Corn grown under annual corn-soybean crop rotation has greater accumulation of certain mineral nutrients and higher yields than corn grown in monoculture. This study was conducted to determine if complex crop rotations (with legumes in the rotation as alfalfa hay as well as soybean row crops) and different levels of agriculture chemical input affect soil fertility and corn mineral nutrient composition. The effects of crop rotation [monoculture corn, corn-soybean 2-yr rotation, corn-soybean- wheat underseeded with alfalfa-alfalfa 4-yr rotation] and input level [high input (fertilizer application for 8.15 Mg ha-1 yield goal, prophylactic herbicide and insecticide application, fall moldboard plow/spring disk and cultivation operations), intermediate input (fertilizer application for 5.33 Mg ha-1 yield goal, pesticide applications based upon pest survey and IPM principles, fall chisel plow/spring disk and cultivation operations), and low input (no fertilizer, herbicide, or insecticide applications, fall chisel plow/spring disk and cultivation operations)] on soil fertility (pH, organic matter, NO3-N, P, K, and total N) and on corn shoot dry weight, mineral nutrient (N, P, Ca, Mg) concentration and accumulation at tassel stage of development were investigated at Brookings, SD. Soil samples taken at the V6 stage of corn development indicated that crop rotation treatments reduced soil pH, increased soil NO3-N level, and decreased soil P level when compared to corn monoculture. Shoots of plants grown under either 2-yr rotation intermediate input or 4-yr rotation no input treatments had greater dry weight, as well as greater P, Ca, and Mg accumulation than these same input treatments in other rotations. These results demonstrate a beneficial effect of crop rotation upon soil fertility and corn mineral nutrition. The results of this experiment are discussed in terms of nutrient synergisms whereby nutrient absorption proceeds at a faster rate than dry weight accumulation

Carpenter-Boggs, Lynne

Pikul, Joseph L., Jr.

Riedell, Walter E.

