Growth parameters of organic blackgram as influenced by the nutrient management techniques

Introduction

Blackgram is one of the important pulse crop of India. 100 grams of Blackgram consists of 25.2 grams of protein, 1.64 g of fat, 1.64 g of fiber, 7.57 mg of iron, 267 mg of magnesium, 379 mg of phosphorous, 983 mg of potassium, 3.35 mg of zinc and 0.981 mg of copper (FAO, 2016). In India Blackgram acreage was 3.16 m h, where the production was 2.24 mt and productivity was 710 kg ha -1 for the year 2024-25. Blackgram productivity often fluctuates and mostly remains low due to various constraints such as low availability of quality seeds, lack of improved short duration varieties, cultivation on marginal lands, low input usage such as deficit fertilizer application, inadequate pest and disease management and improper harvesting and storage practices (Singh et al., 2025) [10] . Among these, nutrient management is one of the improved factors contributing to low productivity. To overcome this, overall management aimed at meeting the requirement of balanced nutrition is essential (Joshi et al., 2023) [6] . The study was conducted at two locations to observe the influence of decomposed organic manures applied and incorporated as basal, along with the application of liquid manures applied as foliar sprays twice, to meet the nutrient demand throughout the crop growing period of blackgram.

Materials and Methods

The field experiments were carried out at Agriculture Research Station, Bhavanisagar, Erode considered as Site-I and at Wetlands Farm, Department of Agronomy, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu considered as Site-II. The experiments were conducted during kharif, 2022 where the rainfall during this period at Site-I was 219.2 mm and at Site-II was 239.0 mm. Soil pH at Site-I was 6.71 and at Site-II was 8.40.

Here, the variety sown was VBN-8 and the spacing adopted was 30 x 10 cm. Other than nutrient management practices, the irrigation and weeding schedule was followed as per TNAU crop production guide. Experiments were carried out in split plot design replicated thrice with four levels of organic manures in main plot applied as basal and incorporated before sowing viz., Farm yard manure (FYM) @ 12.5 t ha -1 , Vermicompost (VC) @ 2.5 t ha -1 , enriched FYM (EFYM) @ 0.75 t ha -1 and enriched VC @ 1 t ha -1 . In sub plot, five liquid manures were applied as foliar sprays twice, at first flowering where, at least 30% flowers were initiated in all plots and 10 days after the first spray viz., Panchagavya @ 3%, Fermented Egg Extract (FEE) @ 5%, Fermented Fish Extract (FFE) @ 5%, Farmers Effective Microorganisms (FEM) @ 5% and Jeevamruth @ 5%. Here, the germination percentage was calculated by using a quadrant in the plot and multiplied for the whole plot area and expressed as a percentage. Maximum duration required for germination was observed and expressed as number of days for maximum germination. The plant height was measured from the base of the plant to the growing tip, whereas the shoot length was measured from collar region to the tip of the primary shoot of the plant and both were expressed in cm. The nodules were collected from plants, averaged and expressed as number of nodules plant -1 . The nodules after separating from the plant were cleaned, weighed and the fresh weight of the nodules was recorded and expressed in grams plant -1 . For dry matter the plant samples were collected from each plot, which were shade dried and oven dried at 65 ± 5 °C for 24 hours, weighed and expressed as kg ha -1 . The readings were taken at 20 DAS, before 1 st spray, before 2 nd spray and at harvest. For nodule parameters the harvest stage readings were not taken. The crop data was analyzed by the method of analysis of variance (ANOVA) given by Panse and Sukhatame, 1954 [8] .

Results

The germination percentage (Fig. 1a) and duration (Fig. 1b) did not show any significance while the germination percentage in Site-I ranged from 95 to 97% and in Site-II it ranged from 98 to 100%.

