Effect of Foliar Application of Micronutrients on Growth and Yield of Greengram (Vigna radiata L.)

Pulses are commonly known as food legumes which are in second position after cereals in production and consumption in India. The word pulse is derived from the Latin word Puls means pottage i.e., seed boiled to make porridge or thick soup. Pulse is a rich source of dietary protein (25%), energy, minerals and vitamins for the vegetarian population. In addition to being an important source of human food and animal feed, plays an important role in sustaining soil fetility. By improving soil physical properties and fixing atmospheric nitrogen, it is a drought resistant crop suitable for dryland farming and predominantly used as an intercrop with other crops. Though have multifarious advantages poductivity is declining year by year due to various reasons. There is need for enhancing the productivity of the crop by adopting low cost production technologies. Greengram is originated from India and Central Asia. In India, greengram is grown over an area about 4.26 Mha with an average production of 2.01 mt. Average grain yield of 472 kg/ha under 2017-2018. Total coverage under mungbean in Uttar Pradesh 0.72 Lakh/ha with a production 0.40 Lakh tonnes and the productivity 555.56 kg/ha. Foliar feeding is the most effective and economic way to improve plant nutrient efficiency (Dixit and Elamathi 2007). Application of nutrient through foliar spray at appropriate stages of crop growth becomes important for their utilization and better performance of the crop (Anandhakrishnaveni et al., 2004).
       
Among them micronutrients play an important role in boosting productivity of greengram. It has been well established that most of the plant nutrients are absorbed through leaves and absorption would be remarkably rapid and nearly complete. More over foliar feeding practice would be more useful in early maturing crops which would be combined with regular plant protection programmes. If foliar nutrition is applied it reduces the cost of cultivation which in turn reduces the amount of fertilizer thereby reducing the loss and also economizing crop production. Foliar application is credited with the advantage of quick and efficient utilization of nutrients elimination of losses through leaching and fixation and regulating the uptake of nutrients by plants (Manonami and srimati 2009). Low productivity of greengram is due to nutritional defeciency in soil and imbalanced external fertilization (Awomi et al., 2012). The fertilization procedure in addition to economic aspects and the effectiveness of the immediate environment in order to achieve sustainable agriculture is also very effective and useful (Fard et al., 2012).
       
Foliar spray of Zn, Fe, Mn significantly increased the yield of crops. Among the micronutrients Zn, Fe nutrition can affect the susceptibility of plant in the stress condition. Fe enters in many plant enzymes that play important role in respiration. The deficiency of Fe in plants causes significant changes in the plant metabolism and induces chlorosis, especially in young leaves and leads to very low re-utilization. Manganese in turn regarded as activator of many different enzymatic reactions and takes part in photosynthesis. Foliar nutrition of micronutrients has been proven to be an excellent method because foliar feeding targets the plants which shows the signs of micronutrient defeciency. Micronutrient application before visible signs of their defeciency can make a crop better either by stimulating more vigorous regrowth and maximizing the yield potential stage period. Application of micronutrients can enhance plant resistant to environmental stresses and produce potential yield . Keeping these points in view, a field experiment was conducted to assess the effect of foliar nutrition on productivity of greengram.
 
Experimental site and soil information
 
A field experiment was conducted during Zaid season 2019 at Crop Research Farm, Department of Agronomy, Sam Higginbottom University of Agriculture Technology and Sciences, Prayagraj, (U.P.) India. The soil of experimental plot was sandy loam in texture, neutral in soil reaction (pH 7.4), low in organic carbon (0.281%) medium in available nitrogen (219 kg/ha), high in phosphorous (11.6 kg/ha) and low in potassium (217.2 kg/ha).
 
