3. Materials and Methods

A field trial was conducted at the Soil and Water Testing Laboratory, Charsadda during April 2017. The experimental site is located at 302m above the sea level at Charsada (34.1682° N, 71.7504° E). The experimental soil was silt loam in texture having low moisture content and low bulk density, non-saline in nature, slightly alkaline in reaction and moderately calcareous, low in organic matter content, deficient in nitrogen and phosphorus, which need an appropriate amount of nitrogenous and phosphatic fertilizers (Table 1). Prior to planting, ten core soil samples, randomly collected from 0-15 cm soil depth were bulked inside a plastic bucket to form a composite sample and was analyzed for various physicochemical properties. The 1^st factor was Nitrogen levels and the 2^nd was Phosphorous levels which were applied at the rate of 0-0, 100-20, 100-40, 100-60, 100-90 kgha^-1, from urea and single superphosphate, respectively. Okra (NHAe47-4) seeds variety was sown in the randomized complete block design with three replications. Four seeds of okra were planted per hole at a spacing of 60 cm x 30 cm and were later thinned off to one seedling per stand. Weeding and other agronomic practices were carried out properly when and where required.

Data was collected on growth parameters

1. Fruit Yield
2. Plant height
3. Number of leaves per Plant
4. Number of branches plant^-1
5. Days to flowering
6. Survival %age
7. Single pod weight

As described by [7]. Difference in mean were illustrated using least significant difference (LSD) test at 5% level of probability.

4. Results and Discussion

4.1. Fruit yield

NP fertilizers have significant effect on the yieldof okra. Treatments 100-20, 100-40, 100-60,

100-90 kg ha^-1showed mean yield of okra plant of 8.86, 11.85, 10.25 and 8.07, tha^-1 respectively while in comparison control showed 6.62. Results indicated the optimum NP fertilizers rate was 100-40 which gave significantly higher yield than other levels of NP fertilizers (Table 2). Our work is in agreement with the early work of [1,8] also reported that different levels of nitrogen and phosphorus fertilizers in combination significantly affect the yield and growth of okra.

4.2. Plant height

Results showed that NP fertilizers have significant effect on the plant height of okra (Table 2).Treatments 100-20, 100-40, 100-60, 100-90 kg ha^-1showed that the mean plant height is 73.45, 79.55,84.42 and 91.44cm respectively, while in comparison control showed 62.78cm (Table 2) [9] indicated that the nitrogen and phosphorus fertilizers at different levels significantly increased plant height of okra. The higher dose of N and P might increase cell division and formation of more tissues resulting in luxuriant vegetative growth and thereby increased plant height [10].

4.3. Number of leaves plant^-1

Results showed that NP fertilizers have significant effect on the number of leaves (Table 2). Treatments 100- 20,100-40,100-60 and100- 90 showed 43.67, 27.67,34.33 and 24.33mean effect on leaves, respectively while the control showed only 20.67 [11]. Studied that nitrogen supply induced more leaves plant^-1. The average leaves plant^-1 (22.8) were found to be maximum in the spacing S-20.

4.4. Number of branches plant^-1

Number of branches plant^-1 treatment 100-20,100-40,100-60 and 100-90 kg ha^-1 showed 6.66, 8.33, 5.33 and 4.33 mean effects respectively while the control only showed 2.33 (Table 2) [12]. Studied number of branches increased significantly in almost all the treatment from T₀and increased slowly with increased in levels of fertilizer T1 to T4 and the highest values had in T4 respectively.

4.5. Days to flowering

For flowering days of okra NP fertilizers have non-significant effect (Table 2). Different treatments combination revealed that the mean effect on days to flowering were 55.66, 44.33, 48.00 and 66.33, respectively while control showed 64.33 [12]. Also showed that days taken to first flowering marginally reduced with the application of nutrients either alone or in combination. However, these were failed to bring about statistically significant variation over control.

4.6. Survival %age

NP fertilizers have significant effect on the survival %age of okra plant (Table 2). Treatment 100-20,100-40,100-60 and 100-90 kg ha^-1showed the mean effect of 88.24, 75.04, 67.46 and 60.37 % respectively. Comparing control with different treatments which showed 52.85 %. Results indicated that the initial NP fertilizers rate is 100-20 which gave significantly higher survival %age than other treatment plots. The lower survival %age in the other fertilizer treatments might be due to excess of applied phosphorus in which the young plants could not survived better.

4.7. Single pod weight

Results showed that treatments 100-20,100-40.100-60 and 100-90 kg ha^-1 have produced 5.43, 7.90, 11.78 and 13.53g on the pod weight, respectively while control only showed 9.73g single pod weight [12]. Nitrogen fertilizer at the rate of 100 kg Nha^-1 had significant effect on pod weight of okra.

5. Conclusions and Recommendations

Among the varying combination of NP fertilizers, 100-40 kg ha^-1 showed overall good results on the yield and yield attributes of okra under the prevailing conditions of the Charsadda area.Therefore, NP fertilizers rate 100-40 kg ha^-1 is recommended to get the maximum yield of okra under the prevailing conditions of Charsadda area.