Full Terms & Conditions of access and use can be found athttp://www.tandfonline.com/action/journalInformation?journalCode=lcss20

Download by: [199.133.80.80] Date: 29 November 2016, At: 04:57

Communications in Soil Science and Plant Analysis

ISSN: 0010-3624 (Print) 1532-2416 (Online) Journal homepage: http://www.tandfonline.com/loi/lcss20

Macro-Nutrient Concentration and Content ofIrrigated Soybean Grown in the Early ProductionSystem of the Midsouth

H. Arnold Bruns

To cite this article: H. Arnold Bruns (2016) Macro-Nutrient Concentration and Content ofIrrigated Soybean Grown in the Early Production System of the Midsouth, Communications inSoil Science and Plant Analysis, 47:17, 2008-2016, DOI: 10.1080/00103624.2016.1225079

To link to this article: http://dx.doi.org/10.1080/00103624.2016.1225079

Accepted author version posted online: 02Sep 2016.Published online: 02 Sep 2016.

Submit your article to this journal

Article views: 42

View related articles

View Crossmark data

Macro-Nutrient Concentration and Content of Irrigated SoybeanGrown in the Early Production System of the MidsouthH. Arnold Bruns

Crop Production Systems Research Unit, USDA-ARS SEA, Stoneville, Mississippi, USA

ABSTRACTMacro-nutrients in soybean (Glycine max L. Merr.) have not been exten-sively researched recently. Concentrations and contents of nitrogen, phos-phorus, potassium, calcium, magnesium, and sulfur (N, P, K, Ca, Mg, and S)were determined for three irrigated cultivars grown using the early soybeanproduction system (ESPS) on two soils (a sandy loam and a clay) in theMississippi Delta during 2011 and 2012. Data were collected at growthstages V3, R2, R4, R6, and R8. No change in macro-nutrients due to soil typeor years occurred andmodern cultivars were similar to data collected >50 yearsago. Mean seed yield of 3328 kg ha−1 removed 194.7 kg N ha−1, 16.5 kg P ha−1,86.0 kg K ha−1, 17.5 kg Ca ha−1, 9.0 kg Mg ha−1, and 10.4 kg S ha−1. Increasedyields over the decades are likely due to changed plant architecture and/orpests resistance, improved cultural practices, chemical weed control, andincreased levels of atmospheric carbon dioxide (CO2). Yield improvements bygenetically manipulating nutrient uptake appear to be unlikely.

ARTICLE HISTORYReceived 7 July 2015Accepted 21 June 2016

KEYWORDSMacro-nutrients; nutritionalrequirements; soybean

Introduction

Nutritional requirements of crops have always been of interest but, more so now than beforebecause of changing economic and environmental dynamics in crop production. Increaseddemands for limited water supplies for uses other than agriculture along with the resultingdepletion of non-renewable water resources, higher energy and fertilizer costs, adoption ofgenetically modified crops, and climate change (Allen et al. 2012), alter the landscape of cropproduction. Concerns over agriculture’s contribution to increased water consumption and itspossible contamination of water resources sources through current production practices alsostimulate a need for more current information about the nutrient requirements of most of ouragronomic crops.

Recently, Bender, Haegele, and Below (2015) reported on an extensive study of biomass production andnutrient uptake of two Maturity Group (MG) 2.8 and one Mg 3.4 soybean cultivars grown on glacialformed soils near 40° N and 42° N latitude. They concluded that supplemental fertility had a modest effecton increasing biomass and yield but none on nutrient portioning. Prior to this study, Ohlrogge’s (1960)extensive review of available literature prior to 1960 on the uptake of essential nutrients by soybean wasconsidered the primary source of nutrient uptake information on that crop. He stated with respect tonitrogen (N) that daily uptake of available soil N plus symbiotic N, acquired via fixation by Bradyrhizobiumjaponicum, consistently increased to a peak of approximately 5.3 kg N ha−1 d−1 90 d after seeding and thenbegan rapidly falling off. Lathwell and Evans (1951) stated that soybean yield was closely correlated with theN accumulated throughout the season. They concluded that seed yield was mainly determined by pods perplant which was determined by N availability during the bloom period. Though much of the N uptake bysoybean is from symbiosis, it can range from 25% to 75% of the total N required, depending upon available

CONTACT H. Arnold Bruns arnold.bruns@ars.usda.gov Crop Production Systems Research Unit, USDA-ARS, SEA, Box 350,Stoneville, MS 38776, USA.This article not subject to US copyright law.

COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS2016, VOL. 47, NO. 17, 2008–2016http://dx.doi.org/10.1080/00103624.2016.1225079

soil moisture (Zapata et al. 1987). Allos and Bartholomew (1959) had reported earlier that only 50%–75% ofthe total N required formaximumyields could be supplied by symbiotic fixation. AddedN fertilizer thoughhas had mixed results with no increase in seed yields being reported in some studies (Long et al. 1965;Maples and Keogh 1969) and increases in yield in others (Brevedan, Egli, and Leggett 1978; Pettiet 1971).

Research on phosphorus (P) in soybean has demonstrated the most common levels of the elementfound in field grown plants to be between 2.5 and 3.0 mg g−1 dry weight (Ohlrogge 1960). Mederski(1950) found in plants grown outdoors in a sand-nutrient culture system that the mean P level of thetop growth 30 d after seeding was 6.5 mg g−1 of the total dry weight. Later, at 6 d pre-bloom, themean total P content was 10.5 mg g−1. Hammond, Black, and Norman (1951) reported shortlythereafter that at maturity between 82% and 85% of the P taken up by a soybean plant will becontained in the seed.

Soybean is considered to require potassium (K) at a level 30%–50% of the N level required bythe plant (Varco 1999). Over 50 years ago, some of the most striking responses of soybean toadded fertilizer were by way of K salts, especially in the Southeastern United States (Ohlrogge1960). However, many of those soils were low in available K at the onset and similar consistentincreases were not obtained in the Midwest. Fertilizing with K salts is known to result inincreases in pods per plant, root nodule number and total mass, improved water stress tolerance,and a decrease in disease incidence (Bharati, Wigham, and Voss 1986; Jones, Lutz, and Smith1977). Sale and Campbell (1986) reported that a reduction in K to deficient levels for soybeanplants growing in a sand culture reduced seed yields, oil levels, seed [K], and an increase in seedprotein concentration. They also reported though that soybean seems to respond to K fertilizationas late as anthesis. Jeffers, Schmitthenner, and Kroetz (1982) demonstrated that K nutrition andsoybean seed quality were closely correlated. Soybean yields from treatments receiving addedfertilizer of 372 kg K ha−1 were 2400 kg ha−1 compared to 1650 kg ha−1 from plots receiving noadditional K. A reduction in the incidence of Phomopsis, a seed mold fungus, of 165 g kg−1 ofseed was also noted.

Calcium is known to be vital to soybean for cell division, root hair development, as a co-factor inseveral enzymatic functions, and aids in plant disease resistance (Willis 1989). However, in excessiveamounts it can interfere with the uptake of other cations, especially magnesium (Mg) and K. Rayar(1981) reported that maximum growth of soybean growing in nutrient solution cultures of varying[Ca] was found to occur at 249.5 µM Ca. Deficiency symptoms were noted at 24.9 µM Ca. At[Ca] > 249.5 µM Ca, tissue [P], [K], and [Mg] began to decline. Calcium is known to be immobileonce taken up by the plant and is not translocated from older tissue to developing cells (Varco 1999)It is therefore essential to have an adequate supply of available Ca throughout the growing seasonalong with sufficient water which has been shown to facilitate Ca uptake (Karlen, Hunt, andMatheny 1982).

Magnesium’s most important function in any green plant is the metal co-factor of the chlorophyllporphyrins. It is also utilized in protein construction in plants. Minimal sufficient levels of Mg insoybean have been determined to be approximately 2.6 mg g−1 of the dry weight. Deficiencies in Mgusually result in an interveinal chlorosis and a general unhealthy appearance of the plant. They aremost frequently noticed in plants growing on light sandy soils with low cation exchange capacity(CEC’s) and seldom noticed on slits, silty clays or clay soils. As mentioned previously excesses in Cacan interfere with Mg uptake and Bruns and Abbas (2010) concluded that an excess of K fertilizer oncorn (Zea mays L.) likely reduced grain yields by interfering with Mg uptake.

Sulfur is essential in the synthesis of the amino acid cysteine and methionine but has seldom beenfound deficient in soybean production. In a summarization of research conducted in the south-eastern US Kamprath and Jones (1986) found that a response to sulfur (S) fertilizer occurred at onlytwo of nine sites. Positive yield responses to S fertility occurred only on soils with ≤4.0 mg kg−1 Swith no responses note for soils with ≥8.0 mg kg−1 S.