English

UNL | Libraries

University of Nebraska - Lincoln 
DigitalCommons@University of Nebraska - Lincoln 
Publications from USDA-ARS / UNL Faculty U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska 
2002 
One Plus One Equals Three: The Synergistic Effects Of Crop 
Rotation On Soil Fertility And Plant Nutrition 
Walter E. Riedell 
USDA-ARS, wriedell@ngirl.ars.usda.gov 
Joseph L. Pikul Jr. 
USDA-ARS 
Lynne Carpenter-Boggs 
USDA-ARS 
Follow this and additional works at: https://digitalcommons.unl.edu/usdaarsfacpub 
 Part of the Agricultural Science Commons 
Riedell, Walter E.; Pikul, Joseph L. Jr.; and Carpenter-Boggs, Lynne, "One Plus One Equals Three: The 
Synergistic Effects Of Crop Rotation On Soil Fertility And Plant Nutrition" (2002). Publications from USDA-
ARS / UNL Faculty. 1061. 
https://digitalcommons.unl.edu/usdaarsfacpub/1061 
This Article is brought to you for free and open access by the U.S. Department of Agriculture: Agricultural Research 
Service, Lincoln, Nebraska at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in 
Publications from USDA-ARS / UNL Faculty by an authorized administrator of DigitalCommons@University of 
Nebraska - Lincoln. 
ONE PLUS ONE EQUALS THREE: THE SYNERGISTIC EFFECTS OF 
CROP ROTATION ON SOIL FERTILITY AND PLANT NUTRITION I 
Walter E. Riedell, Joseph L. Pikul Jr., Lynne Carpenter-Boggs2 
USDA-ARS Brookings, SD and Morris, MN 
wriedell@ngirl.ars.usda.gov, (605) 693-5207 
ABSTRACT 
Corn grown under annual corn-soybean crop rotation has greater accumulation of certain mineral 
nutrients and higher yields than corn grown in monoculture. This study was conducted to determine 
if complex crop rotations (with legumes in the rotation as alfalfa hay as well as soybean row crops) 
and different levels of agriculture chemical input affect soil fertility and corn mineral nutrient 
composition. The effects of crop rotation [monoculture corn, corn-soybean 2-yr rotation, corn-
soybean-wheat underseeded with alfalfa-alfalfa 4-yr rotation] and input level [high input (fertilizer 
application for 8.15 Mg ha- i yield goal, prophylactic herbicide and insecticide application, fall 
moldboard plow/spring disk and cultivation operations), intermediate input (fertilizer application for 
5.33 Mg ha- I yield goal, pesticide applications based upon pest survey and IPM principles, fall chisel 
plow/spring disk and cultivation operations), and low input (no fertilizer, herbicide, or insecticide 
applications, fall chisel plow/spring disk and cultivation operations)] on soil fertility (pH, organic 
matter, N03-N, P, K, and total N) and on corn shoot dry weight, mineral nutrient (N, P, Ca, Mg) 
concentration and accumulation at tassel stage of development were investigated at Brookings, SD. 
Soil samples taken at the V6 stage of corn development indicated that crop rotation treatments 
reduced soil pH, increased soil N03-N level, and decreased soil P level when compared to corn 
monoculture. Shoots of plants grown under either 2-yr rotation intermediate input or 4-yr rotation 
no input treatments had greater dry weight, as well as greater P, Ca, and Mg accumulation than these 
same input treatments in other rotations. These results demonstrate a beneficial effect of crop 
rotation upon soil fertility and corn mineral nutrition. The results of this experiment are discussed 
in terms of nutrient synergisms whereby nutrient absorption proceeds at a faster rate than dry weight 
accumulation. 
INTRODUCTION 
Under conditions of high soil fertility, macronutrient (N, P, and K) and micronutrient (Zn) 
accumulation in corn tissue at physiological maturity, as well as grain yield, were greater in first year 
corn (after soybean) than in corn grown under monoculture (Copeland and Crookston, 1992). We 
were interested in confirming the above results as well as determining if these same results would 
occur under more complex crop rotations and diverse levels of agricultural chemical input. The 
IThe USDA offers its programs to all eligible persons regardless of race, color, age, or national origin, and 
is an equal opportunity employer. Mention of a commercial product does not constitute endorsement by the USDA. 
Contribution to the 2002 Great Plains Soil Fertility Conference, 5-6 March 2002, Denver CO. 
2Current address: Department of Plant Pathology, Washington State University, Pullman, WA 
