W. R. Raun, D. H. Sander and R. A. Olson2 ABSJJRACJ. JOURNAL OF FERTILIZER ISSUES Volume 3, Number 1, January - March, 1986, Pages 18-24

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1 JOURNAL OF FERTLZER SSUES Vlume Number 1 January - March 196 Pages R. Raun D. H. Sander and R. A. Olsn2 ABSJJRACJ Three experiments were established at different times in 194 t evaluate salt effects n crn (Zea mays L.) emergence as affected by rate ( and 20 b/ac) and surce ( with ammnium thisulfate and 9-1-9) f slutin fertilizers placed with crn seed at planting. Emergence cunts were taken at peridic times fllwing planting. n tw f these experiments small amunts f salt (5 lb/ac N +K20) reduced crn seedling emergence nearly 10% whether r nt precipitatin ccurred sn after planting. Salt rates in excess f 10 lb/ac delayed seedling germinatin until precipitatin ccurred resulting in small crn plants emerging in established crn stands. Fertilizer surces did nt significantly affect seedling germinatin. The salt index methd (N +K20 in lb/ac) f determining the detrimental effect f placing fertilizers with crn seed seemed t evaluate well bth the effect f different fertilizer surces and rates f applicatin n crn seedling emergence. Additinal index wrds: (Zea mays L.) Salt injury Salt index. with crn (Zea mays L.) seed have generated C mrjenil cnsiderable recmmendatins cncern with f respect placing t fertilizers seedling emergence ( ). Advantages f applicatins f fertilizer slutins with the seed are varied. Mst yield respnses t starter fertilizers have been fund in the nrthern states where crps are planted early and where sils are wet and cld (7 9). ncreased effectiveness f sme micrnutrients has been fund when starter fertilizers were band applied (7). Sulfur cntaining fertilizers such as ammnium thisulfate when banded in a cncentrated zne temprarily acidify the band area in high ph sils which may result in increased availability f phsphrus brn cpper irn manganese and zinc (4 5). Even a 15 lb/ac salt rate (N + K20) had n effect n reductin f crn stands when ample misture was present in the seed zne (9).N effect n emergence was fund when applying 1 lb f salt/ac as a liquid fertilizer that 1 Cntributin f the Nebraska Exp. Stn. Lincln NE as paper N Research Assistant and Prfessrs Agrnmy Department University f Nebraska-Lincln NE. emplyed ptassium hydrxide as the ptassium surce (6). hile delayed emerged plants were fund when fertilizers were placed with the seed n delay in silking and yields were fund fot these treatments (11). Other data have indicated that either reductins in stands delayed emergence and/r yield lsses will ccur when placing slutin fertilizers with crn seed (2 9 1). Placement f varius slutins with the seed at salt rates less than 20 lb/ac have als shwn reductins in emergence fr ther crps ( 14). Misture cntent f the seed zne influences the way in which slutin fertilizers placed very clse t the seed at planting will affect germinatin. Crps grwn n sandy sils are generally mre susceptible t salt damage when fertilizers are applied with the seed than are fine textured sils because f the rapid drying that can ccur ( ). Diammnium phsphate and urea have been fund t have a txic effect n seedlings when placed with the seed due t the subsequent release f ammnia (71). This txic affect is less prnunced in clay sils with higher catin exchange capacities as the NH + wuld be absrbed by the sil exchange cmplex (14). Substantial dilutin f liquid surces applied with the seed was required befre n delay and r reductin in germinatin tk place when cmpared t slid surces at the same rate (). n the same study a reductin in the respiratin rate f crn seeds was fund when slid r liquid fertilizer surces were applied with the seed. ith an increase in salt cncentratin the plant's ability t absrb water diminishes until it cannt extract water even in wet sils (1). The ph f fertilizer materials applied with the seed demnstrated n effect n crn emergence (9). t has been prpsed that salt index rates f 5 t 7 lb applied with the seed f crn are safe fr sandy and nnsandy sils respectively when the salt index is determined by adding the rate f nitrgen t rate f ptassium as K20 (10 1). Current applicatins f the salt index d nt cnsider added salting agents ther than Nand K20. n light f the different salt rates at which delayed emergence f reductins in stands have been fund and because current recmmendatins are made that exceed these "safe" rates the bjectives f this study were t determine the effect f different fertilizer surces and rates f applicatin with the seed n emergence textured sil. f crn in a fine

