Effect Of Planting Method, Seeding Rate, Row Orientation, And

vegetative production was twice as much on north slopes as itwas on south slopes.Baker (4) noted that photosynthesis incotton (Gossypium hirsutum L.) plants decreased with increasingtemperatures, except in the morning hours.Heslop-Harrison(10) stated that yield in crop plants was related to the totalassimilation of nutrients and to the partitioning of those nutri ents to the different plant parts.Pendleton and Dungan (16)noted that grain yields from spring oats (Avena sativa L.)in north-south rows were higher than grain yields from oatsin east-west rows.Singh and Sikka (22) indicated thatplanting furrows for guar(Pusa sadabahar L.) should runeast and west for proper aeration and maximum light inter ception.Day et al.(9) found that when barley was plantedon east-west beds plants on the south side of the bed pro duced more grain, more heads per unit area, more seeds perhead, and heavier seeds than did plants grown on the northside of the bed.Day et al.(9) reported that spring barleyproduced higher grain yields when it was grown on east westbeds than were obtained from plantings on north-south beds.Adams (1) noted that when ridges were constructed inan east-west orientation the south slope of each ridge hada higher soil temperature than did the north slope.Ludwig,Bunting, and Harper (11) reported that when beds wereoriented in an east-west direction the emergence of cornwas earlier on the south-facing slope of beds than it was onthe north-facing slope.

MATERIALS AND METHODSEffects of planting methods, seeding rates, and rowpositions on beds on the yield and quality of grain from'Maricopa1 wheat were studied for a two-year period (1968and 1969) at Yuma, Arizona.The soil was a Glendale silty-clay loam (sand, silt,and clay 62, 6, and 32%, respectively).methodsTwo planting(on the flat and on beds), three seeding rates58, and 87 kg/ha), and four row positions on bedssouth, east, and west) were investigated.(29,(north,Split-plotstatistical designs, with planting methods as main plots andseeding rates as sub-plots, were used to compare twoplanting methods and three seeding rates.Split-plotdesigns, with seeding rates as main plots and row positionson beds as sub-plots, also were used to compare threeseeding rates and four row positions on beds,Randomizedblock designs were used to compare four row positions on22beds. Both large plots (25 M ) and small plots (0.37 M )were used in the foregoing experiments„The soil was plowed, disked, and floated to providea satisfactory seedbedfor. planting.Flat plantings weremade with a regular grain drill with rows 18 cm apart on aflat seed bed.Red plantings consisted of seeding two rowsspaced 30 cm apart on top of elevated Beds prepared By5'

listing on lOO-cm centers.Bed plantings were accomplishedwith a bed' shaper and two International F-185 planting unitsper bed.Wheat was planted in December and harvested inMay of the following year.Each experiment was planted indry soil and irrigated-up following planting with 8 ha-cmper ha of irrigation water, which brought the soil moisturecontent up to field capacity.Future irrigations were madewhen 65% of the available soil moisture had been used.Ateach irrigation sufficient water was applied to bring thesoil moisture up to field capacity.About 7 5 ha-cm per haof irrigation water were required to produce a wheat graincrop.Bed plantings were cultivated for weed control butno herbicides were applied.Fertilization and other culturalpractices were those suggested for wheat in Arizona (2).At maturity, the following data were recorded: (a)heads per unit area,(b) seeds per head,(d) grain volume-weight, and(c) seed weight,(e) grain yield.All datawere analyzed using the standard analysis of variance andmeans were compared with Student'-Newman-Keulfs test asdescribed by Steel and Torrie (23)„

