Nodulation, nitrogen fixation and nitrogen uptake in pigeonpea (Cajanus cajan (L.) Millsp) of different maturity groups

Abstract

The seasonal patterns of nodulation, acetylene reduction, nitrogen uptake and nitrogen fixation were studied for 11 pigeonpea cultivars belonging to different maturity groups grown on an Alfisol at ICRISAT Center, Patancheru, India. In all cultivars the nodule number and mass increased to a maximum around 60-80 days after sowing and then declined. The nodule number and mass of medium-and late-maturing cultivars was greater than that of early-maturing cultivars. The nitrogenase activity per plant increased to 60 days after sowing and declined thereafter, with little activity at I00 days when the crop was flowering. At later stages of plant growth nodules formed down to 90 cm below the soil surface but those at greater depth appeared less active than those near the surface.All the 11 cultivars continued to accumulate dry matter until 140 days, with most biomass production by the late-maturing cultivars (up to 11 t ha-~ ) and least by the early-maturing determinate cultivars (4 t ha-~). Total nitrogen uptake ranged from 69 to 134 kg ha-t. Nitrogen fixation by pigeonpea was estimated as the difference in total nitrogen uptake between pigeonpea and sorghum and could amount to 69 kg N ha-~ per season, or half the total nitrogen uptake. Fixation by pigeonpea increased with crop duration, but there were differences within each maturity group. The limitations of the methods used for estimating N 2 fixation by pigeonpea are discussed.

Yields and accumulations of N and P in farmer-managed intercrops of maize–pigeonpea in semi-arid Africa

“…In the current study, the quantities of N captured by intercropped pigeonpea reached quantities (%60 kg ha )1 season )1 ) similar to those applied as fertilisers by commercial farmers to maize crops ( Table 2). The additional N captured in a maize-legume intercrop as compared to sole maize crops has been observed in several studies (Ali 1996;Kumar Rao and Dart 1987;Li et al 1999). After harvesting the pods and the stems, the Nrich residues of pigeonpeas increased soil fertility and benefit the subsequent maize crop.…”

Effects of Timing of Drought Stress on Leaf Area Development and Canopy Light Interception of Short‐duration Pigeonpea

“…The reduction in LAI of the control treatment betweeti 88 and 102 DAS was primarily due to leaf abscission (Lopez et al, 1996b), and was as large as the reduction due to water stress at the end of stress 1. Abscising leaves might contribute to yield by meeting the mineral N requiretnents ofthe developing seeds through remobilizalion (Kumar Rao and Dart, 1987). A lack of correlation betweeti leaf area and yield in the control may be because the remaining leaf area is still above critical LAI for these Drought Stress and Leaf Area Developmeni in Pigeonpea Genotypes are arranged in order of increasing time in flowering; their growth habits are as indicated in Table 1 -SE values in parentheses are for comparing means at the same level of treatment I Genotypes are arranged in order of increasing time to flowering: their growth habits are as indicated in Table -SE values in parentheses are for comparing means at the same level of treatment 23 (28) 7(13) 2(9) 1(4) 28 (32) 1 (5) 2(5) ' Genotypes are arranged in order of increasing time to flowering; their growing habits are as indicated in Table 1 Angular transformed values are given in parentheses pigeonpea genotypes.…”

Analysis of soil water matric potential requirement for infection of turnip withPlasmodiophora brassicaeusing negative pressure water circulation technique

“…Calculation of nitrogen fixation from ARA using a theoretical conversion factor of one-third N2 reduced per C 2 H 2 reduced greatly underestimated the amount of N 2 -fixed compared to 10. When the ARA method was compared with other measurement techniques under field conditions, the ARA method greatly underestimated the nitrogen fixation activity (Boddey et al 1984;Rennie and Kemp 1984;Kumar Rao and Dart 1987). This phenomenon may be due to the use of the theoretical conversion factor of one-third N 2 -reduced per C 2 H 2 reduced (Hardy et al 1968) or to the decline of the nitrogenase activity in the presence of acetylene during the assay (Minchin et al 1983).…”