Optimizing maize productivity through split nitrogen application strategies

Introduction

Maize (Zea mays L.) is one of the important food grain crops in India and in world after wheat and rice due to its high value as staple food as well as straw demand for animal feed and also known as corn belongs to family Poaceae. It is one of the most versatile crops having wider adaptability and grown under varied agro-climatic conditions, diverse seasons and ecologies for various purposes. Globally, maize is known as "queen of cereals" because of its highest genetic yield potential among the cereals. Maize being an important cereal crop meets about 60% of the world dietary needs along with wheat and rice. Maize is known as "Miracle crop" in view of its several uses. Therefore, improvement in maize yields is an important task for food security. Nitrogen (N) nutrient plays a key role in several physiological and metabolic processes in plant. The most important role of Nitrogen in the plant is its presence in the structure of the protein and nucleic acids and is essential for enzymatic, biochemical and physiological reactions in plant metabolism (Sharma et al., 2017) [8] . Therefore, adequate supply of Nitrogen is necessary to achieve higher yield and the time of Nitrogen application plays a very important role in maize yield. T Among the agronomic management practices for improved nitrogen use efficiency (NUE), rational use of N fertilizer is a key factor to increase maize production reducing environmental pollution. Improving NUE enhance utilization rate of chemical fertilizers (mainly N). Through enormous research, N uptake, transport and distribution pattern in maize plants are fully understood. For systematic discovery of maize potential to maximize N utilization, biological means are vital to identify genetic, physiological and molecular basis. Nitrogen is often the most limiting nutrient in reducing crop yields. Often times, farmers tend to apply over dose of this nutrient. Due to an increase in its cost, environmental pollution, concerns and demand for mandatory nutrient management, planning and a comprehensive knowledge on N management strategies for optimal nitrogen use is essential. Nitrogen is the major input for corn production and also rate and time application is main factor for proper utilization. Nitrogen (N) fertilizer is an important measure to ensure maize yields, but excessive N inputs make it a difficult problem for optimum N utilization.

In modern agricultural production, N fertilizer application is an important measure or necessary condition to ensure high and stable crop yields. N is the key element for grain formation in maize (Evenson & Gollin, 2003 and Hirel et al., 2001) [1,2] . Maize being a C4 plant, physiologically more efficient in utilizing N than other crops. But paradoxically, maize production systems as a whole generally have low fertilizer N uptake efficiency or recovery efficiency (RE), which is the proportion of applied fertilizer that is being taken up by the plant. Therefore, it is necessary to give optimum dose of nitrogen for improving yield of maize (Li et al., 2010) [3] . Hence, to identify the effect of Nitrogen management on maize yield, the present experiment was planned.

Methodology

This experiment was conducted at Agricultural Research Station, Karimnagar during Kharif & Rabi 2014-15 & 2015-16 in red sandy loam soils. The initial soil status of this experimental site is indicated of high available N (614 kg ha -1 ), P (63 kg ha -1 ) and K (436 kg ha -1 ), respectively. The experiment was carried out in Randomized block design in three replications with 8 treatments i.e., T1. Application of N in 3 splits (33% at basal: 33% at knee height: 33% at tasseling), T2. Application of Nitrogen (N) in 3 splits (10% at basal: 50% at knee height: 40% at tasseling), T3. Application of N in 3 splits (20% at basal: 50% at knee height: 30% at tasseling), T4. Application of N in 4 splits (25% at basal: 25 % at 30 DAS: 25% at knee height: 25% at tasseling), T5. Application of N in 4 splits (10% at basal: 35 % at 30 DAS: 35% at knee height: 20% at tasseling), T6. Application of N in 4 splits (20% at basal: 30 % at 30 DAS: 30% at knee height: 20% at tasseling), T7. Application of N in 5 splits (20% at basal: 20 % at 30 DAS: 20% at knee height: 20% at tasseling: 20 % at grain filling), T8. Application of N in 5 splits (15% at basal: 25 % at 30 DAS: 25% at knee height: 25% at tasseling: 10 % at grain filling). Entire Phosphorus (80 kg ha -1 ) applied as a basal and Potash (80 kg ha -1 ) in two splits i.e. half at basal and remaining half at flowering stage. The recommended dose of NPK use for kharif maize is 200:60:50 kg ha -1 and for rabi 240:80:80 kg ha -1 . Entire quantity of P2O5 and K2O was applied as a basal dose. The sources of nitrogen, phosphorus and potassium were urea, single super phosphate and muriate of potash respectively. The split dose of nitrogen fertilizer was applied by placement at 5 cm away and 5 cm below the seed rows Timely management practices like weed management by inter cultivation via bullock drawn cultivator and pest management by recommended pesticides was done. Need based irrigations were given with 7-10 days interval. Observations were recorded on grain yield and its attributes.

Results

The results indicated that among all treatments highest grain yield (8574 kg ha -1 & 7689 kg ha -1 ) was noticed in application of Nitrogen in 4 splits (10% at basal: 35 % at 30 DAS: 35% at knee height: 20% at tasseling) in both Kharif seasons and was on par to all other treatments. Nonsignificant differences were observed among all the treatments. Lowest grain yield was observed with application of Nitrogen (N) in 3 splits (10% at basal: 50% at knee height: 40% at tasseling). But in Rabi season highest grain yield (8258 kg ha -1 & 7873 kg ha -1 ) was observed with application of Nitrogen in 3 splits (33% at basal: 33% at knee height: 33% at tasseling) in both the years, but it was on par with all other treatments. And also recorded lowest grain yield with application of N in 5 splits (15% at basal: 25 % at 30 DAS: 25% at knee height: 25% at tasseling: 10 % at grain filling). For yield attributes like cob length, cob girth, number of kernel rows per cob and number of kernels per row of cob, non-significant differences were observed in both the seasons. Pooled data reveal that there was no significant difference of observed among the treatments interms of yield and yield attributes. Similarly, highest cob length in nitrogen fertilizer plots and smallest cob length in the plots where nitrogen was not applied reported by Sharifi SR & Taghizadeh (2009) [6] . Rahman et al. (2016) [5] reported that N fertilisation at booting and silking stages caused significant increments in grain yield

Conclusion

In our study it was observed that in Kharif & Rabi seasons, the effect of split application of nitrogen in maize indicated that application of nitrogen in 3 or 4 or 5 splits makes no significant difference for yield and yield attributes.

References

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