229 
Proceedings of the Great Plains Soil Fertility Conference, 
Denver, Colorado, March 5-6, 2002, ed. Alan J. Schlegel. 
objective of our experiment was to investigate the effects and interactions of complex crop rotations 
(with legumes in the rotation as hay as well as row crops) and different agricultural chemical input 
levels on soil fertility and corn mineral nutrient composition. Our experiment included crop 
rotations and input level treatments that mimicked agricultural production systems used by farmers 
in the northern portion of the US corn belt. Such a systems approach, which synthesizes scientific 
inquiry with real world agronomic situations, integrates research results for identification of gaps in 
our knowledge (Peterson et aI., 1993) and improves the probability that experimental results will be 
applied by farmers to solve problems associated with crop production (Weiss and Robb, 1988). 
MATERIALS AND METHODS 
Crop rotation and input level treatments used in this experiment were established in the 1990 
growing season on a Barnes clay loam soil at the Eastern South Dakota Soil and Water Research 
Farm near Brookings, SD. Rotations included a continuous corn monoculture, a corn-soybean 2-yr 
rotation, and a corn-soybean-wheat underseeded with alfalfa-alfalfa 4-yr rotation. Three separate 
input level sub-plot treatments were superimposed upon the main plot rotation treatments. Input 
level treatments for the corn phase of the rotations included high input (fertilizer application for 8.15 
Mg ha-1 yield goal, prophylactic herbicide and insecticide application, fall moldboard plow/spring 
disk and cultivation operations), intermediate input (fertilizer application for 5.33 Mg ha- 1 yield goal, 
pesticide applications based upon pest survey and IPM principles, fall chisel plow/spring disk and 
cultivation operations), and low input (no fertilizer, herbicide, or insecticide applications, fall chisel 
plow/spring disk and cultivation operations). Additional information on treatments can be seen in 
a previous publication (Riedell et aI., 1998). 
Soil samples (0 to 30 cm depth, 2.5 cm diameter) were taken when the corn was in the 6th 
leaf stage (V6) and analyzed for pH, organic matter, N03-N, P (Olsen method), K, and total Kjeldahl 
N (Gelderman et aI., 1987). At the tassel (VT) stage, corn shoots were sampled for dry weight and 
analyzed for N using the Kjeldahl method. Tissue concentrations of P, Ca, and Mg were also 
measured. Mineral nutrient concentration data was multiplied by the shoot dry weight to determine 
mineral nutrient accumulation by the shoots of plants. Data from the 1994 and 1995 growing 
seasons were analyzed using ANOVA and Fisher's restricted LSD values procedures in SAS (a = 
0.1; Steel and Torrie, 1960). Qualitative relationships between plant dry weight, mineral nutrient 
accumulation, and mineral nutrient concentration were also examined using the method of ] arrell 
and Beverly (1981). A sequence of symbols representing differences (T =increased, J =decreased, 
O=no change) in these parameters between corn grown in monoculture and corn grown in either 2-yr 
or 4-yr rotation was generated. The patterns of the symbol sequences were used to determine 
potential response characteristics for these qualitative relationships. 
RESUL TS AND DISCUSSION 
Treatment Effects on Soil Fertility 
Soils under 4-yr rotation had significantly higher levels of N03-N as well as lower pH and 
P levels than those under continuous corn monoculture (Table 1). The soil pH and P level under the 
2-yr rotation were also significantly lower than those seen under corn monoculture. Organic matter, 
K, and total N levels were not significantly affected by rotation. Input level had no significant effects 
upon any of the soil parameters measured at this sample date (data not shown). There were no 
230 
significant rotation by input level interactions for any of the dependent variables. 
Table I. Influence of crop rotation upon soil pH, organic matter, and primary nutrient level as determincd 
from 0-20 cm soil samples taken at the V6 stage of corn development. 
Rotation 
MonocuIture 
2 Year 
4 Year 
pH 
6.6 b 
6.6 b 
Organic 
matter 
gkg-! 
27NS 
26 
26 
N03-N P K 
------------ mg kg-! ------------
11.2 b 6.3 a 132 NS 
14.5 b 4.5 b 133 
