TY  - JOUR
AV  - restricted
UR  - http://dx.doi.org/10.1007/BF00383976
IS  - 4
PB  - Springer Verlag
TI  - Field evaluation of nitrogen fixation and use of nitrogen fertilizer by sorghum/pigeonpea intercropping on an Alfisol in the Indian semi-arid tropics
A1  - Tobita, S
A1  - Ito, O
A1  - Matsunaga, R
A1  - Rao, T P
A1  - Rego, T J
A1  - Johansen, C
A1  - Yoneyama, T
SN  - 0178-2762
VL  - 17
N2  - A field experiment was conducted to obtain the N balance sheet for sole crops and intercrops of sorghum [Sorghum bicolor (L.) Moench] and pigeonpeas [Cajanus cajan (L.) Millsp.]. Intercropping gave a significant advantage over sole cropping in terms of dry matter production and grain yield, as calculated on the basis of the land equivalent ratio and area-time equivalent ratio. The N fertilizer use efficiency and atmospheric N2 fixation by pigeonpea were estimated using 15N-labeling and natural abundance methods. The N fertilizer use efficiency of sorghum was unaltered by the cropping system, while that of the pigeonpea was greatly reduced by intercropping. Although intercropping increased the fractional contribution of fixed N to the pigeonpeas, no significant difference was observed between the cropping systems in total symbiotically fixed N. There was no evidence of a significant transfer of N from the pigeonpea to the sorghum. This study showed that use of soil N and fertilizer N by pigeonpeas was almost the same as that by sorghum in sole cropping, indicating the potential competence of pigeonpeas to exploit soil N. However, when N was exhausted by a companion crop in intercropping, the pigeonpea crop increased its dependency on atmospheric N2 fixation. We conclude that knowledge of how N from different sources is shared by companion crops is a prerequisite to establishing strategies to increase N use, and consequently land productivity, in intercropping systems.
SP  - 241
Y1  - 1994///
EP  - 248
ID  - icrisat3150
KW  - Fertilizer Use Efficiency
KW  -  Intercropping
KW  -  Natural
KW  -  N abudance
KW  -  Nitrogen Fixation
KW  -  Pigeonpea
KW  -  Sorghum
JF  - Biology and Fertility of Soils
ER  -