Agronomy Journal Grow Your Career With ASA
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Published in Agron J 99:1306-1316 (2007)
DOI: 10.2134/agronj2006.0243
© 2007 American Society of Agronomy
677 S. Segoe Rd., Madison, WI 53711 USA
This Article
Right arrow Abstract Freely available
Right arrow Figures Only
Right arrow Full Text (PDF) Free
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Parsons, K. J.
Right arrow Articles by Caldwell, C. D.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Parsons, K. J.
Right arrow Articles by Caldwell, C. D.
Agricola
Right arrow Articles by Parsons, K. J.
Right arrow Articles by Caldwell, C. D.
Related Collections
Right arrow Crop Rotation Systems
Right arrow Nutrient Management
Right arrow Plant Nutrition
Right arrow Soil Fertility and Productivity
Right arrow Animal Waste

Cropping Systems

Soil and Tissue Phosphorus, Potassium, Calcium, and Sulfur as Affected by Dairy Manure Application in a No-Till Corn, Wheat, and Soybean Rotation

Kimberley J. Parsonsa, Valtcho D. Zheljazkovb,*, John MacLeodc and Claude D. Caldwella

a Dep. of Plant and Animal Sciences, Nova Scotia Agricultural College, 50 Pictou Rd., P.O. Box 550, Truro, NS Canada B2N 5E3
b Mississippi State Univ., North Mississippi Research and Extension Center, 5421 Hwy. 145 South, P.O. Box 1690, Verona, MS 38879 USA
c Agriculture and Agrifood Canada, Crops and Livestock Research Centre, 440 University Ave., Charlottetown, PE, Canada C1A 4N6

* Corresponding author (vj40{at}pss.msstate.edu)


   ABSTRACT
TOP
 ABSTRACT
INTRODUCTION
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 CONCLUSIONS
 REFERENCES
 
The hypothesis of this study was that surface applied liquid manure may provide sufficient nutrients to silage corn (Zea mays L.), wheat (Triticum aestivum L.), and soybean [Glycine max (L.) Merr.] under a no-till system in the cool wet climate of Atlantic Canada. A 2-yr field study was conducted investigating the effect of crop rotation and fertility on P, K, Ca, and S availability to corn silage, spring milling wheat, and soybean in Nova Scotia, Canada. The rotations consisted of all six possible combinations of corn, wheat, and soybean, and the fertility treatments consisted of three rates of liquid dairy manure (LDM1–3) at 32.1, 48.1, and 64.3 Mg ha–1, a mineral fertilizer treatment, and a control (no fertility applied). In general, nutrient availability as measured by Mehlich 3 (M3) was not well correlated with tissue concentration. Tissue S in corn was lower when it was grown after soybean than when grown after wheat, and was highest in the LDM1 and in the control treatments. Rotation x fertility effects observed in the wheat nutrient removals were accountable to similar differences in yield. Wheat uptake of P was significantly affected by fertility, with the highest removal of P occurring in the NPK treatment, which also provided the highest yield. Results indicate that Ca uptake by wheat may be hindered by competition with K, and that K applied in manure at higher rates could build up over time. Potassium recovery in wheat was higher from the inorganic NPK treatment (37%) than from manure (from 16 to 4%). There were few differences in M3 available nutrients in 2001. However in 2002, LDM application resulted in higher M3 concentrations of K and Ca; there was a drop in P availability with the LDM3 (at 64.3 Mg ha–1) application; and S availability was highest at LDM1 and LDM3 (32.1 and 64.3 Mg ha–1, respectively). Further long-term studies may be needed to determine if surface applied LDM with no incorporation can sustain silage corn, soybean, and wheat nutrient requirements for P, Ca, K, and S, and maintain efficient nutrient use overtime under no-till conditions.

Abbreviations: DM, dry matter • LDM, liquid dairy manure • M3, Mehlich 3

Received for publication August 25, 2006.

Soil and Tissue Phosphorus, Potassium, Calcium, and Sulfur as Affected by Dairy Manure Application in a No-Till Corn, Wheat, and Soybean Rotation

Kimberley J. Parsonsa, Valtcho D. Zheljazkovb,*, John MacLeodc and Claude D. Caldwella

a Dep. of Plant and Animal Sciences, Nova Scotia Agricultural College, 50 Pictou Rd., P.O. Box 550, Truro, NS Canada B2N 5E3
b Mississippi State Univ., North Mississippi Research and Extension Center, 5421 Hwy. 145 South, P.O. Box 1690, Verona, MS 38879 USA
c Agriculture and Agrifood Canada, Crops and Livestock Research Centre, 440 University Ave., Charlottetown, PE, Canada C1A 4N6

* Corresponding author (vj40{at}pss.msstate.edu)