23.8 a 4.1 b 142 
t Means followed by same letter within columns are not significantly different (LSD, a=O.I). 
Total N 
g kgl 
1.6 NS 
1.6 
1.6 
Newly established alfalfa plantings have the potential to produce a large accumulation of 
N03-N in proportion to the total nitrogen present in the soil (Lyon et al.I924). Nitrogen in legume 
residue is rapidly mineralized (Power et al., 1986) which we believe resulted in the higher levels of 
N03-N in soil under the 4-yr rotation. 
Treatment Effects on Corn Mineral Composition 
Several significant rotation by input level interactions (P=O.O 1 for shoot dry weight, P=O.06 
for P accumulation, P=O.03 for Ca accumulation, P=O.01 for Mg accumulation) were present. Plots 
of these data (Fig. 1) revealed that shoots grown under either 2-yr rotation intermediate input or 4-yr 
rotation low input treatments had greater dry weight, as well as greater P, Ca, and Mg accumulation 
than these same input treatments in other rotations. The similarities between shoot dry weight and 
mineral nutrient accumulations also suggest that the dry weight accumulation of the aerial portion 
of the plants is a major factor affecting mineral nutrient accumulation. Jarrell and Beverly (1981 ) 
noted that the concentration of mineral nutrients in plant tissue is a single-point measurement that 
results from the integration of two dynamic processes: mineral nutrient absorption and dry matter 
accumulation. 
Because nutrient concentration is a result of the quantitative manner in which nutrient 
absorption and dry matter accumulation vary, it is reasonable to consider all three values when 
discussing the nutrient status of a crop (Table 2). N accumulation and N concentration were greater 
in corn grown under 2- and 4-yr rotation when compared with monoculture (Table 2). The defining 
characteristic of nutrient synergism is that nutrient absorption proceeds at a faster rate than dry 
weight accumulation. Important permissive factors thought to be involved in enhanced nutrient 
absorption include: higher ion concentrations in the soil solution, increased root growth, increased 
root activity, faster movement of ions to roots through mass flow of the soil solution, increased 
translocation of nutrients to shoots, and enhanced nutrient absorption mechanisms in the root (J arrell 
and Beverly, 1981). Our soil analysis data suggest that there were higher NO,-N levels in the soil 
under crop rotation which in turn could lead to greater rates of N absorption and accumulation by 
the crop. P nutrient accumulation was greater while P nutrient concentration was 
231 
Input Level: High ~ Intermediate m Low 
~120r--------------------. 
~ .... 
1ii 100 Q. 
S 
... 
.r: 
CI 
~ 
~ 
o 
'0 
o 
.r: 
rn 
C 0.3Il-r---------------------, 
c: 
as Q. 
S 
as 
o 
iC 
'tI 
DI 
::J 
~"""'--l-O.lJO .:) 
3: 
cc 
0.20 ~ 
o 
c: 
0.15 g 
DI 
C!: 0.10 0 
::J 
iC 
0.05 'tI 
DI 
::J 
~""""'-+O.OO .:) 
Figure 1. Shoot dry weight, P accumulation, Ca accumulation, and Mg accumulation of corn plants harvested from the 
rotation-input level treatments at the tassel stage of development. 
less in com grown under rotation when compared with monoculture. This relationship was 
consistent for all input levels under the 2-yr and 4-yr rotations (Table 2). The proposed mechanism 
that explains these responses in dry weight accumulation and P relations is dilution (Jarrell and 
Beverly, 1981). The characteristic that defines nutrient dilution is that crop dry matter accumulation 
proceeds at a faster rate than nutrient absorption. Such a situation would result when com is grown 
in rotation and some negative factor slowed nutrient absorption or a positive factor increased dry 
weight accumulation. Factors that may slow the rate of nutrient absorption include: lower ion 
concentrations in the soil solution, decreased root growth, decreased root activity, decreased rate of 
movement of ions to roots through mass flow, reduced translocation of nutrients to shoots, and 
inhibition of nutrient absorption mechanisms in the root. The lower soil P levels under both crop 
rotation treatments (Table 1) could have been responsible for reduced rates of P absorption and 
accumulation. However, the P dilution seen under crop rotation may also have been the result of 
