Nitrogen and drought management in pearl millet for sustainable productivity and profitability under rain-fed condition of Rajasthan

Introduction

Pearl millet (Pennisetum glaucum), the fourth most important cereal crop, is a popular crop in India as it is tolerant to heat and drought and can grow well on soil with low fertility. Pearl millet is a staple food in many parts of India and among people living in other countries with desert land and little rainfall. It is an excellent source of energy and vitamins & minerals are important for nutritional security. The world's hardest warm-season cereal crop is pearl millet. (Reddy et al., 2012) [12] . In India, pearl millet is grown over an area of 7.55 Mha with an annual production of 9.22 Mt and productivity of 1221 kg ha. (Anonymous 2022-23a) [3] . The major pearl millet growing states are Rajasthan, Maharashtra, Uttar Pradesh, Gujarat and Haryana contributing to 90% of total production in the country. About 45% of the total comes from Rajasthan, which is followed by Tamil Nadu (2%), Maharashtra (6%) Haryana (9%), Uttar Pradesh (19%), and Gujarat (9%). The crop covered around 45.54 lakh hectares in Rajasthan and produced 58.90 lakh tonnes with a productivity of 1296 kg/ha. (Anonymous 2023) [4] . India grows most pearl millet during the rainy (kharif) season, which runs from June/July to September/October. In some areas of Gujarat, Rajasthan, and Uttar Pradesh, pearl millet is also grown in the summer (February-May); in Maharashtra and Gujarat, it is grown on a modest scale in the post-rainy (rabi) season (November-February). Indiscriminate use of high analysis chemical fertilizers results in the deficiency of secondary and micronutrient in soil also make it hard and compact thus reduces water holding capacity of soil too. At this critical juncture, there is an urgent need to optimize nutrient demand to sustain crop production without affecting soil health with protection environment. It has been observed that the prolonged application of FYM makes nutrients available gradually and synchronize with the need of crops.

FYM plays a critical role in availability of various essential nutrients to plants by enhancing the microbial population and their activities in the soil. (Tomar et al., 2023) [13] . Bio-mix are commonly called microbial consortia which are capable of mobilizing important nutritional elements in the soil from nonusable to usable form by the crop plants through their biological processes. Drought induced losses in crop yield probably exceed losses from all other causes, since both the severity and duration of the stress are critical. Various management strategies have been proposed to cope up with drought stress. Using various chemicals to pre-sowing seed priming enhances seed viability, vigor, root length, root-shoot ratio, and yield. Chemicals like ABA, SA and KNO3 at variable concentrations promote germination of seeds, improve seedling growth, activity of various hydrolyses, solubilisation and mobilization of nitrogen from cotyledons to growing embryo, rate of water uptake, resulting in improvement of nitrate content and enhanced yield in various crops ( (Hayat et al., 2010 and Anju et al., 2019) [6,1] .

Materials & Methods

A field experiment was conducted during rainy (kharif) seasons of 2022 and 2023 at Agronomy Research Farm, Rajasthan Agricultural Research Institute, Durgapura, Jaipur, Rajasthanto study the "Nitrogen and Drought management in Pearl millet for Sustainable Productivity and Profitability under Rainfed condition of Rajasthan". The experimental site was located at 26°512 N latitude and 75°472E longitude and at an altitude of 390 m above mean sea level. The mean maximum temperature was 34.9 °C, 34.7 °C and minimum temperature was 21.6 °C, 18.7 °C and total rainfall was 725.2 mm and 604.7 mm during the crop period in the year 2022 and 2023, respectively. Welldrained loamy sand and coarse in texture soil was found at the experimental site. It was low in organic carbon (0.323%) and available nitrogen (140.0 kg/ha), medium in available phosphorus (29.7 kg/ha) and available potash (267.0 kg/ha) with pH 8.05 and EC 0.09 dS m -1 . DTPA extractable Zn and Fe was 0.54 and 2.98 ppm. The experiment was laid out in split plot design with 3 replications and 16 treatment combinations. First factor, 4 treatments of bio-organics, viz. F0: Control, F1: FYM + bio-mix, F2: vermicompost + bio-mix and F3: poultry manure + bio-mix and second factor, 4 treatments of seed priming, viz. P0: control (water), P1: potassium nitrate @ 0.5%, P2: salicylic acis @ 200 ppm and P3: abscisic acid 150 ppm. Bio-mix are microbial bio-fertilizer consortia (consisting of Azotobactor, Azospirillium and phosphate solubilizing bacteria) commercially branded as Bio-mix, convert nutrients present in the soil and in the manure to a form which can easily be absorbed by plants. The experiment was taken on the fixed site continuously for the two years. Certified seeds of pearl millet variety RHB -234 were used for sowing. The seeds were sown manually 2-3 cm deep after seed priming in previously opened furrows as per the treatments with a recommended seed rate of 4.0 kg /ha. In organic plots whole RDF was applied through FYM, Vermicompost and poultry manure after calculating the concentration of nutrients present in them. For applying 100% RDN per hectare through FYM, 12.5 tons of well decomposed FYM., having 0.48, 0.23, 0.49% NPK was applied in the plots before sowing and mixed well, 3 tons of vermicompost having 2.0, 1.4, 0.90% NPK was applied for 100%, in the plots Likewise, 2 tons of poultry manure having 3.0, 2.60, 1.4% NPK was applied for 100%, in the plots before sowing. In both the year crop was sown in second week of July and harvested in first week of October. For working out the economics, prevailing market prices for grain and stover and other inputs were considered. The data were statistically analyzed and both years results are presented.

