Effect of Nitrogen, Phosphorus and Potassium on Yield, Quality, Nutrient Content and Uptake on Hybrid Maize (Zea mays L.)

Maize (Zea mays L.) is one of the most versatile emerging crops having wider adaptability under varied agro-climatic conditions. Globally, maize is known as “queen of cereals” because it has the highest genetic yield potential among the cereals (Tollenaar and Lee, 2006). Currently, nearly 1147.7 million MT of maize is being produced together by over 170 countries from an area of 193.7 million ha with average productivity of 5.75 t ha-1 (Anonymous, 2020a). The USA has the highest productivity (>9.6 t ha^-1) which is double than the global average (4.92 t ha^-1). Whereas, the average productivity in India is 2.43 t ha-1. In India, maize is the third most important food crops after rice and wheat. Among the maize growing countries, India rank 4^th in area and 7^th in production, representing around 4% of the world maize area and 2% of total production. During 2018-19 in India, the maize area has reached to 9.2 million ha (Anonymous, 2020b). The Gujarat state had grown maize in 5.08 lakhs hectare land with production 8.71 million tons and 1714 kg ha^-1 yield in 2015-16 (Anonymous, 2019).

Among the various agronomic factor determining the crops yield, nutrient management is considered as one of the basic factors. Nitrogen though an expensive input is very important as it is intimately involved in the process of photosynthesis and directly reflected in the total dry matter production. Phosphorus is a fascinating plant nutrient. It is involved in a wide range of plant processes from permitting cell division to the development of a good root system and for ensuring timely and uniform ripening of the crop. Potassium is an essential nutrient for plant growth. Potassium plays a vital role as macronutrient in plant growth and sustainable crop production. Hence, an attempt was made to study the effect of different levels of nitrogen, phosphorus and potassium on yield, quality, nutrient content and uptake on hybrid maize (Zea mays l.) under south Gujarat condition.

A field experiment was conducted at College Farm, Deptt. of Agronomy, Navsari Agricultural University, Navsari (Gujarat) during rabi season of the year 2019-20 to study the effect of different levels of nitrogen, phosphorus and potassium on yield, quality, nutrient content and uptake by hybrid maize (Zea mays L.) under south Gujarat condition. The soil of the experimental field was clayey in texture and showed low, medium and high rating of available nitrogen (197.36 kg ha^-1), phosphorus (52.32 kg ha^-1) and potassium (481.40 kg ha^-1), respectively. The soil was found slightly alkaline (pH 7.8) with normal electric conductivity. The maximum temperature ranged between 27.5 to 34.9°C, while minimum temperature ranged between 8.4 to 19.5°C during period of experimentation. Similarly, maximum relative humidity ranged between 76.4 to 91.3% whereas minimum relative humidity ranged between 39.4 to 68.6% during period of experimentation. Sunshine hours per day ranged between 2.5 to 9.0 during the year 2019-20. Twelve treatment combinations consisting of three levels of nitrogen fertilizer i.e. N1 (nitrogen 120 kg ha^-1), N2 (nitrogen 150 kg ha^-1) and N3 (nitrogen 180 kg ha^-1), two levels of phosphorus fertilizer i.e. P1 (phosphorus 30 kg ha^-1) and P2 (phosphorus 60 kg ha-1) and two levels of potassium fertilizer i.e. K1 (potassium 00 kg ha^-1), K2 (potassium 30 kg ha^-1) were tried in factorial randomized block design with three replications. Nitrogen, phosphorus and potassium were given in the form of urea, single super phosphate and murate of potash, respectively. Nitrogen was applied in three splits (50% at basal, 25% at knee stage and 25% at pre-flowering stage) and the entire dose of phosphorus and potassium were applied as basal application at just before sowing in the furrows. Organic manure FYM @ 10 t ha^-1 was applied as common for all treatment before sowing by broadcasting and mixed in the soil. Seeds of hybrid maize GAYMH 3 was dibbled on 20 Nov. 2019 and harvested at 12 March 2020.    