Received for publication August 25, 2006.
The hypothesis of this study was that surface applied liquid manure may provide sufficient nutrients to silage corn (Zea mays L.), wheat (Triticum aestivum L.), and soybean [Glycine max (L.) Merr.] under a no-till system in the cool wet climate of Atlantic Canada. A 2-yr field study was conducted investigating the effect of crop rotation and fertility on P, K, Ca, and S availability to corn silage, spring milling wheat, and soybean in Nova Scotia, Canada. The rotations consisted of all six possible combinations of corn, wheat, and soybean, and the fertility treatments consisted of three rates of liquid dairy manure (LDM1–3) at 32.1, 48.1, and 64.3 Mg ha–1, a mineral fertilizer treatment, and a control (no fertility applied). In general, nutrient availability as measured by Mehlich 3 (M3) was not well correlated with tissue concentration. Tissue S in corn was lower when it was grown after soybean than when grown after wheat, and was highest in the LDM1 and in the control treatments. Rotation x fertility effects observed in the wheat nutrient removals were accountable to similar differences in yield. Wheat uptake of P was significantly affected by fertility, with the highest removal of P occurring in the NPK treatment, which also provided the highest yield. Results indicate that Ca uptake by wheat may be hindered by competition with K, and that K applied in manure at higher rates could build up over time. Potassium recovery in wheat was higher from the inorganic NPK treatment (37%) than from manure (from 16 to 4%). There were few differences in M3 available nutrients in 2001. However in 2002, LDM application resulted in higher M3 concentrations of K and Ca; there was a drop in P availability with the LDM3 (at 64.3 Mg ha–1) application; and S availability was highest at LDM1 and LDM3 (32.1 and 64.3 Mg ha–1, respectively). Further long-term studies may be needed to determine if surface applied LDM with no incorporation can sustain silage corn, soybean, and wheat nutrient requirements for P, Ca, K, and S, and maintain efficient nutrient use overtime under no-till conditions.

Abbreviations: DM, dry matter • LDM, liquid dairy manure • M3, Mehlich 3


   INTRODUCTION
TOP
 ABSTRACT
 INTRODUCTION
MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 CONCLUSIONS
 REFERENCES
 
PHOSPHORUS, K, S, AND Ca are all important nutrients for the growth and development of crops. Phosphorus and K are often applied as inorganic fertilizers (based on soil test recommendations for each crop), and even though several fertilizer sources of Ca and S are available, these elements are less often directly applied for plant nutrition. Most soils in Atlantic Canada are naturally acidic and growers have been applying lime to maintain suitable soil pH. Historically, S was found as impurity in mineral fertilizers. However, current chemical fertilizers contain fewer if any impurities. There has also been a decline in the amount of S supplied through atmospheric deposition due to industrial reductions in SO2 emissions. Supplying P, K, Ca, and S to crops prevents the occurrence of a variety of deficiency symptoms and ensures balanced nutrition and good yields. Although Ca and S are not normally limiting elements in crop production, they play an important role in soil physical and chemical properties.

Besides the important roles of P, K, Ca, and S in many plant functions (Marschner, 1995; Mills and Jones, 1996), these elements also have a direct effect on the end-use quality of the crop. For example, both Ca and P concentrations in soybean seed are related to phytic acid concentration, which affects the nutritional value of the seed as a livestock feed (Gibson and Mullen, 2001). Other examples are the relationship between the Ca concentration of corn silage and the occurrence of tetany in dairy cattle (White and Winter, 1977), as well as the role of S in bread making quality of wheat flour due to its effect on protein distribution and gluten stability (Zhao et al., 1999).

Management practices have a direct effect on P, K, S, and Ca availability and utilization by crops. Manure, as opposed to inorganic fertilizers, supplies nutrients over time through mineralization. Also, the addition of organic matter with manure or with the use of an efficient crop rotation will affect soil properties such as cation exchange capacity and pH, and therefore root and nutrient interactions (Hickman, 2002). Furthermore, the mineral composition of the soil itself has an effect on plant uptake of selected nutrients. Interactions between elements may enhance or suppress nutrient uptake (Marschner, 1995). In addition, the presence or absence of certain elements can affect the general soil quality. For example, Ca is a soil aggregating agent which is known to have a positive effect on soil physical properties and subsequently crop yields (Hamza and Anderson, 2003).

