Row-placed fertilizer for maize grown with an in-row crop
residue management system in southern Wisconsin
R.P. Wolkowski
*Department of Soil Science, University of Wisconsin±Madison, Madison, WI 53706-1299, USA
Received 11 May 1999; received in revised form 23 November 1999; accepted 2 December 1999
Abstract
Re®nements of high residue cropping practices are needed to provide crop producers viable systems that are both economically and environmentally sound. Several tillage treatments in combination with row-placed fertilizer were evaluated in a 3 year study on maize (Zea maysL.) on a Luvic Phaeozem in southern Wisconsin, USA. Tillage treatments included fall chisel, fall and spring in-row residue management (I-RRM) using planter mounted ®nger coulters, and no-till. Row fertilizer treatments consisting of none, fall surface strip, fall subsurface band, and subsurface band at planting were superimposed over tillage treatments. Early season in-row soil temperatures in the fall I-RRM treatment were usually similar to those found in the chisel system and were typically 3±58warmer than those under no-till. The gravimetric water content of the no-till treatment was 20±40 g kgÿ1
higher than those of the chisel and fall I-RRM, which were usually similar. In-row residue management resulted in residue levels of about 30±50% in the row and 80±90% in the inter-row. Residue in chisel and no-till were relatively uniform across the row, averaging 26 and 89%, respectively. Early season crop growth and silking progress were signi®cantly delayed in no-till and were only slightly reduced in the I-RRM treatments when compared to chisel. Grain yield averaged over 3 years was not signi®cantly affected by tillage treatment; however, fall I-RRM was 0.4 Mg haÿ1
higher than spring I-RRM in the ®rst year. Row fertilizer at planting increased in early mass and silking progressed 50% in the second year. When averaged over 3 years, row fertilizer reduced grain water content 10 g kgÿ1
and increased yield 0.5 Mg haÿ1
when compared to the control. A signi®cant interactive effect showed a positive grain yield response to row fertilizer in all tillage treatments except chisel. This research demonstrates that I-RRM, in combination with row fertilizer, offers a high residue alternative to full-width tillage in regions with limited growing season.#2000 Elsevier Science B.V. All rights reserved.
Keywords:Zone tillage; Row clearing; Starter fertilizer; Conservation tillage;Zea maysL.
1. Introduction
The rate of adoption of no-till maize (Zea maysL.) production in the northern Corn Belt of the USA has slowed, presumably because of grower dissatisfaction with performance compared with that of plowing
(Conservation Technology Information Center, 1998). The cooler and wetter spring soil caused by large amounts of surface crop residue have been well documented (Moncrief, 1981; Johnson and Lowery, 1985; Potter et al., 1985). These conditions not only result in slower emergence and growth, but also may affect the stand because of poor planting slot closure. Residue management practices that move residue from the row area have been shown to hasten early
*Tel.:1-608-2633913; fax:1-608-2652595.
E-mail address: [email protected] (R.P. Wolkowski).
season crop development (Kaspar et al., 1990) and reduce the risk of poor stands (Kaspar and Erbach, 1998). Equipment manufacturers have responded to the need to balance productivity with conservation goals by developing many different attachments, which either mount on the planter or on a separate tool bar. These are designed to clear residue from the row area, and in some cases, perform tillage to some depth at varying levels of intensity. Common names for these practices include strip tillage, zone tillage, and row clearing. For the purposes of this paper, this practice will be referred to as in-row residue manage-ment (I-RRM).
Interest in I-RRM has increased dramatically in the last several years. Several studies have reported suc-cess with aggressive in-row tillage on Ontario soils (Raimbault et al., 1991; Janovicek et al., 1997; Opoku et al., 1997). These researchers found drier soil and higher maize dry matter or grain yield following rye (Secale cerealeL.) and red clover (Trifolium pratense
L.). Kaspar et al. (1990) found a positive relationship between the width of a residue free band around the row and maize yield, demonstrating the limitation of surface cover on productivity. However, other researchers (Hallauer and Colvin, 1985) have noted that in-row tillage does not always increase yield over no-till. These authors indicated that there was greater nitrogen (N) stress and maize rootworm (Diabrotica
sp.) feeding damage in the higher residue environment found in the strip- and no-till treatments compared with those found where plowed.
