Received: December 2017; Accepted: May 2018

Transcription

1 Journl of Horticulturl Reserch 2018, vol. 26(1): DOI: /johr EFFECT OF UREA FERTILIZER AND MAIZE COB ASH ON SOIL CHEMICAL PROPERTIES, GROWTH, YIELD, AND MINERAL COMPOSITION OF OKRA, ABELMOSCHUS ESCULENTUS (L.) MOENCH Arun Olsekn ADEKIYA*, Christopher Muyiw ABOYEJI, Oluwgbeng DUNSIN, Ojo Vincent ADEBIYI, Oreoluw Titilope OYINLOLA Crop nd Soil Sciences Dept., Lndmrk University, Omu-Arn Omu-Arn, Nigeri Received: December 2017; Accepted: My 2018 ABSTRACT Field experiments were crried out t the Teching nd Reserch Frm, Lndmrk University, Omu- Arn, Kwr Stte, Nigeri, in the cropping sesons of 2015 nd The soil t the site of the experiment is n Alfisol clssified s n Oxichplustlf or Luvisol. The tril consisted of sole nd combined pplictions of ure fertilizer (U) pplied t 0, 60, nd 120 kg h -1 nd mize cob sh (M) pplied t 0, 3, nd 6 t h -1. The results showed tht U nd M lone or in combintions incresed the soil chemicl properties, growth, yield, nd minerl composition of okr compred with the control. M lone t 3 t h -1 produced optimum soil chemicl properties, yield, nd minerl composition of okr fruit. U lone t 60 kg h -1 produced optimum yield of okr, while growth nd minerl composition were incresed when ure fertilizer ws pplied t 120 kg h -1. The tretment with U pplied t 60 kg h -1 in combintion with M pplied t 3 t h -1 (U 60M 3) produced the highest vlues of okr yield, while U pplied t 120 kg h -1 in combintion with M pplied t 3 t h -1 (U 120M 3) hs the highest growth nd highest N, K, C, Cu, nd Fe contents of okr fruit. Compred with the control nd using the men of the two yers, U 60M 3 incresed okr fruit yield by 93.3%. Therefore, for vible production of okr in low nutrient soil of the Nigeri derived svnn or similr soils elsewhere, 60 kg h -1 U + 3 t h -1 M (U 60M 3) is recommended. However, for improved minerl qulity of okr, 120 kg h -1 U + 3 t h -1 M (U 120M 3) is recommended. Key words: ure fertilizer, mize cob sh, okr yield, okr growth, soil chemicl properties, okr minerl composition INTRODUCTION Okr is vegetble crop tht belongs to the genus Abelmoschus, fmily Mlvcee nd hs two min species Abelmoschus esculentus (L.) Moench nd Abelmoschus cillei (A. Chev.) Stevels (Siemonsm 1982). Okr origintes probbly from Est Afric nd tody is widely distributed in the tropics, subtropics, nd wrmer prts of the temperte region (Echo 2003). It is trditionlly grown in Côte d Ivoire, Ghn, Nigeri, Egypt, Sudn, Togo, Benin, Burkin Fso, Cmeroon, Tnzni, Zmbi, nd Zimbbwe. The economic importnce of okr cnnot be overemphsized. Okr is populr helth food becuse of its high fiber, vitmin C, nd folte content. Okr hs high mount of ntioxidnts. It is lso good source of clcium nd potssium. It contins crbohydrte, proteins, nd vitmin C in lrge quntities (Adeboye & Oput 1996). Some of the problems encountered by okr frmers in Nigeri re the low soil fertility nd lck of cpitl to buy chemicl fertilizers for optimum crop productivity. Most Africn soils re inherently low in orgnic crbon, slightly cidic, nd reltively sndy (Adewole & Dedeke 2012). Consequently, intensive crop production requires high rte of orgnic nd inorgnic fertilizers. As result, the use of orgnic-bsed fertilizer hs found fvor in boosting crop production *Corresponding uthor: e-mil: dekiy2009@yhoo.com

