IMPACT OF RADIATION AND THERMAL INTERCEPTION ON BY-PRODUCT
OF CLUSTERBEAN CROP UNDER DIFFERENT GROWING
ENVIRONMENTS

M. L. KHICHAR*, RAM NIWAS AND B. D. YADAV1

Department of Agricultural Meteorology
CCS Haryana Agricultural University,
Hisar-125 004 (Haryana), India
*(e-mail : mlkhichar@gmail.com)

SUMMARY

A field experiment was carried out on sandy loam soil during two consecutive kharif seasons (July to September) at Dry Land Research Farm, CCS Haryana Agricultural University Hisar, India (29°10′ N latitude, 75°46′ E longitude and 215.2 m altitude), to study light interception and its impact on grain yield and by-product of clusterbean crop. Treatments consisted of two seeding dates, two seeding densities and three seed rates designed in split plot with three replications. The other package of practices for raising the crop was followed as recommended by the university. The photosynthetically active radiation (PAR) was measured with quantum sensor during noon hours at bottom and top of the crop canopy at flowering and pod formation stages. The transmission, reflection and absorption coefficients of PAR were calculated in all the treatment combinations. The air temperature data were taken from agrimet observatory situated at research farm and used for computation of thermal units required by the crop. Radiation and thermal use efficiencies were computed for all the treatments. The transmission and reflection coefficients showed a reverse trend that of absorption coefficient in all the treatment combinations. The dry matter production was recorded at flowering, pod formation stages and harvesting of the crop. Grain yield and its quality parameters (gum and crude protein per cent) were recorded at the harvest of the crop. The crop sown in last week of June absorbed higher PAR as compared to mid July sown crop at flowering and pod formation stages. Row spacing also influenced the PAR absorption and it was higher in narrow (30 cm) than wide (45 cm) spaced crop. The higher seed rate also increased the PAR absorption. June sown crop was more efficient in radiation and heat utilization for biomass production over July sown crop. Wider row spacing was more efficient in radiation use over narrow spaced crop. Increase in seed rate also improved the radiation and thermal use efficiency of the crop. Wider row spacing of 45 cm recorded higher grain yield and more gum content as well as crude protein as compared to 30 cm row spacing. Grain yield increased with seed rate, however, 15 and 20 kg/ha seed rates produced statistically similar yields. The crude protein did not differ among the treatments. Thermal Units (TU) and absorbed PAR explained 60-67 per cent variation in grain yield.

Key words : Radiation , thermal interception, clusterban, environment

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