Plant and Soil 49, 633-639 (1978) Ms. 3523 SOME LOSS MEASURES OF REDUCING LEACHING OF NITRATES BEYOND POTENTIAL ROOTING ZONE IV. INTERCROPPING by BIJAY SINGH, D. S. RANA and G. S. SEKHON Department of Soils, Punjab Agricultural University, Ludhiana 141004, India SUMMARY Soil nitrate profiles under seven treatments of an experiment on intercrop- ping in row crops were studied at sowing and then after harvesting of dif- ferent crops. The estimates of NOa--N in these profiles indicate that inter- cropping in the row crops grown during the rainy season considerably re- duced leaching loss of nitrates. Where the main crop receives the recommend- ed fertilizer amount and the intercrop a small additional application, inter- cropping greatly reduced the amount of unutilized nitrates and hence their leaching beyond root zone. INTRODUCTION Nitrates leach down to the water-table during the months of mon- soon rains 1. A previous paper 4 has indicated that considerable con- trol over nitrate leaching can be exercised by raising deep rooted crops, like maize, during the rainy season. This paper examines the possibility of further reduction in leaching losses of nitrates by in- tercropping in rainy season row crops. MATERIALS AND METHODS Soil samples were taken with a screw-type auger at 15 cm intervals upto a depth of 225 cm in seven treatments of a field experiment conducted at Pun- jab Agricultural University farm in a Tolewal loamy sand (Typic Ustoch- repts). SoiI characteristics of the experimental site are described in Table 1.