The data on seed and stover yield was recorded from the net plot and converted on a hectare basis. The nitrogen content in green gram seed was estimated by micro Kjeldahl’s method as described by Jackson (1973). The protein content of the seed was computed by multiplying the nitrogen percentage with 6.25 for each treatment. Chemical studies about nitrogen, phosphorus, potassium content and their uptake by seed and stover and available nitrogen, phosphorus, potassium status in the soil after harvest of the crop were determined as per different methods viz., Modified Kjeldahl’s method (For N), Wet digestion (Diacid) Vanado molybdo phosphoric acid yellow colour method (for P) and Flame photometric method (for K). The data were analyzed statistically by adopting the standard procedures described by Panse and Sukhatme (1985). The purpose of the analysis of variance was to determine the significant effect of treatments on green gram. Uptake of nutrients by seed and plant was calculated by using following formula:
 

 

 

Effect of nitrogen
 
The data given in Table 3 indicated that application of 180 kg N ha^-1 (N3) recorded significantly the highest grain yield (51.58 q ha^-1) and straw yield (103.69 q/ha). While, the lowest grain yield (42.61 q ha^-1) and straw yield (87.04 q ha^-1) was recorded under treatment N1 (120 kg N ha^-1). Higher grain and straw yield under high level of nitrogen was evidently due to different levels of nitrogen was related to the differences in size of photosynthetic surface and to the relative efficiency of total sink activity, possibly a function of yield attributes and higher plant height, respectively. These results are in conformity with the results of Singh et al. (2015). They reported that application of 150 kg N ha^-1 resulted 21.71 and 2.58 % higher grain and stover yield over 100 kg N ha^-1 in maize.

The data given in Table 1 indicated that different levels of nitrogen exhibited their non-significant influence on crude protein content in grain, while application of 180 kg N ha^-1 (N3) reported significantly the highest crude protein yield (703.6 kg ha^-1). The increase in crude protein content in grain might be due to the fact that nitrogen is an integral constituent of amino acids, which are the basic units of the protein. The results of present investigation are accordance with the findings of Thirupathi et al. (2016). They reported that significantly the highest crude protein content (8.5 %) was recorded with application of 225 kg N ha^-1 as compared to 180 kg N ha^-1 in maize.



The data given in Table 2 indicated that N, P and K content in grain and straw were found non-significant by different nitrogen levels. Numerically the highest value of N, P and K content of 2.187, 0.310 and 1.471 per cent, respectively in grain and N, P and K content of 0.581, 0.205 and 1.103 per cent, respectively in straw was recorded with the application of 180 kg N/ha (N3)  and the lowest value of N, P and K content of 2.124, 0.299 and 1.451 per cent, respectively in grain and N, P and K content of 0.558, 0.195 and 1.074 per cent, respectively in straw was recorded with the application of 120 kg N ha^-1 (N1). The present findings are within the close vicinity of those reported by Der (2014) in maize. They reported that numerically higher value of N, P and K content in grain and straw of 1.606 and 0.401%, 0.307 and 0.206% and 0.469 and 0.884%, respectively, were observed with higher application of nitrogen (150 kg ha^-1).

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Significantly the highest N, P and K uptake of 112.58, 15.99 and 75.91 kg/ha, respectively in grain and N, P and K uptake of 60.33, 21.25 and 114.39, respectively in straw was recorded with application of 180 kg N ha^-1 (N3) over application of 150 and 120 kg N ha^-1. This may be due to increasing nutrient levels increases nutrient uptake in grain and straw. Similar results were recorded by Jadhav et al. (2011). They recorded significantly higher uptake of N (71.74 kg ha^-1), P (10.00 kg ha^-1) and K (13.147 kg ha^-1) by grain and N (56.62 kg ha^-1), P (6.14 kg ha^-1) and K (59.59 kg ha^-1) by stover was recorded by application of nitrogen @ 120 kg ha^-1 in pearl millet.           