2 68 A.O. Adekiy et l. in Nigeri, becuse it is chep nd less likely to pollute the ground wter compred with chemicl fertilizer. It improves soil fertility sttus nd enhnced yield. However, the quntities of the orgnic mendments vilble my not be sufficient for lrge-scle okr production. Integrted use of chemicl fertilizers nd orgnic mteril my be good pproch for sustinble production of crops (Agbede & Adekiy 2012). Corn sh from the combustion of mize cobs, especilly fter ginning, cn be used s fertilizing nd liming mteril. Different woody sh improved soil nd plnt nutrition nd incresed the yield of crops (Abdulhmid & Mustph 2009; Owolbi et l. 2003; Odedin et l. 2003; Awodun et l. 2007; Ewulo et l. 2009). However, its combined use with chemicl fertilizer hs not received reserch ttention. Moreover, the effects of the integrted ppliction of mize cob sh nd ure fertilizer on the soil chemicl properties, growth, yield, nd minerl composition of okr hve not been investigted; therefore, the objectives of this study re (1) to determine the effects of sole nd integrted ppliction of ure fertilizer nd mize cob sh on soil chemicl properties, (2) to determine the effects of sole nd integrted ppliction of ure fertilizer nd mize cob sh on growth nd yield of okr, nd (3) to determine the effects of sole nd integrted ppliction of ure fertilizer nd mize cob sh on minerl compositions of okr. MATERIALS AND METHODS Field experiments were crried out t the Teching nd Reserch Frm, Lndmrk University, Omu-Arn, Kwr Stte, Nigeri, in the cropping sesons of 2015 nd Experimentl field lies between Ltitude 8 o 9 N nd Longitude 5 o 61 E nd is locted in the derived svnn ecologicl zone of Nigeri. The rinfll pttern ws bimodl, with peks in June nd October. The soil t the site of the experiment is n Alfisol clssified s n Oxichplustlf or Luvisol. The men nnul rinfll in the re is bout 1300 mm, nd the men nnul temperture is 32 C. The tril consisted of sole nd combined pplictions of mize cob sh (M) pplied t 0, 3, nd 6 t h -1 nd ure fertilizer (U) pplied t 0, 60, nd 120 kg h -1. The nine tretments were lid out in rndomized complete block design with three replictions. The following tretments were evluted: (1) Control, no ure fertilizer or mize cob sh (U 0M 0); (2) no ure fertilizer + 3 t h -1 M (U 0M 3); (3) no ure fertilizer + 6 t h -1 mize cob sh (U 0M 6); (4) 60 kg h -1 ure fertilizer + no mize cob sh (U 60M 0); (5) 60 kg h -1 ure fertilizer + 3 t h -1 mize cob sh (U 60M 3); (6) 60 kg ure fertilizer + 6 t h -1 mize cob sh (U 60M 6); (7) 120 kg h -1 ure fertilizer + no mize cob sh (U 120M 0); (8) 120 kg h -1 ure fertilizer + 3 t h -1 mize cob sh (U 120M 3); (9) 120 kg h -1 ure fertilizer + 6 t h -1 mize cob sh (U 120M 6). Mize cob sh used for the experiment ws prepred by collecting mize cob from mize frmers, sundried, nd burnt into sh inside bin. The sh ws then sieved to remove pebbles nd unburnt shft. After lnd preprtion (ploughing nd hrrowing), the site ws then lid out to the required plot size of 3 m 3 m. Sowing of okr cultivr NHAe-47-4 ws done in My