Growth Analysis of Baby Corn (Zea mays L.) Under the Effect of Integrated Nutrient Management

Maize (Zea mays L.) is the most versatile crop having wider adaptability in varied ecologies. Presently baby corn is gaining popularity among Indian farming communities mainly due to its short duration, high market rate, nutritive value and also its multiuse. Baby corn requires higher population and plant nutrition than normal grain corn. Therefore the nutrient management is of immense importance for higher corn production. The present study was thus carried out during Kharif season 2015 at the Instructional Dairy Farm (IDF), Nagla, Govind Ballabh Pant University of Agriculture and Technology, Pantnagar, Uttarakhand to analyse the growth of baby corn under the effect of integrated nutrient management. The experimental design was Randomized Block Design with 11 treatments consisting of sole application of NPK fertilizer, sole application of Azotobacter and Azospirillum, and application of Azotobacter and Azospirillum along with NPK fertilizer. The study revealed that Leaf area index was significantly higher at 50 DAS and harvest under 100% NPK+Azot+Azos. Application of 75% NPK+Azot+Azos had significantly higher at 25-50 DAS while 100% NPK+Azot+Azos gave significantly higher at 50 DAS – harvest. The values remained non significant at both the stages, however the highest was recorded at application of 100% NPK+Azot+Azos. The remained non significant at 25 – 50 DAS but at 50 DAS – harvest, the values recorded significantly higher at 100% NPK+Azot+Azos that remained non significant with all the treatments except control and seed treatment with Azotobacter. The too was recorded non significant by different integrated nutrient management practices at 25-50 DAS but at 50 DAS-harvest, the significantly highest was recorded under control, whereas the lowest was found at application of 100% NPK that remained statistically at par with all other treatments except control. Higher dose of nitrogen coupled with biofertilizers improved the plant growth.


INTRODUCTION
Maize is the third most important staple food crop in the world after wheat and rice but in term of productivity, it ranks first followed by rice, wheat and other millets. Presently baby corn is gaining popularity among Indian farming communities mainly due to its short duration, high market rate, nutritive value and also its multiuse. Baby corn is dehusked immature maize ear, harvested within 2-3 days of silking but prior to fertilization (Pandey et al., 1998). Baby corn is used as vegetable, salad, soup, pickle, kheer, murabba, chutney, manchurian, halwa etc. Baby corn is highly nutritive as 100 g of baby corn contains 89.1% moisture, 0.2 g fat, 1.9 g protein, 8.2 mg carbohydrate, 0.06 g ash, 28.0 mg calcium, 86.0 mg phosphorus, 11.0 mg ascorbic acid (Das et al., 2009). Baby corn has a great potential to fetch foreign currency through international trade. There is a great demand of baby corn in international market mainly because of its freshness, taste, nutrition, free from pesticides and its multiuse.
In general, morphology, physiology and agronomy of baby corn differed from grain corn as the varieties grown for baby corn must have high vigour and prolificacy. It responds to higher doses of fertilizer that may normally cause lodging in other cereal crops. Thus nutrient management is a very important aspect for proper growth of baby corn. The leaf area, LAI and dry accumulation per plant was noticed significantly higher at application of 240 kg N ha -1 over 0, 60, 120 and 180 kg ha -1 N reported that inoculation of canola seeds by either Azotobacter, Azospirillum or the mixed inoculum and adding half recommended dose of nitrogen showed high leaf area and save half of the mineral nitrogen recommended dose. Thus the present study was carried out to find out the best integrated nutrient management practice for baby corn under which the crop would show best results in terms of growth.

II.
MATERIAL AND METHODS The experiment was conducted at the Instructional Dairy Farm (IDF), Nagla, Govind Ballabh Pant University of Agriculture and Technology, Pantnagar, Udham Singh Nagar, Uttarakhand, India. The Instructional Dairy Farm is located in the Tarai belt of Shivalik range of Himalayas with humid sub-tropical type of climate at latitude of 29°N and longitude of 79.3°E and situated at an altitude of 243.84 m above the mean sea level. The climate of the Tarai region is broadly humid sub-tropical with harsh winter and hot dry summers. The soil of the experimental field was slightly silty clay loam (Nagla series, Mollisol) in texture, from dark greyish brown to dark grey in humus with weak, fine to medium granular structure.