The mean data pertaining to available N, P₂O₅ and K₂O in soil after harvest of crop were presented in Table 3. The individual effect of nitrogen, phosphorus and potassium levels and interaction effect on available N in soil were found non-significant. However, numerically higher available N, P2O5 and K2O was recorded with application of 180 kg N ha^-1 (N3) and lower available N, P₂O₅ and K₂O was recorded with application of 120 kg N ha^-1 (N1). Similar results were recorded by Sangtam et al. (2017). They reported that significantly higher available N (325.16 kg ha^-1) was recorded under application of 80 kg N ha^-1, however, available phosphorus and available potassium in did not record any significant variations among the different nitrogen doses in maize.

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Effect of phosphorus
 
The data given in Table 3 indicated that application of 60 kg P₂O₅ ha^-1 (P2) recorded significantly highest grain yield (49.05 q ha^-1), whereas, the lower grain yield (45.13 q ha^-1) was recorded under treatment P1 (30 kg P₂O₅ ha^-1). While, different levels of phosphorus do not impart their significant influence on straw yield. This increase in grain yield with the increase in phosphorus level may be attributed probably to the development of extensive root system. Which enabled the plants to absorb more nutrients from the depth and might have growth of the plant enhanced photosynthetic activities. These findings are in conformity with the results of Pandey et al. (2016). They reported that crop was fertilized up to 80 kg ha-1 of phosphorus application enhanced more growth  and seed yield than the 40 kg ha^-1 and control in lentil.

The data given in Table 1 indicated that different levels of phosphorus exhibited their non-significant influence on crude protein content in grain, while application of 60 kg P₂O₅ ha^-1 (P₂) recorded significantly highest crude protein yield (664.5 kg ha^-1). This finding closely associated with those of Raskar et al. (2013) and Khan and Singh (2017) in maize.

The data given in Table 2 indicated that N, P and K content in grain and straw was found non-significant effect due to different phosphorus levels. However, numerically the highest value of N, P, K content of 2.168, 0.307 and 1.470 per cent, respectively in grain and N, P, K content of 0.575, 0.202 and 1.097 per cent, respectively in straw was recorded with application of 60 kg P₂O₅ ha^-1  (P₂) and the lowest value of N, P, K content of 2.143, 0.302 and 1.451 per cent, respectively in grain and N, P, K content of 0.564, 0.197 and 1.083 per cent, respectively in straw was recorded with application of 30 kg P₂O₅ ha^-1 (P1). This finding closely associated with those of Singh et al. (2015). The results of the study indicated the application of phosphorus upto 40 kg P₂O₅ ha^-1 recorded significantly higher nitrogen, phosphorus and potassium content in seed and straw and their uptake as compared to absolute control and 20 kg P₂O₅ ha^-1 but was at par with 60 kg P₂O₅ ha^-1 in mung bean.

However, N, P, K uptake by grain and N, P uptake by straw was recorded significantly higher with application of 60 kg P₂O₅ ha^-1 (P2), while, K uptake by straw was found non-significant by phosphorus levels. This may be due to increasing nutrient level increases nutrient uptake in grain and straw. Singh et al. (2015). The results of the study indicated the application of phosphorus upto 40 kg P₂O₅ ha^-1 recorded significantly higher nitrogen, phosphorus and potassium uptake by seed and straw as compared to absolute control and 20 kg P₂O₅ ha^-1 but was at par with 60 kg P₂O₅ ha^-1 in mung bean.

The mean data pertaining to available N, P₂O₅ and K₂O in soil after harvest of crop were presented in Table 3. The individual effect of nitrogen, phosphorus and potassium levels and interaction effect on available P in soil were found non-significant. There is numerically high phosphorus present in soil with respect of application of high dose of phosphorus. The present findings are within the close vicinity of those reported by Der (2014) in maize. They observed that significantly higher available P₂O₅ (30.70 kg ha^-1) was recorded under application of 75 kg P₂O₅ ha^-1, however, available nitrogen and available potassium in did not record any significant variations among the different phosphorus doses in maize.
 
