Impact of Phosphorous and Zinc Levels on the Productivity of Green Gram (Vigna radiate L.)

Mung bean is one of the important Kharif pulses in Pakistan and is grown mainly for its edible seeds; therefore, fertilizers management is an important factor for improving mungbean growth and yield. A eld experiment was conducted during the summer of 2013 at Palato Farm of the University of Agriculture Peshawar, Amir Muhammad Khan Campus Mardan, to determine the effect of phosphorus (P) and Zinc (Zn) on the yield and yield component of mungbean. The experiment consisted of four levels of P (0, 25, 50, and 75 kg ha −1 ) and four levels of Zn (0, 5, 10, and 15 kg ha −1 ). Data associated with the number of leaves and plant height illustrated that the higher number of leaves plant −1 (8.8) by an average was observed when P was applied at the rate of 75 kg ha −1 followed by 0 kg phosphorous (P) ha −1 (8.7) and Zn (Zn) application at the rate of 10 kg ha −1 produced a maximum number of leaves plant −1 (9) followed by 15 kg ha −1 (8.8) where 0 kg ZN ha −1 resulted in (7.7). Similarly, Zn signicantly affected plant height, while P and interaction between P and Zn levels were non-signicant. The higher plant height (95.1 cm) was observed when P was applied at the rate of 75 kg ha −1 , followed by 50 kg P ha −1 (93.6 cm). Higher plant height (95.8cm) was recorded when ZN was applied at the 5 kg ha −1 followed by 10 kg ha −1 (95.1cm). Higher numbers of nodules (13.1) were observed with the application of 50 kg P ha −1 followed by 75 kg P ha −1 (12.3), while the lowest (10.6) nodules were observed in the control plot. P application at the rate of 25 kg ha −1 produced a higher grain yield than 75 and 50 kg ha-1 and Zn application at the rate of 5 kg ha-1 produced a higher grain yield than 10 and 15 kg ha −1 . Therefore, a lower rate of P 25 kg ha −1 and Zn


Introduction
Mungbean (Vigna radiate L.), also called green gram, is an important summer-growing pulse crop in Pakistan (Hakim et  Its seed is more palatable nutritive, digestible, and non-atulent than other pulses (Teferie et al., 2020;Tarafder et al., 2020). The unique and common feature of mungbean is the root nodules that contain aerobic bacteria called rhizobia which x atmospheric nitrogen in the root and thus enhance soil fertility (Singh et al, 2021;Ashraf et al., 2003). It is also a substitute for animal protein and forms a balanced diet when used with cereals (Detzel et al., 2021). In Pakistan, mungbean is cultivated as a minor crop and  (Brady and Weil, 2004). Nodule establishment and its function are important sinks for P, and nodules usually have the highest P content in the plant (Sulieman et al., 2015). It is supposed that P is effectively translocated into grain at high rates since P is necessary for producing protein, phospholipids and phytin in bean grain (Rahman et al., 2008). Poor nodulation and poor plant vigour are observed in beans grown in P de cient soils (Bindraban et al., 2020). Among other essential factors, an appropriate supply of micronutrients is also required for crops' proper growth and yield. The importance of Zn as a micronutrient in crop production has increased in recent years (Amanullah et al., 2020;Thapa et al., 2021). Hence Zn is considered the most yield-limiting micronutrient (Arunachalam et al., 2013). Therefore, the present experiment was designed to study the effect of different levels of P and Zn on the yield of mungbean and nd out the best combinations of P and Zn for higher yield and yield components of mungbean under the agro-climatic condition of Mardan.

Experimental design
A eld experiment was conducted during the summer of 2013 at Palato Farm of the University of Agriculture Peshawar, Amir Muhammad Khan Campus Mardan (Figure 1), to determine the effect of P and Zn on the yield and yield component of mungbean. The experiment was conducted in a randomized complete block design with three replications, and the plot size was 2 m x 1.8 m. Mungbean variety "Ramzan" was sown in lines having ve rows 35cm apart on July 2, 2013. The experiment consisted of four levels of P (0, 25, 50 and 75 kg ha -1 ) and four levels of Zn (0, 5, 10, and 15 kg ha -1 ). SSP and ZnSO 4 will be used as the source of P and Zn, respectively and applied as a whole during seedbed preparation. All other agronomic practices, such as weeding, irrigation, plant protection measures, etc., were normal and uniform for all the experimental units. shows that P and Zn signi cantly in uence the number of leaves plant -1 . While Interaction between P and Zn levels was found non-signi cant. The mean value of the data indicated that a higher number of leaves plant -1 (8.8) was observed when P was applied at the rate of 75 kg ha -1 followed by 0 kg phosphorous ha -1 (8.7), where 50 kg P ha -1 resulted in the lower number of leaves plant -1 (8). The higher number of leaves plant -1 (9) was recorded when Zn was applied at the rate of 10 kg ha -1 followed by 15 kg ha -1 (8.8), where 0 kg Zn ha -1 resulted in (7.7) lower number of leaves plant -1 .
Data associated with plant height are presented in gure 2-D. Statistical analysis of the data shows that Zn signi cantly affects plant height while P and Interaction between P and Zn levels were found nonsigni cant. Mean data shows that higher plant height (95.1) was observed when P was applied at the rate of 75 kg ha -1 followed by 50 kg P ha -1 (93.6), where 0 kg P ha -1 results from low plant height (88.6).