III. RESULTS AND DISCUSSION Leaf Area Index (LAI)
The LAI remained non significant under different integrated nutrient management practices at 25 DAS. At 50 DAS and harvest, significantly higher LAI was recorded with application of 100% NPK+Azot+Azos that remained at par with 100% NPK, 50% NPK+Azot+Azos and 75% NPK+Azot+Azos at 50 DAS and with 100% NPK and 75% NPK+Azot+Azos at harvest stage. Among the biofertilizer treatments, the LAI at 50 DAS remained non significant, however combined seed treatment produced the higher LAI followed by seed treatment with Azotobacter. At harvest, seed treatment with Azot+Azos produced significantly highest LAI than seed treated with either of biofertilizers. Nitrogen is the main constituent of chlorophyll that keeps leaf greener for longer period and also improved photosynthesis that finally resulted into better leaf growth and development. The data pertaining to LAI is given in table 1.

Mean Crop Growth Rate ( CGR )
At 25-50 DAS, the highest (CGR ) was recorded with application of 75% NPK+Azot+Azos that remained significantly at par with application of 100% NPK, 50% NPK+Azot+Azos and 100% NPK+Azot+Azos, whereas at 50 DAS ± harvest, the higher (CGR ) values were recorded with application of 100% NPK + Azot + Azos that was significantly similar to 100% NPK, 50% NPK + Azot, 50% NPK+Azot+Azos and 75% NPK+Azot+Azos. Among the biofertilizer treatments, the (CGR ) at 25-50 DAS and 50 DAS-harvest remained non significant with each other, however combined seed treatment recorded higher (CGR ) at both the stages followed by seed treatment with Azotobacter. The lowest ( CGR ) was recorded under control at both the stages. The higher ( CGR ) value might be caused due to better plant growth at combined application of nitrogen and bioferilizers.

Relative Growth Rate ( RGR )
The data pertaining to ( RGR ) indicated that it declined with advancement of crop age. The highest and the lowest ( RGR ) values were recorded with application of 100% NPK+Azot+Azos and under control at both 25-50 DAS and at 50 DAS ± harvest crop stages, respectively.
Among the biofertilizer treatments, the highest ( RGR ) values were recorded at seeds treated with Azotobacter+Azospirillum followed by seed treatment with Azotobacter.

Net Assimilation Rate ( NAR )
The net assimilation rate was recorded non significant by different integrated nutrient management practices at 25-50 DAS. At 50 DAS-harvest, significantly higher ( NAR ) value was recorded with application of 100% NPK+Azot+Azos that remained statistically at par with all the treatments except control and seed treatment with Azospirillum. The ( NAR ) was recorded non significant among the treatments where either alone or combined biofertilizers were used for seed treatment, but combined seed treatment with biofertilizer and seed treatment with Azotobacter produced the highest ( NAR ) followed by seed treatment with Azospirillum. The ( NAR ) was recorded significantly lower with alone application of 50% NPK than all treatments having 50% NPK+ seed treatments with biofertilizers.

Leaf Area Ratio ( LAR )
The leaf area ratio was recorded non significant by different integrated nutrient management practices at 25-50 DAS. At 50 DAS-harvest, the significantly highest ( LAR ) was recorded under control, whereas the lowest ( LAR ) was found with application of 100% NPK that remained statistically at par with all other treatments except control.
Among the biofertilizers treatments, ( LAR ) remained non significant, however seed treatment with Azospirillum recorded the highest ( LAR ) followed by seed treatment with Azot+Azos. The LAR remained non significant among the treatments having combined application of 50% NPK + biofertilizers, but the highest ( LAR ) was noticed with application of 50% NPK+Azos followed by 50% NPK+Azot. The data pertaining to NAR and LAR is given in table 3.

Conclusion
Combined application of nitrogen and bioferilizers improved photosynthesis that finally resulted into better leaf growth and crop growth. The present study concluded the benefits of integrated nutrient management including use of biofertilizers in combination of chemical fertilizers and its positive effect on growth of baby corn.