CHAPTER IV Bangladesh Agron. J. 2023, 26(1): 96-103 EFFECTS OF PLANTING GEOMETRY AND FERTILIZER MANAGEMENT ON LIGHT INTERCEPTION, CHLOROPHYLL CONTENT AND PRODUCTIVITY IN BABY CORN CULTIVATION S.S. Kakon*, J.A. Chowdhury, M.Z. Ali, M.R. Karim and D.A. Chowdhury Agronomy Division, Bangladesh Agricultural Research Institute, Joydebpur, Gazipur 1701, Bangladesh *Corresponding author, Email: kakonbari@gmail.com (Received: 28 August 2023, Accepted: 20 September 2023) Keywords: Light Interception, Chlorophyll Content and Productivity, Baby Corn Abstract A field experiment was conducted during during rabi seasons (December to March) of 2019-20 and 2020-21 to find out optimum plant spacing and fertilizer levels on yield of baby corn. Three plant spacing viz, S1=40 cm × 20 cm (1,25000 plants ha−1), S2=50 cm × 20 cm (100000 plants ha−1) and S3 =60 cm × 20 cm (83333 plants ha−1) and three fertilizer doses viz, F1 = 150- 30- 50- 25-3. 5- 1.5 kg ha−1of NPKSZnB (Recommended fertilizer dose for baby corn), F2 = F1 + 25% NPK and F3 = F1 + 50% NPK, were used as treatments. Results revealed that, planting geometry and fertilizer levels showed great influence on leaf area index (LAI), light interception, dry matter production and yield of babycorn. LAI was found the highest with the population of 125000 plants ha−1 receiving N225 P45 K75 kg ha−1.Light absorption was maximum at densely plant population with N225P45K75 kg ha−1. Response of soil-plant-analysis development (SPAD) value to planting geometry and fertilizer level was found significant. Plants grown with 40 cm × 20 cm spacing (125000 plants ha−1) with recommended ferltilizer dose + 50% N- P- K of RF gave the highest dehusked cob yield over the years (3.42 and 3.73 t ha–1) which was followed by 40cm × 20 cm (1,25,000 plants ha−1) with recommended fertilizer dose + 25% N-P-K of RF. Though S1F3 combination gave the highest gross return (Tk.333140 ha– 1 in 2019-20 and Tk. 378900 ha–1 in 2020-21) but the highest benefit cost ratio over the years (3.64 and 3.83) was recorded in S1F2 treatment. The overall results indicated that 40 cm × 20 cm (1,25,000 plants ha−1) with fertilizer dose of RFD + 25% NPK (N187.5 P37.5K62.5 S25Zn3. 5B1.5 kg ha−1) might be economically profitable for baby corn production. Introduction Babycorn (Zea mays L.) is an immatured, dehusked and unfertilized maize ear, harvested within two days of silk emergence but prior to fertilization (Ramchandrappa et al., 2004). Change in food habit from non-vegetarian to vegetarian aggravated the consumption of vegetables especially babycorn. Babycorn ends its life cycle within 75 days and enters its reproductive phase during 50-55 DAS. Nitrogen is the most important nutrient for maize production and application of varied levels had significant influence on growth and yield of babycorn (Thakur et al.,1997). It is a low calorie vegetable having higher fibre content without cholesterol. Besides nutritive advantage, it is also free from residual effect of pesticides as it is harvested within a week of tassel emergence and the young cob is wrapped up tightly with husk and well protected from insects and pests Recently it is becoming popular very rapidly as vegetables, salad, pasta, soup, pakora, chutney, cutlets chat, dry vegetable. To sustain the heavy cattle population, baby corn can provide a valuable supplementary source of green fodder. Optimum crop geometry is one of the important factors for higher production leading to efficient utilization of resources and also harvesting as much as solar radiation and in turn better photosynthesis. The yield of baby corn of our