Effect of Foliar Application of Banana Pseudostem Sap on Yield of Cowpea ( Vigna unguiculata L. Walp.)

. Improved soil fertility is a requirement for enhanced crop production. Combination of inorganic and organic fertilizers improve crop productivity while reduce environmental degradation. An experiment was carried out at Eastern University, Sri Lanka to study the effect of Foliar Application of Banana Pseudostem Sap on Yield of Cowpea ( Vigna unguiculata L. Walp.) in sandy regosol. The experiment was laid out in Randomized Complete Block Design having five treatments viz; recommended inorganic fertilizer N, P, K as basal and N as topdressing (T1), N, P, 1⁄2 K as bas al with recommended N as topdressing and foliar spray of 1% , 3%, 5% and 7% banana pseudostem sap solution (T2 -T5) at 3 rd , 5 th , 7 th and 9 th week after planting. The results revealed that significant difference (P<0.05) were noted on number of pods per plant at 1 st and 2 nd picking. Higher number of pods per plant, maximum pod length and girth were in T2 while low in T1. Sun dried weights of pods and number of seeds per pod were significantly (P<0.05) varied at each picking. Further, cowpea yield at each picking were higher in T2 compared to tested treatments. The present study suggested that, among the tested treatments N, P, 1⁄2 K as basal with recommended N as topdressing and foliar spray of 1% Pseudostem sap solution at 3 rd , 5 th , 7 th and 9 th WAP would be the most suitable for cowpea production in sandy regosol.


Introduction
The most dominant crop in the family Leguminoseae is cowpea (Vigna unguiculata L. Walp) which plays significant role in economy of the most of the countries. Farmers prefer to cultivate cowpea due to its drought tolerance features, high protein content, nitrogen fixing ability and wide adaptability. Cowpea has gained more attention recently from consumers due to health beneficial properties, including anti-diabetic, anti-cancer, anti-hyperlipidemic, antiinflammatory and anti-hypertensive properties (Jayathilake et al., 2018). Presently fertilizer has become an essential part in modern agriculture and it is very common that excessive doses of nitrogen and other inorganic fertilizers are applied to vegetable gardens and fields to attain high yield (Baitilwake et al., 2011). Continuous use of these chemical fertilizers depletes essential soil nutrients and minerals that are naturally found in fertile soil. Therefore, substitution of chemical fertilizers by the low cost organic manures is very important for sustainability of agriculture production and maintain of soil fertility for future generation.
Banana is the most important fruit crop widely cultivating in Sri Lanka mainly for fruit purpose. But after the fruit harvest huge quantity of pseudostem is generated as a waste. Pseudostem sap contains essential macro and micro nutrients, growth promoting substances like cytokinin and GA3 (Gibberellic Acid) and it can use as an organic nutritive supplier to the crops for increase their crop growth and yield. This nutritive enriched sap can be applying to the plants as the foliar spray to enhance the plant growth and yield, and it is a one of the more cost effective fertilizer can found naturally.

Methodology
This experiment was carried out to study the impact of foliar spray of banana pseudostem on cowpea yield in sandy regosol. Experiment was carried out using Randomized Complete Block Design. Treatments were; T1: Recommended N, P and K as basal and topdressing The banana (Musa acuminate l.) pseudo stem was collected and it was cut into two pieces and outer sheaths (2-3), damage and dried parts were removed. After the removal of sheaths, it was washed out to remove dust and the tiny materials. Then washed pseudostem was cut in to small pieces (1cm -5cm) and chopped by using motor and pistil. Then chopped paste was squeezed in muscling cloth and extraction was filtered. Then insoluble particles of extraction were removed by using centrifugation for 10mins at 6000rpm (Sharma et al., 2017). 1%, 3%, 5% and 7 % of banana pseudostem sap solutions were prepared by adding 1ml, 3ml, 5ml and 7ml of banana pseudostem saps in to four conical flasks respectively and it was volumerized in to 100ml by using water. Banana pseudostem sap was sprayed 3 rd , 5 th , 7 th and 9 th week after planting. 25ml of banana pseudostem sap solution was applied to each and every plant by using hand spray bottle. All agronomic practices were maintained as per the recommendation of Department of Agriculture, Sri Lanka, except treatments. Yield components were recorded and analysed by using statistical software.

