Data on influence of different nitrogen fertilizer rates and plant density on grain yield and yield components of Water Efficient Maize (WEMA) variety

Plant density and applications of nitrogen fertilizer have been recognized as the main crop management techniques to improve maize yield. The data showed effect of different nitrogen fertilizer rates and plant density on grain yield and yield components of water efficient maize. A Field experiment was conducted during the 2015/16 and 2016/17 planting seasons in two (Taung and Mafikeng) localities of North–West Province, South Africa to evaluate the influence of N fertilizer rates and plant density on grain yield and yield components of Water Efficient Maize (WEMA) variety. The experiment was laid out in split plot fitted into a randomized complete block design with four replicates in each site. The main plot effect was three plant densities (33333, 44444 and 55555 plants/ha) and nitrogen rates (0, 60, 120, 180 and 240 kg N ha−1) constituted the subplot. The parameters measured were grain yield and grain yield components. Data were analyzed with analysis of variance (ANOVA) of GenStat 11th edition. Differences in the treatment means were tested by Duncan Multiple Range Test (DMRT) at 5% level of probability. Regression and correlation analyses were used to determine relationship between grain yield, yield components and nitrogen rates.


a b s t r a c t
Plant density and applications of nitrogen fertilizer have been recognized as the main crop management techniques to improve maize yield. The data showed effect of different nitrogen fertilizer rates and plant density on grain yield and yield components of water efficient maize. A Field experiment was conducted during the 2015/16 and 2016/17 planting seasons in two (Taung and Mafikeng) localities of North-West Province, South Africa to evaluate the influence of N fertilizer rates and plant density on grain yield and yield components of Water Efficient Maize (WEMA) variety. The experiment was laid out in split plot fitted into a randomized complete block design with four replicates in each site. The main plot effect was three plant densities (33333, 4 4 4 4 4 and 55555 plants/ha) and nitrogen rates (0, 60, 120, 180 and 240 kg N ha −1 ) constituted the subplot. The parameters measured were grain yield and grain yield components. Data were analyzed with analysis of variance (ANOVA) of GenStat 11th edition. Differences in the treatment means were tested by Duncan Multiple Range Test (DMRT) at 5% level of probability. Regression and correlation analyses were used to determine relationship between grain yield, yield components and nitrogen rates.

Value of the data
• The data showed the effect of different nitrogen fertilizer rates on grain yield and yield components. • The data revealed the effect of plant density on grain yield and yield components.
• The data indicated the effect of interaction of nitrogen fertilizer rates, plant densities and locations on grain yield and yield components. • The data can be used by crop nutritionist and general agronomist.

Data description
The data shows the influence of different nitrogen fertilizer rates and plant density on grain yield and yield components of Water Efficient Maize (WEMA) variety under different field conditions. The experiment was carried out during 2015/16 and 2016/17 planting seasons. The meteorological data of experimental locations ( Table 1 ). The effect of each treatment factors on grain yield, total shoot biomass yield, stover, yield and harvest index were presented in Table 2 . Table 3 indicates the influence of each treatment factors on shelling percentage, grain/cob ratio and one thousand seed weight. The interaction effect of location, plant densities and nitrogen fertilizer rates on grain yield, total shoot biomass, stover yield and harvest index as presented in Table 4 . Table 5 displays the interaction effect of location, plant densities and nitrogen fertilizer rates on harvest index, grain/cob ratio and one thousand seed. Table 6 exhibits relationship between grain yield, yield components and nitrogen rates. Table 7 presents correlation relationship between grain yield and yield components. The supplementary data indicates the raw dataset of grain yield and yield components (Excel sheet 1). Also, supplementary data shows analyzed that Table 1 Effect of treatments factors on harvest index, shelling % 10 0 0 seeds and grain/cob ratio of WEMA.