country is 0.99-1.1 t ha−1 (BARI, 2008). But its potentiality is 5 t ha−1 (BARI, 2004). Nevertheless, it is Effects of planting geometry and fertilizer management on baby corn 97 not cultivated all over the country due to the lack of appropriate production technology. Growth of baby corn are affected by cultural management practices especially fertilizer application. The application of 150:75:40 kg ha−1 NPK + 10 t FYM was found to be optimal for obtaining high baby corn and fodder yields with good quality (Ramchandrappa et al., 2004). Though the spacing requirements of grain and fodder maize are well defined, such information is meager in baby corn. The duration of crop being short, the need for nutrient management and other package of practices may also differ from the grain or fodder crop of maize. Therefore, the experiment was undertaken to find out optimum plant spacing and fertilizer levels on yield of babycorn. Materials and Methods The experiment was conducted at the Research Field of Agronomy Division BARI, Gazipur, Bangladesh during rabi season (December to March) of 2019-2020 and 2020-2021. The soil was clay loam with pH 6.1. Soils of the experimental plots were collected and analyzed. The average maximum (30.5°C) temperature was found in the month of December at early stage of crop establishment and minimum (7.5°C) in the month of February during the crop growing season (Figure 1). The physical and chemical properties of soil are presented in Table 1. Table 1. Physical and chemical properties of experimental soil at Gazipur, Bangladesh pH OM (%) Total N (%) Exchangeable K (meq 100g soil−1) Available P (g ml−1) Available S (g ml−1) Available Zn (µg ml−1) Available B (g ml−1) 6.23 1.29 0.112 0.098 15.23 24.94 0.654 0.168 VL VL VL O O L VL Critical Levels - 0.12 7.0 10.00 0.60 0.20 L= Low, VL= Very low Three plant spacing viz., S1= 40 cm × 20 cm (1,25000plants ha−1), S 2= 50 cm × 20 cm (100000 plants ha−1) and S3 = 60 cm × 20 cm (83333plants ha−1) and three fertilizer doses viz., F1 = 150- 30- 50- 25-3. 5- 1.5 kg ha−1 NPKSZnB (Recommended fertilizer dose), F2 = F1 + 25% NPK and F3 = F1 + 50% NPK, were used. The experiment was laid out in a randomized complete block design with three replications. The unit plot size was 4 m × 3.6 m. Seeds of BARI Baby corn-1 were sown on 12 December 2019 and on 3 December 2020. Fertilizers were applied as per treatments. One-third of nitrogen and full amount of Triple super phosphate (TSP), Muriate of potash (MoP), Zinc sulphate and Boric acid were applied at the time of final land preparation. The remaining N (urea) was top dressed in two equal splits at 25 DAS and 45 DAS, respectively and mixed thoroughly with the soil as soon as possible for better utilization. A light irrigation was given after sowing of seeds for uniform germination. Two irrigations were done at 30 and 45 DAS. Thinning’s were done at 10 DAS and weeding at 15 and 25 DAS. Leaf area was measured by an automatic leaf Area Meter (L13200 C, LICOR, USA). For dry matter estimation, 5 plants were sampled started from 20 DAE at 15 days interval up to maturity. Dry weight of the samples was taken after drying at 80C in an oven for 72 h. CGR (g m-2 day−1), was calculated using equation as suggested by Yellam as follows. Light interception (LI) by the crop was recorded at five times, for example, 25, 45, 60 DAS and at harvest at around 11:30 am to 13:00 pm of baby corn by Sunfleck Ceptometer (Model Decagon, Pulman, Washington, USA). Four readings each of PARinc and PARt were recorded at different spots of each plot. The proportion of intercepted PAR (PARint) was