RESULTS AND DISCUSSIONAverage grain yields and grain volume-weights forowheat grown in 25 M plots with two planting methods andthree seeding rates in 19 68 and 1969 are reported in Table1.Flat and bed methods of planting resulted in similarwheat grain yields in 1968, 1969', and when the 1968 and 1969data were combined„In 1968, when wheat was planted on theflat, the three seeding rates resulted in similar grainyields.When wheat was grown on beds, the 58 and 87 kg/haseeding rates resulted in higher grain yields than wereobtained when wheat was planted at 29 kg/ha.In 1969 andwhen the 1968 and 1969 data were combined, the threeseeding rates within each planting method resulted insimilar wheat grain yields.Since the two planting methodsresulted in similar grain yields, each grower should usethe planting method that is best adapted to his individualfarming operation.In areas where flood irrigation ispossible, flat planting may be desirable; however, infields that cannot be flood irrigated and where surfacedrainage is a problem planting wheat on beds may Be ad- visable.Since the three seeding rates, within eachplanting method, resulted in similar wheat grain yields afarmer should use the lowest suggested seeding rate for his

Table 1.Average grain yields and grain volume-weights for Maricopa wheat grownwith two planting methods and three seeding rates at Yuma, Arizona in1968, 1969, and when the 1968 and 1969 data were averaged.Grain yields(kg/ha)Grain volume- weights(kg/hi)Seeding rates(kg/ha)196819691968 -6919681969Flat2958873199 a3357 a3483 a4880 a4982 a5017 a4040 a4170 a4 250 a75 a75 a75 a78 a78 a78 a78 a79 a79 aBed2958873118 a3552 b3568 b4183 a4443 a4331 a3651 a3998 a3950 a78 a78 a78 a78 a78 a78 a78 a78 a78 a121212PlantingmethodsC.V.(% 1968-69. 291*nsnsnsnsnsSignificance of differences: .Between planting methodsBetween planting rates.ns**nsns.ns. ns. ;Legend: ns not significant at 5%, * significant at 5%, ** signifi cant at 1% „Means followed by the same letter, within planting methods and betweenseeding rates, are not different at the 5% level of significance (Student-*Newman Keul test)

area to reduce seed costs to a minimum.This practice wasalso suggested by Niffenegger and Davis (12).In 1968, bed plantings resulted in higher wheatgrain volume- weight than did flat plantings, and seedingrates within planting methods resulted in similar grainvolume-weight„In 1969 and when the 1968 and 1969 data werecombined, wheat grain volume-weights were similar for thetwo planting methods and for the three seeding rateswithin each method.Since wheat grain volume-weight, ingeneral, was not influenced by planting methods or seedingrates these cultural practices may not be important con siderations for most wheat growers in Arizona.Tables 2, 3, and 4 present the average number ofheads per unit area, number of seeds per head, seed weight,and grain yield for wheat grown in 0.37planting methods and threeseedingplots with tworates in 1968 and 1969.\Flat and bed methods of planting wheat resulted in similarnumbers of heads per unit area in 1968 and when the 1968and 1969 data were combined.In 1969, flat planting pro duced more heads per unit area than did bed planting.Method of planting had no significant effect on seeds perhead, and seed weight of wheat in 1968, 1969, and when the1968 and 1969 data were combined.Bed planting resulted inhigher wheat grain yields in 1968., flat planting producedhigher yields in 1969, but when the 1968 and 1969 data werecombined no significant differences in grain yields were

Table 2„PlantingmethodFlat,BedC.V.Average number of heads per unit area, number of seeds per head, seedweight, and grain yield for Maricopa wheat grown with two plantingmethods (flat and bed) and three seeding rates at Yuma, Arizona in1968.Seedingrate(kg/ha)Heads in0.37 m 2(no. )Seeds perhead(no. )Weight of1,000 seeds(g)Grain yieldin 0.37 M 2(g )295887106 a121 b117 b40 b37 ab35 a31.7 a31. 7 a32.1 a132 a141 a132 a295887104 a116 b124 b38 a37 a .35 a33.3 a34.3 a34.1 a' 131 a145 a148 a(%)9789ns**ns*nsns*nsSignificance of differences :Between planting methodsBetween planting ratesLegend: ns not significant at 5%, * significant at 5%, ** signifi cant at 1%.'.Means followed by the same letter, within planting methods and betweenseeding rates, are not different at the 5 % level of significance (Student-NewmanKeul test).

