soil. In the same study, interrow soil water content was higher with in-row residue removal than with conventional tillage. Fortin (1993) concluded that in-row residue removal provided a row environment similar to that provided by conventional tillage and an interrow environment better suited for conserving soil water than conventional tillage systems. By preparing strip-tilled rows in the fall, the soil in these rows may dry and warm in the spring allowing for timely planting and faster corn development as compared to that under no-tillage management. Because southcentral Illinois has large areas of soils that are poorly drained, the soils are often cool and wet during the spring. Hence, strip tillage appears to be well suited to the area.
Soil fertility researchers have not examined the response of corn grown in
strip-tilled rows to method of fertilizer application. Injecting a band of fertilizer
while performing strip tillage before planting may allow optimal conditions
for corn growth and development. The objective of this study is to assess the
effects of fall versus spring and broadcast versus banded applications of fertilizer
P and K and strip tillage on the growth, P and K uptake, and grain yield of
corn.
This experiment was initiated in the fall of 1994 at the Brownstown Agronomy Research Center on a field previously in corn under no-tillage management. The soil is a Cisne silt loam (fine, montmorillonitic, mesic Mollic Albaqualfs) with a nearly level slope. Cisne soil is poorly drained due to its very slowly permeable subsoil. Chemical characteristics of the surface six inches of soil were a pH of 6.2, organic matter content of 1.846, available P content of 65 lb/acre, and exchangeable K content of 241 lb/acre.
A randomized complete block design with four replications was used. Individual plots were 20 ft wide by 70 ft long. Tillage treatments included no-till and fall and spring strip tillage. Fertilizer P and K treatments were none, surface broadcast in the fall, and fall and spring injection. Strip tillage was accomplished with a gang of three Rawson coulters. The gang of coulters tilled a twelve-inch wide band of soil to a depth of three to four inches. The granular fertilizer materials 0-44-0 and 0-0-60 were used to provide 46 lb P2O5/a and 24 lb K2O/a, respectively. Appropriate amounts of the fertilizer materials were mixed and either broadcast by hand or injected on 30-inch spacings at a depth of 4 inches through knives behind ripple coulters. The P and K mixture was delivered to the knives by a Gandy Orbit-Air pneumatic applicator. For the appropriate treatments, banded applications of fertilizer P and K were injected at the same time that strip tillage was performed.
The fall treatments were applied on 8 November 1994. All vegetation was killed with a burndown application of Roundup and 2,4-D on 24 May 1995. The spring treatments were subsequently applied on June 12. Pioneer Brand 3317 was planted in 30-inch row spacings at 30,800 seeds/acre on June 14. The seed was placed into the previously prepared strip-tilled rows as well as into the no-till plots using a no-till planter. All plots received a sidedressed application of anhydrous ammonia at a rate of 150 lb N/a on July 13.
Soil temperature was measured at a depth of two inches in the seed row from
planting until the V6 (six fully expanded leaves) growth stage. Temperature
was measured twice a week between 3:00 and 5:00 p. m. Emergence of the corn
seedlings was determined every other day from beginning of emergence until no
newly emerged plants were observed. Aboveground tissue of five whole plants
was collected at random from each plot at the V6, VT (tasseling), and R6 (physiological
maturity) growth stages. The tissue was dried, weighed, ground, and analyzed
for total P and K. Grain moisture content and yield were determined by machine
harvesting 210 ft (3 rows by 70 ft) of plot on Oct. 23. Grain yields were adjusted
to 15.5 % moisture.
Differences in soil temperature among the tillage and fertilizer treatments were only observed at 23 days after planting (Table 1). On this date, soil temperature in the row was 2.9 to 3.6 °F higher in the strip tillage/fall broadcast treatment than in all of the no-tillage treatments. Emergence of the corn seedlings was similar among the treatments (Table 1). The lack of treatment effects on soil temperature and plant emergence were probably due to high soil temperatures at planting. About 11 inches of rain were received at the Brownstown Center during the month of May. Hence, planting was delayed until the second week of June. Soil temperatures had already reached 80 °F when the corn was planted. At soil temperatures this high, one would not expect treatment effects on soil temperature and early plant development to vary widely.
Tillage and fertilizer effects on dry-matter accumulation and P and K uptake
at three growth stages are reported in Table
2. No significant differences in dry-matter accumulation or P and K uptake
were observed at V6 or R6. At tasseling (VT), however, corn subject to the no-till/no
P and K fertilization and strip tillage/spring banded fertilizer treatments
had significantly higher aboveground dry-matter accumulation and P and K uptake
than corn subject to the strip tillage treatments of no applied fertilizer and
fall broadcast and banded fertilizer. Because the measure of P and K uptake
is the product of P and K concentration of the plant, respectively, and the
dry matter accumulated by the plant, the observed differences could be due to
one or a combination of these components. Indeed, the noted differences were
associated with biomass accumulation and not to the P or K concentration of
the plant, because no variations in these components were noted among the various
treatments (data not shown). Grain yield did not vary among the tillage/fertilizer
treatments (Table 2); however, grain production
was highest for the strip tillage/spring banded fertilizer treatment and lowest
for the no-till/fall banded fertilizer treatment.
Results from the first year of this study showed few significant differences
in soil temperature, aboveground dry-matter accumulation, and P and K uptake.
Planting corn in strip-tilled rows, regardless of method of fertilizer application,
offered no early growth or grain yield advantages as compared to corn grown
under no-tillage management. This study will be continued in 1996.
Table 1: Effect of tillage and fertilizer treatment on soil temperature and plant emergence, 1995
1Senior Research Specialist, University of Illinois, Brownstown Agronomy Research Center, Brownstown, IL.
Berry, W.A.J., and J.B. Mallett. 1989. The effect of removing maize surface residue from the seed-row on seedzone temperature, soil water and maize development. South Mr. J. Plant Soil 6:108-112.
Fortin, M.-C. 1993. Soil temperature, soil water, and no-till corn development following in-row residue removal. Agron. J. 85:571-576.