calculated using the following equation and expressed in percentage: Light interception {PARint (%)} = PARinc – PARt PARinc × 100 where, PARinc = Incident PAR, PARt = Transmitted PAR, PARint = Intercepted PAR 98 Kakon et al. Soil-Plant-Analysis Development (SPAD) Value. Leaf chlorophyll content may be used as an indirect indicator of crop N status. Chlorophyll meter values (SPAD) were taken using a portable SPAD meter (Model SPAD-502, Minolta crop., Ramsey, NJ) starting from 35 DAS with 15-day interval. BARI Babycorn-1 was harvested on 04 March 2020 (85 days after sowing) and on 08 March 2021. The yield component data was taken from 5 randomly selected plants from each plot. At harvest, the yield data was recorded plot wise. The collected data were analyzed statistically and means were adjudged by LSD test at 5% level of significance using MSTAT-C package. Fig. 1. Mean temperature prevailed during baby corn growing periods. Results and Discussion Growth analysis Leaf area index (LAI) varied at different plant spacing and fertilizer level. LAI increased up to 60 DAS and thereafter decreased in all treatments (Fig. 2). Maximum LAI (3.89 in 2019-20 and 3.98 in 2020-21) was recorded at 65 DAS in S1F3 (125000 plants ha−1× × N 225P45K75kg ha−1) treatment followed by S1F2 (100000 plants ha−1 ×× N187.5 P37.5K62.5kg ha−1) treatment. Higher LAI indicates better leaf area expansion, which might help in solar radiation interception for more dry matter production. The lowest leaf area index (1.5 in 2019-20 and 2.10 in 2020- 21) was found in S3 × F1followed by S2 × F1 treatment. Higher leaf area index in closer spacing was observed due to increased plant density which accommodates more number of plants and can also be ascribed to lesser value of spacing (Wasnik et al., 2012). Total dry matter (TDM) production increased gradually with the advancement of plant growth in both the plant spacing and different fertilizer doses (Figure 3). TDM of baby corn was higherinS1F3 (125000 plants ha−1 × N225P45K75kg ha−1) followed by S1F2 treatment. The lowest TDM was observed from S2 × F1 treatment. Total dry matter reduced in plant spacing S3 (60cm × 20 cm) under all fertilizer treatments. It might be due to lower population (83,333plants ha−1) and leaf senescence caused by might reduce the photosynthetic efficiency and Effects of planting geometry and fertilizer management on baby corn 99 ultimately reduced the dry matter accumulation (Figure 2). The treatments which gave the higher value in leaf area index (LAI) were performed better in total dry matter production. Similar findings were also observed with Tollenaar et al. (1997). a) 2019-2020 b) 2020-2021 Fig. 2. Leaf Area Index of baby corn plant as influenced by planting density and fertility level. a) 2019-2020 b) 2020-2021 Fig. 3. Total dry matter of baby corn plant as influenced by planting density and fertilizer levels. Significant effect on CGR value at all growth periods was found in both the plant spacing and different fertilizer doses (Figure 4). CGR values were increased with the progress of the growth and development of the crop. CGR of baby corn was higher in S1F3(125000 plants ha−1×× N225P45K75kg ha−1) followed by S1F2 treatment. The lowest CGR was observed from S2 × F1 treatment. CGR reduced in plant spacing S3 (60cm × 20 cm) under all fertilizer treatments. 