Nitrogen management in a maize-groundnut crop rotation of humid tropics: effect on N2O emission.
Development of appropriate land management techniques to attain sustainability and increase the N use efficiency of crops in the tropics has been gaining momentum. The nitrous oxides (N2Os) affect global climate change and its contribution from N and C management systems is of great significance. Thus, N transformations and N2O emission during maize-groundnut crop rotation managed with various N sources were studied. Accumulation of nitrate (NO3- ) and its disappearance happened immediately after addition of various N sources, showing liming effect. The mineral N retained for 2-4 weeks depending on the type and amount of N application. The chicken manure showed rapid nitrification in the first week after application during the fallow period, leading to a maximum N2O flux of 9889 g N2O-N m(-2) day(-1). The same plots showed a residual effect by emitting the highest N2O (4053 microg N2O-N m(-2) day(-1)) during maize cultivation supplied with a half-rate of N fertilizer. Application of N fertilizer only or in combination with crop residues exhibited either lowered fluxes or caused a sink during the groundnut and fallow periods due to small availability of substrates and/or low water-filled pore space (<40%). The annual N2O emission ranged from 1.41 to 3.94 kg N2O-N ha(-1); the highest was estimated from the chicken manure plus crop residues and half-rate of inorganic N-amended plots. Results indicates a greater influence of chicken manure on the N transformations and thereby N2O emission.
Khalil
M I
MI
Soil Science Division, Bangladesh Institute of Nuclear Agriculture, Mymensingh. bina@bdmail.net
Rosenani
A B
AB
Van Cleemput
O
O
Fauziah
C I
CI
Shamshuddin
J
J
D000383:Agriculture / Q000379:methods*; D000818:Animals; D010367:Arachis / Q000254:growth & development*; D002645:Chickens; D004784:Environmental Monitoring / Q000379:methods; D006813:Humidity; D008372:Manure; D009566:Nitrates / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D009609:Nitrous Oxide / Q000378:metabolism*; D012987:Soil; D013995:Time; D014329:Tropical Climate; D014872:Water Movements; D003313:Zea mays / Q000254:growth & development*
D008372:Manure; D009566:Nitrates; D012987:Soil; D009609:Nitrous Oxide; D009584:Nitrogen