Table 3.PlantingmethodAverage number of heads per unit area, number of seeds per head, seedweight, and grain yield for Maricopa wheat grown with two plantingmethods (flat and bed) and three seeding rates at Yuma, Arizona in1969.Seedingrate(kg/ha)Heads in0.37 M 2(no.)Seeds perhead(no.)Weight of1,000 seeds(g)Grain yieldin 0.37 M 2(g)Flat295887146 a144 a148 a42 b39 a38 a41.5 a42.6 a41.5 a254 a239 a233 aBed295887121 a126 a133 a44 b40 a40 a41.4 a42.2 a42.2 a255 a214 a225 a9628**nsns**nsns*nsC.V.(%),Significance of differences:Between planting methodsBetween planting ratesLegend: ns not significant at 5%, * significant at 5%, ** significant at 1%.Means followed by the same letter, within planting methods and betweenseeding rates, are not different at the 5% level of significance (Student-NewmanKeul test).

Table 4.PlantingmethodAverage number of heads per unit area, number of seeds per head, seedweight, and grain yield for Maricopa wheat grown with two plantingmethods (flat and b e d ) and three seeding rates in Yuma, Arizona in1968 and 1969 (2-year average).Seedingrate. (kg/ha)Heads in0.37 M 2(no. )Seeds perhead(no.)Weight of1,000 seeds(g)Grain yieldin 0.37 M 2(g)Flat295887126 a132 a132 a41 b38 a37 a36.6 a37.2 a36.8 a 'Bed295887113 a121 b128 c.41 b39 a38 a37.3 a38.3 a38. 2 a7545ns**ns**nsnsnsnsC.V.(%) 193 a190 a182 a193 a’179 a 186 aSignificance of differencesBetween planting methodsBetween planting ratesLegend: ns not significant at 5%, * significant at 5%, ** signifi cant at 1%.Means followed by the same letter, within planting methods and betweenseeding rates, are not different at the 5% level of significance (Student-NewmanKeul test).

observedoIn 1968 and when the 1968 and 1969 data werecombined, high rates ofseedingresulted in more wheatheads per unit area than did the low rate of seeding;however, in 1969 rate ofon heads per unit area.seedinghad no significant effectIn 1968, 1969, and when the 1968and 1969 data were combined low rates ofseedingresultedin more wheat seeds per head than did the high rate ofseeding„In 1968, 1969, and when the 1968 and 1969 datawere combinedseedingrates had no significant effect onwheat seed weight or grain yield„In 1968, when both flatand bed planting methods were used and when the 1968 and1969 data for bed plantings were combined the 58 and 87kg/haseeding rates resulted in more heads per unit area,than did the 29 kg/ha rate.In 1969, when flat and bedmethods of planting were used and when the 19 68 and 1969data for flat plantings were combinedseedingrates had nosignificant effect on number of heads per unit area.In 1968 the 87 kg/haseedingrate resulted infewer seeds per head than did the 29 kg/ha rate on flatplantings;usedhead.however, when the bed method of planting wasseeding rate did not significantly influence seeds perIn 1969 and when the 1968 and 1969 data were combinedthe 58 and 87 kg/haseeding rates resulted in fewer wheatseeds per head than did the 29 kg/ha rate in both flat andbed plantings.influenced byWheat seed weight and grain yield were notseeding rate in both flat and bed plantings