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 20 35 50 65 80 Le af a re a in d e x Days after sowing S1x F1 S2x F1 S3x F1 S1x F2 S2x F2 S3x F2 S1x F3 S2x F3 S3x F3 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 20 35 50 65 80 Le af a re a in d e x Days after sowing S1x F1 S2x F1 S3x F1 S1x F2 S2x F2 S3x F2 S1x F3 S2x F3 S3x F3 0 200 400 600 800 1000 1200 1400 1600 1800 20 35 50 65 80 To ta l d ry m at te r (g m – 2 ) Days after sowing S1x F1 S2x F1 S3x F1 S1x F2 S2x F2 S3x F2 S1x F3 S2x F3 0 200 400 600 800 1000 1200 1400 1600 1800 20 35 50 65 80 To ta l d ry m at te r (g m – 2 ) Days after sowing S1x F1 S2x F1 S3x F1 S1x F2 S2x F2 S3x F2 S1x F3 S2x F3 100 Kakon et al. a) 2019-2020 b) 2020-2021 Fig. 4. Crop Growth Rate of baby corn plant as influenced by planting geometry and fertilizer levels. Light Interception Light interception steadily increased up to 60 DAS and decreased at harvest. Light Interception varied at different plant spacing and fertilizer doses (Figure 5). a) 2019-2020 b) 2020-2021 Fig. 5. Light interception by baby corn canopy as influenced by planting density and fertilizer levels. Combination of S1F3 (125000 plants ha−1 × N 225P45K75 kg ha−1) was favorable for light penetration to the upper of the canopy, which resulted better LI and the lowest LI was found in S3F1 (83,000 plants × 150- 30- 50- 25-3. 5- 1.5 kg ha−1NPKSZnB). Higher light absorption by the plants of treatment S1F3 is presumably because of larger leaf surface availability for 0 5 10 15 20 25 30 35 40 0-20 20-35 35-50 50-65 C ro p G ro th R at e ( g m – 2 d ay – 1 ) Days after sowing S1× F1 S2× F1 S3× F1 S1× F2 S2× F2 S3× F2 S1× F3 S2× F3 S3× F3 0 5 10 15 20 25 30 35 40 45 0-20 20-35 35-50 50-65 C ro p G ro w th R at e ( g m – 2 d ay – 1 ) Days after sowing S1× F1 S2× F1 S3× F1 S1× F2 S2× F2 S3× F2 S1× F3 S2× F3 S3× F3 0 10 20 30 40 50 60 70 80 90 100 45 60 At harvest L ig h t in te rc e p ti o n (% ) Days after sowing S1x F1 S2x F1 S3xF1 S1xF2 S2xF2 S3x F2 0 10 20 30 40 50 60 70 80 90 45 60 At harvest L ig h t in te rc e p ti o n (% ) Days after sowing S1x F1 S2x F1 S3xF1 S1xF2 S2xF2 S3x F2 https://www.hindawi.com/journals/tswj/2013/193018/fig3/ Effects of planting geometry and fertilizer management on baby corn 101 photosynthesis as evident by higher leaf dry- weight. This indicates that population is the main factor influencing the net radiation absorbed by the plants. Higher penetration of radiation below the canopy indicates lower interception of solar radiation at the canopy. The maximum light was intercepted at 60 DAS corresponded to higher LAI. These results indicated that the more the LAI, the greater the light interception. These results are in conformity with the findings of several earlier researchers Amanullah et al., (2010). SPAD value SPAD value was influenced by planting geometry and fertilizer level (Figure 5). SPAD meter measure the leaf greenness which indicated the leaf chlorophyll content. Regardless of treatment, SPAD values decreased with the plant age (Figure 6). Maximum SPAD values were observed at 65 DAS which declined progressively reaching the lowest at 80 DAS. The higher SPAD values of baby corn leaves at 65 DAS were probably due to the less sink demand for N from the source (leaf). SPAD value increases with the increase of fertilizer (especially nitrogen). Conversely, lower SPAD values at 80 DAS and afterwards might have been due to remobilization of N from leaves to reproductive organs as grain formation was started after 60 DAS. SPAD values increased with the increase of fertilizers levels irrespective of population density. The highest SPAD value was found in S1F3 (125000 plants ha−1×× N225P45K75 kg ha−1). Fig. 6. SPAD value on baby corn plant as influenced planting geometry and fertility levels. Yield component and yield Plant population, yield components and yield of baby corn were significantly