Dept. of Soil Science and Agricultural Chemistry, J. N. Krishi Vishwa Vidyaiaya, Jabalpur, M. P.
1Assistant Soil Physicist, now a Ph D. student and Urbana, Illinois.
2Professor of Soil Physics, University of Illinois, Urbana, Illinois.
In the 1970 kharif season, a field experiment was conducted on a clay loam soil of Jabalpur, M. P. to determine the state of oxidation of paddy soil and the yield of paddy under two water levels and two levels of added organic matter. Water level was maintained 5 cm above and 10 cm below the soil surface in 3.6 m × 3.6 m plots. Split treatments of no added organic matter and of 18000 Kg/ha (dry weight) green Ipomea were applied to each water level treatment. The concentration of ferrous iron in the 0–5 cm surface soil receiving orgnic matter and surface flooding attained its maximum limit of 2000 ppm. after six weeks of flooding and then declined to 1000 ppm. These concentrations were 10 to 20 times higher than those measured in the other three treatments. Average paddy yields were 69, 54, 68 and 64 q/ha for the flooded plots without and with organic matter respectively. None of the treatments significantly influenced the weight of roots per unit volume of soil at depths of 0–10, 10–17.5 and 17.5–25 cm.
Moisture regimes, green manuring