Soybean production in the lower Mississippi River Valley (31° N–34° 30ʹ N) has undergonesweeping changes during the past 25 years. Adoption of the ESPS which involves planting MG IV

COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS 2009

and V cultivars prior to 1 May, along with supplemental irrigation, has been fully accepted bygrowers in the region. Prior to development of ESPS this region grew MG V thru MG VII cultivars,planted in mid-May to early June which experienced drought and heat stress resulting in poor seedyields. Newer cultivars better adapted to the ESPS and most recently the nearly complete adoption oftwin-row planting has all lent to a mean increase in yields for Mississippi alone, from approximately1411 kg ha−1 (Gregory and Corley 1996) to 2755 kg ha−1 in 2011 (MSUCares.com 2014). Using theformer mean yield, Varco (1999) states that the nutrient removal through seed harvest wasequivalent to 123.0 kg N ha−1, 11.2 kg P ha−1, and 39.2 kg K ha−1. The objectives of this experimentwere (1) to acquire detailed information on some of the macro-nutrient compositions of irrigatedsoybean cultivars now commonly grown in the Lower Mississippi River Valley in the ESPS systemand (2) to compare these data from two contrasting soils commonly used to grow soybean in theregion employing recently adopted production practices to past data sets from other areas.

Materials and methods

The experiment was conducted during the 2011 and 2012 growing seasons at two sites. One site was aBosket fine sandy loam site (fine-loamy, mixed, active, thermic Mollic Hapludalfs), located on theMississippi State University Delta Branch Research and Extension Center. Soil tests prior to initiatingthe experiment showed this site to have a pH = 6.8, organic matter (OM) = 18.3 g kg−1,P = 54.0 kg ha−1, and K = 53.7 kg ha−1. The second site was a Dundee silty clay (fine-silty, mixed,active, thermic Typic Endoaqualfs) located on private property leased by the Crop Production SystemsResearch Unit of the United States Department of Agriculture—Agricultural Research Service (USDA-ARS). Soil tests at this site showed a pH = 6.7, OM = 22.8 g kg−1, P = 38.0 kg ha−1, andK = 64.9 kg ha−1. A pre-plant annual application of 0–33–66, N–P–K was applied both years of theexperiment. The experimental design employed in the study was a randomized complete blockreplicated three times. Experimental units were one of three soybean cultivars, Asgrow1 (Monsanto;St Louis, MO) AG4303 (MG 4.3), Pioneer1 (DuPont; Johnston, IA) 94B73 (MG 4.8), and AsgrowAG5503 (MG 5.5). Plots were eight 12 m rows seeded in a twin-row configuration planted with aMonosem1 NG3 (Monosem; Edwardsville, KS). Each row of a twin-row unit was spaced 25 cm apartand centered on 102 cm between units. A seeding rate of 30 seed m−2 occurred on 14 April 2011 atboth locations, 23 April 2012 on the Dundee soil, and 25 April 2012 on the Bosket soil. The previouscrop at both sites in 2011 was corn (Zea mays L.) and soybean in 2012.

Weed control was achieved by the herbicide combinations of metolachloro and glyphosateapplied according to label directions for soybean crops grown in Mississippi. Furrow irrigations ofapproximately 25.0 mm each were applied about every 10 d or 10 d after a rain event of 25.0 mm ormore on the Dundee soil site beginning at growth stage V4 (four trifolates unfolded) as defined byRitchie et al. (1994) and continuing until R7. Irrigations on the Bosket soil required a 7-d scheduledue to the poor water holding capacity of the soil.

Beginning at growth stage V3 (three trifolates unfolded) and continuing at R2 (full flowering), R4(full pod), R6 (full seed), and R8 (full maturity), three randomly selected plants from each plot wereharvested from either row 2 or row 7. Sampling was done on individual cultivars as they reached thedescribed growth stage (Ritchie et al. 1994) and as weather would permit. Leaf area of each harvestedplant was measured using a LiCor1 LI-3100C (Li-Cor Inc., Lincoln NE) leaf area meter at R2, R4, andR6. Leaves, stems, and pods from each plot were placed in separate bags, oven dried at 70°C for atleast 76 h, weighed, and then ground to pass a 2.0 mm screen. A minimum 2.5 g sample of theground tissue was placed a 5 ml plastic sample bottle and sealed for later analysis. Individual sampleswere analyzed by Waters Agricultural Laboratories, Inc.1 (Camilla, GA). Total tissue [N] wasdetermined by the LECO1 combustion method as described by Sweeney and Rexroad (1987),while an open vessel wet digestion method described by Miller (1998) was used to determine allother elements analyzed in this experiment.

