Soil Fertility Conservation for Sustainable Field Maize Production

Abstract

Experiments on various cropping systems, were conducted at Nakhon Sawan Field Crop Research Centre in 1981 - 2002 to evaluate soil fertility with 3 cropping systems namely maize-sorghum, maize-mungbean and maize-lab lab were the factors. The kind of fertilizers namely non-fertilized, chemical fertilizer with 10-5-5 kg N-P2 O5- K2O / rai and chicken manure plus chemical fertilizer were other factors. The design was 3x4 factorial in RCB, and it was shown that average maize yield (maize-sorghum) was 187 kg/rai from 1999- 2002; decreased 56 % when was compared with that was 425 kg/rai from 1981- 1985. Application of chicken manure at the rate of 1 ton / rai / year for the last 13 years improved soil fertility and increased maize yield. Average maize yield was 727 kg/rai from 1990- 2002 in the plot with chicken manure application was 86 % higher than non fertilizer application that was 391 kg /rai. Growing legume into the cropping systems also improved soil fertility and increased yield of main crops. An appropriate cropping systems namely maize-mungbean with a recommended rate of fertilizer application resulted in a higher marginal rate of return compared to this same system with chicken manure application. However, the latter improved more soil fertility than the previous systems. So farmers should grow maize-mungbean instead of maize-sorghum with either fertilizer application at the recommended rate or chicken manure at rate of 1 ton / rai / year