14in 1968, 1969, and when the 1968 and 1969 data werecombined.*Since planting methods had no significant effect onheads per unit area, seeds per head, seed weight, and grainyield each grower may wish to use the planting method bestadapted to his specific conditions.Because low seedingrates increase the number of seeds per head, reduce seedcost, and reduce visible lodging it would be advisable forgrowers to use this practice.Average heads per unit area, seeds per head, seedweight, and grain yields for wheat grown at three seedingrates and in two row positions on east-west beds in 1968and 1969 are reported in Tables 5, 6, and 7.when the 1968 and 1969 data were combinedIn 1968 andhigh rates ofseeding resulted in more wheat heads per unit area thandid low rates; however, in 1969 heads per unit area were notinfluenced by seeding rates.Seeds per head were notinfluenced by seeding rates in 1968; however, in 1969 andwhen the 1968 and 1969 data were combined low seeding ratesresulted in more seeds per head than did high rates.Seedweight and grain yield were not influenced by seeding ratesin 1968, 1969, or when the 1968 and 1969 data were combined,In 1968, 1969, and when the 1968 and 1969 data werecombined the south row position on beds resulted in morewheat heads per unit area, more seeds per head, and highergrain yields than did the north row position; however, row

Table 5.Seedingrate(kg/ha)Average number of heads per unit area, number of seeds per head, seedweight, and grain yield for Maricopa wheat grown at three seedingrates and two row positions (north and south) on beds at Yuma, Arizonain 1968.RowpositionHeads in0.37 M 2(no. )Seeds perhead(no. )Weight o f1,000 seeds(g)Grain yieldin 0.37(g)34.0 a32.3 a109 a153 bnorthsouth92 a117 b35 a41 b58no rthsouth107 a123 b35 a39 b35.0 a33.7 a130 a160 b87northsouth115 a133 b33 a38 b34.7 a33.6 a129 a167 b29„C.V.(%).1310617****ns**nsnsns**Significance of differences:Between planting ratesBetween row positionsLegend : ns not significant at 5%, * significant at 5%, ** significant at 1%.Means followed by the same letter, within seeding rates and between rowpositions, are not different at the 5 % level of significance (Student-NewmanKeul test).

Table 6.Seedingrate(kg/ha)Average number of heads per unit area, number of seeds per head, seedweight, and grain yield for Maricopa wheat grown at three seedingrates and two row positions (north and south) on beds at Yuma, Arizonain 1969-RowpositionHeads in0.37 M 2(no.)29northsouth109 a134 b58nprthsouth87northsouthC.V.(%)Seeds perhead(no. )Weight of1,000 seeds(g)Grain yieldin 0.37 m 2(g)43 a44 b41.2 a41.5 a192 a241 b111 a136 b39 a43 b42.0 a42.5 a179 a249 b112 a150 b37 a42 b41.9 a42.4 a175 a259 b147217ns*****nsnsns**Significance of differences:Between planting ratesBetween row positionsLegend : ns not significant at 5%, * significant at 5%, ** significant at 1%.Means followed by the same letter, within seeding rates and between rowpositions, are not different at the 5% level of significance (Student-Hewman-Keultest)-

Table 7„Seedingrate(kg/ha)Average number of heads per unit area, number of seeds per head, seedweight, and grain yield for Maricopa wheat grown at three seedingrates and two row positions (north and south) on beds at Yuma, Arizonain 1968 and 1969 (2-year average).RowpositionHeads1 ip0. 37' M 2(no. )Seeds perhead(no.)Weight of1,000 seeds(g)yieldGrain ;in 0. 37 M 2(g )29no rthsouth100 a125 b39 a43 b37.6 a '36.9 a58northsouth109 a129 b37 a41 b38.5 a38.1 a154 a205 b87northsouth113 a141 b35 a40 b38. 3 a38.0 a152 a213 bC.V.(%). 150 a197 b127316*******nsnsns**Significance of differences :Between planting ratesBetween row positionsLegend: ns not significant at 5%, * significant at 5%, ** signifi cant at 1 %.Means followed by the same letter, within seeding rates and between rowpositions, are not different at the 5% level of significance (Student-Newman-Keultest).