Many producers have opted to omit the use of row-placed fertilizer at planting because of the time needed to ®ll planter-mounted fertilizer boxes and the fact that many ®elds have very high soil test levels. Rehm et al. (1990) and Bundy and Widen (1991) demonstrated the value of row-placed fertilizer in ridge- and no-till systems, respectively, suggesting that there is an increased potential for row-placed fertilizer response in high residue systems. It is not clear if maize grown with I-RRM responds to row-placed fertilizer as these researchers have shown for no- and ridge-till systems. Fertilizer banding while conducting I-RRM prior to planting may replace the need to use row fertilizer at planting, thereby improving the ef®ciency of both tillage and planting operations.
Currently there is very little information available to evaluate row fertilizer placement in I-RRM
sys-tems. This study was conducted to examine the bene®t of row-placed fertilizers on the growth, development, nutrient uptake, and yield of maize grown in I-RRM and other tillage systems.
2. Materials and methods
2.1. Experimental site
Field plots were established on a Luvic Phaeozem near Arlington, WI, USA in fall 1993. The site had been in continuous maize production for the previous 10 seasons and had been no-tilled for the three seasons prior to the initiation of the study. Initial soil test results for the site were water pH 5.6, organic matter (loss on ignition) 3.9 g kgÿ1
, Bray P1phosphorus (P)
48 mg kgÿ1
, and exchangeable potassium (K) 167 mg kgÿ1
. The soil test P and K levels are both considered excessively high for maize production on this soil in Wisconsin (Kelling et al., 1998). Tillage (no-till, fall I-RRM, spring I-RRM, and chisel) was the main plot treatment, while row fertilizer (none, fall surface band, fall inject, or planting 55) was the subplot treatment. The 55 treatment was placed
5 cm to the side and 5 cm below the seed. The fall treatments were either dribbled on the surface or injected 5 cm deep in the future row area. Individual plot size was 10.5 m by 3 m with a row spacing of 76 cm (four rows). All measurements were taken from the middle two rows of each plot. Treatments were replicated four times in a split-plot treatment arrange-ment and were conducted on the same plots for the 3 years of the study.
2.2. Treatment application
Stalks were chopped following maize harvest each fall, and I-RRM was performed on appropriate plots with Yetter ``Residue Manager'' coulters (Yetter Man-ufacturing, Colchester, IL, USA)1attached to a Kinze planter (Kinze Manufacturing, Williamsburg, IA, USA). A zone, 20±25 cm wide, was cleared with the intention of disturbing no more than 1±2 cm of
soil. Fall chisel plowing to a depth of 20 cm was also done at this time. The chisel system utilized twisted shovels and the soil was disked twice to a depth of 10 cm just prior to planting. The spring I-RRM treat-ment was conducted at planting using the same equip-ment and settings that were used in the fall treatequip-ment. The surface soil water content was approximately 250 g kgÿ1
when tilled. Fluid row fertilizer was applied at a total rate of 10138 kg NPK haÿ1
in 1994 and 8107 kg NPK haÿ1
in 1995 and 1996 using the fertilizer attachment on the maize planter. All plots received a sidedress application of 202 kg haÿ1
N as urea±ammonium nitrate solution.
2.3. Measurements
Soil temperature and water content data were col-lected weekly in the row area beginning in mid-April between 16:00 and 17:00 h when temperature differ-ences between tillage treatments would be greatest at depths of 5±10 cm from the no-till, fall zone, and chisel main plots using a digital pyrometer (Barn-stead-Thermolyne, Dubuque, IA, USA). Readings were also taken from the spring I-RRM treatment after planting in 1996. Three temperature readings were taken and averaged from each depth from all replications. Water content was determined gravime-trically from three 10 cm soil cores taken with a 1.5 cm probe from the area where temperature mea-surements were made.
