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Abstract 5- SUMMARY AND COlWLUSION This study was an attempt to investigate the effect of plant spacing and nitrogenous fertilizer on the dry seed yield and quality of three varieties of cowpea. Two field experiments were carried out during the summer season of 198) and 1934 at EI-Mania, Kalubia. The experimental design used was a split-split plot vdth four replications. Three cultivars i.e Azmerly, Cream-7 and Fetriat were gro~~ at the main plots while three plant spacings (10,)0 and 40 em.) splitted the main plots to act as sub-plots. Howev2r, nitrogen levels (0,75 and 150 kE. of calcium nitrate/ fed.) were the sub-sub-plots. The recorded data included some vegetative gro~th characters, chemical constituents of the plants, flowering, fruit-setting, dry seed yield components w1d its quality as well as chemical constituents of dry seeds. Obtained results were as follows: I. Plant growth characteristics: The three used cultivars varied in their stem lerig”tharid/;i~ameteras well as their totalfreah and dry weight. Azmerly variety was superior in this rest>ec·’c. Plant growth characteristics expressed as stem diameter as well as total plant fresh and dry weiGh~ were enhaned by wide spacings (30 and 40 cm.) and increasing nitrogen fertilization level. stem lengt::. and branching were also stimulated by r~trogen application whereas they were not significantly affecter. by spacing. The plants of the variety Azmerly showed the most vigorous growth than other ones specially whei. sown at 40 cm. apart and fertilized with 150 kg of calcium nitrate per I fed. II. Chemical composition of plant parts: Chlorophyll and carotene contents of cowpea plant leaves tended to increase by increasing level of N-fertilization, whereas they were not significantly affected by spacing. The uptake of NPK was increased by wide spacili:3 as well as by increasing nitrogen fertilization le~21. Total carbohydrate content in cowpea foliage was 8i;- nificantly increasei as the nitrogen level increase~ whereas it did not reflect any significant difference as a result of spacing. -81- III. Flowering and fruit-setting: Total nlli~berof flowers per plant increased as both spacinR between plants and nitrogen level incrc2- sed. The highest total number of flowers per plant was obtained with the combination of the widest spacing (40 cm.) ~~d the highest nitrogen level (150 k~ of ce.Lc Lum nitrate / fed.). The response of flowering to spacing or ni tro£c_t level varied among the three used varieties. Azmerly variety showed the best response, Cream~7 was inte~- ~ediate, whereas Fetriat variety ranked last in thia respect. Ji’ruti - setting percentage did not reflect any significant difference as a result of plant spacing or nitrogen fertilization. IV. Yield components: Azmerly variety outyielded the other two varieties either in yield per plant or per feddan. Azmerly variety was superior than other used varieties in its number of pods per plant and n~~beI’ of seeds per pod. Numbe r of pods per plant significantly Lncr-eaacu as both spacing between plants and nitrogen level irrcrea, sed. Number of seeds per pod slightly increased as nitrogen level increased whereas it did not reflect any significant increase as a result of plant densi t:;~. The average weight of lOO-seeds did not reflect any signific~t difference due to either spacing 01 nitrogen fertilization. The closest spacing (IDem.) produced the lowest seed yield per plant, but the highest seed yield per feddan. Dry seed yield per plant increased as nitrogen level increased. Dry seed yield per feddan significantly increasG~ as nitrogen level increased up to 150 kg. of calciu~ nitrate / fed. at the closest spacing (10 em.). HO~;Gver, at wider spacine (30 or 40 em.) such yield increased with 75 kg of calcium nitrate / fed., but shov.ed no increase above this rate. Generally, the highest yield of cowpea seed pe .:•- feddan was obtained from plants of the variety Azme~~y grovm at lOcm. apart and fertilized with 150 kg of calcium nitrate / fed. v. Chemical constituents of seeds: ’£he seeds of the variety Azmerly contained higL,JI’ amounts of chemical constituents, in gener~ than the other two varieties. The dry seeds content of NPK, total carbohydrat~ and Protein-N did not reflect any significant differences as a result of plant spacing. ciitrogen fertilization significantly increased N and K contents, but did not affect P content in dr:,: seeds. Ira tal carbohydrate and protein-N contents Ln dr, seeds,which are the major components of seed reserve food, were significantly increased as the nitrogen level increased. Generally it may be concluded that dry seeds O~ the variety Azmerly,which yield highest seed yield, contained highest N, P, K, protein and carbohydrate content compared with other varieties under conditio~3 of this work. |