The humid agroclimatic conditions of Kerala,India permit the cultivation of an array of bamboo species of which Dendrocalamus strictus Roxb.(Nees.) is an important one on account of its high growth rate and multiple u...The humid agroclimatic conditions of Kerala,India permit the cultivation of an array of bamboo species of which Dendrocalamus strictus Roxb.(Nees.) is an important one on account of its high growth rate and multiple uses. Stand density, a potential tool in controlling the productivity of woody ecosystems, its effect on growth and root distribution patterns may provide a better understanding of productivity optimization especially when bamboo-based intercropping options are considered.Growth attributes of 7-year-old bamboo(D. strictus) stands managed at variable spacing(4×4 m, 6×6 m, 8×8 m,10×10 m, 12×12 m) were studied. Functional root activity among bamboo clumps were also studied using a radio tracer soil injection method in which the radio isotopeP was applied to soil at varying depths and lateral distances from the clump. Results indicate that spacing exerts a profound influence on growth of bamboo. Widely spaced bamboo exhibited higher clump diameters and crown widths while clump heights were better under closer spacing. Clump height was 30% lower and DBH 52%higher at the widest spacing(12×12 m) compared to the closest spacing(4×4 m). With increasing soil depth and lateral distance, root activity decreased significantly. Root activity near the clump base was highest(809 counts per minute, cpm; 50 cm depth and 50 cm lateral distance) at 4×4 m. Tracer study further showed wider distribution of root activity with increase in clump spacing. It may be concluded that the intensive foraging zone of bamboo is within a 50-cm radius around the clump irrespective of spacing. N, P and K content in the upper 20 cm was 2197,21, and 203 kg/ha respectively for the closely spaced bamboo(4×4 m) which were significantly higher than corresponding nutrient content at wider spacings. About 50% of N, P and K were present within the 0–20 cm soil layer, which decreased drastically beyond the 20 cm depth.The results suggest that stand management practices through planting density regulation can modify the resource acquisition patterns of D. strictus which in turn can change growth and productivity considerably. Such information on root activities, spatial and temporal strategies of resource sharing will be helpful in deciding the effective nutrition zone for D. strictus. Further, the study throws light on the spatial distribution of non-competitive zones for productivity optimization yields, especially when intercropping practices are considered.展开更多
The influence of cultivation measures,such as adjustment of bamboo strand structure,sun bathing of the bamboo shots and top-pruning on shoot,on culm morphology were studied.The results were summarized as follows: The ...The influence of cultivation measures,such as adjustment of bamboo strand structure,sun bathing of the bamboo shots and top-pruning on shoot,on culm morphology were studied.The results were summarized as follows: The individual numbers per clump was negative correlated with malformation rate of culm,the optimal individual numbers per clump was 4-5.From high malformation rate of new bamboo with different shooting period to low malformation rate,there appeared in turn earlier shooting,middle shooting and latter shooting.Some measures such as removal of weak and small shoot and normal culm shoot increased malformation numbers,malformation rate and ground diameter of new bamboo by 39.2%,118.3% and 151.9% respectively.Sun bathing of the bamboo shots increased the number of shoot,bamboo emerging,malformation and malformation rate by 17.6%,35.4%,79.8%,33.0% respectively.Top-pruning on time was negative correlated with the number of shoot,bamboo emerging and malformation rate,and the optimal height of top-pruning is 10-15 cm.展开更多
基金financially supported by the Kerala Agricultural University
文摘The humid agroclimatic conditions of Kerala,India permit the cultivation of an array of bamboo species of which Dendrocalamus strictus Roxb.(Nees.) is an important one on account of its high growth rate and multiple uses. Stand density, a potential tool in controlling the productivity of woody ecosystems, its effect on growth and root distribution patterns may provide a better understanding of productivity optimization especially when bamboo-based intercropping options are considered.Growth attributes of 7-year-old bamboo(D. strictus) stands managed at variable spacing(4×4 m, 6×6 m, 8×8 m,10×10 m, 12×12 m) were studied. Functional root activity among bamboo clumps were also studied using a radio tracer soil injection method in which the radio isotopeP was applied to soil at varying depths and lateral distances from the clump. Results indicate that spacing exerts a profound influence on growth of bamboo. Widely spaced bamboo exhibited higher clump diameters and crown widths while clump heights were better under closer spacing. Clump height was 30% lower and DBH 52%higher at the widest spacing(12×12 m) compared to the closest spacing(4×4 m). With increasing soil depth and lateral distance, root activity decreased significantly. Root activity near the clump base was highest(809 counts per minute, cpm; 50 cm depth and 50 cm lateral distance) at 4×4 m. Tracer study further showed wider distribution of root activity with increase in clump spacing. It may be concluded that the intensive foraging zone of bamboo is within a 50-cm radius around the clump irrespective of spacing. N, P and K content in the upper 20 cm was 2197,21, and 203 kg/ha respectively for the closely spaced bamboo(4×4 m) which were significantly higher than corresponding nutrient content at wider spacings. About 50% of N, P and K were present within the 0–20 cm soil layer, which decreased drastically beyond the 20 cm depth.The results suggest that stand management practices through planting density regulation can modify the resource acquisition patterns of D. strictus which in turn can change growth and productivity considerably. Such information on root activities, spatial and temporal strategies of resource sharing will be helpful in deciding the effective nutrition zone for D. strictus. Further, the study throws light on the spatial distribution of non-competitive zones for productivity optimization yields, especially when intercropping practices are considered.
文摘The influence of cultivation measures,such as adjustment of bamboo strand structure,sun bathing of the bamboo shots and top-pruning on shoot,on culm morphology were studied.The results were summarized as follows: The individual numbers per clump was negative correlated with malformation rate of culm,the optimal individual numbers per clump was 4-5.From high malformation rate of new bamboo with different shooting period to low malformation rate,there appeared in turn earlier shooting,middle shooting and latter shooting.Some measures such as removal of weak and small shoot and normal culm shoot increased malformation numbers,malformation rate and ground diameter of new bamboo by 39.2%,118.3% and 151.9% respectively.Sun bathing of the bamboo shots increased the number of shoot,bamboo emerging,malformation and malformation rate by 17.6%,35.4%,79.8%,33.0% respectively.Top-pruning on time was negative correlated with the number of shoot,bamboo emerging and malformation rate,and the optimal height of top-pruning is 10-15 cm.