Maize (Pioneer Brand `3578', RM 104 d) was planted 23 April, and 2 and 13 May, in 1994±1996, respectively, at a rate to establish a ®nal population of 74 100 plants haÿ1
. Three separate crop residue mea-surements were taken and averaged from individual
plots within 2 weeks after planting with a pin-type apparatus. This device centered 20 pins in a transect over the row on a 4 cm spacing to determine the horizontal distribution of residue over the row. Emer-gence counts were taken each year approximately 2±3 weeks after planting with all visible plants counted in 2 m of row. Final population counts were taken from 10 m of row just prior to canopy closure. Five plants were randomly collected for nutrient analysis at the V6 and V12 (Ritchie et al., 1993) stages of growth and were dried, weighed, and ground in a Wiley mill to pass a 2 mm screen. The ground tissue was analyzed according to the procedures of the UW Soil and Plant Analysis Laboratory (Schulte et al., 1987). Plant silking was measured on 27 and 26 July, and 5 August in 1994±1996, respectively, with the number of plants silked counted per 10 m of row in individual plots. Grain yield was determined by machine harvesting and shelling the maize from the middle two rows of each plot. Grain yields are reported at 155 g kgÿ1
water content.
Data were analyzed with an analysis of variance for a split-plot treatment arrangement using the proce-dures of the Statistical Analysis System (SAS Insti-tute, Cary, North Carolina), where signi®cance was found atp<0.05 a Fisher's LSD was calculated.
3. Results and discussion
3.1. Growing season air temperature and precipitation
The mean monthly air temperature and total pre-cipitation for the growing seasons for 1994±1996 are
Table 1
Mean monthly air temperature and total precipitation recorded at Arlington, WI, 1994±1996
Month Temperature (8C) Precipitation (mm)
1994 Departurea 1995 Departurea 1996 Departurea 1994 Departurea 1995 Departurea 1996 Departurea
April 7.9 0 6.7 ÿ1.3 6.9 ÿ1.1 58 ÿ14 86 13 67 ÿ5
shown in Table 1. These data were collected approxi-mately 3 km from the study location. Temperature and precipitation varied both within and between seasons. Growing conditions were least favorable in the mid-summer of 1995 when it was hotter and drier than the 30 year average.
3.2. Soil temperature and water content
The effect of tillage treatment on the early season soil temperature at the 5 cm depth is shown in Fig. 1. The spring I-RRM temperatures in 1996 were similar to those in the fall treatment, with the exception of day
150 when they were lower. The temperature in the chisel treatment at both depths was typically about 18C warmer, but not signi®cantly different from those found in the fall I-RRM treatment. Both treatments were usually several degrees higher than no-till except when measurements were recorded shortly after rain-fall events. Overall, these data clearly demonstrate the cooler conditions experienced during most of the early growing season under no-till. The data also show that both I-RRM systems resulted in early season soil temperatures that were similar to those found under chisel. The effect of tillage on the gravimetric soil water content is shown in Fig. 2. These data show
Fig. 1. Effect of tillage on early season soil temperature recorded at a 5 cm depth, Arlington, WI, 1994±1996 (measurements taken between 16:00 and 17:00 h CDT). LSD (where signi®cant at
p0.05) presented as a bar above sampling dates.
the relatively higher water content in the no-till treat-ment and the similarity in water content in the row between the I-RRM and chisel treatments. Soil water content values for each tillage treatment were similar when measurement timing followed a precipitation event.
3.3. Surface crop residue
The effect of tillage treatment on surface crop residue levels is shown in Table 2. The readings collected by the pin method were used to create a residue pro®le across the row, and to provide an estimation of the overall residue cover for each tillage treatment. The overall residue cover across tillage treatment was similar in all years. The difference between the average residue levels for the fall and spring I-RRM treatments was not substantial. The residue levels for both the chisel and no-till were typical for those systems. The use of a chisel with twisted shovels and the need to disk twice to prepare a seed bed resulted in crop residue cover less than 30% in 2 of 3 years. Evaluation of the residue pro®le across the row showed that the I-RRM treatments left between 30 and 50% residue in the row area, which is important to recognize with respect to soil surface protection (data not shown).