Experimental design and treatment combination
 
The present investigation was laid out in randomized block design (RBD) consisted of 9 treatments and replicated thrice. viz., T₁- Control ( RDF + water spray) , T₂- RDF + Fe 0.5% at 30 DAS, T₃- RDF + Zn 0.5% at 30DAS, T₄- RDF + Mn 0.5% at 30 DAS, T₅- RDF + Fe 0.5% + Zn 0.5% + Mn 0.5% at 30 DAS, T₆- RDF  + Fe 0.5 % at 45DAS, T₇- RDF + Zn 0.5% at 45 DAS, T₈- RDF + Mn 0.5% at 45 DAS and T₉- RDF + Fe 0.5 % + Zn 0.5% + Mn 0.5% at 45 DAS. Combination of micronutrient sprayed @ 0.5% at 30 and 45 DAS.
 
Crop management
 
The greengram variety Samrat (PDM-139) sown at the rate of 20 kg/ha with a spacing of 30 × 10 cm. The recommended dose of fertilizer NPK 20:40:20 kg/ha sources Nitrogen as urea, phosphorous as single super phosphate (SSP) and potassium as muriate of potash (MOP) at the time of sowing in all treatments. Uniformly the first irrigation was given at 10 days after sowing and subsequent irrigations as per crop need. Hand weeding was done twice at 21 and 40 days after sowing. Plant protection measures were followed as per recommended for the region.
 
Plant sampling
 
Plant protection measures were followed as per recommendation for the region. Five random plants were selected from each plot to record observations on nodulation and plant growth parameters. Similarly, 5 random plant samples were collected from each plot at the time of harvest for recording observations on plant yield attributing characters.
 
Statistical analysis
 
Experimental data collected was subjected to statistical analysis by adopting Fisher’s method of analysis of variance (ANOVA) as outlined by Gomez and Gomez (1984). Critical Difference (CD) values were calculated wherever the ‘F’ test was found significant at 5 per cent level.

Effect of foliar applied micronutrients on plant height of greengram
 
Plant height was recorded at 15, 30, 45 and 60 DAS which was significantly influenced by foliar nutrition of micronutrients (Table 1). At 60 DAS maximum plant height (42.42 cm) was observed with RDF + Fe 0.5% + Zn 0.5% + Mn 0.5% at 30 DAS which was 14.5% higher than control (36.11 cm) whereas all other treatments were statistically at par with RDF along with foliar spray of 0.5% Fe, Zn, Mn at 30 DAS. This might be due to significant improvement in the synthesis of chlorophyll with iron nutrition. Whereas, Mn acts as a activator for enzymes in growth process and it helps iron in chlorophyll formation (Lohry, 2007). Zinc in auxin mixture (Basavarajeswari et al., 2018).
 

 
Effect of foliar applied micronutrient on number of nodules/plant
 
In the present investigation root nodule increased with crop age upto 45 DAS after that it was declined. The number of nodules was recorded at 15, 30, 45 and 60 DAS which was significantly influenced by the application of RDF along with foliar spray of 0.5% Fe at 30 and 45 DAS. At 45DAS maximum no. of nodules was obtained with RDF + Fe 0.5% at 30 DAS (11) which was significantly superior over rest of treatments except RDF along with foliar spray of Fe 0.5% at 45 DAS (9.87) presented in Table 1. Increase in nodule count might be due to increased infection and rhizobial colonization in rhizosphere because of increased availability of micronutrient Meena et al., (2012).
 
Effect of foliar applied micronutrient on Dry matter accumulation of greengram
 
Dry matter accumulation increased with crop age upto 60 DAS and maximum were obtained at 60DAS. At 15, 45 and 60 DAS there was no significant variation was found. However, at 30 DAS, maximum was obtained with application of RDF along with foliar spray of Fe 0.5% at 30 DAS (32.11) which was significantly superior over control (16.12) and RDF along with foliar spray of Zn 0.5% at 45DAS. It might be due to Iron (Fe) and zinc (Zn) involved in various physiological processes such as, enzyme activation (Yaseen et al., 2010), chlorophyll formation (Habib, 2009), electron transport and stomata regulation (Oosterhuits and Weir, 2010). The foliar spray of 0.5% FeSO₄ + 0.1% citric acid and FeSO₄ alone treated plots probably because of increased availability of Fe to the plants.
 