Effect of potassium
 
The data given in Table 3 indicated that application of 30 kg K₂O ha^-1 (K2) recorded significantly the highest grain yield (49.16 q ha^-1), whereas, the lowest grain yield (45.02 q ha^-1) was accumulated under treatment K₁ (00 kg K₂O ha^-1). Different levels of potassium did not influence significant on straw yield. Improvement in grain and straw yield might be attributed to an overall improvement in growth and yield attributes at all the stages of crop growth. The present finding of increase in grain yield was in accordance with the research findings of Mandal et al. (2020) recorded higher grain yield (7.86 t ha^-1) was obtained with 150 kg K₂O ha^-1 which was statistically similar to 120 kg K₂O ha^-1 (7.78 t ha^-1 of grain) in maize.

The data given in Table 1 indicated that different levels of potassium exhibited their non-significant influence on crude protein content in grain, while application of 30 kg K₂O ha^-1 (K₂) reported significantly the highest crude protein yield (666.7 kg ha^-1). The results of present investigation are conformity with results observed by Balpande et al. (2016). They reported that significantly high protein yield was observed due to application 30 kg K₂O ha^-1 in pigeon pea.

The data given in Table 2 indicated that N, P and K content in grain and straw was found non-significant by different potassium levels. However, numerically the highest value of N, P, K content of 2.169, 0.308 and 1.470 per cent, respectively in grain and N, P, K content 0.581, 0.205 and 1.097 per cent, respectively in straw was recorded with application of 30 kg K₂O ha^-1 (K₃) and the lowest value of N, P, K content of 2.143, 0.302 and 1.451 per cent, respectively in grain and N, P, K content of 0.562, 0.197 and 1.083 per cent, respectively in straw was recorded by control (K₁). The results of present investigation are conformity with results observed by Patil et al. (2017). They reported that no significant difference in primary nutrients content (N, P and K) in grain and stover of maize with varied levels of K2O i.e., 50, 75, 100 and 125 per cent of recommended dose of K₂O.

The data given in Table 2 indicated that N, P and K uptake by grain was found significant due to different potassium levels. Significantly the highest N, P and K uptake by grain of 106.7, 15.2 and 1.81 kg ha^-1, respectively was recorded with application of 30 kg K₂O ha^-1 (K₂), while, N, P and K uptake by straw was found non-significant due to different potassium levels. Increased uptake of nitrogen might have resulted in vigorous growth and higher photosynthetic rate which led to better uptake of N throughout the crop growth period, increased uptake of phosphorus might be due to availability of sufficient potassium at different stages of crop growth which favoured the better root growth and dry matter production and increased uptake of potassium by maize may be ascribed to more availability of potassium at critical stages from the added fertilizer sources and native soil potassium. This finding closely associated with those of Balpande et al. (2016). They reported that high N and P uptake was observed due to application of 30 kg K₂O ha^-1 and Potassium uptake was increased significantly with increasing the levels of K in pigeon pea.

Alam et al. (2021) recorded significantly higher N, P and K uptake of 513.74, 105.03 and 491.72 mg kg^-1, respectively by application of K90 mg kg^-1 level by fodder maize over control (K0 mg kg^-1).

The mean data pertaining to available N, P₂O₅ and K₂O in soil after harvest of crop were presented in Table 3. The individual effect of nitrogen, phosphorus and potassium levels and interaction effect on available K₂O in soil were found non-significant. There are high potassium present in soil with respect of application of high dose of potassium. The present findings are within the close vicinity of those reported by Ranpariya et al. (2017) in green gram. They observed that significantly higher available K₂O (216 kg ha^-1) was recorded under application of 60 kg K₂O ha^-1, however, available nitrogen and available phosphorus in did not record any significant variations among the different potassium doses in green gram.

From the results of one year experimentation, it can be concluded that rabi hybrid maize (GAYMH 3) should be fertilized with 180 kg N ha^-1 (50% at basal, 25% at knee high stage and 25% at pre-flowering stage), 60 kg P₂O₅ ha^-1 and 30 kg K₂O ha^-1 for getting higher yield and monetary returns under south Gujarat condition.

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