Pod girth
There was no significant difference (P>0.05) in pod girth at 1 st and 2 nd picking. However, there was a significant difference in (P<0.05) pod girth at 3 rd picking is shown in table 3. T2 recorded the maximum pod girth (2.66cm) and T1 recorded the lowest pod girth (2. increased by foliar application of micronutrients when compared to control. The maximum increase in the pod girth was recorded in the foliar application of humic acid, zinc and boron in pungent pepper than control (Manas et al., 2014). Mehraj et al. (2015) reported that foliar application of micronutrients increased okra pod girth than control treatment.

Number of seeds per pod
Application of different concentration of banana pseudo stem sap significantly influence (P<0.05) the number of seeds per pod is confirmed with P values 0.040 and chi square values 10.00 at 1 st , 2 nd and 3 rd picking (Table 4). Maximum numbers of seed were observed in T2 and minimum numbers of seed were observed in T1. Sharifi et al. (2018) reported that number of seed per fruit or seed yield was significantly influenced by foliar application of water soluble fertilizer as the foliar application and significantly higher seed yield recorded with application of foliar application of water soluble fertilizer at 2 % at flowering and pod filling stages while lowest data obtained in control treatment in soybean.

ILNS Volume 79
Sun dried weight per pod Table 5 represents the different concentration of banana pseudo stem sap application on sun dried weight of pods. At all the picking stages, maximum dry weight of pod were observed in T2 and minimum fresh weight of pod was observed in T1. At 1 st , 2 nd and 3 rd picking maximum weight of pod was observed in T2 (1.82 g, 2.30 g and 2.49 g) followed by T3 (1.55 g, 2.03 g and 2.22 g) while lowest weight of pod was observed in T1 (1.38 g, 1.86 g and 2.05 g).  reported the evident that significantly maximum fruit weight was obtained in banana pseudostem sap at 1 % because banana pseudostem sap contain the N and K in higher rates and these elements increased the efficiency of metabolic process of the trees and encouraged the growth of pomegranate. Similar findings were obtained by Patil et al. (2014) in garlic. Deore et al. (2010) reported experiment data in chili, revealed that the foliar application of novel organic liquid fertilizer 2% shows the maximum fruit weight (g).

Cowpea yield
It was found that, there were significant differences (P<0.01) at 1 st , 2 nd and 3 rd picking is shown in table 6. At 1 st , 2 nd and 3 rd picking, the highest mean value for total seed yield was obtained in T2 (1.94 tons/ha, 3.04 tons/ha, 3.03 tons/ha) while, minimum mean value was obtained in T1 (0.44 tons/ha, 0.73 tons/ha, 1.01 tons/ha). However, there were no significant differences (P>0.05) among treatments except T2 and T1 at 1 st and 2 nd picking. Farouk and Amany (2012) stated that pod yield per plant, seed quality and total seed yield significantly increased with foliar application of chitosan, especially at 250 mg/l.

Conclusion
The results revealed that there was significant difference (P<0.05) were observed in number of pod, 1 st and 2 nd picking, pod length at 2 nd and 3 rd picking and pod girth at 3 rd picking among treatments. Maximum length and girth of pod was observed in T2 while minimum length and girth of pod was observed in T1. Number of seeds per pod at each picking had significant variation (P<0.05) and it was high in sap treated plants compared with control. Sun dried weight of cowpea pod was significantly influenced by the banana pseudo stem sap application. All three pickings, maximum sun dried weight of pod was observed in T2 while lowest sun dried weight of pod was observed in T1. According to cowpea yield, highest cowpea seeds were obtained in T2 and low in control. Application of different concentration of banana pseudostem sap increased yield component of cowpea grown in sandy regosol compared to recommended inorganic fertilizer. The present study concluded that among the tested treatments N, P, 1⁄2 K as basal with recommended N as topdressing and foliar spray of 1% Pseudostem sap solution at 3 rd , 5 th , 7 th and 9 th WAP would be the most suitable for cowpea production in sandy regosol.