affected by plant spacing and fertilizer doses (Table 2) in both the years. Number of cob per plant, cob wt. with husk, dehusked cob weight, dehusked cob yield and fodder yield varied significantly due to variation of treatments. Maximum plants were recorded in S1F1, S1F2 and S1F3 treatments and minimum plants were recorded in S3F1, S3F2S3F3 treatments. Significantly the highest number of cob per plant (2.80 in 2019-20 and 3.00 in 2020- 21), dehusked cob weight/ plant (69.04g in 2019-20 and 58.67g in 2020-21) were obtained from S3F3 treatment followed by, S2F3 treatment. Higher dehusked cob yield (3.42t ha−1 in 2019- 20 and 3.73 t ha−1 in 2020-21) was recorded from S1F3 treatment followed by S1F2 treatment.It might be due to higher number of plants. The result coincides with the findings of Kunjir et al., (2007). The lowest green cob yield average over the years (2.32 and 2.36 t ha−1) were obtained from S3F1 treatment which was statistically similar with S2F1 treatment. 0 10 20 30 40 50 60 70 35 50 65 80 S P A D V a lu e Days after sowing S1x F1 S2x F1 S3xF1 S1xF2 S2xF2 S3x F2 S1x F3 S2xF3 S3xF3 102 Kakon et al. Table 2. Plant population, yield attribute and yield of baby corn as influenced by plant spacing and fertilizer levels (2019-20 and 2020-21) Treatment Plant m−2 (no.) Cob wt. with husk (g plant−1) Cob wt. dehusked (g plant−1) Cob plant−1 (No.) 2019-20 2020-21 2019-20 2020-21 2019-20 2020-21 2019-20 2020-21 S1× F1 10.00 10.34 97.64 116.33 30.94 31.30 2.53 2.51 S2× F1 8.00 8.10 109.80 119.59 34.13 34.03 2.59 2.67 S3× F1 6.33 6.74 118.50 131.33 38.38 42.07 2.68 2.73 S1× F2 9.67 9.87 103.40 121.33 48.51 41.78 2.57 2.67 S2× F2 7.67 7.74 113.25 127.00 53.58 48.67 2.64 2.70 S3× F2 6.67 6.77 121.93 144.00 59.02 54.00 2.72 2.78 S1× F3 9.67 9.59 109.80 126.90 56.57 49.63 2.61 2.60 S2× F3 7.00 7.63 118.65 131.33 62.17 54.00 2.70 2.70 S3× F3 6.67 6.62 127.20 147.33 69.04 58.67 2.80 3.00 LSD(0.05) 2.65 0.20 11.23 1.17 3.31 1.12 0.21 0.055 CV (%) 4.30 3.44 3.63 3.56 4.65 4.41 5.05 4.03 Treatment Yield dehusked (t ha−1) Yield withhusk (t ha−1) Fodder yield (t ha−1) 2019-20 2020-21 2019-20 2020-21 2019-20 2020-21 S1× F1 2.65 2.83 11.45 12.08 28.26 29.63 S2× F1 2.49 2.62 9.42 10.84 26.01 25.93 S3× F1 2.32 2.36 8.86 9.80 24.02 24.07 S1× F2 3.30 3.57 13.50 13.33 31.18 32.10 S2× F2 2.71 3.12 11.89 12.00 29.64 29.32 S3× F2 2.50 2.71 10.06 11.02 26.94 26.85 S1× F3 3.42 3.73 14.02 14.15 32.98 33.33 S2× F3 3.01 3.24 12.50 12.90 31.01 32.10 S3× F3 2.70 2.81 11.03 11.57 28.05 27.47 LSD(0.05) 0.13 0.08 3.05 0.14 4.20 0.92 CV (%) 4.73 3.29 6.01 5.68 5.61 5.83 Significantly the highest green fodder yield was recorded in S1F3 (32.98 t ha−1in 2019- 20 and 33.33 t ha−1 in 2020-21) treatment. Hussain (2014) reported that higher dose of fertilizer application resulted the increased fodder yield. The lowest fodder yield was obtained from S3F1 treatment in both the years. Yield attributes increased with increased rates of N might be due to the fact that application of nitrogen to the maize plants maintained greenness of leaves for longer period which in turn helped in greater dry matter accumulation and this might have contributed much as a major source for the development of sink and thereby improved the yield attributes. Significantly the highest fodder yield was recorded in closer spacing with higher level of NPK indicating a faster growth under influence of higher level of NPK fertilization might have played a significant role in reducing competition for photosynthates and nutrients with other plants resulting in healthy plants. Cost benefit Analysis Cost and return analysis is an important