SOLAR-RADIATION AND POTENTIAL CROP PRODUCTION AT LUDHIANA

Solar-radiation data from 1985 to 1989 for Ludhiana environment were a nalysed to estimate the potential crop production. Ludhiana (31-degree s-N received annual atmospheric radiation 11 672 MJ/m2. Of this, 42-62 % reached the earth's surface as global radiation. Monthly means of da ily global radiation varied from 10.5 MJ/m2/day in December to 23.5 MJ /m2/day in June. The average annual global radiation received was 6 44 8 MJ/m2. Based on 1% photosynthetic efficiency, this amount of radiati on could produce 38.5 Mg/ha dry matter annually under optimum conditio ns of nutrition and other growth factors. Actual dry-matter production was 15,17 and 20 Mg/ha in maize (Zea mays L)-wheat (Triticum aestivum L. emend. Fiori & Paol.), rice (Oryza sativa L.)-wheat, and Tice-pota to (Solanum tuberosum L)-wheat rotations respectively.