The plant height (Table 1) progressed from 20 DAS to harvest across all treatments. Significant difference was not noted from the flower initiation stage. By harvest, the plant height was higher with EFYM (51.5 cm) which was on par with VC application (50.1 cm) in Site-I and VC (46.9 cm) which was on par with EFYM (44.9 cm) application in site-II, respectively. In Site-I and II, highest plant height was recorded by Panchagavya application (50.7 & 45.8 cm), respectively. Shoot length (Fig. 1c) was recorded higher with EFYM application (11.6 cm) at Site-I, and at Site-II, with the VC application (9.7 cm). Primary branches plant -1 (Fig. 1d) were recorded to be higher with EFYM application (5.99 plant -1 ) in Site-I and with VC application (5.64 plant -1 ) in Site-II. Number of nodules plant -1 (Fig. 2), Showed significant effect with the application of manures and non-significant application with the foliar sprays. Sizeable difference was observed between 20 DAS stage and before 1 st spray during flowering. Before 2 nd spray readings, showed significant higher number of nodules under EFYM application (53.5 plant -1 ) in Site-I and with VC application (60.3 plant -1 ) in Site-II. Similarly, the fresh weight of the nodules (Fig. 2) progressed with growth until the stage before 2 nd spray. By the stage before 2 nd spray, the application of EFYM (0.6356 g) recorded increased fresh weight in Site-I and the application of VC (0.6802 g) recorded highest weight in Site-II. Dry matter production (Table 2) showed significant influence with the application of manures as well as foliar sprays. At 20 DAS there was no significance difference for both the treatments. At the stage before 1 st spray, the manures showed significant influence and later at the stage before 2 nd spray the significant difference was observed with both the main and sub plots. At harvest the interaction effect was seen among the treatments. At harvest significantly higher dry weight was recorded with the application of EFYM (3930 kg ha -1 ) and Panchagavya spray (3845 kg ha -1 ) in Site-I and with the application of VC (3719 kg ha -1 ) and Panchagavya spray (3623 kg ha -1 ) in Site-II, respectively. Interaction effect showed significant dry matter production with the treatment EFYM @ 0.75 t ha -1 + Panchagavya spray @ 3% (4356 kg ha -1 ) in Site-I and with VC @ 2.5 t ha -1 + Panchagavya spray @ 3% (4058 kg ha -1 ) in Site-II, respectively.

Discussion

Better performance by blackgram was recorded during the kharif season in the current study, as conditions such as adequate distribution of temperature and rainfall were favorable for crop growth due to higher moisture availability and improved nutrient uptake (Vanaja et al., 2015) [13] . Enrichment enhances the nutrient content of the manures, along with improvement in soil properties and increased soil organic carbon content, thereby supporting plant development.

Improved nodule growth may be attributed to an increase in the root volume and surface area, which provides better opportunities for nodule formation and enhances plant performance as a result of better nutrient availability, leading to increased fresh weight of the nodules in the case of the enriched FYM and vermicompost (Thiagarajan and Somasundaram, 2019

and Ajaykumar et al., 2022) [12,11,1] .

In addition to higher nutrient content, the availability of nutrients both from the soil through manures and directly to the foliage through foliar spray, might have created complementary maturation conditions leading to greater dry matter accumulation. Vermicompost has been reported to have a lower pH and C:N ratio and to reduce soil EC, which may enhance soil conditions and thereby plant growth, particularly in problematic soil conditions compared to the FYM, which has a higher pH and C:N ratio (Dey et al., 2019) [3] . The influence of Panchagavya on crop growth at both locations indicates its ability to improve the biochemical properties of the plant, while the increase may also be due to the presence of beneficial microorganisms (Somasundaram et [11,7,4,9] .

Conclusion

The study conducted in two distinct locations to evaluate the performance of organic manures and foliar sprays on the growth of blackgram in complete organic conditions showed noticeable results. Progressive growth was observed with the treatment application where the treatments did not show any influence on germination while the manures have shown positive influence on plant height, shoot length, number and fresh weight of the nodules and primary branches. The influence of foliar application was shown in the plant height. Interaction effect of the manure application and foliar sprays was shown significantly on the plant dry matter production. All the parameters excluding the nodule growth showed better performance in Site-II. The results clearly show the effect of the treatments and how the time of application influence the growth of the crop. Here, distinct results were observed in the locations indicating the influence of soil type on the performance of manures. For better growth of the crop, combined application of manures along with utilizing multiple sources is productive.

References

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