3.4. Plant growth
Table 3 shows the main effects of tillage and row fertilizer on the emergence, plant weight and
nutrient content at the V6 and V12 growth stages, silking percentage, and ®nal population for 1995. Similar data were collected in 1994 and 1996, but are not shown in this paper. The emergence measure-ments presented in Table 3 were selected from a series that was taken over a period when the maize was ®rst observed to be ``spiking'', usually in the chisel treatment. These data show that emergence was delayed in the no-till. Most of the planted seeds successfully emerged in the no-till treatment, which was con®rmed by the observation that ®nal stands were only slightly lower in the no-till treatment (data not shown). The effect of the delayed emer-gence and slower growth in no-till was manifested throughout most of the season as plant weight at the V6 and V12 growth stages and silking progress measurements were often lower in no-till when compared to other tillage systems. The early growth and development of the maize in the both I-RRM treatments were similar, and while usually greater than no-till, lagged somewhat behind that observed in the chisel. Emergence was not affected by row fertilizer treatment; however, the 55 row fertilizer treatment promoted early season dry matter accumu-lation when compared to the control. The dry matter accumulation for the fall fertilizer treatments was lower than that measured in the 55 placement (Table 3). Tissue nutrient concentration was some-what variable with respect to treatment. Concentra-tion of P or K was sometimes higher in the no-till treatment, presumably because of the lower dry matter content in that treatment. The most consistent response was that for the tissue K concentration, which tended to be higher at the V6 growth stage where fertilizer was applied in the 55 placement. This placement guaranteed the application of fertili-zer near the seed compared to the fall placement where planting was intended over a treated zone. The fall treatment would also have permitted more time for ®xation of P and K by the soil. No consistent interactive effects between tillage and fertilizer place-ment relative to early season growth or tissue nutrient concentration were observed.
3.5. Grain water content and yield
Table 4 shows the individual year and 3 year averaged main effects of tillage and fertilizer on maize
Table 2
Average crop residue cover as affected by tillage system, Arlington, WI, 1994±1996a
aNumbers in parentheses are the standard deviation for crop residue cover for each tillage systemn48.
bI-RRM, using Yetter ``Residue Manager'' coulters (Yetter Manufacturing, Colchester, IL, USA).
Table 4
Main effect of tillage and fertilizer treatment on maize yield and grain water content at Arlington, WI, 1994±1996
Effect Moisturea(g kgÿ1) Yielda(Mg haÿ1)
1994 1995 1996 3 year
average
1994 1995 1996 3 year
average
Tillageb
Fall I-RRM 294 258 252 268 12.0 9.8 9.6 10.5
Spring I-RRM 306 264 267 279 11.1 9.3 9.5 10.0
Chisel 289 241 252 261 11.5 10.1 9.4 10.4
No-till 307 269 260 279 11.5 9.6 9.7 10.2
LSD(0.05) 10 17 NS 13 0.6 NS NS NS
Fertilizerc
None 301 260 263 275 11.6 9.4 9.1 10.0
FS 300 258 256 271 11.7 9.7 9.7 10.4
FI 297 261 257 272 11.4 9.7 9.6 10.2
55 297 252 255 268 11.5 10.1 9.8 10.5
LSD(0.05) NS 50 NS 50 NS 0.4 0.5 0.3
Significance(Pr>F)
Tillage 0.01 0.03 0.35 0.03 0.04 0.34 0.93 0.19
Fertilizer 0.71 0.01 0.28 0.03 0.68 0.02 0.03 0.01
TF 0.87 0.47 0.12 0.30 0.17 0.91 0.02 0.02
aNS: Not signi®cant.
bTillage: FR, fall in-row residue management (I-RRM); SR, spring I-RRM; CH, chisel; NT, no-till. I-RRM treatments used Yetter ``Residue Manager'' coulters (Yetter Manufacturing, Colchester, IL, USA). Fall chiseled and spring disked twice prior to planting.
cRow fertilizer: none, no row fertilizer; FS, fall surface; FI, fall inject; 55, 5 cm to the side and 5 cm below seed with planter. Main effect of tillage and fertilizer treatment on maize emergence, early season mass and nutrient concentration, and silking progress, Arlington, WI, 1995
Effect Emergence
(plants mÿ1)
V6a V12a Silk (%) Populationb
Weight (g plantÿ1)
P (g kgÿ1)
K (g kgÿ1)
Weight (g/plantÿ1)
P (g kgÿ1)
K (g kgÿ1)
Tillagec
FR 5.2 0.9 4.5 40.2 21 3.5 25.7 27 70.1
SR 4.6 0.9 4.6 39.4 22 3.4 23.0 22 69.6
CH 5.6 1.1 4.7 40.1 28 3.2 21.0 60 71.1
NT 3.0 0.8 4.4 39.2 16 3.9 32.7 14 68.9
LSD(0.05) 0.7 NS NS NS 6 0.2 8.0 13 NS
Row fertilizerd
None 4.6 0.8 4.5 38.6 18 3.5 25.0 24 70.4
FS 4.6 0.9 4.4 39.1 20 3.5 24.8 29 68.6
FI 4.6 0.8 4.8 39.5 20 3.7 26.6 25 70.6
55 4.6 1.2 4.5 41.8 30 3.3 26.1 45 69.6
LSD(0.05) NS 0.1 NS 2.4 3 0.2 NS 9 NS
Significance(Pr>F)
Tillage 0.01 0.11 0.92 0.76 0.01 0.01 0.03 0.01 0.51
Fertilizer 0.94 0.01 0.28 0.05 0.01 0.01 0.68 0.01 0.55
TF 0.48 0.73 0.63 0.42 0.36 0.52 0.18 0.62 0.50
aNS: Not signi®cant. bPlants haÿ1(1000).