2010 H. A. BRUNS

The four center rows of each plot were harvested at maturity (R8) for yield determination. Datafor leaf area [N], [P], [K], [Ca], [Mg], and [S] along with their total contents in the leaf, stem, pod,seed, and residue (dead stem and pod tissue at harvest) were first analyzed using the PROC MIXEDprocedure of SAS 9.4 (Statistical Analysis System SAS Institute, Cary, NC) for individual sitescombined over years with years as a fixed effect. A lack of significance between years and anyinteractions involving years at both sites led to the reanalysis of all data, except for leaf area andyield, with both sites and years being combined and treated as an individual random environmentaleffect. For these analyses, the GLIMMIX and ANOVA procedures of SAS was employed.

Results and discussion

Dry matter accumulation of the various plant tissues and total plant are depicted in Figure 1. Drymatter accumulation for the leaves and stems as well as the whole plant appear to have followed asigmoidal pattern in this study as has been observed in other published data on soybean growth(Ritchie et al. 1994). The loss in total dry matter between R6 and R8 would be due to the abscissionof leaflets and petioles as the plants matured. Peak leaf area occurred at R4 as shown in Figure 2.Differences in leaf area among years as shown in Figure 2 are most likely a result of slight variationsin development at sampling between the 2 years. At R6 plants in 2012 had abscised more leaves bythe time sampling was done than plants at this growth stage in 2011. This growth stage was reachedmuch earlier in 2011 (mid-July) because of earlier seeding that year and a mean maximum airtemperature of 36.1°C 14 d prior to sampling which likely hastened plant development (MSUCares.com 2015). In 2012 planting occurred 12 and 13 d later than 2011and the mean maximum airtemperature 14 d prior to sampling was 25.5oC which likely delayed plant development to R6 tomid-August. Total day length at this time would be approximately 30 min less than in mid-July andwould stimulate leaf abscission in preparation for plant maturity, thus resulting in less leaf area perplant at R6 in 2012 than was observed in 2011 (Major et al. 1975).

The concentrations of macro-nutrients in the tissues of irrigated soybean in this experiment wereobserved to be similar to data reported in other studies completed well over 50 years ago (Table 1)(Ohlrogge 1960). A lack of cultivar differences or differences between soils or years does not supportfurther research into cultivar development or soil fertility management centered on improvingnutrient uptake improvement. Based on these data, improvements in soybean yields over the decadesin which the crop has been a major source of farm income in the United States and elsewhere hasevidently come by way of factors other than increased macro-nutrient uptake and utilization. Yieldincreases have likely occurred by genetic changes in plant architecture and/or pests resistance along

0

5

10

15

20

25

30

35

40

45

V3 R2 R4 R6 R8

g p

er p

lan

t

Growth Stages

Leaf

Stem

Pods

Seed

Residue

Total

Figure 1. Dry matter accumulation per plant (g) of irrigated soybean at five different growth stages and grown in twin-rows in theLower Mississippi River Valley.

COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS 2011

with improved cultural practices such as refined planting dates, irrigation, and improved weedcontrol. Research on increased carbon dioxide (CO2) levels and its effect on dry bean (Phaseolusvulgare L.) yields though have shown significant gains through CO2 fertilization (Porter andGrodzinski 1989) which would suggest that the elevated CO2 levels that has occurred over recentdecades as being partly responsible for increases in seed production.

Except for Ca, micro-nutrient concentrations (Table 1) and contents (Table 2) in the leavesdeclined after R4. Calcium is mainly incorporated into structural tissue such as cell walls, making itimmobile and much of it returns to the soil with leaf senescence. As discussed previously, leaf areapeaked at R4 and then began to decline as leaves aged and started to senesces. This senescence wouldaccount for much of the decline in macro-nutrient content of Ca in the plants’ leaf tissue. However,data on macro-nutrient concentrations (Table 1) show that except for Ca, all other nutrients thatwere analyzed for declined between R4 and R6. These elements are mobile in plant tissue and aretranslocated to the strong sinks of developing seed as evidenced by the large increases in nutrientcontent of the pods between R4 and R6 (Table 2). This remobilization of nutrients from the leaves todeveloping pods and seed however does not nearly account for the large increase in nutrient contentin the reproductive structures, as the concentrations of these elements in the pods either remainsconstant (N and S) or significantly declines (P, K, Ca, and Mg) from R4 to R6. The observedincreases in content of macro-nutrients in the reproductive structures between R4 and R6 are thus aresult of elements that are taken up during this time and incorporated directly into that tissue.

