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K. SATHISH BABU*, P. V. RAMESH BABU, M. SRINIVASA REDDY AND P. KAVITHA
Department Agronomy, Agricultural College, Mahanandi – 518 502, Andhra Pradesh, India.
A field experiment was conducted at Agricultural College Farm, Mahanandi on sandy loam soils to know the response of maize to higher levels of NPK and Zn nutrition on yield attributes, yield and economics. The experiment was laid out in randomized block design with 10 treatments consisting of three higher levels of nutrients and six treatments of higher levels of nutrients in combination of Zinc and each treatment was replicated thrice. Result showed that application of 350-100-100 kg N-P2O5-K2O ha-1 along with foliar application of 0.2% ZnSO4 at 15 and 25 DAS (T10) gave the highest cob length (19.79 cm), number of grains row-1 (39.70), grain weight cob-1 (216.39 g), test weight (323.00), grain yield (8734 kg ha-1) and stover yield (11275 kg ha-1) which in turn on par with T9 (T3 + Foliar application of 0.2% ZnSO4 at 15 and 25 DAS and significantly superior over control (T1). However, number of cobs plant-1, number of grain rows cob-1 were not significantly influenced by higher levels of NPK and Zn nutrition. Highest gross returns (` 113537.67 ha-1) and net returns (` 74114.67 ha-1) were recorded with application of 350-100-100 kg N-P2O5-K2O ha-1 along with foliar application of 0.2% ZnSO4 at 15 and 25 DAS (T10). The highest B:C ratio was obtained with application of 250-60-60 kg N-P2O5-K2O ha-1 along with foliar application of 0.2% ZnSO4 at 15 and 25 DAS (T8).
Economics, Maize, Yield attributes, Yield.
Maize (Zea mays L.) is one of the most versatile emerging crops having wider adaptability under varied agro-climatic conditions and successful cultivation in diverse seasons and ecologies for various purposes. Globally, maize is known as ‘‘Miracle crop’’ because of its highest genetic yield potential than other cereals. Maize is the third most important cereal crop and cultivated in 160 countries on almost 150 m. ha and contributes to 36% (78.2 m. t) in the total grain production of the world. In India, maize is cultivated in an area of 9.23 m. ha with production of 23.67 m.t with an average yield of 2.56 t ha-1 (IIMR, 2016). In Andhra Pradesh, maize is cultivated in an area of 4.07 lakh ha with a production of 24.9 lakh t and an average yield of 6697 kg ha-1 (IIMR, 2016). The nutrient management is one of the most important factors that affect the growth and yield of maize. The recommendations presently made are based on the response of maize to nitrogen at constant levels of P and K and also farm level reports are available with response of the crop to foliar application of zinc irrespective of the availability of zinc in the soil. Since the crop is spreading to newer areas there is a need to find out the appropriate levels of nutrients and the response of crop to applied nutrition. Hence, an attempt is being made to study the response of maize to increased levels of N, P K and foliar application of Zn.
A field experiment was conducted under irrigated conditions during rabi 2015-16 at Agricultural College Farm, Mahanandi, (Scares Rainfall Zone of A.P.) on sandy loam soils with slightly alkaline pH (7.98), low in organic carbon (0.46%), medium in available nitrogen (298 kg ha-1) , high in available phosphorus (48kg ha-1), available potassium (687 kg ha-1) and sufficient in available zinc (1.32 ppm).Weather during the crop period is normal without any marked deviation from mean of the experimental site. The experiment was laid out in a randomized block design with ten treatments and replicated thrice. The treatment details are T1: Control, T2: 250-60-60 kg N-P2O5-K2O ha-1, T3: 300-80-80 kg N-P2O5-K2O ha-1, T4: 350-100-100 kg N-P2O5-K2O ha-1, T5: T2 + Foliar application of 0.2% ZnSO4 at 15 DAS, T6: T3 + Foliar application of 0.2% ZnSO4 at 15 DAS, T7: T4 + Foliar application of 0.2% ZnSO4 at 15 DAS, T8: T2 + Foliar application of 0.2% ZnSO4 at 15 and 25 DAS, T9: T3 + Foliar application of 0.2% ZnSO4 at 15 and 25 DAS,
T10: T4 + Foliar application of 0.2% ZnSO4 at 15 and 25 DAS and crop was sown on ridges with 75 cm row spacining and 25 cm spacing between plants within the row. Maize hybrid ‘P3396’ was used in the study. The amount of nitrogen in the form of urea was applied in three splits i.e., at sowing, at knee height stage and remaining at tasseling stage and phosphorous and potash was applied through SSP and MOP as basal at the time of sowing and the foliar feedings of zinc was given at 15 and 25 DAS. All the nutrients were applied as per the treatments.Data on yeild attributes, yield were recorded and subjected to analysis ov variance(ANOVA) and economics worked out based on present price of product in market.
The maximum values of yield attributes like, cob length (19.79 cm), number of grains row -1 (39.70), grain weight cob-1 (216.39 g), test weight (323.00), were recorded with the treatment T10 (T4 + Foliar application of 0.2% ZnSO4 at 15 and 25 DAS) which was at par with the treatment T9 (T3 + Foliar application of 0.2% ZnSO4 at 15 and 25 DAS) and signifiantly superior over T1 (Control) (Table 1). However, the number of cobs pe plant and grain rows per cob were not singnifacantly influenced by different higher levels of nutrients. The increase in yield attributes due to application of influenced levels of N, P, K and foliar application of zinc, which resulted in higher chlorophyll content and this had apparently a
positive effect on photosynthetic activity, synthesis of metabolites and growth regulatory substance, oxidation and metabolic activities and ultimately better growth and development of crop that led to increase in yield attributes of maize. These findings were in accordance with the research findings of Mohan Kumar et al. (2015), Nithin Krishna et al. (2015) and Manwar and Mankar (2015).
The maximum grain yield (8734 kg ha-1) and stover yield (11275 kg ha-1) was recorded with the treatment that received 350-100-100 kg N-P2O5-K2O ha-1 along with foliar application of 0.2% ZnSO4 at 15 and 25 DAS (T10) and significantly superior over the rest of the treatments tried in the study except the grain yield obtained with the treatments of T9 (T3 + Foliar application of 0.2% ZnSO4 at 15 and 25 DAS) and T7 (T4 + Foliar application of 0.2% ZnSO4 at 15 DAS). However harvest index (43.85) was significantly higher with the application of 350-100-100 kg N-P2O5-K2O ha-1 along with foliar application of 0.2% ZnSO4 at 15 DAS (T7) and significantly superior over T2 (250-60-60 kg N-P2O5-K2O ha-1) and Control (T1) (Table 2). Highest grain, stover yield and harvest index might be due to better translocation of photosynthates from source to sink, higher growth attributing characters and higher yield attributing characters like cob length, number of grains per cob, grain weight cob-1 and test weight. These results were in conformity with the findings of Nandita Jena et al. (2013) and Manasa and Devaranavadagi (2015).
The highest gross returns and net returns (` 113537.67 ha-1 and ` 74114.67 ha-1, respectively) was recorded with the treatment that received 350-100-100 kg N-P2O5-K2O ha-1 along with foliar application of 0.2% ZnSO4 at 15 and 25 DAS (T10) and significantly superior over control (T1). However, application of 250-60-60 kg N-P2O5-K2O ha-1 along with foliar application of 0.2% ZnSO4 at 15 and 25 DAS (T8) resulted in significantly higher B: C ratio (1.99) and superior over the application of 250-60-60 kg N-P2O 5-K2O ha-1 alone (T2) and control (T1) (Table 3). These findings were in conformity with those of Rakesh Kumar et al. (2015) and Rizwan Patel et al. (2015).
From, the above investigation, it is clearly indicated that the higher level of nitrogen, phosphorus, potassium along with foliar application of Zn had significant influence in increasing the productivity and profitability of maize. The higher yield attributes and yield of maize was with the application of 350:100:100 kg NPK ha-1 alongwith foliar application of 0.2% ZnSO4 at 15 and 25 DAS (T10). However, the economic yield was obtained with the application of 250:60:60 kg NPK ha-1 alongwith foliar application of 0.2% ZnSO4 at 15 and 25 DAS (T8).
It is therefore concluded that the better yields can be acheieved in maize with the application of 250:60:60 kg NPK ha-1 alongwith foliar application of 0.2% ZnSO4 at 15 and 25 DAS (T8).