Many studies have been conducted on the mineralization of elements such as N, P, and K from animal manures in various climates and soil conditions (Ebeling et al., 2003; Egrinya-Eneji et al., 2003; Eghball et al., 2002; Schmitt et al., 2001). However, there are relatively few that focus on nutrients such as Ca and S (Egrinya-Eneji et al., 2003). It has been demonstrated that the addition of Ca and S (supplied as gypsum), equivalent to 40 kg S ha–1, can increase dry matter (DM) yields and N uptake by forage in Atlantic Canada (Zheljazkov et al., 2006). In regions with high precipitation, such as Atlantic Canada, S could be easily washed from the surface soil. According to Environment Canada (2003), SO2 emissions in Atlantic Canada have been reduced by >50% for the period 1980 to 2000 (from {approx}3.8 million to {approx}1.6 million Mg yr–1). Due to the reduction of anthropogenic SO2 emission, the use of high purity fertilizers, and continuous cropping with high-yielding varieties, S deficiencies have been reported in Canada and Europe (MacGrath et al., 1996; Riley et al., 2002). Interest in S studies has increased, especially in European countries due to the rise in organic agriculture and to the increased use of environmental technologies for the reduction in SO2 emissions (Eriksen and Askegaard, 2000). Eghball et al. (2002) also indicated that since S mineralization is required to render S plant-available from manure sources, availability can range widely and net immobilization is possible. Eriksen and Askegaard (2000) also indicate that when manure is the sole source of S, its availability to plants is expected to be low. Calcium availability from manures was generally found to be >55% by Eghball et al. (2002). However, Egrinya-Eneji et al. (2003) found that mineralization from manure and the possibility of soil Ca accumulation varies depending on the specific manure type and soil properties.

Most research has indicated that P availability in soil will vary depending on the type of P source and the soil properties (Ebeling et al., 2003; Eghball et al., 2002), although generally P availability from all manures is considered high, with {approx}75% of P from dairy manure in the inorganic form (Eghball et al., 2002). Similarly, plant available K is thought to be quite high in manures (up to 100%) (Eghball et al., 2002), and the application of manure to soils has been shown to increase soil K (Reider et al., 2000).

Rotation is also expected to have an effect on the nutrient dynamics due to differences in nutrient demands and differences in composition of residues (Soon and Arshad, 2002). Cropping systems that include rotation and fertility application have been investigated previously, with a focus on nutrient balances and the ability of the system to provide nutrients to the crops while avoiding excessive nutrient loss to the surrounding environment (Eriksen and Askegaard, 2000; Knights et al., 2000; Reider et al., 2000). When fertility treatments are applied at a rate based on crop N requirements only, there is a risk of applying excessive amounts of other nutrients (Reider et al., 2000). Rotations can be designed such that nutrient imbalances formed by such practices are offset, and nutrient cycling reaches an equilibrium. Therefore, it is important to assess the ability of specific rotations under specific conditions to supply crops with the nutrients they need. The objective of this study was to assess crop nutrient (P, K, Ca, and S) removal within rotations of corn, wheat, and soybean following application of LDM when compared with mineral fertilizer, under no-till conditions in humid cool climate.


   MATERIALS AND METHODS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
RESULTS AND DISCUSSION
 CONCLUSIONS
 REFERENCES
 
Site Description
A two year field experiment was conducted in 2001 and 2002 on a 300 by 90 m field (2.7 ha) on a silt loam Timberland soil in Truro Nova Scotia. The experimental design was a split-plot with crop rotation as the main plot (six levels) and fertility treatment as the subplot (five levels). There were three replicate blocks containing one 30 by 30 m plot of each rotation randomized within; each whole plot had five fertility treatments (6 by 30 m) randomized within. Relevant initial soil characteristics have been provided as well (Table 1). Certain nutrient levels are assigned a qualitative descriptor (Table 1) either E, H, or M which corresponds to excessive, high, or medium ranges, respectively (Nova Scotia Department of Agriculture and Fisheries Quality Evaluation Services, 2001). Initial LDM properties and nutrient application rates are provided in Table 2.


View this table:
[in this window]
[in a new window]

  		Table 1. Initial soil characteristics from May 2001.

 

View this table:
[in this window]
[in a new window]

  		Table 2. Initial liquid dairy manure (LDM) properties and nutrient application rates.

 
Rotation and Fertility Treatments
This experiment consisted of the initial 2 yr of a no-till system of six rotations involving corn, wheat, and soybean: wheat-corn, wheat-soybean, corn-soybean, corn-wheat, soybean-wheat, soybean-corn. The wheat (SS-Maestro) was seeded at a rate of 140 kg ha–1 using a no-till seeder. Corn was planted at a rate of 69,000 seed ha–1 (76-cm row spacing), and soybean (Dekalb 2601R Roundup Ready) was inoculated with Sowfast inoculant and seeded at a rate of 66 kg ha–1 (76-cm row spacing).

The five fertility treatments included three rates of LDM1 to LDM3 applications of 32.1, 48.1, and 63.4 Mg ha–1, a single inorganic fertilizer treatment, and an unfertilized (unamended) control (Table 2). The manure was liquid dairy from the Nova Scotia Agricultural College farm, and manure tests were performed each season before application to determine the nutrient content. Inorganic fertility treatments were applied according to soil test recommendations from the provincial soil testing facility (Nova Scotia Department of Agriculture and Fisheries Quality Evaluation Services, 2001).