Macro-nutrient concentrations of stem tissue remained comparatively constant from V3 to R2 andthen began to significantly decline thereafter for most elements (Table 1). By contrast, the totalcontents of the elements analyzed significantly increased from R2 to R6, with Ca and Mg showingsignificant increases between R4 and R6 (Table 2). At maturity (R8), though, the crop residue, which islargely stem tissue, showed that the contents per plant of the elements analyzed for had declined greatlyfrom the levels observed at R6. During the sampling processes at R4 and R6, a considerable amount ofthe macro-nutrients contained in the stems would have been what was being translocated to thedeveloping seed along with what was incorporated into the stem tissue itself. By R8 all translocationhad ceased and only the elements incorporated into the cells of the stem would have remained.

Macro-nutrient concentrations and content of most of the elements in the seed at R8 were withinrange of previously published data (Bellaloui, Stetina, and Molin 2014; Morse 1950; Ohlrogge 1960;Porter and Grodzinski 1989). Except for K, Ca, and Mg, concentrations of all other elements in the seedwere much higher than in the residue (Table 1). However, the total contents of all the elements in theseed were considerably greater than that remained in the residue (Table 2). Based on these data from

0

200

400

600

800

1000

1200

1400

1600

1800

V3 R2 R4 R6

cm

-2

Growth Stage

2011

2012

Figure 2. Total plant leaf area of irrigated soybean at four growth stages grown in twin-rows at two sites in the Lower MississippiRiver Valley.

2012 H. A. BRUNS

Tables 1 and 2, the 3328 kg ha−1 grand average seed yield (48 bu/A) of this experiment removed about194.7 kg N ha−1, 16.5 kg P ha−1, 86.0 kg K ha−1, 17.5 kg Ca ha−1, 9.0 kg Mg ha−1, and 10.4 kg S ha−1. Theamount of macro-nutrients returned to the soil in the residue and abscised leaves were not calculated inthis experiment because the total weight of that material per hectare was not determined. It would notbe possible in the field to determine from what plant abscised leaves between R4 and R6 had come fromand by R8 those leaves would be badly decomposed. The amount of the measured elements availablefrom this soybean residue for succeeding crops will be very dependent on fall and winter rainfall,temperature, and soil type that influence leaching, microbial activity, as well as the pH of the soil.

The macro-nutrient contents of the whole plant at the observed growth stages are presented inTable 3. Two elements (N and P) had significant (P ≤ 0.05) steady increases in content from R2 toR8, while S content significantly increased from R2 to R6 and tended towards an increase from R6 toR8. Nutritionally soybean is known to be a rich source of protein for human and livestock diets but acomparatively high producer of phythate, a P storage compound in plants that is important ingermination but indigestible by humans and monogastric animals. This can lead to deficiencies iniron (Fe) and zinc (Zn) by binding with phythate in the gut, preventing these elements from beingabsorbed into body (Andrews 2015).

Sulfur is a component of the essential amino acids cysteine and methionine which areincorporated into the protein contained in the seed. These factors help explain the continuedincrease in N, P, and S throughout the growing season. Potassium, Ca, and Mg are not as muchof a seed component and appear primarily in structural tissue (Ca), water utilization andenzymatic reactions (K), particularly photosynthesis (K and Mg) and the overall seasonal growthof the plant.

Table 1. Macro-nutrient concentration (mg g−1) of irrigated soybean at five different growth stages grown in the lower MississippiRiver Valley †.