tool to evaluate the economic feasibility of crop production. Benefit cost analysis of baby corn production has been presented in Table 3. Gross return and BCR depends on grain yield. Among the treatments, the highest gross return (Tk. 333140 ha–1in 2019-20 and Tk.378900 ha–1 in 2020-21) was obtained from S1F3 treatment Effects of planting geometry and fertilizer management on baby corn 103 and the lowest gross return (Tk. 226477 ha−1 in 2019-20 and Tk.267350 ha−1in 2020-21) was found in S3F1 treatment. The highest gross margin (Tk. 239685 ha−1 in 2019-20 and Tk.278949 ha−1 in 2020-21) was obtained from S1F3 treatment. The highest benefit cost ratio (3.64 in 2019- 20 and 3.80 in 2020-21) was also obtained from S1F2 treatment (Table 3) which was followed by S1F3 and S2F3. Table 3. Cost benefit analysis of babycorn as influenced by planting geometry and fertilizer level Spacing fertilizer Gross return (Tk. ha−1) Cost of production (Tk. ha−1) Gross margin (Tk. ha−1) BCR 2019-20 2020-21 2019-20 2020-21 2019-20 2020-21 2019-20 2020-21 S1× F1 278683 329350 84560 92752 194123 236598 3.30 3.55 S2× F1 243073 292250 81820 88552 161253 203698 2.97 3.30 S3× F1 226477 267350 77450 85352 149027 181998 2.92 3.13 S1××F2 317917 360450 87280 94231 230637 266220 3.64 3.83 S2××F2 290897 326600 83020 90649 207877 235952 3.50 3.60 S3×× F2 255380 299550 79350 87449 176030 212102 3.22 3.43 S1× F3 333140 378900 93455 99951 239685 278949 3.56 3.79 S2××F3 305033 354000 87850 94745 217183 259255 3.47 3.74 S3××F3 272610 310900 81665 89545 190945 221355 3.34 3.47 Price (Tk.kg−1): Baby corn (with husk) = 12 in 2019-20 and 15 in 2019-20; Fodder = 5 Conclusion Results reveled that fertilizer dose 187.5- 37.5- 62.5- 25- 3.5- 1.5 kg ha-1 of NPKSZnB (RFD + 25% NPK) with plant spacing 40 cm × 20 cm would be optimum for getting higher yield and better economic return at Joydebpur. References Amanullah, A., M. Asif and K. Nawab. 2010. Impact of planting density and P-fertilizer source on the growth analysis of maize. Pak. J. Bot. 42(4): 2349–2357. BARI. 2008. BARI Annual Research Report. 2007- 08. Effect of season and population density on growth, fodder production and yield of baby corn at different locations. Agronomy division, BARI, RARS, Hathazari, Chittagong, Bangladesh. BARI. Production technology of baby corn (in Bengali). Agronomy Division, BARI, Joydebpur, Gazipur, Bangladesh. Hussain, A. 2014. Effect of different combinations of organic and inorganic nutrients on productivity and profitability of baby corn varieties in Kashmir Valley. Ph.D. thesis, Sher-e-Kashmir University of Agricultural Sciences & Technology of Kashmir, Division of Agronomy, Shalimar Campus, Srinagar– 190025. Kunjir, S.S., S.A. Chavan, S.B. Bhagat and N.B. Zende. 2007. Effect of planting geometry, nitrogen levels and micronutrients on the growth and yield of sweet corn. Crop Prot. Prod. 2: 25- 27. Ramachandrappa, B.K., I.I.V. Nanjappa and I.I.K. Shivakumar. 2004. Yield and quality of baby corn (Zea mays L.) as influenced by spacing and fertilization levels. Acta Agron. Hung. 52: 237-243. Thakur, D.R., O.M. Prakash, P.C. Kharwara and S.K. Bhalla. 1997. Effect of nitrogen and plant spacing on growth, yield and economics of baby corn (Zea mays). Indian. J. Agron. 42(3): 479-483. Tollenaar, M., A. Aguilera and S.P. Nissanka. 1997. Grain yield is reduced more by weed interference in an old than in a new maize hybrid. Agron. J. 89: 239-246. Wasnik, V.K., A.P.K. Reddy and S.S. Kasbe. 2012. Performance of winter maize under different rates of nitrogen and plant population in Southern Telangana region. Crop Res. 44(3): 269-273.