Soil and Plant Sampling
Baseline soil samples were collected from the field before fertility treatment applications in May 2001. In addition, soil samples from a depth of 0–15 cm were collected each fall at the harvest of each crop. Soil samples were air dried at 22°C and sieved to pass a 2-mm mesh size. Plant samples of each crop were also collected at harvest. Only plant material normally removed from the system by harvesting was collected for nutrient analysis. Wheat samples were collected as grain and as aboveground plant parts. Grain was harvested using a small plot combine, whereas aboveground parts were taken from two randomly placed 1-m2 quadrats. Three whole corn samples were collected from each plot for nutrient analysis, and whole plots were harvested as silage and weighed for yield determination. Soybeans were harvested using a small plot combine. All plant samples were ground to 1 mm using a Wiley mill or a coffee grinder.

Sample Analysis
Aqua Regia Procedure
Plant tissue samples were extracted for total concentration of nutrients using aqua regia digestion (Sastre et al., 2002), which is a 3:1 mixture of hydrochloric acid (37%) and nitric acid (70%). Two grams of tissue were placed in acid washed 250 mL Pyrex digestion tubes. Twenty-eight milliliters of aqua regia was added to each tube and then left overnight for 16 h. The next day the samples were decomposed at 130°C for 2 h. Clean watch glasses were placed over each of the tubes to provide reflux. The suspension was then filtered through ashless Whatman 42 filter paper and diluted to a 50-mL volume with 0.5 mol L–1 HNO3. These samples were then transferred to plastic specimen containers and kept at 4°C until analysis could be performed.

Mehlich 3 Extraction Procedure
To determine nutrient availability in the soil, we used M3 extractant (Mehlich, 1984), which is a standard extractant used in the Atlantic Provinces soil testing laboratories. The extraction was conducted using 10 g of air dried, sieved (2-mm mesh size) soil placed in sealable specimen cups with the addition of 100 mL of M3 solution (1:10 soil–solution). The specimen cups were then placed on a reciprocating shaker for 15 min. The samples were filtered through Whatman 42 filter paper and stored in a cooler at 4°C until analysis could be performed. Elemental analysis of all samples was performed using Inductively Coupled Argon Plasma (ICAP) spectroscopy Model 61 (Thermo Jarrell Ash, Franklin, MA) following the standard procedure outlined in the instrument's manual. Standards for ICAP were prepared using the same matrix as the samples (either 0.5 mol L–1 HNO3 or M3 extractant).

Calculations and Statistical Analysis
Total nutrient removal in harvested tissues was calculated as the product of the tissue concentration of each nutrient and the DM accumulation (Cox and Cherney, 2001). Cumulative nutrient balances were calculated as a sum of the nutrients removed in the crops (kg ha–1) subtracted from the total amount of nutrient applied through manure or inorganic fertilizers (kg ha–1) summed over each year of the 2-yr experiment. This simple form of nutrient balance (Tunney et al., 2003) can identify gross differences in nutrient inputs compared to outputs, and will highlight the need for further investigation if surpluses or deficiencies exist. It is a simplified calculation in which the output represents removal in the harvested plant parts only.

Apparent nutrient (P and K) recovery (ANR) was also calculated for each crop by the difference method:

Formula 1[1]
Statistical analysis of all data sets was performed using the general linear model procedure in SAS (SAS Institute, 1990). The split plot linear model was used for all ANOVAs, and these P values are provided in the results tables. Means comparisons for main effects were performed using the LSD method. Any significant interaction effects identified are displayed graphically to better characterize these interactions.


   RESULTS AND DISCUSSION
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
CONCLUSIONS
 REFERENCES
 
Corn Nutrient Uptake
There was no effect of fertility on corn P or S tissue concentration, and consequently there was no fertility effect on overall removal of these nutrients in 2001 (Table 3). The absence of differences in corn P content is likely due to excessive initial soil test P (90.3 mg kg–1). However, both tissue K concentration and K removal were affected by the fertility treatments. Corn tissue K concentration was generally higher in the manure treatments, and when coupled with DM yields, K removal was highest in LDM1 and LDM 2 (32.1 and 48.1 Mg ha–1). Corn Ca removal was also significant and differences were mainly due to numerical differences in tissue Ca concentration. That is, LDM2 at a rate of 48.1t ha–1 resulted in more Ca removed in corn silage than the other manure treatments and the control (Table 3).


View this table:
[in this window]
[in a new window]

  		Table 3. Effect of fertility and rotation on dry matter (DM) corn yields, and nutrient (P, K, Ca, S) status from 2001 and 2002.