cTillage: FR, fall in-row residue management (I-RRM); SR, spring I-RRM; CH, chisel; NT, no-till. I-RRM treatments used Yetter ``Residue Manager'' coulters (Yetter Manufacturing, Colchester, IL, USA). Fall chiseled and spring disked twice prior to planting.
grain water content and yield. Producers favor treat-ments that reduce grain water content because of the extra cost associated with drying. Tillage signi®cantly affected grain water content in the ®rst 2 years and in the 3 year average. Grain water content was lowest in the chisel and highest in the no-till and spring zone treatments, suggesting faster maturity in the chisel system. The grain water content found in the fall I-RRM system was not different from that found in the chisel system. The use of row-placed fertilizer reduced grain water content, with the greatest overall reduction found with the spring 55 placement. There was no difference in grain water content between the row fertilizer treatments. Grain yield was not signi®cantly affected by tillage, with the exception of 1994 where the spring zone treatment was signi®cantly lower than the fall zone treatment. The spring zone treatment tended to be inferior to the fall zone treatment with respect to both grain moisture and yield, although differences were not always signi®cant at thep0.05 level of probability. The reason for this response is not readily obvious. It is also surprising that the no-till treatment overcame the early season growth de®cit to produce a yield similar to the other tillage treatments. Grain yield was signi®cantly increased with the use of the planter-applied 55 fertilizer placement in 1995 and 1996, as well as the 3 year average, when com-pared to the no fertilizer treatment. The fall fertilizer treatment yields were intermediate and were not dif-ferent from the 55 placement.
A signi®cant interaction between tillage and ferti-lizer placement was observed for both the 1996 season and the 3 year average yield. A response to row fertilizer was observed in all tillage systems, except the chisel in spite of the fact that the initial P and K soil test at this location were both in the excessively high range for maize production. It is possible that the lack of response to fall row fertilizer in the chisel system was due to the disruption of the band caused by spring disking, although this would not explain why the spring 55 placement did not increase yield in the chisel. The row fertilizer response in the no-till and zone tillage systems, while mixed, demonstrates the need for this practice in high residue systems in the northern Corn Belt of the USA. The small amount of row fertilizer applied in this study would not affect the time ef®ciency of planting which some suggest.
4. Conclusion
Three years of research demonstrated that I-RRM offers a high residue alternative to a chisel plow system for maize production, especially for highly erodible land. Although economics were not consid-ered in this study, considerable fuel and labor savings would be realized in the I-RRM treatments because of at least two fewer trips over the ®eld. The equality of crop yield showed that early season temperature and plant growth de®cits in no-till were apparently over-come, although no-till resulted in greater water con-tent. This would reduce pro®tability because of drying costs. In-row residue management resulted in average residue levels of about 15% lower than no-till; how-ever, there was only 30±50% in the row. The 55 fertilizer placement at planting was slightly better than fall applications of a similar amount of fertilizer except in 1994 where early planting reduced response. A signi®cant interactive effect between tillage and fertilization showed a strong row fertilizer response in the reduced tillage treatments. An I-RRM system would be an appropriate high-residue row crop pro-duction system on medium- and ®ne-textured soils. It would be especially adapted to regions of the world with a limited growing season or where crop residue maintains cool soil temperatures. Producers should be encouraged to use a complete row-placed fertilizer.
Acknowledgements
The author expresses his appreciation to the Fluid Fertilizer Foundation, St. Louis, MO, USA and the Potash and Phosphate Institute, Atlanta, GA, USA for the ®nancial support of this research.
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