Effect of foliar applied micronutrient on crop growth rate of greengram
 
Results revealed that non-significant response of crop growth rate. Higher crop growth rate at 45-60 DAS was found with foliar spray of RDF + Fe 0.5% + Zn 0.5% + Mn 0.5 % at 30 DAS (1.69 g/m²/day) (Table 1). It might be due to application of iron increased dry weight of root nodules, dry matter accumulation at all stages of greengram growth (Yadav, 2001).
 
Effect of foliar applied micronutrients on yield attributes of greengram
 
Among all the yield attributing characters the no. of pods/plant was significantly influenced by combined foliar application of micronutrient. The maximum no. of pods/plant was obtained with RDF along with 0.5% Fe, Zn, Mn at 30 DAS (58.40) which was significantly superior over control (46.93) by 19.64%. 
       
Non-significant results were registered by the foliar application of micronutrient on no. of grains/pod and test weight (g). The beneficial effects of foliar nutrition of micro nutrients on mungbean were also reported by several researchers Kumawat et al., (2005). The micronutrients might have enhancing role in seed setting that resulted in improvement in no. of seeds per pod. Greater mobilization of photosynthesis to the developing seeds by application of micronutrients might be the reason for increase in seed weight.
 
Effect of foliar applied micronutrient on yield of greengram
 
Seed yield and stover yield was significantly influenced with the application of micronutrient. Maximum seed yield was obtained with RDF along with 0.5% Fe, Zn, Mn at 30 DAS (1384 kg/ha) (Table 2) which was significantly superior over rest of the treatments except RDF along with foliar spray of 0.5 % Fe, Zn, Mn at 45 DAS (1282 kg/ha). RDF along with foliar spray of Fe, Zn, Mn @ 0.5% at 30 DAS produced 33.16% more yield over control (925kg/ha). Similarly, maximum stover yield was obtained with RDF along with 0.5% Fe, Zn, Mn at 30 DAS (2253.33 kg/ha) which was significantly superior over control (1343.33 kg/ha) by 40.38%. The highest yield obtained with application of micronutrients along with RDF might be due to increased availability of nutrients in balanced proportion.
 
 
Effect of foliar applied micronutrients on economics of greengram
 
Experimental results revealed that foliar nutrition of micronutrients was significantly influenced the economics of greengram. Higher gross return was obtained with RDF + Fe 0.5% + Zn 0.5% + Mn 0.5% at 30 DAS (99285.5 Rs/ha) (Table 2), which was significantly superior over rest of treatments except RDF + Fe 0.5% + Zn 0.5% + Mn 0.5% at 45 DAS (91804 Rs/ha). Higher net return was obtained at RDF + Fe 0.5% + Zn 0.5% + Mn 0.5% at 30 DAS (59912.5 Rs/ha) which was significantly superior over rest of all treatments except with RDF + Fe 0.5% + Zn 0.5% + Mn 0.5% at 45 DAS (50684 Rs/ha). Higher benefit cost ratio was obtained at RDF + Fe 0.5% + Zn 0.5% + Mn 0.5% at 30 DAS (1.51) which was significantly superior over rest of all treatments except with RDF + Fe 0.5% + Zn 0.5% + Mn 0.5% at 45 DAS (1.23).

To boost the productivity of greengram need to apply sufficient quantity of micronutrients especially in the form of foliar spray which has advantage of quick and efficient utilization of nutrients elimination of losses through leaching and fixation and regulating uptake of nutrient by plants. In present investigation the results clearly indicate that recommended dose of fertilizer along with foliar spray of 0.5% Fe, Zn, Mn at 30 DAS was found more productive (1384 kg/ha) over control by 33.16% as well as net returns (59912 Rs) by 49.3% over control.

The authors are thankful to Department of Agronomy, Naini Agricultural Institute, Prayagraj, Sam Higginbottom University of Agriculture Technology and Sciences, (U.P.) India for providing necessary facilities to undertake the studies.