 
Similar to yield results, corn did not respond to rotation or fertility treatments in 2002 with only one exception. Corn tissue concentration of S was significantly lower after soybean than after wheat (Fig. 1 ). Also, within the wheat-corn rotation, plants in the control treatment and the LDM1 had the highest S concentration (Fig. 1). One possible explanation of this interaction effect is that S is being immobilized throughout the field season by the soybean residues and by the higher rates of manure applied within the wheat-corn rotation. Eghball et al. (2002) also indicated S immobilization as a possibility when manure is the main source of S. In addition, Knights et al. (2000) indicated that more than 90% of S in the surface layer of most soils is in the organic form, and immobilization is therefore likely to occur. Further evidence is suggested by Warman and Cooper (2000), that S from organic sources may not be available until several years after application. Due to the large C:S ratios in plant material, net mineralization amounts are lower in soils with high residues when compared to untreated soils (Reddy et al., 2002). Therefore, the combination of manure and residue resulted in different amounts of S taken up by corn. Since most of the above ground plant parts of the wheat were removed from the system, soybean leaves behind more residues for immobilization to occur. Differences between types of residues (above and below ground) may also have an effect on mineralization rates (Soon and Arshad, 2002). In addition, on visual assessment of the weed presence in 2001, weed pressures appeared to be higher under soybean production, than under wheat production. Therefore, weeds could be contributing to the immobilization of S by plant biomass.


Figure 1
View larger version (15K):
[in this window]
[in a new window]

  		Fig. 1. Interaction effect of rotation and fertility treatment on corn tissue S concentrations (g kg–1) in 2002.

 
Reddy et al. (2002) found that from initial immobilization, re-mobilization of S occurred after 10 wk of incubating wheat and soybean residues on two different soils. This could be a possible explanation for the lack of positive correlation between soil available S and corn tissue concentrations of S (compare Tables 3 and 5), and for no differences in M3-S between soybean-corn and wheat-corn rotations. In addition, it has been suggested that M3 may not be the best extractant for prediction of plant available S in the acidic soil types of Nova Scotia (Warman and Cooper, 2000; Warman and Sampson, 1992). Rotation did not significantly affect corn tissue concentration of P, K, and Ca.


View this table:
[in this window]
[in a new window]

  		Table 5. Late season Mehlich 3 soil nutrient composition according to fertility treatment across all rotations.

 
Soybean Nutrient Uptake
In 2001, soybean seed K and nutrient removal of P, K, and S were all affected by fertility (Table 4). In general, P, K, and S removal with soybean seemed to follow the same trend as the differences in seed yield. In addition, soil K availability appeared to follow a similar trend as seed K, and the Pearson correlation coefficient (between seed K and soil M3-K) was found to be 0.56 with a P value of 0.01.


View this table:
[in this window]
[in a new window]

  		Table 4. Effect of fertility and rotation on soybean seed yields, and seed nutrient (P, K, Ca, S) status from 2001 and 2002.

 
In 2002, rotational effects were not significant for either soybean variable (Table 4), but fertility had an effect on P, K, and Ca removal, and on Ca concentration in the seed. Both P and K removal differences are likely due to differences in yields. However, Ca concentration in the soybean responded in another manner. The NPK and unamended control treatments had higher seed Ca concentrations than the LDM2 and LDM 3 (48.1 and 64.3 Mg ha–1) treatments. This trend was opposite to the effect observed in the soil of higher M3-Ca with the application of manure (Table 5). Correlation analysis of soil and tissue Ca revealed no significant correlation with a P value of 0.28. Alternatively, the effect of fertility on seed Ca could be related to the dilution effect, since trends in both seed yields and seed size support this possibility. This is supported by a correlation coefficient of –0.56 (P value = 0.002) between seed size and Ca concentration in 2002. As a result of the treatment effect on tissue Ca, the significant differences in Ca removal did not follow exactly the same trend as P and K removal. Ca removal in the LDM1 of 32.1 Mg ha–1 was significantly higher than Ca removal from the control. Gibson and Mullen (2001), found that K and several other nutrients were negatively correlated with seed filling rates, and therefore, increases in these particular nutrient concentrations were associated with reductions in DM accumulation.

Our results are supported by the results of Schmitt et al. (2001), who found that manure increased P accumulation in soybean by as much as 14% compared with the control. Also, it was similarly concluded that this increase was mainly due to increases in DM production, as opposed to increased tissue concentration of P. In addition, Gibson and Mullen, (2001) reported similar concentrations of P in soybean seed at maturity. The apparent P recovery from manure ranged from 25 to 8.5% and was higher in LDM1 and LDM2 treatments compared with LDM3 (Table 6). It is typical for P recovery to decrease with increasing P application rates (Eghball and Power, 1999).


View this table:
[in this window]
[in a new window]

  		Table 6. Apparent P and K recovery in each crop according to fertility treatment.

