Effect of different fertility levels on growth and yield of rabi sorghum (Sorghum bicolor L. Moench) genotypes under receding soil moisture environment

Introduction

Sorghum (Sorghum bicolor L. Moench) is grown in tropics and subtropics climates especially in the semi-arid tropics. It is extensively grown around the world, including Africa, Asia, Australia and America. Sorghum is called as "camel crop" because of drought, water logging and salinealkaline tolerance. It is one of the most efficient C 4 plant in terms of photosynthesis. Apart from grains, it provides valuable fodder which is one of the principal roughage feeds in India. Sorghum is grown in India on an area of 4.6 m ha, producing 4.50 m t with a productivity of 988 kg ha -1 (Anon., 2023). Maharashtra, Karnataka, Andhra Pradesh and Telangana are the leading states for rabi sorghum. Rabi sorghum is grown on residual soil moisture in post-rainy season and its productivity is dependent on the quantity of rain during the pre-sowing monsoon and the waterholding capacity of the soil. Soil moisture conservation, use of high-yielding cultivars and fertilizer management play a major role in improving the productivity of rabi sorghum. In this context, the performance of various sorghum genotypes were evaluated under different fertility levels in receding soil moisture environment.

Materials and Methods

A field experiment was conducted to study the "Effect of different fertility levels on growth and yield of rabi sorghum genotypes under receding soil moisture environment" at All India Coordinated Research Project on Sorghum, Main Agricultural Research Station, University of Agricultural Sciences, Dharwad(Karnataka) during rabi 2021-22. Soil of the experimental site was clay with a good water holding capacity and CEC. Recommended dose of fertilizer (50:25:0 kg N:P 2 O 5 :K 2 O /ha) was applied at basal. The experiment consisted of 32 treatment combinations comprising four fertilizer levels (0% RDF, 50% RDF, 100% RDF (50:25:0kg NPK ha -1 ) and 150% RDF and eight sorghum genotypes (G 1 -SPH-1897, G 2 -SPV-2735, G 3 -SPV-2644, G 4 -CSV-29R, G 5 -CSV-26, G 6 -CSV-22R, G 7 -M35-1 and G 8 -CSH-15R) with two replications. The field experiment was laid out in a split plot design.

Sowing of sorghum seeds was done manually with a row spacing of 45cm and 15cm between plants. Thinning was done by retaining one plant per hill to maintain optimum plant population. All the other agronomic practices were followed uniformly in all the treatments. The data collected from the experiment was subjected to statistical analysis as described by Gomez and Gomez (1984) [2] . The level of significance used in F test was P=0.05.

Results and Discussion

Fertility levels (Table1 and 2)

The data revealed that, application of 100% RDF (50:25:0 kg NPK ha -1 ) recorded significantly higher grain (36.28 q/ha) and fodder yield (6.57t/ha) over 0 and 50% RDF and it was on par with 150% RDF. The per cent increase in grain yield was to an extent of 24.7 and 6.02 higher over 0% and 50% RDF respectively. Significant improvement in higher grain and fodder yield could be attributed to profound influence of N and P fertilization on growth and development of the crop due to increase in nutrient accumulation and their translocation to sink. Similar results were reported by Sumeriya et al., (2005) [4] . The higher grain yield at 100% RDF might be due to higher values of yield parameters viz., grain weight (68.7 g/panicle) and 1000-seed weight (30.5 g), The better performance of these yield parameters might be attributed to mineral nutrition especially nitrogen which plays an important regulative functional role in plant system through synthesis and translocation of growth hormones which help in better growth and development of plant (Bringer at al., 1980). Similarly, the same treatment gave significantly higher gross returns (Rs. 99702/ha), net returns (Rs.61119/ha) and BC ratio(2.58) compared to 0% and 50% RDF which was due to higher grain and fodder yield (Table 1). The results are in agreement with the findings of Mali et al., 2000 [3] .

Performance of genotypes (Table1 and 2)

Among the tested genotypes, the variety SPV-2644 exhibited significantly higher grain yield (40.81q/ha), Stover yield (7.42 t/ha), gross returns (Rs.111312/ha), net returns (Rs.74..9 /ha) and BC ratio (2.95) as compared to checks (CSV-29R, CSV-26, CSV-22R and M35-1) followed by SPH-1897. The per cent increase in grain yield was to the tune of 26.4,14.28,27.05 and 36.44 over CSV-29R, CSV-26,CSV-22R and M35-1 respectively. The higher grain yield was mainly due to higher grain weight (70.8 g/panicle) and higher 1000-grain weight (32.56 g). Similarly, the same variety exhibited significantly higher fodder yield (7.42 t/ha) over checks.The better performance of the new varieties and hybrids was due to influence of nutrients on protein synthesis, involvement in several physiological and metabolic processes in the plant system (Tisdale et al., 1990) [5] . Further, significantly higher gross returns (Rs.111312/ha), net returns (Rs. 74339/ha) and BC ratio (2.95) was recorded with SPV-2644 over checks.The higher returns was mainly due to higher grain and fodder yield.

Interaction effect

The data on interaction effect of fertility levels and genotypes revealed that, the new variety SPV-2644 produced significantly higher grain yield of 43.74q/ha with 150% RDF compared to others but at par with 100% RDF (43.62q/ha).These results were in conformity with the findings of Dashora et al., (2014)

Conclusion

Based on the experimental results, it could be inferred that, application of 100% recommended doze of fertilizer (50:25:0kg NPK ha -1 ) found optimum for rabi sorghum genotypes for getting higher grain yield, fodder yield and net returns. Further, test varieties SPV-2644 and SPH-1897 produced higher grain yield compared to check varieties (CSV-29R, CSV-26, CSV-22R and M35-1).

References

1. Anonymous. India -area, yield and production for the year 2022-23. USDA, Foreign Agricultural Service; 2023.
2. Gomez KA, Gomez AA. Statistical procedures for agricultural research. 2nd ed. New York: John Wiley & Sons; 1984. p. 241-271.
3. Mali AL, Sumeriya HK, Singh I. Yield and monetary returns of sorghum cultivars under different fertility levels. Agriculture Science Digest. 2000;20:168-170.
4. Sumeriya HK, Singh P, Mali AL. Studies on the effect of fertility levels on growth and productivity of sorghum (Sorghum bicolor (L.) Moench). Crop Research. 2005;30:69.
5. Tisdale SL, Nelson WL, Beaton JD. Soil fertility and fertilizer. 4th ed. New York: MacMillan Publishing Company; 1990.