2 RAUN SANDER AND OLSON 19 f 1 f :. f l i t t MATJE!RTAlS AND MJETJHlODS Three experiments were established in 194 at the Mead Field Labratry at Mead Nebraska n a Sharpsburg silty clay lam (Typic Argiudll). Pineer 77 crn was planted at a depth f tw inches using an adapted Buffal till ridge planter n June 27 and July 24 (Experiments 1 2 and ) t btain different envirnmental cnditins fr crn emergence. Three rates (5 10 and 20 lb/ac)f salt (N + K20 in lb/ac)were used in experiment 1 while experiments 2 and emplyed fur rates ( and 20 lb/ac) f salt applied with the seed. Fur fertilizer surces were used in all experiments with ammnium thisulfate (7-21-7T) and 9-1-9(N-P205-K20). The and were ammnium plyphsphate (APP). The was frmulated frm by adding ptassium chlride. The T cnsisted f ne tw three and fur gallns f ammnium thisulfate (ATS)/acadjusted accrdingly with t frmulate the and 20 lb salt rates. All surces were applied with a planter driven "Jhn Blue" squeeze pump. The fertilizer was frmulated frm ammnia rthphsphruc acid urea and ptassium hydrxide. Due t the different analyses f the surces used salt rates were cnstant fr each surce but the nitrgen (N) phsphrus (P) ptassium (K) and sulfur (S) rates varied. A cmpletely randmized blck (Experiments 2 ) r cmpletely randmized (Experiment 1) statistical design with a factrial treatment arrangement was used with three (Experiments 2 ) and tw (Experiment 1) replicatins. A planting rate f 2260 seeds/ac was emplyed in 0-inch rws. Sixteen plants per 10 linear ft represented 100% emergence. Plt length was 0 ft. The center 10 ft frm each plt was marked fr seedling emergence cunts. Seedling cunts began when the first plants were visible and cntinued until there were n further changes. Each experiment was disked prir t planting. mmediately fllwing planting each experiment received a bradcast treatment f 1.25 pints f Rundup per acre. Sil misture was determined at the tw inch depth at planting. Table 1 shws sil misture at planting and sil test data fr each experiment. Standard analysis f variance with single degree f freedm cntrasts and regressin were used t evaluate treatments ().n the third experiment data frm the 20 lb salt rate using was nt btained due t mechanical errr.!rjes1ljlts AND D TSC1lJSST0 N Numbers f emerged plants by surce rate and experiment are fund in Figure 1. Precipitatin receiv- ed fllwing planting fr each experiment is illustrated at the bttm f Figure 1. The envirnments present at planting and emergence were markedly different fr each experiment. These three envirnments prvided variable sil misture and seed bed cnditins with which the farmer culd be cnfrnted. Dates selected fr discussin represented pints at which n further change in emerged plants was fund prir t and fllwing any rainfall that may have ccurred during the experiments. Table 1. Planting time sil characteristics f the experimental area and cnductivity f the fertilizer surces Planting June datecnductivity Sil misture % at planting Surface 2 inches Sil pht Bray & Kurtz P. ppm t K. ppm t Surce T t Surface 0-6 inch sample Exp #1 June Exp July #2 # mmhs 52 Seedbed cnditins fr the first planting n June were generally pr. Excessive spring precipitatin resulted in a rugh clddy seedbed. Hwever plants emerged quickly and unifrmly althugh emergence was nly 0% where n fertilizer was applied. There was relatively little change in the number f emerged plants frm the time cunts were started (10 days after planting) t the time cunts were terminated 17 days after planting (Figure 1). Sil misture at the planting depth equalled r exceeded 20% during mst f the perid. Presumably because f the high sil misture there was n significant effect f the different fertilizer surces n seedling emergence regardless f applied salt rate. Hwever as the rate f salt increased seedling emergence decreased in a linear manner (Table 2) Fr each pund f applied salt seedling emergence decreased 1.75 percent (Figure 2).

