Optimum planting time for Maize (Zea mays L.) in Northern Sudan Abdel Rahman Ahmed Mohamed 1 and Eltahir Siddig Ali 2 Abstract The optimum planting time of maize is a key factor for grain yield maximization. Therefore, this study was conducted at Hudeiba Research Station Farm for two consecutive years (2005-2007) to determine the appropriate planting time for maize in northern Sudan, in such a way that maize growers will have optional planting dates all the year round. Cultivar Hudeiba-1 was used in a randomized complete block design, with three replicates. Thirteen sowing dates starting from 17 July to 19 January at 15 days interval were tested in each year. The results showed that, sowing date had a significant effect on maize grain yield and the other measured yield components. Grain yield of maize increased significantly from sowing dates ranging from 17 September to 18 November in both years. October the third sowing dates gave the highest mean grain yields in both years separately and combined as 3176, 2951 and 3063 kg/ha, respectively. However, sowing between 17 of September and the 18 th of November can be considered as reasonable optimum sowing dates for farmers to obtain comparable grain yields. From the regression analysis, results also indicated that sowing dates earlier than the third week of September or later than the first week of December resulted in substantial grain yield reduction for the two years separately and combined. In addition, these results fully supported the previous recommendation for growing maize as a winter crop in northern Sudan. Introduction Maize (Zea mays L.) is the fourth cereal crop in Sudan, after sorghum, wheat and millet, but recently gained more importance as a forage and industrial crop than other cereal crops. The crop has a high potential in northern Sudan, being grown during both summer and winter seasons and yields ranging from 2 t/ha to 5 t/ha can be obtained under optimal conditions. The optimum planting date of maize in Sudan is one of the key components for farmers and growers to get better maize yields. The warm mean daily temperature and the stem borer infestation are the two major abiotic and biotic stresses that limit maize production in northern and other parts of Sudan. Earlier investigators research in northern Sudan showed that maize could be grown all the year round. In this regard, El karouri and Mansi (1980) reported that the mean daily temperature is the most important environmental factor that greatly influences maize final yields. While, Babiker (1997) reported that poor or no yields were obtained with delayed sowing dates due to stem borer damage at Rahad Research Station. In contrast, El Karouri and Mansi (1980) obtained high maize forage yield from winter sowing (November- December) in Khartoum area. In northern Sudan, although research on maize in the past focused more on breeding aspects, however, Imam (1965) found that the optimum planting time for maize under Hudeiba Research Station conditions would be from the last week of September to the end of October, 1 Hudeiba Research Station, (ARC) 2 Gezira Research Station, (ARC) 1
while, Ibrahim (1995) on the same site obtained high maize grain yield from November sowing as compared with that of December or January, which could be attributed to the suitable low temperatures at the nicking stage. A long- term maize sowing date experiment was conducted during 1999-2000 season at Hudeiba Research Station by the first author. It showed that maize could be grown all the year round, However, substantial maize grain yields were obtained when sown from the first week of August to the end of January. The recommendation for maize to be grown as a winter crop showed that, the optimum sowing date was the first week of October (Abdel Rahman et al., 2003). However, their results were obtained from three planting dates (October, November and December). Furthermore, the Husbandry Committee argued that one month sowing interval is too long and it is better to use the 15-days interval. Therefore, in this study 13 sowing dates were used to determine the optimum planting time for maize in such a way that maize growers will have optional sowing dates and also, to fine- tune the previous optimum sowing date recommended for northern Sudan. Materials and Methods This study was carried out during two years (2005-2007) at Hudeiba Research Station Farm to determine the optimum planting time for maize in northern Sudan. Thirteen sowing dates at 15 days interval started from 17 July to 19 January were tested in each year Mean daily and monthly temperature during the two growing periods for different sowing dates is presented in Table 1. Cultivar Hudeiba-1 was used in this study. The seeds were treated with Gaushw at a rate of 1 g/kg seeds and planted in holes spaced at 30 cm and 60 cm intra and inter row spacing, respectively. The crop was thinned to one plant/hole ten days after emergence to give