Result and Discussion

Growth and Growth indices: All the growth and growth indices viz., Dry matter accumulation, leaf area, leaf area index, crop growth, relative growth rate and leaf area duration and no. total of tillers per meter row length were significantly influenced by bio-organics and seed priming (Table 1 & 2 and Fig. 1 &2). Results revealed that significantly higher dry matter accumulation/plants, leaf area/plant, leaf area index and no. of total tillers/meter row length were found under treatment F3: poultry manure +Biomix which was being at par with vermicompost + bio-mix. Likewise, CGR, RGR and LAD were significantly higher under treatment F3 and it remained at par with F2. Organic manures along with bio-mix had significant favourable effects on soil physical, chemical and biological properties which directly or indirectly influence the plant growth and growth indices characters by increasing the water holding capacity of soil, increasing organic carbon, enhancing microbial activity in the soil which is resulted into more availability of nutrients by solubilizing or mobilizing the fixed pool of nutrients in the soil. Results were also in close conformity with those found by Ankit et al. (2019) [2] and Kumar et al. (2022) [7] . The seed priming with P3: abscisic acid @150 ppm was obtained significantly maximum dry matter accumulation/plants, leaf area/plant, leaf area index and no. of total tillers/ meter row length and being similar with P2: salicylic acid @ 200 ppm where is CGR, RGR and LAD were significantly higher under treatment P3 and it remained at par with P2. The photosynthetic rate may have increased as a result, which in turn may have increased the plants' supply of carbohydrates. This, in turn, may have enhanced the plants' vertical and lateral growth, improving their leaf area and dry matter accumulation, which in turn produced an increase in the leaf area index and other growth indices. These results also corroborate with the findings of Niranjan Raj et al. (2007) [10] and Balaji et al. (2019) [5] . Yield attributes and yield: viz., no. of effective tillers/ meter row length, length of ear head, girth of ear head, no. of grains/ear head, grain, stover and biological yield/ plot of pearl millet were also significantly influenced by the different bio-organic treatments and seed priming (Table 2 & 3 and Fig. 3). Among the different treatments tried, application of poultry manure+ bio-mix and Vermicompost + bio-mix (F3 and F2) recorded highest no. of effective tillers (29 and 27 /meter row length in pooled data), length of ear head (32. 73 The increased translocation of photosynthates towards sink development may have been caused by the beneficial effects of organic manures, which are essential for root development, energy translocation, and plant metabolic processes. The fact that proper decomposition and mineralization of organic manures due to increased microbial activity resulted in an increased supply of available P and N with other essential plant nutrients directly to the plant as well as solubility effects on fixed form of P could be the cause of the beneficial effect of combined use of organic manures (poultry manure or vermicompost) and Biomix on grain and stover yields. (Patel et al. (2014) [11] . These findings are in close agreement with those reported by Meena et al. (2017) [8] and Yadav et al. (2023) [14] .

Various seed priming treatments, seed priming with abscisic acid @ 150 ppm was showed significantly maximum no. of effective tillers (25 / meter row length in pooled data) length of ear head (30.65 &in 2022 and 27.50 & 26.80 cm in 2023), girth of ear head (28.85 mm in pooled data), no. of grains/ear head (2198 & 2150 in 2022 and 1965 & 1934 in 2023), grain (2290 & 2229 g/ plot in pooled data), stover (5356 & 5318 g/ plot in pooled data) and biological yield (7707 & 7617 g/ plot in pooled data) over control and was statistically at par with salicylic acid @ 200 ppm during both the years. It was also found that with sufficient moisture in the plant and soil, plant nutrients particularly N, P and K were more available and might have translocated to produce more dry matter. Secondly, higher yield with no moisture stress might be due to its key role in root development by reducing mechanical resistance of soil, higher transpiration, greater nutrient uptake and more photosynthesis due to metabolic activities in the plant. The results are also in cognizance with those of (Menaka et al. 2008) [9] .

Conclusion

Based on the results of present investigation, it is concluded that long term application of poultry manure @ t/ha with Bio-mix @ 2l/ha and seed priming with abscisic acid @ 150 ppm or salicylic acid @ 200 pmm treatments can be prevent nitrogen deficiency and drought management and produce economically higher grain (2484 g/plot) and stover (5627 g/plot), biological (8412 g /plot) yield and with highest net returns (63.6 Rs/plot).

References

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