for both 2015 nd 2016 cropping sesons. Three seeds of okr were sown per hole t interrow spcing of 0.6 m nd intrrow spcing of 0.6 m, giving plnt popultion of plnts h -1. Two weeks fter sowing, thinning to one plnt per stnd ws done followed by mnul weeding, nd mize cob sh nd ure fertilizer were pplied in ring form to the soil. Mnul weeding ws done during the plnting seson, nd insect pest control ws crried out using cypermethrin contining preprte pplied t the rte of 1.0 kg h -1.i. The soil ws nlyzed before the strt of the experiment nd t hrvest. The soil smples collected were bulked, ir dried, nd sieved using 2- mm sieve nd nlyzed for prticle size; soil orgnic mtter; N, P, K, C, nd Mg contents; nd ph. Soil smples t hrvest were collected from 0 to 0.15 m depth in 2015 nd 2016 on n individul plot bsis nd similrly nlyzed for chemicl properties s described by Crter (1993). Prticle size ws determined by the hydrometer method (Gee & Or 2002). Soil orgnic crbon ws determined by the procedure of Wlkley nd Blck using the dichromte wet oxidtion method (Nelson & Sommers 1996). Orgnic mtter (OM) ws clculted by multiplying C

3 Inorgnic nd orgnic fertiliztion of okr 69 by Totl N ws determined by the micro- Kjeldhl digestion method (Bremner 1996). Avilble P ws determined by Bry-1 extrction followed by molybdenum blue colorimetry (Frnk et l. 1998). Exchngeble K, C, nd Mg were extrcted using 1 M mmonium cette. Therefter, K level ws determined on flme photometer, nd C nd Mg were determined by ethylenediminetetrcetic cid EDTA titrtion (Hendershot & Llnde 1993). Hevy metls were determined by using the method of Udo et l. (2009). The Fe, Cu, Zn, Cr, nd Cd levels were determined by tomic bsorption spectrophotometer. Soil ph ws determined using soil wter medium t rtio of 1 : 2 with digitl electronic ph meter. The smple of bout 2 g of the sh used ws nlyzed for N, P, K, C, nd Mg s described by Tel nd Hgrty (1984). N ws determined by the micro-kjeldhl digestion method. Smples were digested with nitric perchloric sulfuric cid mixture for the determintion of P, K, C, nd Mg. Phosphorus ws determined colorimetriclly using the vndomolybdte method, K ws determined using flme photometer, nd C nd Mg were determined by the EDTA titrtion method (Horwitz & Ltimer 2005). At hrvest, 10 okr fruits of uniform sizes were rndomly collected from ech plot in ech yer nd nlyzed for minerl contents. Minerl elements of okr fruits were determined ccording to the methods recommended by the Assocition of Officil Anlyticl Chemists (AOAC 2003). N ws determined by the micro-kjeldhl digestion method. One grm of ech smple ws digested using 12 cm 3 of the mixture of HNO 3, H 2SO 4, nd HCLO 4 (7 : 2 : 1 v/v/v). Contents of Cu, Fe, Zn, K, nd C were determined by tomic bsorption spectrophotometry. Plnt height, number of leves, nd lef re t mid-flowering stge were determined by using the model {LA = 0.34(LW) 1.12 } developed by Omoliye et l. (2015), where LA = lef re, L = lef length, nd W = lef width. Pods were hrvested t four dys intervl, counted, nd weighed. Pod weight ws evluted bsed on the cumultive number of pods t eight hrvests. Dt collected for okr yield nd growth prmeters, soil chemicl properties, nd