3 20 EMERGENCE OF CORN AS AFFECTED BY SOURCE AND RATE OF SOLUTON 102!92 <10 \\.. D.... <10 <]0 <ld <ld \ " \ \ <ld \ \ ---s " '->.- "O-<r... ii.. 1\ \ \\ ::: \ \ \ \ " 0 '- <] 0 '<] '0 w!! u 0 N -!! " \. '0.. \ r '!\.! % sudld paful)w % SJUDld pafij Figure 1. Emerged crn plants as ffected by surce rate and time fr experiments 1 2 and.

4 Ua ċ Ew "1'j.. -" "-!J'Ci" 0: 0 E.p4.. c0. B C _0_0_0. 0 C _e" D-.')-D.-u---c. 20 bp 2 :::::====: P "' B E.p _0_0-0 /F'-'== 0' C.. -." / /0 :='-5./ S [:: /:i.;r' _D._6 / " " 4 "v--< Days After Planting ;p C Z 0 w.. " 0: c 0 0 E J" ' E.p C 0/ 1(--x---5 1/.-_ l:J.-C::;/' " E xp 2 4 /x_x-x./.""o ' 10/0 /0 /.:J-D-Q / /"-e:.-' g..-" " E.p.l;;"-'-'== -0 c //:="_"'_ 0_ 0_0_ : -115 :-: 0/.O-O-' -0>< 0/ 0 0 t r:n ;p Z t: t::rj ;p Z t: r-' r:n Z 1.:0 r:: <:> u" Q: t Days After Planting -----"y-+ t'v...

5 22 EMERGENCE OF CORN AS AFFECTED BY SOURCE AND RATE OF SOLUTON Table 2. Analysis f variance f emerged plants fr experiments 1 2 and. Surce f variatin df PR F Experiment #1-17 days after planting June 25: Rate Surce Rate*surce Errr Ttal Cntrasts Rate linear Rate quadratic C.V Experiment #2-9 and 19 days after planting July 4 and July : Rep Rate Surce Rate*surce Errr Ttal C.v. Cntrasts Rate linear Rate quadratic 2 ** July 4 July * ** ** Experiment # - 1 and days after planting Aug 6 and Aug 1: Rep Rate Surce Rate*surce Errr Ttal c.v. Cntrasts Rate linear Rate quadratic vs rest 2 ** Aug 6 Aug 1 ** ** Exp 2 July " (R) r.40 * 100r: _----cr 2 0t-- Exp Jun" " (R) r c- _ 40t- _ _ Exp " July1.4(R) 6 r'.44 * "-"-"-'-..6l '-"--"-"-" !: Figure 2. Percent emerged plants (average ver surces) vs rate f applied salt experiments 1 2 and. * - r significant at O. prbability level with 5 df - r significant at 0.01 prbability level with 0 df errr. R = rate f applied salt..-.. Ol Salt rate b/ac A gust 1 * Exp = 6.1 u- 1. 9(R) ".52 -.::::.::..:::"'. - '. -. ' is. -= "OJ)... E ' Exp " (R) ----:-: August 6 * : O -- i-- "" Salt rate b/ac ** - significant at and 0.10 prbability levels respectively - nnsignificant Sil cnditins fr planting were imprved fr the secnd experiment (planted June 27) cmpared t the first experiment. N rainfall was received fr seven days fllwing planting. Cnsistent with the first experiment there was n significant difference in seedling emergence amng fertilizer surces nine days after planting (Table 2). Hwever variatin was high since seedlings were still emerging. Plant emergence was significantly reduced depending n the amunt f salt applied. Regressin analysis indicated that plant emergence nine days after planting decreased frm 41% where n fertilizer was applied t nly 14% where 20 lb f salt/ac was applied (Figure 2). Precipitatin (1.09inches) received frm July 4 thru July 6 greatly changed plant emergence in the fllwing 10 day perid. Emergence increased t nearly 100% where n fertilizer was applied (Figure 2). Nineteen days after planting seedling emergence increased t ver 75% fr all surces and salt rates. Fertilizer surces did nt affect seedling germinatin (Table 2). Precipitatin did nt greatly influence the relative effect that increasing salt rates had n seedling emergence since slpes relating emergence t salt rate fr bth nine days and 19 days after planting are sur-