a population of 55555 plants/ha. The treatments were arranged in a randomized complete block design, with three replications. The plot size was 3 m wide and 5 m long comprised of 5 rows. The experiment received 86 kg N/ha as urea three weeks after planting. The plots were kept weed free manually and irrigated every 7 to 10 days. Grain yield was assessed and the harvested ears were shelled and air-dried. Samples of five ears taken at random from the plots were used to determine the yield components. Data for grain yield and other agronomic traits were collected and analyzed using the analysis of variance (ANOVA) standard procedure for the randomized complete block design. The Statistical Analysis System (SAS) package was used. Table 1. Mean daily and monthly temperature for the different sowing dates at Hudeiba Meteorological Station during 2005-2007. Month 2005/ 2006 2006/2007 Mean daily and monthly temperature (ºC ) 1-15 16-30 Mean 1-15 16-30 Mean July 31.8 34.6 33.2 34.9 34.4 34.6 August 34.4 32.8 33.6 33.7 34.4 34.0 September 34.0 32.7 33.4 34.3 34.5 34.3 October 32.3 33.4 32.9 34.4 34.2 34.3 November 27.6 27.7 27.7 29.5 29.2 29.3 December 27.1 24.4 25.8 22.0 23.0 22.5 January 24.2 25.6 24.6 19.2 20.9 20.0 February 24. 24.9 24.5 21.7 25.7 23.7 March 25.8 25.9 25.9 26.5 26.6 26.5 April 28.0 31.1 29.5 28.7 32.1 30.4 2
Results Grain yield (kg/ha) Sowing date significantly (P 0.05) affected grain yield in both years, with the highest grain yield obtained from the first week of October sowing date for the two years separately and combined. High grain yield was obtained from 17 September to 18 November sowing date (Table 2). The regression analysis, results also indicated that sowing dates earlier than the third week of September or later than the first week of December resulted in substantial grain yield reduction for the two year separately and combined, as presented in Table 2 and Figure 1-3. Table 2. Effect of sowing date on maize grain yield in kg/ha for actual and fitted values from experiments grown at Hudeiba Research Station Farm during two seasons. Sowing Date First season Second season Combined Actual Fitted Actual Fitted Actual Fitted 17 July 495 e -185.78 250 f -202.46 372 f -194.12 2 August 300 e 591.76 268 f 497.69 284 f 544.73 17 August 676 e 1233.44 496 f 1074.39 585 f 1153.92 2 September 875 e 1739.26 1175 d 1527.63 1025 e 1633.45 17 September 2339 bc 2109.22 1946 bc 1857.42 2143 bc 1983.32 3 October 3176 a 2343.31 2951 a 2063.76 3063 a 2203.54 18 October 2634 b 2441.55 2173 b 2146.64 2404 b 2294.09 3November 2545 b 2403.92 2224 b 2106.06 2385 b 2254.99 18 November 2135 bc 2230.43 1818 bc 1942.04 1977 cd 2086.23 4 December 1843 cd 1921.07 1624 c 1654.56 1733 d 1787.82 19 December 1397 d 1475.86 847 de 1243.62 1122 e 1359.74 4 January 538 e 894.78 468 ef 709.24 503 f 802.01 19 January 424 e 177.85 431 ef 51.39 428 f 114.62 SE± 246 222 234 Means followed by the same letters within the same column are not significantly different at P 0.05 according to DMRT. 3
Figure 1: Effect of sowing date on grain yield (kg/ha) of maize grown at Hudeiba Research Station Farm, 2005/06. Figure 2: Effect of sowing date on grain yield (kg/ha) of maize grown at Hudeiba Research Station Farm, 2006/07. 4
Figure 3: Effect of sowing date on grain yield (kg/ha) of maize grown at Hudeiba Research Station Farm, combined. Yield components Measured yield components were significantly affected by sowing date in both years, except for 100- kernel weight in the first year (Table 4). Kernel number per ear reflected similar trend to that of grain yield, where sowing dates earlier than the third week of September or later than the first week of December resulted in substantial reduction for the two years, as presented in Table 3. On the other hand, ear weight was less affected by sowing date, although significant higher ear weights were revealed by late September and October sowing dates (Table 5). The three yield components used; number of kernels/row, 100-kernel weight and ear weight were significantly (P 0.01) and positively correlated to grain yield with (r) values of 0.936, 0.692 and 0.986 for the three yield components, respectively. 5
Table 3. Effect of sowing date on number of kernels per ear of maize grown at Hudeiba Research Station Farm during two seasons. Sowing date 2005/ 2006 2006/ 2007 Mean 17 July 70 96 83 2 August 72 102 87 17 August 100 181 140 2 September 217 249 233 17 September 331 261 296 3 October 441 358 399 18 October 592 398 495 3November 467 318 393 18 November 396 336 366 4 December 386 291 338 19 December 293 232 263 4 January 171 97 134 19 January 142 83 113 Mean 317 231 274 S.E.+ 29.6** 23.9** Table 4. Effect of sowing date on 100- kernel weight (g) of maize grown at Hudeiba Research Station Farm during two seasons. Sowing date 2005/ 2006 2006/ 2007 Mean 17 July 19 19 19 2 August 19 21 20 17 August 23 24 23 2 September 21 24 22 17 September 22 23 22 3 October 23 26 24 18 October 22 27 25 3November 23 22 22 18 November 22 21 21 4 December 21 21 21 19 December 22 22 22 4 January 23 17 20 19 January 21 13 17 Mean 22 22 22 S.E.+ Ns 1.17* 6
