http://oar.icrisat.org/id/eprint/3150 2011-10-24T11:54:05Z info:eu-repo/semantics/descriptiveMetadata http://oar.icrisat.org/3150/ Field evaluation of nitrogen fixation and use of nitrogen fertilizer by sorghum/pigeonpea intercropping on an Alfisol in the Indian semi-arid tropics Tobita, S Ito, O Matsunaga, R Rao, T P Rego, T J Johansen, C Yoneyama, T Pigeonpea Sorghum 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. Springer Verlag 1994 Article PeerReviewed application/pdf en http://oar.icrisat.org/3150/1/JA_1473.pdf Tobita, S and Ito, O and Matsunaga, R and Rao, T P and Rego, T J and Johansen, C and Yoneyama, T (1994) Field evaluation of nitrogen fixation and use of nitrogen fertilizer by sorghum/pigeonpea intercropping on an Alfisol in the Indian semi-arid tropics. Biology and Fertility of Soils, 17 (4). pp. 241-248. ISSN 0178-2762 http://dx.doi.org/10.1007/BF00383976 info:eu-repo/semantics/objectFile info:eu-repo/semantics/humanStartPage