okr minerl compositions were subjected to nlysis of vrince (ANOVA) using SPSS 17.0, nd mens were seprted using Duncn s multiple rnge test (DMRT) t p = 0.05 probbility level. RESULTS Initil soil fertility sttus nd chemicl properties of the mendments used for the experiment The physicochemicl properties of the soil nd the mize cob sh re given in Tble 1. The soil ws sndy lom in texture, high in snd, low in both silt nd cly, cidic, nd low in orgnic mtter. Totl N, vilble P, nd exchngeble K, C, nd Mg ccording to the criticl level of 3.0% OM, 0.20% N, 10.0 mg kg -1 vilble P, cmol kg -1 exchngeble K, 2.0 cmol kg -1 exchngeble C, nd 0.40 cmol kg -1 exchngeble Mg meet the criteri recommended for crop production in ecologicl zones of Nigeri (Akinrinde & Obigbesn 2000). The vlues of hevy metls in the experimentl soil before experimenttion were ll below the permissible limits of Fe 100 mg kg -1, Zn 300 mg kg -1, Cu 100 mg kg -1, Cr 100 mg kg -1, nd Cd 3 mg kg -1 by WHO/FAO (Kbt-Pendis & Mukherjee 2007). The nlysis of mize cob sh showed tht the ph ws strongly lkline nd it lso contined high level of K, C, nd Mg nd trce vlues of N nd P. Tble 1. Soil properties before experimenttion nd nutrient content of mize cob sh used for the study Soil property Soil vlues Mize cob sh vlues Snd (%) 76 Silt (%) 13 Cly (%) 11 Texturl clss Sndy lom ph (wter) Orgnic mtter (%) 2.04 Totl N (%) Avilble P (mg kg -1 ) Exchngeble K (cmol kg -1 ) Exchngeble C (cmol kg -1 ) Exchngeble Mg (cmol kg -1 ) Fe (mg kg -1 ) Zn (mg kg -1 ) Cr (mg kg -1 ) Cu (mg kg -1 ) Cd (mg kg -1 )

4 70 A.O. Adekiy et l.

5 Inorgnic nd orgnic fertiliztion of okr 71 The vlues of hevy metls (Fe, Zn, Cr, Cu, nd Cd) in the mize cob sh were lower thn the vlues reported for wood sh in the literture Fe 19.5 mg kg -1, Zn 700 mg kg -1, Cr 86 mg kg -1, Cu 145 mg kg -1, nd Cd 21 mg kg -1 (Etiégni & Cmpbell 1991) Effect of ure fertilizer nd mize cob sh on the soil chemicl properties Tble 2 shows the effect of ure fertilizer nd mize cob sh on soil chemicl properties t the end of the experiment in 2015 nd Yer (Y) s n individul fctor did not influence soil chemicl properties. Ure fertilizer (U) lone incresed the mounts of soil elements, except K, Zn, Cu, Fe nd Cr, nd the increse in N, P, C nd Mg contents of the soil in comprison with the not fertilized control. There were no significnt differences in ph but orgnic mtter contents incresed due to 60 nd 120 kg h -1 ure ppliction s sole. Mize cob sh (M) lone incresed the soil ph, orgnic mtter, nd P, K, C, Mg, Zn, Cu, Fe, nd Cr levels of the soil significntly. In ll tretments in which mize cob sh lone or combined with ure fertilizer were pplied, there were no significnt differences between mize cob doses, with some little exceptions. The interctive effects of Y U nd Y M were not significnt. Combining ure fertilizer with mize cob sh (U M), ure fertilizer pplied t 120 kg h -1 + mize cob sh pplied t 3 t h -1 (U 120M 3), hs significntly incresed the vlues of N, K, C, nd Mg. The vlues of these nutrients t U 120M 3 were not significntly different from tht of ure fertilizer pplied t 120 kg h -1 + mize cob sh pplied t 6 t h -1 (U 120M 6). Ure fertilizer pplied t 120 kg h -1 + mize cob sh pplied t 6 t h -1 (U 120M 6) hs the highest vlues of ph, orgnic mtter, nd P, which were lso similr to those of U 120M 3. However, the vlues of Zn, Cu, Fe, nd Cr were not significnt for (U M). Also, Y U M ws not significnt for soil chemicl properties. Tble 3. Effect of ure fertilizer nd mize cob sh on minerl composition of okr fruit Yer Ure fertilizer (kg h -1 ) Mize cob sh (t h -1 ) N (%) f * 95.4 h 88.6 f 0.31 g 7.2 f ef de c 0.75 cd 15.2 c ef e c 0.70 d 15.1 c d g e 0.40 f 12.9 e c bc b 0.60 b 16.2 b c cd b 0.59 b 16.1 b bc f d 0.51 e 14.1 d b f 90.6 f 84.4 f 0.30 g 7.1 f ef c c 0.75 bc 14.9 d ef c c 0.69 c 14.8 d d e e 0.40 f c b b 0.62 cd 15.8 c c b b 0.60 d 15.2 c bc d d 0.49 e 14.1 e b SE± Source Yer (Y) ns ns ns ns Ure U ns Mize cob sh (M) ns Y U ns ns ns ns ns Y M ns ns ns ns ns U M ns ns Y U M ns ns ns ns ns *For explntion see Tble 2 K (%) C (%) Cu (%) Fe (%)

6 Okr yield (t h -1 ) Okr plnt height (m) Number of leves of okr/plnt Okr lef re (m 2 ) 72 A.O. Adekiy et l. Effect of ure fertilizer nd mize cob sh on minerl composition of okr fruit The result of the effects of ure fertilizer nd mize cob sh on minerl composition of okr fruit re presented in Tble 3. Yer (Y) s n individul fctor did not influence okr minerl composition significntly except Cu. Ure fertilizer (U) incresed okr minerl composition significntly, more t 120 kg h -1 ure. With mize cob sh lone (M) K, C, Cu, nd Fe contents of okr fruit incresed significntly compred with the control but there were no difference between mize cob sh doses. The highest increse in the minerl elements in okr fruit were scored t the highest ure nd both mize cob sh doses. The interctive effects of Y U, Y M nd Y x U x M were not significnt for okr fruit minerl compositions. Using the mens of the two yers nd compred with the control, U 120M 3 incresed N, K, C, Cu, nd Fe contents of okr fruit by 68.1%, 98.3%, 89.0%, 203.2%, nd 177.8%, respectively. Effect of ure fertilizer nd mize cob sh on growth prmeters nd yield of okr fruit Figures 1 4 show the men effects of ure fertilizer nd mize cob sh on the growth nd yield of okr. Mize cob sh lone t 3 nd 6 t h -1 incresed the height of plnts, re nd number of leves nd fruit yield compred with the control without differences between doses. 0,9 0,8 0,7 0,6 0,5 0,4 0,3 0,2 0,1 0,0 g f f e cd de Ure fertilizer nd mize cob sh c 1,2 1 0,8 0,6 0,4 0,2 0 Fig. 2. Influence of ure fertilizer nd mize cob sh on okr leves re bsed on the mens from two yers. For explntion see Fig f e e d Ure fertilizer nd mize cob sh Fig. 3. Influence of ure fertilizer nd mize cob sh on okr leves number bsed on the mens from two yers. For explntion see Fig d e cd d cd cd cd bc Ure fertilizer nd mize cob sh c c b b b b b b Fig. 1. Influence of ure fertilizer nd mize cob sh on the height of okr plnts bsed on the mens from two yers. U = Ure fertilizer in kg h -1 ; M = Mize cob sh in t h -1 ; verticl brs show stndrd errors; brs mrked with different letters show mens significntly different t 5% level using Duncn's multiple rnge test Ure fertilizer nd mize cob sh Fig. 4. Influence of ure fertilizer nd mize cob sh on okr yield bsed on the mens from two yers. For explntion see Fig. 1.