 
Wheat Nutrient Uptake
In 2001 there were no differences in wheat nutrient concentration (Table 7). However, wheat grain K concentration showed some marginal differences (P = 0.08) between fertility treatments. The NPK and the LDM2 (48.1 Mg ha–1) had greater grain K concentration than the LDM1 (32.1 Mg ha–1). The observed response may be related to the interaction between the treatment effect on soil K availability (Table 5) and other abiotic or biotic factors. In contrast to these findings, Askegaard et al. (2003) found no response of wheat and oats to K fertility application, despite low soil K concentration. However Matsi et al. (2003) indicated that wheat grain contained an average K concentration of 4.0 g kg–1 at harvest, and that straw accumulation of K was higher when LDM was applied. The overall concentrations of some nutrients in the wheat tissues appeared lower than some reference ranges. However, timing (hence plant maturity) of tissue sampling has an effect on analysis results (Marschner, 1995; Mills and Jones, 1996). Wheat grain Ca in 2001 also had significant differences between fertility treatments; however, there were no significant differences in soil M3-Ca (Table 5) or wheat Ca concentration (Fig. 2 ).


View this table:
[in this window]
[in a new window]

  		Table 7. Effect of fertility treatment and rotation on wheat grain and wheat tissue concentrations of P, K, Ca, and S.

 

Figure 2
View larger version (14K):
[in this window]
[in a new window]

  		Fig. 2. (A) The effect of fertility treatment on wheat phosphorus removal in 2002, and (B) the interaction effect of rotation and fertility on wheat tissue calcium concentration in 2002.

 
In 2002 there was no treatment effect on wheat grain or tissue concentration of P, K, or S; however, there was a significant interaction effect between rotation and fertility on tissue concentration of Ca (Fig. 2B). Even though soil M3-Ca appears to increase with the addition of manure (Table 5), wheat uptake of Ca appears to be lower in all manure treatments, especially when grown after corn (Fig. 2B). Also, control and NPK treatments within the corn-wheat rotation had higher tissue Ca. It appears this could be related to an antagonistic effect of increased soil K concentration on Ca (Table 5). Marschner (1995) reported that the Ca requirement is augmented when the external concentration of other cations is high due to the ability of cations to displace Ca from binding sites on the surface of the plasma membrane. This inference is further supported by a correlation coefficient between soil K concentration and tissue Ca concentration of –0.6.

Potassium concentration may be one factor affecting the wheat Ca. However, the soybean-wheat rotation results do not support the same scenario. It is possible that differences in residue type (either corn or soybean) have an effect on the uptake of Ca by wheat. Since monocots generally require less Ca than dicots (Marschner, 1995), and soybean leaves a higher proportion of residue on the soil surface compared with corn, plots that contain soybean residues may contain more organically bound Ca than those with corn residues. Differences in soil Ca due to rotation may not have been detectable by statistical analysis if the Ca had become available by the end of the season (at the time of soil sampling) or if the M3 extractant was strong enough to extract the labile organically bound Ca. Furthermore, despite differences in wheat Ca, wheat grain did not show the same response to rotation. There were no differences in Ca concentration of the wheat grain tissues in 2002, indicating that the crop was equally able to redistribute Ca to the grain regardless of Ca status.

There was also a significant effect of fertility on wheat removal of P in 2002 (Fig. 2A). Phosphorus removal by wheat s appears to be due to differences in wheat yields, with the inorganic fertility treatment removing more P than all manure treatments and the control removing the least.

Since there were no significant differences between wheat grain tissue concentration for either P, K, Ca, or S in 2002, we assume that the interaction effect observed for nutrient removal was mainly due to yield differences. Each nutrient appeared to follow the same interaction pattern as grain yields (Fig. 3 ). The NPK treatments for both rotations removed equivalent amounts of nutrients (either P, K, Ca, or S); however, the three manure treatments differed by rotation. In general, wheat after corn seemed to remove more nutrients from the manure treatments, as can be seen by comparing the highest and lowest rates of manure between each rotation. In general, wheat yield responded better to inorganic fertility than to manure, and this was also reflected in the differences between apparent recovery of K (Table 6). In both seasons, apparent K recovery in wheat was higher in the inorganic fertilizer treatment compared with the manure treatments, with 37% recovery in 2001 and 19% in 2002. Within the manure treatments, K recovery ranged from 3 to 15%, with few significant differences in either season. There were no differences between apparent P recovery in wheat (Table 6).


Figure 3
View larger version (22K):
[in this window]
[in a new window]

  		Fig. 3. Interaction effect of rotation and fertility on wheat grain P removal, wheat grain potassium removal, wheat grain Ca removal, wheat grain S removal, and wheat grain yield in 2002.

 
Soil Nutrient Availability
According to the Nova Scotia Department of Agriculture and Fisheries rate classification table, mean M3-P, K, and Ca across all treatments were in the high plus (H+), medium plus (M+), and medium (M) range, respectively. Since there were no significant differences between rotations, Table 5 indicates M3 extractable nutrient means according to fertility treatment only. Soil results from the 2001 field season demonstrated few differences (Table 5). However, M3-K was higher in the highest manure rate (LDM3) compared with both the inorganic treatment and the control. In addition, although none of the other variables show significance, in general, concentrations of nutrients tended to be lower in the control treatment than in all other treatments. Askegaard et al. (2003) found that manure application and moderate output from plant residues resulted in positive K balances. Also Chen and Samson (2002) found that after the first year of manure application, soil K concentrations were higher than inorganic treatments in the following years of a corn-soybean rotation.