increased rate dry matter accumulation in the crop rotation treatments (Fig. 1). Factors leading to 
increased dry matter accumulation include: enhanced photosynthesis, lower respiration, improved 
translocation of photosynthate to points of need, greater turgor potential, less disease and pest 
pressure, lower rate of senescence, and better crop hormonal balance. Whether there were other 
factors involved in this P level dilution response, and the relative contribution of changes in nutrient 
absorption vs changes in dry matter accumulation under crop rotation cannot be determined from our 
232 
Table 2. Qualitative representation of differences in total mineral nutrient accumulation, dry weight accumulation, 
and mineral nutrient concentration between corn grown under monoculture and 2-yr or 4-yr rotation. 
Input Level Element ilAccumulation ilDry Weight ilConcentration Response 
2-yr Rotation" 
High N i" 0 i Synergism 
p 0 0 1 Dilution 
Ca 0 0 0 None 
Mg i 0 i Synergism 
Intermediate N i i i Synergism 
p t i 0 None I 
Ca i i 0 None 
Mg i i i Synergism 
Low N i i i Synergism 
p i i 1 Dilution 
Ca i i i Synergism 
Mg i i i Synergism 
4-yr Rotation 
High N i i i Synergism 
p i i 1 Dilution 
Ca i i 1 Dilution 
Mg i i 0 None 
Intermediate N i i i Synergism 
p 0 i 1 Dilution 
Ca i i 1 Dilution 
Mg i i 1 Dilution 
Low N i i i Synergism 
p i i 1 Dilution 
Ca i i 1 Dilution 
Mg i i 1 Dilution 
Symbols represent more (i ), less (L ), or no change (0) between values obtained from corn grown under 
monoculture or rotation 
Proposed response involved as determined by sequence of the three qualitative symhols for each element (after 
Jarrell and Beverly, 1981) 
233 
data. It is interesting to note that the proposed mechanisms involved for Ca and Mg nutrient 
relations for com grown under the 2-yr and the 4-yr rotations were different (Table 2). Injust about 
every instance, the 2-yr rotation showed a synergism for Ca and Mg while the 4-yr showed a dilution. 
Such a situation would result if Ca and Mg under the 2-yr rotation were being absorbed at a faster 
rate than dry weight accumulation and/or dry matter accumulation was at a faster rate than Ca and 
Mg absorption under the 4-yr rotation. Although the specific reasons for the differences in the 
response mechanisms are not clear, our data suggest that there may be some factors that are 
promoting dry weight accumulation in the 4-yr rotation when compared with the 2-yr rotation. 
CONCLUSIONS 
Our data clearly demonstrate the beneficial effect of crop rotation on shoot dry weight and 
mineral nutrient accumulation in com. However, the data collected in our study allow only 
speculation of the actual mechanisms involved in these responses. Additional studies (e.g. 
interactions of soil fertility, root growth, and nutrient use efficiency) using a more reductionist 
approach will be needed to reach a mechanistic understanding of crop rotations. 
REFERENCES 
Copeland, PJ., and RK. Crookston. 1992. Crop sequence affects nutrient composition of com and 
soybean grown under high fertility. Agron. J. 84:503-509. 
Gelderman, R, R Neal, S. Swartos, and L. Anderson. 1987. Soil testing procedures in use at the 
South Dakota State Soil Testing Laboratory. Pamphlet 101, Plant Science Department, South Dakota 
State University. 
Jarrell, W.M., andR.B. Beverly. 1981. The dilution effect inplant nutrition studies. Adv. Agron. 34: 197-
224. 
Lyon, T.L., J.A. Bizzell, and B.D. Wilson. 1924. An inquiry into the reason for the large 
accumulation of nitrates in soil following the growth of clover or alfalfa. J. Amer. Soc. Agron. 
16:396-405. 
Peterson, G.A., D.G. Westfall, and C.V. Cole. 1993. Agroecosystem approach to soil and crop 
management research. Soil Sci. Soc. Am. J. 57: 1354-1360. 
Power, J.F., J.W. Doran, and W.W. Wilhelm. 1986. Uptake of nitrogen from soil fertilizer and crop 
residues by no-till com and soybeans. Soil Sci. Soc. Am. J. 50:137-142. 
Riedell, W.E., T.E. Schumacher, S.A. Clay, M.M. Ellsbury, M. Pravecek, and P.D. Evenson. 1998. Corn 
and soil fertility responses to crop rotation with low, medium, and high inputs. Crop Sci. 38:427-433. 
Steel, R.G.D., and J.H. Torrie. 1960. Principles and procedures of statistics: A biometrical approach. 1 st 
ed. McGraw-Hill, New York. 
Weiss, A., and J.G. Robb. 1988. Systems and the business of agriculture. J. Prod. Agric. 1 :230-234. 
234 