Grain yield and yield traits (kg ha -1 )
Results showed that P and Zn levels signi cantly affected the number of pods ( gure 3A). While Interaction between P and Zn levels was found non-signi cant (Figure 3). The mean value of the data indicated that higher numbers of pods (10.3) were observed when P was applied at the rate of 25 kg ha -1 followed by 75 kg P ha -1 (10), where the control plot resulted in the lower number of pods (9.2). For Zn, higher numbers of pods (10.2) were observed when Zn was applied at the 5 kg ha -1 followed by 10 kg Zn ha -1 (10.1). Control plots resulted in lower numbers of pods (9). Similarly the grains pod -1 were also affected by Zn and P application ( Figure 3B). In comparison, P and interaction between P and Zn levels were found non-signi cant. Mean data shows that a maximum number of grains pod -1 (10.1) was observed when P was applied at the rate of 50 kg ha -1 followed by 25 kg P ha -1 (10). Whereas P application at the rate of 50 kg ha -1 resulted in a lower number of grains (9.6). The higher number of grain pod -1 (10.3) was recorded when Zn was applied at the rate of 5 kg ha -1 followed by 10 kg ha -1 (10), whereas the control plot resulted in the lower number of grains (8.7).
Maximum numbers of nodules (13.1) were observed with the application of 50 kg P ha -1 followed by 75 kg P ha -1 (12.3), while the lowest (10.6) nodules were observed in the control plot ( Figure 3C). Similarly, higher numbers of nodules (12.7) were observed with the application of 15 kg Zn ha -1 and followed by the control plot (11.7), while the lowest (11.1) nodules were observed on 10 kg Zn ha -1 . Results on grain yield showed that that a higher grain yield (826.7 kg ha -1 ) was observed when P was applied at the rate of 25 kg ha -1 , followed by 50 kg P ha -1 (792.5 kg ha -1 ), where a lower grain yield (737.4 kg ha -1 ) were obtained from the control plot. Higher grain yield (835.0 kg ha -1 ) was recorded when Zn was applied at the rate of 5 kg ha -1 followed by 15 kg ha -1 (800 kg ha -1 ). Whereas lower grain yield (719.9 kg ha -1 ) was recorded at plot had 10 kg Zn ha -1 .
Maximum (4493.4 kg ha -1 ) biological yield was observed with the application of 25 kg P ha -1, while the lowest (3543.1 kg ha -1 ) biological yield was observed for 75 kg P ha -1 (Table 1). Similarly, Zn has a maximum biological yield (4511.1 kg ha -1 ) with the application of 15 kg ha -1 , while the lowest (3630.3 kg ha -1 ) was recorded in the control plot. Higher (39.4) thousand-grains weight was observed with the application of 25 kg P ha -1 .followed by (38.8g) at the rate of 75 kg p ha -1 ( Table 2). While the lowest (36.8g) thousand grains weight were observed for the control plot. Similarly, Zn has a signi cant in uence on thousand grains weight, having a higher thousand grains weight (42.3g) for application of 15 kg Zn ha -1 , while the lowest (34.4g) thousand grains weight was recorded in the control plot. P and Zn had signi cant effects, while their interaction was non-signi cant. The higher harvest index (21.73%) was observed when P was applied at the rate of 75 kg ha -1 followed by 0 kg ha -1 (20.54%), where 25 kg ha -1 resulted in a lower harvest index (19.30%) ( Table 3).. For Zn higher harvest index (23.0%) was observed when Zn was applied at the rate of 5 kg ha -1 , followed by a control plot (21.3%). Furthermore, the application of 15 kg Zn ha -1 resulted in a lower harvest index (18.3%).

Discussion
Micronutrient insu ciency is the primary cause of low crop development and production in arable soils (Imtiaz et al., 2011). Due to intensive agricultural practices, unwise use of mineral nutrition, breeding of high yielding and advanced varieties, and removal of huge quantities of nutrients at every crop harvest with lower nutrients returns to soils, the degree and extent of nutrient de ciency in arable soils has recently had serious consequences, resulting in lower micronutrients including zinc (Zn) in soil (Kanwal et al., 2019). Therefore to we conducted a eld experiment on different Zn rates in combination with P rates to determine its effect on mungbean growth, yield and yield components. Our results showed that P and  2000) reported that Zn is essential for active enzymatic activity, root cell elongation, and reducing free radical damage to the cell. Another possible explanation for these results that when Zn and P applied to soil improved soil physical and chemical properties which consequently improved mungbean growth, yield and yield component (Singh, et al., 2013). A previous study documented that compared to control, Zn increased branches numbers in plants and leaf area of mungbean (Haider et al., 2021). Nair studied the genetic diversity of mungbean for iron and zinc and discovered a large potential for improvement through bioforti cation, nding 20-40 g Zn concentration kg -1 for dry mungbean seed, which was virtually identical in our work. Overall the results showed that the addition of Zn and P fertilizer to soil can improve growth, yield and yield component of mungbean.

Conclusion
Our results showed that the growth, yield and yield components of mungbean were improved in Zn and P fertilizer application. On the basis of our results it is concluded that P application at the rate of 25 kg ha -1 produced a higher grain yield as compared to 75 and 50 kg ha -1 . Whereas, Zn application at the rate of 5 kg ha -1 produced a higher grain yield than 10 and 15 kg ha-1 hence lower rate of 5 kg ha-1 is recommended for higher yield of mungbean in agro-ecological condition Mardan.

Declarations
Con ict of Interest Map representing an experimental location in Mardan city, KPK Province, Pakistan, using Google maps.  Effect of P and Zn application on pods plant -1 , grains pod -1 , nodules plant -1 and grain yield (kg ha -1 ) of mungbean.