Tissue Element V3 R2 R4 R6 R8 lsd0.05 =

Leaves N 47.35 50.72 48.07 34.10 3.20P 2.94 3.38 2.83 2.21 0.20K 19.61 18.21 15.33 13.28 1.36Ca 16.56 16.11 14.85 21.38 1.40Mg 5.69 5.50 4.00 3.29 0.40S 2.64 2.80 2.75 2.22 0.20

Stems N 22.04 20.87 15.04 11.10 2.14P 2.38 2.59 2.35 1.80 0.26K 30.91 34.36 23.55 14.91 2.70Ca 16.05 14.87 10.95 10.48 1.36Mg 5.15 4.96 3.85 3.49 0.38S 1.72 1.67 1.28 1.09 0.22

Pods N 38.96 40.04P 4.47 3.87*K 28.49 25.94*Ca 10.98 7.89*Mg 4.28 3.80*S 2.20 2.18

Seed N 58.51P 5.56K 21.59Ca 5.26Mg 2.70S 3.13

Residue N 11.09P 1.40K 21.27Ca 9.54Mg 4.26S 0.83

†Means of three cultivars (AG4303, 94B73, and AG5503), 2 years (2011 and 2012), two sites (Tunica clay and Bosket fine sandyloam), three replications, and three plants.

COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS 2013

Data on the cultivars used in this experiment showed no consistent differences in nutrientconcentration or content during the growing season (Table 4). At maturity (R8) there weresignificant (P ≤ 0.05) differences in residue dry weight between all three cultivars along withtotal P content (Table 4). Other differences were noted between AG5503 and the other twocultivars for total N, and K content and between AG4403 and the other two cultivars for totalCa and Mg content. No significant differences were noted among the three cultivars for total Scontent in the residue. No significant differences between cultivars were observed for seedweight per plant or total macro-nutrient content of any of the elements analyzed (Table 4).

Table 2. Macro-nutrient content (mg plant−1) of irrigated soybean at five different growth stages grown in the lower Mississippi RiverValley†.

Tissue Element V3 R2 R4 R6 R8 lsd0.05 =

Leaves N 71.72 139.94 414.03 204.70 127.87P 4.43 9.28 24.32 13.43 8.67K 29.65 50.95 139.07 81.44 38.82Ca 24.85 44.78 125.75 123.21 55.55Mg 8.22 14.54 32.74 17.37 12.8S 3.95 7.74 23.95 13.31 8.3

Stems N 26.87 54.52 138.21 171.99 61.48P 2.88 6.7 21.22 26.54 5.48K 37.9 89.5 210.49 228.30 85.71Ca 19.78 38.6 100.94 153.28 48.26Mg 6.11 12.31 34.23 47.84 16.0S 2.15 4.43 11.91 16.33 6.0

Pods N 194.76 830.92*P 20.73 80.74*K 136.77 538.88*Ca 44.84 160.0*Mg 18.28 74.92*S 10.27 45.26*

Seed N 1366.13P 129.90K 505.0Ca 124.20Mg 63.73S 74.41

Residue N 102.50P 12.81K 189.82Ca 87.20Mg 38.33S 8.50

†Means of three cultivars (AG4303, 94B73, and AG5503), 2 years (2011 and 2012), two sites (Tunica clay and Bosket fine sandyloam), three replications, and three plants.

Table 3. Whole plant macro-nutrient content (mg) of irrigated soybean at five different growth stages, and grown in twin-rows inthe lower Mississippi River Valley†

Element V3 R2 R4 R6 R8 lsd0.05 =

N 98.59 194.46 748.64 1207.59 1468.61 321.4P 7.3 15.98 66.41 120.71 142.76 36.83K 67.59 140.87 486.61 848.62 694.76 221.94Ca 44.63 83.38 273.42 436.49 211.39 112.24Mg 14.33 26.85 85.58 140.14 102.03 35.21S 6.10 12.67 46.24 74.9 82.92 21.36

†Means of three cultivars (AG4303, 94B73, and AG5503), 2 years (2011 and 2012), two sites (Tunica clay and Bosket fine sandyloam), three replications, and three plants.

2014 H. A. BRUNS

Conclusion

Based on these data, it appears that macro-nutrient concentrations in soybean has basically remainedunchanged despite improvements in yield. These data do not encourage the exploration of improvingsoybean yields by seeking changes in nutrient uptake and utilization by the plant. It does provide informa-tion on nutrient concentration and content of soybean which has largely been ignored for nearly 50 y. Datasuch as this can be useful in revising and refining soil fertility recommendations for soybean productionwhich could be useful given the steady increase in seed yields (41.6 kg ha−1 y−1) over the past25 y (USDA-NASS 2015).

Disclaimer

Trade names used in this publication are solely for the purpose of providing specific information. Mention of a tradename, propriety product, or specific equipment does not constitute a guarantee or warranty by the USDA-ARS anddoes not imply approval of the named product to exclusion of other similar products. The author declares there is noconflict of interests regarding the publication of this article.