6 - > RAUN SANDER AND OLSON 2 l- prisingly similar. One wuld expect precipitatin t mve the salt frm the seed and greatly reduce r eliminate the salt effect (Figure 2). Sme seeds apparently lacked misture fr germinatin until precipitatin ccurred. Salt and seed cntact did nt affect germinatin and seedling emergence as lng as the seeds nt yet germinated remained dry. The third experiment was planted n July 24 in rder t simulate planting cnditins in dry sils. hile sil temperatures were higher than spring cnditins pssibly increasing salt damage seedling emergence was mre rapid reducing salt cntact time. t remained dry except fr 0.5 inches f precipitatin recrded tw days after planting. Maximum seedling emergence was btained at abut 1 days after planting. Even withut adequate precipitatin t mve fertilizer salts frm the seed there was n significant difference in seedling emergence amng fertilizer surces (Table 2). Once n further changes in emergence had been btained fr all treatments an artificial watering f 1.25 inches 27 days after planting f the third experiment was applied t the entire study. The fllwing day 0.95 inches f precipitatin was recrded. Cunts taken 10 days after watering shwed a significant main effect f fertilizer surce which was nt present at any time prir t watering in experiments 1 2 r. Over rates there were significantly mre newly emerged plants fr cmpared t the three ther fertilizer materials. This was pssibly due t the frmulatin f which resulted in lwer cnductivity cmpared t ther fertilizers f equal salt cntent (Table 1). The delayed seedling emergence apprximately a mnth after planting was significant nly fr the but there was a trend fr this t ccur with all fertilizer surces especially at the higher salt rate applicatins (Figure ). Seedlings that emerge this late essentially becme weeds cmpeting fr misture and nutrients with almst n chance f reprductive develpment. Althugh the main effect f surces was nt significant it is imprtant t nte that ne culd apply and.4 times as much P205 using at the same salt rate versus the ther surces ( T 9-1-9respectively). t is therefre cnceivable that in certain areas sufficient P fertilizatin culd take place when applied with the seed using while having n significant reductin in stands. hile this study did nt evaluate different planters and j ) i r r. Figure. Delayed emerged plants at high rates f salt applied with the seed. (.