One Plus One Equals Three: The Synergistic Effects Of
Crop Rotation On Soil Fertility And Plant Nutrition

DigitalCommons@University of Nebraska

University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Publications from USDA-ARS / UNL Faculty U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska 2002 One Plus One Equals Three: The Synergistic Effects Of Crop Rotation On Soil Fertility And Plant Nutrition Walter E. Riedell USDA-ARS, wriedell@ngirl.ars.usda.gov Joseph L. Pikul Jr. USDA-ARS Lynne Carpenter-Boggs USDA-ARS Follow this and additional works at: https://digitalcommons.unl.edu/usdaarsfacpub  Part of the Agricultural Science Commons Riedell, Walter E.; Pikul, Joseph L. Jr.; and Carpenter-Boggs, Lynne, "One Plus One Equals Three: The Synergistic Effects Of Crop Rotation On Soil Fertility And Plant Nutrition" (2002). Publications from USDA-ARS / UNL Faculty. 1061. https://digitalcommons.unl.edu/usdaarsfacpub/1061 This Article is brought to you for free and open access by the U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Publications from USDA-ARS / UNL Faculty by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. ONE PLUS ONE EQUALS THREE: THE SYNERGISTIC EFFECTS OF CROP ROTATION ON SOIL FERTILITY AND PLANT NUTRITION I Walter E. Riedell, Joseph L. Pikul Jr., Lynne Carpenter-Boggs2 USDA-ARS Brookings, SD and Morris, MN wriedell@ngirl.ars.usda.gov, (605) 693-5207 ABSTRACT Corn grown under annual corn-soybean crop rotation has greater accumulation of certain mineral nutrients and higher yields than corn grown in monoculture. This study was conducted to determine if complex crop rotations (with legumes in the rotation as alfalfa hay as well as soybean row crops) and different levels of agriculture chemical input affect soil fertility and corn mineral nutrient composition. The effects of crop rotation [monoculture corn, corn-soybean 2-yr rotation, corn-soybean-wheat underseeded with alfalfa-alfalfa 4-yr rotation] and input level [high input (fertilizer application for 8.15 Mg ha- i yield goal, prophylactic herbicide and insecticide application, fall moldboard plow/spring disk and cultivation operations), intermediate input (fertilizer application for 5.33 Mg ha- I yield goal, pesticide applications based upon pest survey and IPM principles, fall chisel plow/spring disk and cultivation operations), and low input (no fertilizer, herbicide, or insecticide applications, fall chisel plow/spring disk and cultivation operations)] on soil fertility (pH, organic matter, N03-N, P, K, and total N) and on corn shoot dry weight, mineral nutrient (N, P, Ca, Mg) concentration and accumulation at tassel stage of development were investigated at Brookings, SD. Soil samples taken at the V6 stage of corn development indicated that crop rotation treatments reduced soil pH, increased soil N03-N level, and decreased soil P level when compared to corn monoculture. Shoots of plants grown under either 2-yr rotation intermediate input or 4-yr rotation no input treatments had greater dry weight, as well as greater P, Ca, and Mg accumulation than these same input treatments in other rotations. These results demonstrate a beneficial effect of crop rotation upon soil fertility and corn mineral nutrition. The results of this experiment are discussed in terms of nutrient synergisms whereby nutrient absorption proceeds at a faster rate than dry weight accumulation. INTRODUCTION Under conditions of high soil fertility, macronutrient (N, P, and K) and micronutrient (Zn) accumulation in corn tissue at physiological maturity, as well as grain yield, were greater in first year corn (after soybean) than in corn grown under monoculture (Copeland and Crookston, 1992). We were interested in confirming the above results as well as determining if these same results would occur under more complex crop rotations and diverse levels of agricultural chemical input. The IThe USDA offers its programs to all eligible persons regardless of race, color, age, or national origin, and is an equal opportunity employer. Mention of a commercial product does not constitute endorsement by the USDA. Contribution to the 2002 Great Plains Soil Fertility Conference, 5-6 March 2002, Denver CO. 2Current address: Department of Plant Pathology, Washington State University, Pullman, WA 229 Proceedings of the Great Plains Soil Fertility Conference, Denver, Colorado, March 5-6, 2002, ed. Alan J. Schlegel. objective of our experiment was to investigate the effects and interactions of complex crop rotations (with legumes in the rotation as hay as well as row crops) and different agricultural chemical input levels on soil fertility and corn mineral nutrient composition. Our experiment included crop rotations and input level treatments that mimicked agricultural production systems used by farmers in the northern portion of the US corn belt. Such a systems approach, which synthesizes scientific inquiry with real world agronomic situations, integrates research results for identification of gaps in our knowledge (Peterson et aI., 1993) and improves the probability that experimental results will be applied by farmers to solve problems associated with crop production (Weiss and Robb, 1988). MATERIALS AND METHODS Crop rotation and input level treatments used in this experiment were established in the 1990 growing season on a Barnes clay loam soil at the Eastern South Dakota Soil and Water Research Farm near Brookings, SD. Rotations included a continuous corn monoculture, a corn-soybean 2-yr rotation, and a corn-soybean-wheat underseeded with alfalfa-alfalfa 4-yr rotation. Three separate input level sub-plot treatments were superimposed upon the main plot rotation treatments. Input level treatments for the corn phase of the rotations included high input (fertilizer