7 Inorgnic nd orgnic fertiliztion of okr 73 Using the men of the two yers, it incresed the yield, plnt height, lef re, nd the number of leves of okr by 26.7%, 15.4%, 12.3%, nd 26.7%, respectively. Similrly, ure pplied lone incresed more thn cob sh the growth of okr plnts. The growth increse depended on the ure dose contrry to the yield, which did not depend on the ure dose. Ure fertilizer pplied t 60 kg h -1 in combintion with mize cob sh pplied t 3 nd 6 t h -1 (U 60M 3 nd U 60 M 6) cused the highest yield of okr fruit, while ure fertilizer pplied t 120 kg h -1 in combintion with mize cob sh pplied t 3 nd 6 t h - 1 (U 120M 3 nd U 120M 6) resulted in the highest growth prmeters. Compred with the control nd using the men of the two yers, U 60M 3 incresed okr fruit yield by 93.3%. DISCUSSION The fct tht mize cob sh or ure fertilizer lone or in combintions incresed soil orgnic mtter nd N, P, K, C, nd Mg contents cn be explined by the low initil soil fertility sttus of the experimentl field (Tble 1), which confirms the erlier findings (Prk et l. 2004; Ewulo et l. 2009; Abdulrheem & Ojeniyi 2015). Ure fertilizer lone incresed soil orgnic mtter nd N, P, K, C, nd Mg reltive to the control, probbly becuse of the enhnced microbil ctivity tht led to enhnced production nd minerliztion of orgnic mtter from nturl (ntive) source in soil (Ewulo et l. 2009). Incresed soil orgnic mtter nd nutrients cused by ure fertilizer cn lso be relted to the ddition of crbon through okr root biomss nd crop residues. Mize cob sh improved the bsl sttus of the soil through the increse in soil ph. The clcium oxide content of soil turns into clcium hydroxide in the presence of wter. Clcium hydroxide rects with the crbon dioxide in the ir, which results in the formtion of clcium crbonte. As result, wood-sh enhnces the lime content of the soil (Steenri et l. 1999). However, ure reduces soil ph becuse of its cid producing nture. The soil nutrient sttus incresed t 3 t h -1 mize cob sh nd usully did increse with 6 t h -1. The exception ws found for P nd K becuse their content ws higher t the higher dose. The combintion of ure nd mize cob sh incresed N vilbility importnt for microbil ction tht relesed of nutrients. In generl, the combintion of ure fertilizer nd mize cob sh incresed soil nutrient concentrtion more thn their sole use. The significnt increse in the growth nd yield of okr in response to mize cob sh or/nd ure fertilizer compred with the control could be dduced to the fct tht the soil ws low in nutrients. Higher mounts of N, P, K, C, nd Mg nd higher soil ph re essentil for the growth nd yield of okr (Abdulrheem & Ojeniyi 2015). On n verge, yield of 20 t h -1 of okr removes from soil bout 60, 25, nd 90 kg of N, P 2O 5, nd K 2O h 1 (Prbhkr 1996). The result tht mize cob sh t 3 t h -1 incresed the growth nd yield of okr most implies tht this mount corresponds with other soil fctors nd okr requirements. Nitrogen strongly stimultes growth through expnsion of the crop cnopy nd better interception of solr rdition (Milford et l. 2000). It lso strengths plnt roots, enbling plnts to tke in more wter nd nutrients, which llows plnt to grow more rpidly (Solngi et l. 2015). Also the result tht growth prmeters of okr incresed with the increse of ure doses up to 120 kg h -1 while yield ws incresed with ure dose of 60 kg h -1 cn testify tht in the experimentl condition, the 120 kg h -1 dose ws over optiml for yield of fruits. This result grees with tht of Verm et l. (1970) who found tht okr fruit production ws depressed s N rte ws incresed nd concluded tht fruit yield t this excessive N rte ws declined due to reduction in fruit number per plnt. Chuhn nd Gupt (1973) cited by Mjnbu et l. (1986) reported tht dry mtter yield in okr significntly incresed with N fertiliztion but it ws not correlted with fruit yield increse. Mjnbu et l. (1986) fixed the optimum N requirement for okr production to be 50 kg h -1. From our experiment, it is possible to conclude tht U 60M 3 ws most dequte for the okr production in this soil-climtic zone.