7 24 EMERGENCE OF CORN AS AFFECTED BY SOURCE AND RATE OF SOLUTON planting depths treatment by planting methd interactins culd exist due t different seed bed cmpactin as influenced by tillage and planter design that affect seed-fertilizer cntact. n additin ne wuld expect t increase the prbability f seed-fertilizer cntact with increasing rates due t the surging flw assciated with squeeze pumps. t is pssible that a prtin f what was measured in terms f reducing emergence with increasing rates was actually due t a greater prbability f having seed-fertilizer cntact. r n significant effect n seedling emergence. Even the inclusin f ammnium thisulfate in did nt reduce seedling emergence when cmpared t ther surces. The fertilizer surce which is claimed t have less ptential fr inhibiting seedling emergence was n mre effective than ther fertilizer surces in these studies. The summatin f b N + K20/ac fr seed placed fertilizer was fund t be an adequate index f salt tlerance regardless f fertilizer surce. CONCUJSnO UERA1J1R1E CRED n general the effect f fertilizer salts n crn seedling emergence has been thught t be largely related t sil misture at planting and/r whether r nt adequate water is received t leach salt frm the seed area thus preventing injury. The three experiments in this study had widely varying sil misture cnditins. Sil misture at planting in the first experiment was 20% in the seed area cmpared t seven and five percent fr the fllwing tw planting dates (Table 1). During the secnd experiment adequate precipitatin was received after nine days t mve fertilizer salts frm the seed area while inadequate precipitatin was received t mve fertilizer salts frm the seed area in the third experiment. hile the severity f the salt effect is greatest in experiment and the least in experiment 2 as expected it is surprising that the effects f salt were nt greater than encuntered in experiment and less than fund in experiment 1. The effects f the amunt f salt applied n crn seedling emergence were relatively unifrm cnsidering the differences in envirnment in the three experiments. Even small amunts f salt (51b/ac)reduced final seedling emergence 9 and 7 percent in experiments 1 2 and respectively. t is apparent that sil misture at planting and especially subsequent precipitatin after planting affects ttal germinatin much mre than it affects germinatin due t applied salt ( percent seedling emergence fr checks experiments and respectively). Recmmendatins f 5 t 7 b f salt (N + K20)/ac appear t present a relatively lw risk f substantial germinatin injury and lss f crn stands but rates exceeding 7 b f salt prbably will prduce an unacceptable lss f crn stands unless precipitatin ccurs sn after planting. Seedlings may emerge due t a late precipitatin but the cntributin f such plants t grain yield will vary greatly depending n when they germinate in relatin t the rest f the stand. Late germinatin culd result in cmpetitr plants that culd reduce yields. Fertilizer surces can ptentially affect crn germinatin and seedling emergence differently. n this study hwever different fertilizer surces had little 1. Barber S. A. R. D. Munsn and. B. Dancy Prductin Marketing and Use f Ptassium Fertilizers. n R. A. Olsn (ed.) Fertilizer Technlgy and Use. p. 1. Sil Sci. Sc. f Amer. Madisn. 2. Bates T. E Respnse f crn t small amunts f fertilizer placed with the seed.. Summary f 22 field trials. Agrn. J. 6: Baweja A. S. and T. E. Bates Respnse f crn t small amunts f fertilizer placed with the seed. V. Cmparisn f dry and liquid frms. Agrn. J. 6: Beatn J. D Sulphur: One key t high yields in small and carse grains. Slutins 24(6): Hester Sulphur - the furth majr nutrient? Fert. Slutins. 2(6): Miller M. H. T. E. Bates D. Singh and A. S. Bawej Respnse f crn t small amunts f fertilizer placed with the seed.. Greenhuse 6:65-6. studies. Agrn. J. 7. Mrtvedt J. J Band fertilizer placement - hw much and hw clse? Fert. Slutins. 20(6): Mrtvedt J. J. and P. M. Girdan Grain srghum respnse t irn in a ferrus sulfate - ammnia thisulfate - ammnium plyphsphate suspensin. Sil Sci. Sc. Am. Prc. 7: Rehm G Fertilizer Placement: Hw much and hw clse t crn seed. Slutins. 27(7): Rehm G.. and E. J. Penas Using starter fertilizer fr crn. Cp. Ext. Serv University f Nebraska Lincln. NebGuide G Richards J. E. T. E. Bates and S. C. Sheppard The effect f bradcast P applicatins and small amunts f fertilizer placed with the seed n cntinuusly crpped crn (Zea mays L.). Fertilizer Research. Vl. 6 N. : Snedecr G Statistical Methds. p wa State Cllege Press Ames A. 1. Spiva C Bradcast r band?: The case fr banding. Slutins. 24(5): Stevensn C. K. and T. E. Bates Effect f Nitrgen t Phsphrus Atm Rati f Ammnium Phsphates n Emergence f heat (Triticum vulgare). Agrn. J. 60: