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M. RAMANJINEYULU, M. SRINIVASA REDDY*, P.V. RAMESH BABU AND P. KAVITHA
Department Agronomy, Agricultural College, ANGRAU, Mahanandi, A.P., India
A field experiment was conducted at Agricultural College Farm, Mahanandi on sandy loam soils to know the response of maize to secondary and micronutrients with pioneer hybrid P3369. The experiment comprised of 9 treatments consisting of recommended dose of fertilizer of NPK through soil application and foliar application of secondary and micronutrients at 25 DAS. Results showed that Foliar application of micronutrient mixture along with RDF recorded significantly highest grain yield (4702 kg ha-1) and Stover yield (7318 kg ha-1) as compared to RDF (3773 and 6430 kg ha-1 of grain and Stover yield, respectively). Yield attributes viz., number of rows cob-1(16.97), number of grains row-1(36.99), cob length (19.86 cm) were highest with the application of RDF + foliar application of ZnSO4 @ 0.2 per cent (T7) and highest hundred grain weight (31.26g) was recorded with RDF + foliar application of one per cent each of CaNO3, MgNO3 and sulphur + foliar application of ZnSO4 @ 0.2 per cent . However, number of cobs plant-1 and cob girth was not influenced by secondary and micronutrients. The treatment with RDF + foliar application of micronutrient mixture @ 0.2 per cent (T9) recorded the highest gross returns, net returns and B: C ratio.
Maize, Secondary nutrients, Micronutrients, Yield attributes and Yield.
Maize (Zea mays L.) is the most important food grain crop next only to rice and wheat in World and India. It is one of the most important cereal crops in the world’s agricultural economy, both as a food and feed crop and its value added products have a good export potential. Due to its versatile characteristics of suitability and adaptability to various Agro-climates, maize is gaining popularity among the Indian farmers. It is known as the ‘‘Queen of Cereals’’ due to its high yielding potential. Globally maize is cultivated in an area of 170.39 million hectares with a production of 883.46 million tonnes and productivity of 5.18 tonnes ha-1 (www.indiastat.com). In India, it is grown in an area of 8.55 million hectares with a production of 21.73 million tonnes and an average productivity of 2540 kg ha-1. In Andhra Pradesh, it is cultivated in an area of 9.72 lakh hectares with a production of 48.55 lakh tonnes and productivity of 4994 kg ha-1. To achieve higher yields in maize, the crop require large quantities of soil nutrients for its growth and development but most of the farmers use only fertilizers that supply major nutrients of N, P and K and less attention is paid to secondary and micro nutrients which led to rapid depletion of secondary and micronutrients necessitating
periodic or yearly supply of these nutrients. Although the requirement of secondary and micronutrients is less as compared to the primary nutrients, nevertheless their deficiency can limit the crop growth and production. Furthermore, the adequate supplies of these nutrients help to increase the efficiency of applied fertilizers. Therefore, a field study was undertaken to optimize the nutrient management strategy for higher productivity of maize and evaluating the effects of secondary (Ca, Mg and S) and micronutrients of zinc and their mixture (Fe, Mn, Zn, Cu, B and Mo) with recommended dose of nitrogen, phosphorus and potassium.
A field experiment was conducted on maize hybrid P3369, under irrigated conditions during kharif, 2015 on sandy loam soils of Agricultural College Farm, Mahanandi, Andhra Pradesh. The soil of the experimental site was neutral pH (7.58), medium in organic carbon (0.46%), N (287 kg ha-1), P2O5 (149 kg ha-1) and high in K2O (742 kg ha-1). Exchangeable calcium, magnesium (10.41 and 7.22 C mol. (P+) kg-1) and available sulphur(13.32 kg ha-1) were sufficient in availability whereas, micronutrients availability (Fe, Mn, Zn, Cu, B and Mo) was more than their critical limits
The experiment was laid out in a randomized block design having ten treatments and replicated thrice. The treatments consisting of T1 : Control, T2 : RDF: 250-60-
60 kg N-P2O5-K2O ha-1, T3 : RDF + foliar application of one per cent CaNO3 , T4 : RDF+ foliar application of one per cent MgNO3, T5 : RDF + foliar application of one per cent sulphur, T6 : RDF + foliar application of one per cent each of CaNO3, MgNO3 and sulphur, T7 : RDF + foliar application of ZnSO4 @ 0.2 per cent, T8 : RDF + foliar application of one per cent each of CaNO3, MgNO3 and sulphur + foliar application of ZnSO4 @ 0.2 per cent and T9 : RDF + micronutrient mixture @ 0.2 per cent. The crop was sown on ridges with a spacing of 75cm x 15cm on second fortnight of July 2015 and harvested on
23. 11.2015. The recommended dose of nitrogen was applied in three splits i.e., at sowing, at 30-35 DAS and remaining at 50-55 DAS in the form of urea, where as entire dose of phosphorus and potassium was applied as basal dose at the time of sowing in the form of diammonium phosphate and muriate of potash respectively. The secondary and micronutrients were supplied as foliar spray at 25 DAS in the form of CaNO3, MgNO3, wettable sulphur, ZnSO4 and micronutrient mixture [Boron (B) 1.5%, Copper (Cu) 0.5%, Iron (Fe) 3.4%, Manganese (Mn) 3.2%, Molybdenum (Mo) 0.05% and Zinc (Zn) 4.2%]. Carbofuran 3G granules @ 5 kg ha-1 were applied to control the stem borers. All the cultural practices were taken up as per the recommendations made by ANGRAU.
The results indicated that different combinations of secondary and micronutrients had significant effect on yield attributes of maize (Table 1).The maximum values of yield attributes like number of rows cob-1(16.97), number of grains per row (36.99), cob length (19.86 cm) were recorded with the treatment T7 (RDF + foliar application of ZnSO4 @ 0.1 per cent) which was comparable with T9 (RDF + Foliar application of 0.1 per cent micronutrient mixture). However, highest hundred grain weight was recorded with T8 (RDF + foliar application of one per cent each of CaNO3, MgNO3 and sulphur + ZnSO4 @ 0.2 per cent) which was on par with T9 (RDF + Foliar application of 0.2 per cent micronutrient mixture). Data on number of cobs per plant and cob girth was not influenced by secondary and micronutrients.
A marked increase of these yield attributes were nearly found with ZnSO4. Zinc is an essential micronutrient required for the promotion of the meristematic and physiological activities such as leaf spread, root development, plant dry matter production, greater availability of metabolites and nutrients leading to efficient absorption and translocation of water and nutrients and interception of solar radiation.
Nitrogen in the presence of sufficient zinc shows its optimal performance and promotes higher photosynthetic activities leading to the production of enough assimilates for subsequent translocation to various sinks and there by leading to production of higher sink components like number of cobs plant-1, cob length, cob girth, number of rows cob-1, number of grains row-1 and 100-grain weight. The results are in conformity with the findings of Aruna et al. (2006), Parasuraman et al. (2008), Bishnu hari et al.(2010) and Khan et al. (2014).
Among the secondary nutrients, T4 (RDF + foliar application of one per cent MgNO3) had shown profound effect with respect to yield attributes and remaining treatments are comparable with other. This increment on yield attributes might be due to the presence of magnesium, as grain number are direct index of pollen viability and where magnesium is proved to increase the fruit set and pollen viability, and significantly affect the pollen formation (Mahgoub et al.2010 and Siam et al.2008). This element will also participate in the transportation of carbohydrates to the sink organs (Barlog and Frckowiak-Pawalak 2008).
Data regarding the grain yield and stover yield (Table 1) showed that the treatment with T9 (foliar application of 0.2 per cent micronutrient mixture with RDF) recorded highest grain (4702 kg ha-1) and stover yields (7318 kg ha-1) which was on par with T7 (RDF + foliar application of 0.2 per cent ZnSO4), while the lowest grain and stover yields were recorded with T1 (Control). This increase may be due to the additional availability of micronutrients as foliar application which had beneficial effect on physiological processes, plant metabolism, growth etc. which will directly put forth for higher grain yield. Synergetic role of micronutrients in improving plant growth and other biochemical and physiological activities was given by (Kassab et. al, 2004 and Zeiden et. al, 2010).
The nutrients also enhance the carbohydrate supply to kernels by diverting the assimilates from sources, increasing yield components like cob length, cob girth, number of rows cob-1, number of grains row-1 and test weight, which have direct influence on grain yield. Similar results were reported by Aruna et al. (2006), Ghaffari et al (2011) and Salem et al. (2012).
The successful adoption of nutrient management practice is finally determined by the net financial gain (Table 2). The best nutrient management practice was foliar application of 0.2 per cent micronutrient mixture with RDF (T9) attaining highest ( 38,338 ha-1) net field benefits with B:C ratio of 1.68 which was comparable with foliar application of 0.2 per cent ZnSO4 + RDF (T7) ( 36,927 ha-1) and superior over remaining treatments.
Based on the findings of study, it can be recommended that foliar application of 0.2 % micronutrient mixture along with recommended dose of NPK is feasible for enhancing yield and profitability of maize.