18position on beds had no significant effect on seed weight inany instance.The south row position on beds within eachseeding rate consistently resulted in more heads per unitarea, more seeds per head, and higher grain yields than didthe north row position.Seed weight was not influenced byrow position on beds within seeding rates.Since seeding rates did not significantly influencefinal grain yields in any instance, growers should useminimum seeding rates to reduce seed cost, lodging, andmutual shading.It is believed that the south row positionon beds resulted in more heads per unit area, more seedsper head, and higher grain yields than did the north row.position because the south position on beds has a higheraverage temperature than did the north position.Table 8 summarizes the average heads per unit area,seeds per head, seed weight, and grain yield for wheatgrown at three seeding rates and two row positions onnorth-south beds in 1969.High rates of seeding resultedin heavier seed weights than did the lower rate; however,heads per unit area, seeds per head, and grain yields ofwheat were not influenced by seeding rates.Wheat plantsgrown in the west row position on beds produced more headsper unit area and lighter seeds than did plants grown inthe east row position.Row position on beds had nosignificant effect on number of seeds per head or grainyields,

Table8.Seedingrate(kg/ha)Average number of heads per unit area, number of seeds per head, seedweight, and grain yield for Maricopa wheat grown at three seedingrates and two row positions (east and west) on beds at Yuma, Arizonain 1969.RowpositionHeads in0.37 m 2(no.)Seeds perhead(no.)Weight of1,000 seeds(g)Grain yieldin 0.37 m 2(g)29eastwest110 a111 a40 a39 a42.0 b41.6a186 a177 a58eastwest108 a120 b38 a37 a43.1 b42.4 a178 a187 a87eastwest111 a117 a37 a37 a43.2 b42. 7 a178 a180 aC.V.(%)6435ns*nsns***nsnsSignificance of differences :Between planting ratesBetween row positionsLegend: ns not significant at 5 %, * significant at 5 %, ** signifi cant at 1%.Means followed by the same letter, within seeding rates and between rowpositions, are not different at the 5% level of significance (Student-Newman-Keultest).

20The foregoing data suggest that when wheat is grownon north-south beds lower seeding rates should be used foreconomical grain production.Average heads per unit area, seeds.per head, seedweight, and grain yields for wheat grown in 0.37 M2plotson the north and south sides of east-west beds in 1968 and1969 are reported in Table 9.In 1968, 1969, and when the1968 and 1969 data were combined, the south row position onbeds resulted in more heads per unit area, more seeds perhead, and higher grain yields than did the north row posi tion; however, row position had no significant effect onseed weight.Plants grew better in the south row position thanin the north row position because the south portion of thebed received more solar radiation, had higher average soiltemperatures, had accelerated germination and emergence,and produced plants that may have had a higher rate ofphotosynthesis during later stages of development.Table 10 shows the average number of heads per unitarea, number of seeds per head, seed weight, and grain yieldfor wheat grown in 0,37 Mpositions in 19 69,2plots on beds with two rowWhen beds were constructed in the north-south direction,wheat grown in rows on the west side of thebed produced more seeds per head and heavier seeds than didwheat planted on the east side of the bed,Row position hadno significant effect on heads per unit area or grain yield,

Table 9.Average number of heads per unit area, number of seeds per head, seedweight, and grain yield for Maricopa wheat grown on beds with two rowpositions (north and south)"at Yuma,-Arizona in 1968, 1969, and whenthe 1968 and 1969 data were averaged.2Heads in 0.37 M(no. )Row position.19681969North104SouthWeight of1,000 seedsSeeds per head(no. 41.712414013239 *434133.2C

similar wheat (Triticum aestivum L.) grain yields„ When wheat was grown on beds the 58 and 87 kg/ha seeding rates resulted in higher grain yields than were obtained from the 29 kg/ha rate. Low rates of seeding resulted in more wheat seeds per head than did the higher rate of seeding. Seeding rates had no significant effect on seed weight or grain