application for 8.15 Mg ha-1 yield goal, prophylactic herbicide and insecticide application, fall moldboard plow/spring disk and cultivation operations), intermediate input (fertilizer application for 5.33 Mg ha- 1 yield goal, pesticide applications based upon pest survey and IPM principles, fall chisel plow/spring disk and cultivation operations), and low input (no fertilizer, herbicide, or insecticide applications, fall chisel plow/spring disk and cultivation operations). Additional information on treatments can be seen in a previous publication (Riedell et aI., 1998). Soil samples (0 to 30 cm depth, 2.5 cm diameter) were taken when the corn was in the 6th leaf stage (V6) and analyzed for pH, organic matter, N03-N, P (Olsen method), K, and total Kjeldahl N (Gelderman et aI., 1987). At the tassel (VT) stage, corn shoots were sampled for dry weight and analyzed for N using the Kjeldahl method. Tissue concentrations of P, Ca, and Mg were also measured. Mineral nutrient concentration data was multiplied by the shoot dry weight to determine mineral nutrient accumulation by the shoots of plants. Data from the 1994 and 1995 growing seasons were analyzed using ANOVA and Fisher's restricted LSD values procedures in SAS (a = 0.1; Steel and Torrie, 1960). Qualitative relationships between plant dry weight, mineral nutrient accumulation, and mineral nutrient concentration were also examined using the method of ] arrell and Beverly (1981). A sequence of symbols representing differences (T =increased, J =decreased, O=no change) in these parameters between corn grown in monoculture and corn grown in either 2-yr or 4-yr rotation was generated. The patterns of the symbol sequences were used to determine potential response characteristics for these qualitative relationships. RESUL TS AND DISCUSSION Treatment Effects on Soil Fertility Soils under 4-yr rotation had significantly higher levels of N03-N as well as lower pH and P levels than those under continuous corn monoculture (Table 1). The soil pH and P level under the 2-yr rotation were also significantly lower than those seen under corn monoculture. Organic matter, K, and total N levels were not significantly affected by rotation. Input level had no significant effects upon any of the soil parameters measured at this sample date (data not shown). There were no 230 significant rotation by input level interactions for any of the dependent variables. Table I. Influence of crop rotation upon soil pH, organic matter, and primary nutrient level as determincd from 0-20 cm soil samples taken at the V6 stage of corn development. Rotation MonocuIture 2 Year 4 Year pH 6.6 b 6.6 b Organic matter gkg-! 27NS 26 26 N03-N P K ------------ mg kg-! ------------11.2 b 6.3 a 132 NS 14.5 b 4.5 b 133 23.8 a 4.1 b 142 t Means followed by same letter within columns are not significantly different (LSD, a=O.I). Total N g kgl 1.6 NS 1.6 1.6 Newly established alfalfa plantings have the potential to produce a large accumulation of N03-N in proportion to the total nitrogen present in the soil (Lyon et al.I924). Nitrogen in legume residue is rapidly mineralized (Power et al., 1986) which we believe resulted in the higher levels of N03-N in soil under the 4-yr rotation. Treatment Effects on Corn Mineral Composition Several significant rotation by input level interactions (P=O.O 1 for shoot dry weight, P=O.06 for P accumulation, P=O.03 for Ca accumulation, P=O.01 for Mg accumulation) were present. Plots of these data (Fig. 1) revealed that shoots grown under either 2-yr rotation intermediate input or 4-yr rotation low input treatments had greater dry weight, as well as greater P, Ca, and Mg accumulation than these same input treatments in other rotations. The similarities between shoot dry weight and mineral nutrient accumulations also suggest that the dry weight accumulation of the aerial portion of the plants is a major factor affecting mineral nutrient accumulation. Jarrell and Beverly (1981 ) noted that the concentration of mineral nutrients in plant tissue is a single-point measurement that results from the integration of two dynamic processes: mineral nutrient absorption and dry matter accumulation. Because nutrient concentration is a result of the quantitative manner in which nutrient absorption and dry matter accumulation vary, it is reasonable to consider all three values when discussing the nutrient status of a crop (Table 2). N accumulation and N concentration were greater in corn grown under 2- and 4-yr rotation when compared with monoculture (Table 2). The defining characteristic of nutrient synergism is that nutrient absorption proceeds at a faster rate than dry weight accumulation. Important permissive factors thought to be involved in enhanced nutrient absorption include: higher ion concentrations in the soil solution, increased root growth, increased root activity, faster movement of ions to roots through mass flow of the soil solution, increased translocation of nutrients to shoots, and enhanced nutrient absorption mechanisms in the root (J arrell and Beverly, 1981). Our soil analysis data suggest that there were higher NO,-N levels in the soil under crop rotation which in turn could lead to greater rates of N absorption and accumulation by the crop. P nutrient accumulation was greater while P nutrient concentration was 231 Input Level: High ~ Intermediate m Low ~120r--------------------. ~ .... 