
TY  - JOUR
A1  - Wetselaar, R 
A1  - Norman, MJT 
T1  - Recovery of available soil nitrogen by annual fodder crops at Katherine, Northern Territory
JF  - Australian Journal of Agricultural Research
JO  - Aust. J.  Agric. Res.
Y1  - 1960
VL  - 11
IS  - 5
SP  - 693
EP  - 704
KW  - 
UR  - https://doi.org/10.1071/AR9600693 
N2  - In 1958-59, a field trial was carried out at Katherine, N.T., to compare the recovery. of available soil nitrogen by fodder sorghum, Sudan grass, and bulrush millet when grown after an all-grass ley, a legume ley, and a long period of fallow. After 6 years of grass, available soil nitrogen remained low throughout the cropping season at all soil levels to a depth of 5 ft, and nitrogen yield from the fodder crops averaged only 17 lb/acre. After 7 years of Townsville lucerne, available soil nitrogen was low at the start of the season, but soil nitrogen was quickly mineralized and, in the absence of a crop, was leached to give a peak concentration of nitrate nitrogen at 2&ndash;3 ft. All three crops intercepted this mineral nitrogen efficiently to give an average aboveground nitrogen yield of 75 lb/acre, approximately half the nitrate nitrogen available in the 5 ft soil layer on uncropped land at the end of the season. After 5 years of clean fallow, soil nitrogen had been mineralized and leached to a considerable depth, 260 lb of nitrate nitrogen per acre being accumulated in the 0&ndash;5 ft layer. Fodder sorghum and Sudan grass depleted soil nitrogen appreciably in the 0&ndash;2 ft layer, and gave an average above-ground nitrogen yield of 62 lb/acre. Bulrush millet depleted soil nitrogen throughout the 0&ndash;5 ft profile to give a nitrogen yield of 154 lb/acre. Bulrush millet is therefore regarded at Katherine as an outstanding crop for the recovery of deep accumulations of soil nitrate nitrogen and their conversion to harvestable fodder protein. 
ER  -