In 2002, the effect of manure on M3-K was similar to the previous year in that soil K concentrations were higher in all LDM treatments compared with the control, but also compared to the NPK treatment. Similarly, Reider et al. (2000) found that soil K concentration increased over a 3-yr application of LDM, when applied at a rate based on the N requirements of the crop. Although K availability varied according to fertility treatment, it does not yet appear to be increasing over time. With further sequences of the rotation, possibilities of nutrient buildup may become apparent. The M3-Ca and S appear to follow a similar trend as K, with LDM treatments higher than the control treatment. In addition, there were no significant differences in pH between fertility treatments in either growing season. Therefore, under the conditions of our experiment, soil pH was not a factor affecting nutrient availability between treatments.

Also in 2002, there was a drop in M3-P in the LDM3 (68.4 Mg ha–1) in comparison with the other LDM treatments, despite having the highest P input of all treatments. Several authors have indicated an increase in soil P availability with the use of manure or composts in comparison with inorganic treatments (Siddique and Robinson, 2003; Chen and Samson, 2002; Mkhabela, 1998). However, it has also been stated previously that the addition of available Ca in manures can result in a decrease in P availability due to the formation of Ca-P precipitates (Siddique and Robinson, 2003). However, in this instance there was a contradiction between LDM rates, since the lower LDM rates appeared to enhance soil available P compared with the unamended treatment. Furthermore, it is well documented that P availability depends not only on the source of P, but also on the soil environment (Ebeling et al., 2003; Eghball et al., 2002). Phosphorus mineralization from organic materials such as manure are dependent on the soil microbial activity. If the high rate of LDM were to suppress microbial activity, then mineralization would be slowed. Other researchers have reported an increase in soil sorption capacity for P with the addition of manures (Laboski and Lamb, 2004); however, this occurs in fewer cases than the opposite effect. In our study, there is insufficient evidence to determine if microbial activity has been affecting the mineralization or immobilization of this high rate of manure. Also in view of the role of plant residue in mineralization, it must be noted that for all crops in 2001 there was a suppression of yield in the LDM3, and therefore less plant residue remained in the LDM3 plots. Despite these observations, the concentration of M3-P did not appear to have a significant impact on crop yields in 2002. Since initial and subsequent soil tests revealed that P concentration were in the high range for each crop, it is expected that soil P was sufficient to supply all crops during this experiment.

Nutrient Balances
To identify significant rotation x fertility interactions, statistical analysis of nutrient balance was performed by separating data according to crop grown in 2002. This assures that differences in cumulative amounts of nutrients included effects caused by removals from the previous seasons crop harvest. For example, soybean grown after wheat in combination with a high rate of LDM left less excess P than when it was grown after corn at the same fertility rate (Fig. 4 ). Values represent the amount of nutrient applied in excess of crop removal after two growing seasons. Our results indicated that the main effect of fertility was significant in all cases (Table 8), and the interaction effect of rotation x fertility was significant for P under soybean rotations (Fig. 4).


Figure 4
View larger version (15K):
[in this window]
[in a new window]

  		Fig. 4. Interaction effect of rotation and fertility on cumulative amount of P applied in excess of crop removal under two soybean rotations (kg ha–1).

 

View this table:
[in this window]
[in a new window]

  		Table 8. Cumulative amounts of P, K, and Ca applied in excess of crop removals according to crop seeded in 2002 and fertility treatment.{dagger}

 
As was expected, the highest amount of K added that was not removed by the crop came from the highest LDM rate (64.3 Mg ha–1), regardless of crop rotation (Table 8). Also, even at the lowest LDM rate (32.1 Mg ha–1), the amount of K that was applied in the manure was greater than the amount removed over the 2-yr period. In addition, surplus K was consistently added with the inorganic fertility treatment (NPK) comparable with the lowest LDM rate (32.1 Mg ha–1). Since most of the K in manure and inorganic fertilizer is considered available, the residual K is predominantly present as soil exchangeable and aqueous forms and is at risk of leaching from this system. Another possible fate of excess K is that it can enter one of the less mobile fractions such as nonexchangeable K, or less likely as lattice K (Askegaard et al., 2003). Furthermore, M3-K in our experiments did not indicate an increase in the exchangeable-K fraction from 1 yr to the next (Table 5). Askegaard et al. (2003) also indicated that in a coarse sandy soil, exchangeable K concentration should be below 30 mg kg–1 to reduce soil K losses through leaching in the fall; however, this value would be much higher (and leaching lower) in a soil with >5% clay concentration, which the field soil has.