1ii 100 Q. S ... .r: CI ~ ~ o '0 o .r: rn C 0.3Il-r---------------------, c: as Q. S as o iC 'tI DI ::J ~"""'--l-O.lJO .:) 3: cc 0.20 ~ o c: 0.15 g DI C!: 0.10 0 ::J iC 0.05 'tI DI ::J ~""""'-+O.OO .:) Figure 1. Shoot dry weight, P accumulation, Ca accumulation, and Mg accumulation of corn plants harvested from the rotation-input level treatments at the tassel stage of development. less in com grown under rotation when compared with monoculture. This relationship was consistent for all input levels under the 2-yr and 4-yr rotations (Table 2). The proposed mechanism that explains these responses in dry weight accumulation and P relations is dilution (Jarrell and Beverly, 1981). The characteristic that defines nutrient dilution is that crop dry matter accumulation proceeds at a faster rate than nutrient absorption. Such a situation would result when com is grown in rotation and some negative factor slowed nutrient absorption or a positive factor increased dry weight accumulation. Factors that may slow the rate of nutrient absorption include: lower ion concentrations in the soil solution, decreased root growth, decreased root activity, decreased rate of movement of ions to roots through mass flow, reduced translocation of nutrients to shoots, and inhibition of nutrient absorption mechanisms in the root. The lower soil P levels under both crop rotation treatments (Table 1) could have been responsible for reduced rates of P absorption and accumulation. However, the P dilution seen under crop rotation may also have been the result of increased rate dry matter accumulation in the crop rotation treatments (Fig. 1). Factors leading to increased dry matter accumulation include: enhanced photosynthesis, lower respiration, improved translocation of photosynthate to points of need, greater turgor potential, less disease and pest pressure, lower rate of senescence, and better crop hormonal balance. Whether there were other factors involved in this P level dilution response, and the relative contribution of changes in nutrient absorption vs changes in dry matter accumulation under crop rotation cannot be determined from our 232 Table 2. Qualitative representation of differences in total mineral nutrient accumulation, dry weight accumulation, and mineral nutrient concentration between corn grown under monoculture and 2-yr or 4-yr rotation. Input Level Element ilAccumulation ilDry Weight ilConcentration Response 2-yr Rotation" High N i" 0 i Synergism p 0 0 1 Dilution Ca 0 0 0 None Mg i 0 i Synergism Intermediate N i i i Synergism p t i 0 None I Ca i i 0 None Mg i i i Synergism Low N i i i Synergism p i i 1 Dilution Ca i i i Synergism Mg i i i Synergism 4-yr Rotation High N i i i Synergism p i i 1 Dilution Ca i i 1 Dilution Mg i i 0 None Intermediate N i i i Synergism p 0 i 1 Dilution Ca i i 1 Dilution Mg i i 1 Dilution Low N i i i Synergism p i i 1 Dilution Ca i i 1 Dilution Mg i i 1 Dilution Symbols represent more (i ), less (L ), or no change (0) between values obtained from corn grown under monoculture or rotation Proposed response involved as determined by sequence of the three qualitative symhols for each element (after Jarrell and Beverly, 1981) 233 data. It is interesting to note that the proposed mechanisms involved for Ca and Mg nutrient relations for com grown under the 2-yr and the 4-yr rotations were different (Table 2). Injust about every instance, the 2-yr rotation showed a synergism for Ca and Mg while the 4-yr showed a dilution. Such a situation would result if Ca and Mg under the 2-yr rotation were being absorbed at a faster rate than dry weight accumulation and/or dry matter accumulation was at a faster rate than Ca and Mg absorption under the 4-yr rotation. Although the specific reasons for the differences in the response mechanisms are not clear, our data suggest that there may be some factors that are promoting dry weight accumulation in the 4-yr rotation when compared with the 2-yr rotation. CONCLUSIONS Our data clearly demonstrate the beneficial effect of crop rotation on shoot dry weight and mineral nutrient accumulation in com. However, the data collected in our study allow only speculation of the actual mechanisms involved in these responses. Additional studies (e.g. interactions of soil fertility, root growth, and nutrient use efficiency) using a more reductionist approach will be needed to reach a mechanistic understanding of crop rotations. REFERENCES Copeland, PJ., and RK. Crookston. 1992. Crop sequence affects nutrient composition of com and soybean grown under high fertility. Agron. J. 84:503-509. Gelderman, R, R Neal, S. Swartos, and L. Anderson. 1987. Soil testing procedures in use at the South Dakota State Soil Testing Laboratory. Pamphlet 101, Plant Science Department, South Dakota State University. Jarrell, W.M., andR.B. Beverly. 1981. The dilution effect inplant nutrition studies. Adv. Agron. 34: 197-224. Lyon, T.L., J.A. Bizzell, and B.D. Wilson. 1924. An inquiry into the reason for the large accumulation of nitrates in soil following the growth of clover or alfalfa. J. Amer. Soc. Agron. 16:396-405. Peterson, G.A., D.G. Westfall, and C.V. Cole. 1993. Agroecosystem approach to soil and crop management research. Soil Sci. Soc. Am. J. 57: 1354-1360. Power, J.F., J.W. Doran, and W.W. Wilhelm. 1986. Uptake of nitrogen from soil fertilizer and crop residues by no-till com and soybeans. Soil Sci. Soc. Am. J. 50:137-142. Riedell, W.E., T.E. Schumacher, S.A. Clay, M.M. Ellsbury, M. Pravecek, and P.D. Evenson. 1998. Corn and soil fertility responses to crop rotation with low, medium, and high inputs. Crop Sci. 38:427-433. Steel, R.G.D., and J.H. Torrie. 1960. Principles and procedures of statistics: A biometrical approach. 1 st ed. McGraw-Hill, New York. Weiss, A., and J.G. Robb. 1988. Systems and the business of agriculture. J. Prod. Agric. 1 :230-234. 234 

https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=2066&amp;context=usdaarsfacpub

One Plus One Equals Three: The Synergistic Effects Of Crop Rotation On Soil Fertility And Plant Nutrition

Abstract

Similar works

Full text

Available Versions

UNL | Libraries

DigitalCommons@University of Nebraska