References

Allen, L. H., K. J. Boote, J. W. Jones, P. H. Jones, R. R. Valle, B. Acock, H. H. Rogers, and R. C. Dahlman. 2012.Responses of vegetation to rising carbon dioxide: Photosynthesis, biomass, and seed yield of soybean. GlobalBiogeochemical Cycles. [Online]. doi:10.1029/GB001i001p00001.

Allos, H. F., and W. V. Bartholomew. 1959. Replacement of symbiotic fixation by available nitrogen. Soil Science87:61–66. doi:10.1097/00010694-195902000-00001.

Andrews, R. 2015. Phytates and phytic acid. [Online]. http://www.precisionnutrition.com/all-about-phytates-phytic-acid.

Bellaloui, N., S. R. Stetina, and W. T. Molin. 2014. Soybean seed nutrition as affected by cotton, wheat, and fallowrotation. Food and Nutrition Sciences 5:1605–1619. doi:10.4236/fns.2014.516173.

Bender, R. R., J. W. Haegele, and F. E. Below. 2015. Nutrient uptake, partitioning, and remobilization in modernsoybean varieties. Agronomy Journal 107:563–573. doi:10.2134/agronj14.0435.

Bharati, M. P., D. K. Wigham, and R. D. Voss. 1986. Soybean response to tillage and nitrogen, phosphorus, andpotassium fertilization. Agronomy Journal 78:947–950. doi:10.2134/agronj1986.00021962007800060002x.

Brevedan, R. E., D. B. Egli, and J. E. Leggett. 1978. Influence of N nutrition on flower and pod abortion and yield ofsoybeans. Agronomy Journal 70:81–84. doi:10.2134/agronj1978.00021962007000010019x.

Bruns, H. A., and H. K. Abbas. 2010. Additional potassium did not decrease aflatoxin or fumonisin nor increase cornyields”. Crop Management 9.[Online]. doi:10.1094/CM-2010-0216-01-RS.

Gregory, T. L., and S. D. Corley. 1996. Mississippi Ag Report 96-17: 1-4, USDA-NASS-MASS-MDAC. Jackson, MS:Mississippi Department of Agriculture and Commerce.

Hammond, L. C., C. A. Black, and A. G. Norman. 1951. Nutrient uptake by soybeans on two Iowa soils. IowaAgricultural Experiment Station Research Bulletin 384:463–512.

Jeffers, D. L., A. F. Schmitthenner, and M. E. Kroetz. 1982. Potassium fertilization effects on phomopsis seed infection,seed quality and yield of soybeans. Agronomy Journal 74:886–890. doi:10.2134/agronj1982.00021962007400050028x.

Table 4. Total plant nutrient content (mg) in the crop residue and seed of three irrigated soybean cultivars at maturity (R8) overtwo growing seasons grown at two sites in the lower Mississippi River Valley†.

Residue wt (g) Total N Total P Total K Total Ca Total Mg Total S

Cultivar 94B73 9.01 99.72 10.45 164.84 99.87 40.2 8.97AG4303 6.29 66.08 8.55 158.73 61.87 30.34 5.62AG5503 12.41 141.65 19.5 245.74 99.74 44.49 10.98

Seed wt (g) Total N mg Total P mg Total K Total Ca Total Mg Total S

Cultivar 94B73 23.3 1373.11 132.3 500.48 117.76 62.78 75.72AG4303 22.1 1275.27 127.47 473.13 120.74 65.2 73.84AG5503 24.6 288.61 130.01 541.37 134.17 63.09 73.62

†Means of two sites, 2 years (2011 and 2012), three replications, and three plants. Means within a column that are bolded aresignificantly different @ P ≤ 0.05 from other means within the same column of data.

COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS 2015

Jones, G. D., J. A. Lutz Jr., and T. J. Smith. 1977. Effects of phosphorus and potassium on soybean nodules and seedyield. Agronomy Journal 69:1003–1006. doi:10.2134/agronj1977.00021962006900060024x.

Kamprath, E. J., and U. S. Jones. 1986. Plant response to sulfur in the southeastern United States. In Sulfur inagriculture, ed. M. A. Tabatabia, 323–43. Madison, WI: Agronomy Monograph. 27, ASA, CSSA, and SSSA.

