Sj. Kerley, The effect of soil liming on shoot development, root growth, and cluster root activity of white lupin, BIOL FERT S, 32(2), 2000, pp. 94-101
The effects of a limed soil upon root and shoot growth of white lupin (Lupi
nus albus L.) were investigated using soil tubes and pots. After 75 days in
the soil tubes, the combined taproot and lateral root dry weight in limed
soil (2.5% CaO w/w) was significantly less than in neutral pH soil (by 57%)
. However, the dry weight and numbers of cluster roots remained comparable
between the treatments, demonstrating for the first time that the cluster r
oots respond differently to the rest of the root system. Cluster roots acco
unted for 17% of the total root biomass in neutral soil, increasing signifi
cantly to over 30% in limed soil. When grown for 43 days in pots containing
soil with different additions of lime (0.5-2.5% CaO w/w), soil citrate con
centrations were higher than in the neutral pH soil treatment in all except
the 2.5% lime treatment, in which they were lower. In both experiments, sh
oot dry weights were lower in the presence of the limed soil compared with
those in the neutral pH soil. Although a reduction in shoot dry weight was
not apparent at 21 days in the limed-soil tubes, the initiation of fewer ma
instem leaf primordia indicated a slower shoot development than occurred in
the neutral soil. Plants grown in the limed-soil tubes showed leaf yellowi
ng and some chlorosis within 9 days. At the final harvest, the shoot phosph
orus and manganese concentrations were significantly lower in plants grown
in limed soil compared with those in the neutral pH soil, whereas the conce
ntration of calcium was higher.