Treatment factors
Harvest index Shelling % Thousand seed mass Grain/cob ratio Means with the same letter on the same column and treatment are not significantly different at P ≤ 0.05. using least different significant difference (LSD). * * Significant at 5% probability.  obtained from raw data to estimate relationship between grain yield, yield components and nitrogen rates (Excel sheet 2-4).  Table 5 Interaction effect of N rates, plant density and location on 10 0 0 seeds and grain/cob ratio. 3.5 0.21 Table 6 Relationship between grain yield, yield components and N fertilizer rates.

Water efficient Maize for Africa
Water Efficient Maize for Africa (WEMA) is a drought-tolerant maize variety grown in Africa, particularly in the Southern African Development Community (SADC). It is purposely bred to cope with increasing drought conditions brought about by climatic variability in many parts of Africa. It was launched in 2008 by the African Agricultural Technology Foundation (AATF), and was developed through conventional breeding, but speeded up by marked assisted selection procedures. It is a partnership project between AATF, Monsanto's, and the National Agricultural Research Institute (NARS). Target countries for its use include Kenya, Mozambique, South Africa, Uganda and Tanzania. The major aim behind the development of this variety, as opposed to the common varieties, was to increase yields by 20-30% under moderate drought conditions and by 12-24% under high intensity drought conditions. The first three varieties were released in 2014. WE3127 variety was among the first three varieties released in South Africa [1] .

Description of study area
The  ( Fig. 1 ). The soil of North-West University (NWU) Research Farm belongs to Ferric Luvisol type and soil of Taung Experimental Station was classified as Rhodic Ferralsol type. The chemical properties of Ferric Luvisol are pH (4.41) total N (0.13%), available P (43 mg/kg) and K (241 mg/kg). However, the Rhodic Ferralsol had the following chemical properties, pH (5.38), total N (0.10 %), available P (27 mg/kg) and K (207.5 mg/kg) across two planting seasons.
The experimental sites were ploughed and harrowed two after ploughing. The layout of the experiment at each location was in the split plot arrangement fitted into a randomized complete block design with four replicates. The main plot effect was the three plant densities (33,333, 4 4,4 4 4 and 55,555 plants/ha) while the five N fertilizer rates (0.60, 120,180 and 240 kg N/ha) constituted the sub plot effect. Each subplot measured 6 m x 4 m with a total experimental plot size of 30 m × 76 m (0.228 ha) at each site ( Fig. 2 ). The distance of 1 m and 2 m were maintained between plots and replicates respectively. Each experimental site has sixty subplots. Maize (WE 3127) seed sowing was done at inter and intra row spacing of 1m × 0.3m, 0.75 m × 0.3m and 0.9 m × 0.2 m to achieve the density of 33,333, 44, 4444 and 55,555, respectively by drilling method. The fertilized was applied in split method, by applying 30% of the each rate as basal treatment at planting using NPK 20:7:3 while 40% and 30% remaining quantity from each rate was applied as top dressing at 3 and 5 weeks after sowing (WAS) using lime ammonium nitrate (LAN, 28%). Both fertilizer types are granular type. Weeding was done manually at 3 and 7 weeks after sowing.

Data collection
Maize plants were harvested within the middle row from each plot with harvested area of 8 m 2 . The ears were air dried for six weeks after harvesting until uniform moisture content of 12% was attained. The ears were threshed manually. Data on yield and its components were evaluated as follows: Yield = x actual plot area Total biological yield = grain yield + stover yield [3] Harvest Index = Economic yield(kg) Total bio log ical yiel d(kg) [4] Shelling percentage = Grain weight of shel l edears Weight of unshel l ed ears x 100 Grain /cob ratio = Dry weight grain Dr y weight of ear s −dr yweight grain x 100 (CIMMYT, 2013) While thousand seed weight was obtained with aid of weighting scale

Statistical analysis
All data obtained were subjected to analysis of variance (ANOVA) using the GenStat 11th edition. Differences between the treatment means were separated using Duncan Multiple Range Test (DMRT) test at 5% level of probability. Regression and correlation were used to estimate relationship between N rates, grain yield and yield components using Excel program.

Conflict of Interest
Regarding the publication of this manuscript, the author declare no conflicts of interest.