Since relatively small amounts of P and Ca were applied in the inorganic treatments, it appears that P and Ca are both negatively balanced after the 2-yr period in the NPK treatments, although the P deficit appeared to be much larger than the Ca deficit (Table 8). Under this assumption, crops must have drawn from the existing pools of P and Ca in the soil. Within the LDM treatments, the P and Ca balances indicate increasing surpluses with increasing application rates, as was expected. However, there was no corresponding increase in soil M3-P or Ca. These elements must therefore be present in the soil in some other nonexchangeable pool, or have left the system through one of several possible vectors. They could be bound in plant material such as crop residues and weeds or could be lost through leaching.

Within the soybean rotations, there was a significant interaction between rotation and fertility on the cumulative amount of P remaining after two seasons (Fig. 4). The main differences between rotations occurred at the lowest and the highest LDM treatments. In particular, at the higher rate of LDM, in corn-soybean rotation, the cumulative amount of P applied in excess was higher than in the wheat-soybean rotation. However, the reverse was true at the lowest LDM rate. The observed effect is a result of a combination of differences in P removal between corn and wheat in 2001 and between soybean rotations in 2002. Even though there were no statistical interaction effects on P removal in soybean seed in 2002, differences due to rotation by fertility interaction in the amount of excess P after two seasons are distinguishable.

In general, it appears the inorganic fertilizer treatment resulted in less P being applied in excess of crop requirements compared with the LDM2 and LDM3 (of 48.1 and 64.3 Mg ha–1). This can be attributed to the fact that inorganic P was applied according to the soil test recommendations, whereas P in the manure was not the primary nutrient determining application rates. When manure is applied according to crop N requirements, the amount of P varies depending on the N:P ratio of the type of manure (Tunney et al., 2003). In this case, it appears that all three nutrients (P, K, and Ca) were supplied in excess to crop uptake and removal with LDM2 and LDM3 rates. However, it is also important to note that in several instances nutrient removal was low as a result of lower yields relative to achievable yields in the region. It is expected that in the subsequent years of this long-term study, as yields increase with improved soil properties, so will nutrient removals, and excess nutrients will be moderated.


   CONCLUSIONS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 CONCLUSIONS
REFERENCES
 
Corn response to treatments was weak in the first 2 yr of this experiment; however, there were important observations on S uptake. Interaction effects indicated that immobilization may be a factor in S nutrition early in the season. Combinations of organic material from LDM and plant residues resulted in variable S availability to corn.

The main observation from soybean nutrient use was the effect of fertility treatment on seed concentrations of Ca. Our results suggest that the suppression in seed Ca from manure treatments may be related to the associated increase in yield via seed size (hence a dilution effect). Most differences found in wheat mineral concentration were also related to yield. However, K does appear to be affecting Ca uptake by wheat. Since manure seems to enhance soil available K pools, Ca nutrition may be a future concern with the use of high rates of LDM. Our results indicate that at higher LDM rates, K use efficiency, and the possibility of P, S, and Ca immobilization and impeded uptake of these nutrients may be a concern.

Residue type did have an effect on nutrient availability as early as in the second year of rotation. In this system soybean seemed to leave the largest reserve of aboveground plant material on the soil surface, and therefore inclusion of soybean in rotations may be important for maintaining soil organic matter and nutrient balances. However, the immediate effect of rotation on nutrient immobilization may be a concern for mineral nutrition of corn, soybean, and wheat under no-till system on similar soil types in Atlantic Canada.


   ACKNOWLEDGMENTS
 
Authors acknowledge the financial support by the East Coast Commodities, Inc. This work was also partially supported by Agriculture and AgriFood Canada, AgriFutures Nova Scotia grant #190 awarded to V.D. Zheljazkov (Jeliazkov) et al., and by Nova Scotia Department of Agriculture and Fisheries AgriFocus 2000 Technology Development grant DEV21-022 awarded to Dr. V.D. Zheljazkov (Jeliazkov). We thank Mr. A. Findlay MacRae from AgraPoint Int., Mr. Paul McNeil, Mr. Jeff Key, Mr. Alden Knight, Mr. Doug MacDonald, and Mrs. Jean Lynds from the Nova Scotia Agricultural College for their great support, encouragement, and help with the experiments.


   REFERENCES
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 CONCLUSIONS
 REFERENCES
 





This Article
Right arrow Abstract Freely available
Right arrow Figures Only
Right arrow Full Text (PDF) Free
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Parsons, K. J.
Right arrow Articles by Caldwell, C. D.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Parsons, K. J.
Right arrow Articles by Caldwell, C. D.
Agricola
Right arrow Articles by Parsons, K. J.
Right arrow Articles by Caldwell, C. D.
Related Collections
Right arrow Crop Rotation Systems
Right arrow Nutrient Management
Right arrow Plant Nutrition
Right arrow Soil Fertility and Productivity
Right arrow Animal Waste

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
The SCI Journals Crop Science Vadose Zone Journal
Journal of Natural Resources
and Life Sciences Education		 Soil Science Society of America Journal
Journal of Plant Registrations Journal of
Environmental Quality		 The Plant Genome