Table 5. Effect of sowing date on ear weight (g) of maize grown at Hudeiba Research Station Farm during two seasons. Sowing date 2005/ 2006 2006/ 2007 Mean 17 July 26 30 28 2 August 27 25 26 17 August 31 37 34 2 September 34 54 44 17 September 52 65 58 3 October 78 66 82 18 October 55 85 60 3November 40 83 61 18 November 41 72 57 4 December 42 61 51 19 December 42 51 42 4 January 36 23 30 19 January 29 24 27 Mean 42 52 47 S.E.+ 4.87** 5.85** Table 6. Correlation between grain yield and yield components Trait Grain yield (kg/ha) Number of kernels/row 100 kernel weight (g) Number of kernels/row 0.936 ** 100 kernel weight (g) 0.692 ** 0.729 ** Ear weight (g) 0.986 ** 0.898 ** 0.714 ** n =13 ** Significantly different at P 0.01. Discussion The study revealed that, substantial maize grain yield was obtained from the sowing dates of 17 September to 18 November. Such results could be attributed to the observed low scores of the stem borer recorded during this planting time, due to the absence of sorghum, which represents the main source of the insect pest. Moreover, the average mean daily temperature is within the optimum range as reported by Asghari and Hanson (1984). The highest grain yield resulted from sowing at the first week of October was in line with the findings of Imam (1965) who obtained high maize grain yield from 29 September sowing and with Mukhtar et al. (2007) who reported high maize grain yield amounting to about 5000 kg/ha from winter sowing. The sowing date range suggested by this study is longer than that of Imam (1965) for Hudeiba Research Station conditions and El karouri and Mansi (1980) for Khartoum area, but it is shorter as compared with that reported by Mukhtar et al. (2007). This could be attributed to the favorable temperature and probably low stem borer infestation in Dongla area, in contrast with the situation at Rahad, where stem borer damage caused drastic reduction in grain yield of maize as reported by Babiker (1997). 7
The low grain yields resulted from the early sowing dates could be attributed mainly to the stress of the high temperatures during fertilization and grain development. Babiker (1984) reported that temperature above (33 ºC) had adverse effect on maize fertilization and grain development and attributed the low yield to early maturity and hence, short grain-filling periods. This was evident by the reduction in number of kernels/ear resulted from January sowings in addition to the high stem borer infestation during these sowing dates (Table 3 and 4). On the other hand, though the stem borer damage is negligible during November- January sowings, however, the low temperature and the aphid's infestation greatly reduced maize growth and grain yield, particularly in the second year of the study. Conclusion The results reported here in clearly indicated that substantial maize grain yield could be obtained from sowing dates of 17 September to 18 November. This gives farmers and growers optional sowing dates for raising maize in northern Sudan. Furthermore, high maize grain yield can be obtained beyond that range if other constraints mentioned in the text are efficiency controlled. Recommendations Based on the results of this study, the Crop Husbandry Committee is kindly requested to recommend the following. The optimum planting time for maize in northern Sudan is the first week of October. However, sowing between 17 th of September to 18 th of November could be a reasonable option for the farmers. References Asghari, M., and R. G. Hanson. 1984. Nitrogen, climate and previous crop effect on corn yield and grain N. Agronomy Journal. 76: 536-542. Babiker, E. A. 1984. Maximum yield with corn (Zea mays L.) as affected by irrigation, plant density, nutrition and hybrid. Ph.D. Thesis. The Ohio State university, USA. Babiker, E. A. 1997. Effect of sowing date and plant density on growth and yield of irrigated maize (Zea mays L.) at Rahad (Sudan). U. of K J. Agric Sci., 7 (1) p. 1-19. El Karouri, M. O. H. and Mansi, M.G. 1980. Performance of sorghum (Sorghum vulgare) and maize (Zea mays L.) as forages in Irrigated saline soils of the Sudan. Experimental Agriculture. 16, 431-436. Ibrahim, A. M. 1995. Maize cultivar and sowing date experiment. Hudeiba Research Station. Ann. Rep. 1995/1996, ARC, Sudan. Imam, A.I. 1965. Maize agronomy experiment. Hudeiba Research Station, Ann. Rep. 1995/65, ARC, Sudan. Abdel Rahman, A. M. Magboul, E. Lazim. and Abdelatief, E. Nour. 2003. Effect of sowing date and cultivar on yield and yield components of maize in northern Sudan. NCHC, June, 2003. ARC, Wad Medani, Sudan. Mukhtar, A. M., Eltahir, S. A., Siraj, O. M. and Hamada, A. A. 2007. Effects of weeds on growth and yield of maize (Zea mays L.) in Northern State, Sudan. Sudan Journal of Agricultural Research. Vol. 8: 1-7. 8