8 74 A.O. Adekiy et l. Tble 4. Correltion coefficient between soil chemicl properties nd minerl composition of okr Okr minerl composition Soil chemicl property N K C Cu Fe ph -292 (ns) (ns) (ns) (ns) (ns) Orgnic mtter 0.77* (0.015) 0.912* (0.001) 0.940* (0.000) 0.796* (0.010) 0.861* (0.003) N 0.900* (0.001) 0.783* (0.030) 0.730* (0.042) 0.759* (0.039) 0.746* (0.040) P 0.839* (0.005) 0.922* (0.000) 0.937* (0.000) 0.840* (0.005) 0.957* (0.000) K (ns) 0.913* (0.001) 0.874* (0.002) 0.903* (0.001) 0.923* (0.000) C 0.707* (0.033) 0.983* (0.000) 0.987* (0.000) 0.886* (0.001) 0.921* (0.000) Mg 0.677* (0.045) 0.947* (0.000) 0.963* (0.000) 0.818* (0.007) 0.852* (0.004) * p< 0.05; ns = not significnt t p< Included in brckets re p vlues The ppliction of ure fertilizer nd mize cob sh lone or in combintion incresed N, P, K, C, Cu, nd Fe contents in okr fruits compred with the control nd is consistent with the soil chemicl properties in this experiment; the correltion between soil chemicl properties nd minerl composition of okr fruit were positive nd significnt (except for ph) (Tble 4). Mize cob sh incresed N, P, K, C, Cu, nd Fe contents of okr fruits only up to 3 t h -1 level. Ure fertilizer pplied t 60 kg h -1 in combintion with mize cob sh pplied t 3 t h -1 (U 60M 3) hs the highest N, P, K, C, Cu, nd Fe contents of okr fruits. This ws dduced to mximum vilbility of nutrient especilly N from ure fertilizer nd P, K, C, nd Mg from mize cob sh t blnced proportion. CONCLUSION Ure fertilizer nd mize cob sh lone or in combintion incresed soil chemicl properties, growth, yield, nd minerl composition of okr compred with the control. Mize cob sh pplied lone t 3 t h -1 produced optimum soil chemicl properties, yield, nd minerl composition of okr fruit. Ure fertilizer lone t 60 kg h -1 produced optimum yield of okr while growth nd minerl composition ws incresed t 120 kg h -1 ure fertilizer. Tretment with ure fertilizer pplied t 60 kg h -1 in combintion with mize cob sh pplied t 3 t h -1 produced the highest vlues of okr yield while ure fertilizer pplied t 120 kg h -1 in combintion with mize cob sh pplied t 3 t h -1 hs the highest N, K, C, Cu, nd Fe contents of okr fruit. Therefore, for vible production of okr in low nutrient soil of the Nigeri-derived svnn or similr soils elsewhere, 60 kg h -1 ure fertilizer + 3 t h -1 mize cob sh is recommended. REFERENCES Abdulhmid N.A., Mustph S Influence of griculturl wood sh on some physico-chemicl properties of sndy lom soils t Miduguri, Nigeri. Journl of Legue of Reserchers in Nigeri 10(1): Abdulrheem M.I., Ojeniyi S.O Combined ppliction of ure nd swdust sh in okr production: Effects on yield nd nutrients vilbility. Nigerin Journl of Soil Science 25: Adeboye O.C., Oput C.O Effects of glex on growth nd fruit nutrient composition of okr (Abelmoschus esculentus L. Moench). Ife Journl of Agriculture 18(1 & 2): 1 9. Adewole M.B., Dedeke O.A Growth performnce, yield nd nutritionl qulity of Amrnthus cruentus L. under repeted pplictions of poultry mnures. Ife Journl of Science 14(2): Agbede T.M., Adekiy A.O Effect of wood sh, poultry mnure nd NPK fertilizer on soil nd lef nutrient composition, growth nd yield of okr (Abelmoschus esculentus). Emirte Journl of Food nd Agriculture 24(4): Akinrinde E.A., Obigbesn G.O Evlution of the fertility sttus of selected soils for crop production in five ecologicl zones of Nigeri. In: Bblol O. (Ed.), Proceedings of the 26 th Annul Conference

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