Karlen, D. L., P. G. Hunt, and T. A. Matheny. 1982. Accumulation and distribution of K, Ca, and Mg by selecteddeterminate soybean cultivars grown with and without irrigation. Agronomy Journal 74:347–354. doi:10.2134/agronj1982.00021962007400020021x.

Lathwell, D. J., and C. E. Evans. 1951. Nitrogen uptake from solution by soybeans at successive stages of growth.Agronomy Journal 43:264–270. doi:10.2134/agronj1951.00021962004300060004x.

Long, O. H., J. R. Overton, E. W. Counce, and T. McCutchen. 1965. Lime and fertilizer experiments on soybeans, 391.Knoxville, TN: University of Tennessee Agriculture Experiment Station Bulletin.

Major, D. J., D. R. Johnson, J. W. Tanner, and I. C. Anderson. 1975. Effects of day length and temperature on soybeandevelopment. Crop Science 15:174–179. doi:10.2135/cropsci1975.0011183X001500020009x.

Maples, R., and J. L. Keogh. 1969. Soybean fertilization experiments. Arkansas Agriculture Experiment Station ReportSeries 178. Fayette, AR: University of Arkansas.

Mederski, H. J. 1950. Relation of varying phosphorus supply to dry matter production, and to N and P partitionduring the development of the soybean plant. Abstracts of Doctoral Dissertations, Ohio State University. Vol. 64.

Miller, R. D. 1998. Nitric-perchloric acid wet digestion in an open vessel. In Handbook of reference methods for plantanalysis, ed. Y. P. Karla, 57–62. Boca Raton, FL: CRC Press.

Morse, W. J. 1950. Chemical composition of soybean seed. In Soybean and soybean products, ed. K. S. Markley, Vol. 1,135–154. New York, NY: Interscience Publications, Inc.

MSUCares.com. 2014. Soybean production in Mississippi. Mississippi State, MS: Mississippi State University. [Online].http://msucares.com/crops/soybean/verified (accessed November 17, 2014).

MSUCares.com. 2015. Delta agricultural weather center. Mississippi State, MS: Mississippi State University. [Online].http://www.deltaweather.msstate.edu (verified July 7, 2015).

Ohlrogge, A. J. 1960. Mineral nutrition of soybeans. Advances in Agronomy 12:229–263.Pettiet, J. V. 1971. Are nitrogen fertilizers needed for soybean? Mississippi Agricultural and Forestry Experiment.

Station Information. Sheet 1147. Mississippi: Mississippi State University.Porter, M. A., and B. Grodzinski. 1989. Growth of bean in high CO2: Effect on shoot mineral composition. Journal of

Plant Nutrition 12:129–244. doi:10.1080/01904168909363941.Rayar, A. 1981. Effect of calcium concentration on growth and ion uptake in soybean plants in solution culture. Z.

Pflanzenphysiologie 105:59–64. doi:10.1016/S0044-328X(81)80008-6.Ritchie, S. W., J. J. Hanway, H. E. Thompson, and G. O. Benson. 1994. How a soybean plant develops. Special Report

53, Revised Edition Service. Ames, IA: Iowa State University Cooperative Extension Service.Sale, P. W. G., and L. C. Campbell. 1986. Yield and composition of soybean seed as a function of potassium supply.

Plant and Soil 96:317–325. doi:10.1007/BF02375136.Sweeney, R. A., and P. R. Rexroad. 1987. Comparison of LECO FP-228 “nitrogen determinator” with AOAC copper

catalyst Kjeldahl method for crude protein. Journal of AOAC 70:1028–1030.USDA-NASS. 2015. National Agricultural Statistics Service, Quick Stats. [Online]. http://quickstats.nass.usda.gov/

results/70E45139-5E90-3981-AD01-932E3B1BB73F?pivot=short_desc (Verified July 7, 2015).Varco, J. J. 1999. Nutrition and fertility requirements. In Soybean production in the Midsouth, eds. L. G. Heatherly, and

H. F. Hodges, 53–70. Boca Raton, FL: CRC Press.Willis, H. 1989. Growing great soybeans, 1. Austin, TX: Acres USA, March, 6–8.Zapata, F., S. K. A. Danso, G. Hardarson, and M. Fried. 1987. Time course of nitrogen fixation in field-grown soybean

using nitrogen-15 methodology. Agronomy Journal 79:172–76. doi:10.2134/agronj1987.00021962007900010035x.

2016 H. A. BRUNS