【目的】通过比较不同施肥水平下木薯氮磷钾养分积累、分配和产量的差异,探讨粤北坡岗地优质高产木薯氮磷钾养分的最佳用量。【方法】以木薯品种南美119为材料,采用"3414"方案,在粤北翁源进行大田试验。试验共设14个处理。【...【目的】通过比较不同施肥水平下木薯氮磷钾养分积累、分配和产量的差异,探讨粤北坡岗地优质高产木薯氮磷钾养分的最佳用量。【方法】以木薯品种南美119为材料,采用"3414"方案,在粤北翁源进行大田试验。试验共设14个处理。【结果】施肥处理的氮素主要分配到地上部,不施肥处理的氮素则主要分配到根部;不同施肥处理的磷素均主要分配到地上部;不施肥处理和不施钾处理的钾素主要分配到根部,不施氮处理的钾素在根、冠间分配较均衡。在木薯不同生长阶段,植株氮磷钾含量均呈下降趋势,但施氮、磷、钾化学肥料处理植株氮磷钾含量的下降速度小于不施氮、磷、钾化学肥料的处理。处理N2P2K2的氮、磷、钾含量和积累量在各生育期均为最大,不施肥处理(N0P0K0)的氮、磷、钾含量和积累量在各生育期均为最小(P<0.05)。产量最高的是N2P3K2处理,为22 694.06 kg.hm-2,其次是N2P2K2处理,为21 417.87 kg.hm-2。【结论】木薯产量、氮磷钾养分积累及其在根冠间的分配,对施肥水平高度敏感,适当比例的氮磷钾肥配合施用既可以显著增加木薯植株的氮磷钾含量和积累量,又可以提高产量。在粤北坡岗地木薯生产中,氮素最重要,在氮素得到满足的条件下,磷素较钾素更重要。在本试验条件下,氮磷钾养分最佳用量为358.80 kgN.hm-2、89.10 kg P2O5.hm-2和187.50 kg K2O.hm-2。展开更多
The effects of reforestation on carbon （C） sequestration in China＇s Loess Plateau ecosystem have attracted much research attention in recent years. Black locust trees （Robinia pseudoacacia L.） are valued for thei...The effects of reforestation on carbon （C） sequestration in China＇s Loess Plateau ecosystem have attracted much research attention in recent years. Black locust trees （Robinia pseudoacacia L.） are valued for their important use in reforestation and water and soil conservation efforts. This forest type is widespread across the Loess Plateau, and must he an essential component of any planning for C sequestration efforts in this fragile ecological region. The long-term effects of stand age on C accumulation and allocation after reforestation remains uncertain. We examined an age-sequence of black locust forest （5, 9, 20, 30, 38, and 56 yr since planting） on the Loess Plateau to evaluate C accumulation and allocation in plants （trees, shrubs, herbages, and leaf litter） and soil （0-100 cm）. Allometric equations were developed for estimating the biomass of tree components （leaf, branch, stem without bark, bark and root） with a de- structive sampling method. Our results demonstrated that black locust forest ecosystem accumulated C constantly, from 31.42 Mg C/ha （1 Mg = 106 g） at 5 yr to 79.44 Mg C/haat 38 yr. At the ＇old forest＇ stage （38 to 56 yr）, the amount of C in plant biomass significantly decreased （from 45.32 to 34.52 Mg C/ha） due to the high mortality of trees. However, old forest was able to accumulate C continuously in soil （from 33.66 to 41.00 Mg C/ha）. The C in shrub biomass increased with stand age, while the C stock in the herbage layer and leaf litter was age-independent. Reforestation resulted in C re-allocation in the forest soil. The topsoil （0-20 cm） C stock increased constantly with stand age. However, C storage in sub-top soil, in the 20-30, 30-50, 50-100, and 20-100 cm layers, was age-independent. These results suggest that succession, as a temporal factor, plays a key role in C accumulation and re-allocation in black locust forests and also in regional C dynamics in vegetation.展开更多
文摘【目的】通过比较不同施肥水平下木薯氮磷钾养分积累、分配和产量的差异,探讨粤北坡岗地优质高产木薯氮磷钾养分的最佳用量。【方法】以木薯品种南美119为材料,采用"3414"方案,在粤北翁源进行大田试验。试验共设14个处理。【结果】施肥处理的氮素主要分配到地上部,不施肥处理的氮素则主要分配到根部;不同施肥处理的磷素均主要分配到地上部;不施肥处理和不施钾处理的钾素主要分配到根部,不施氮处理的钾素在根、冠间分配较均衡。在木薯不同生长阶段,植株氮磷钾含量均呈下降趋势,但施氮、磷、钾化学肥料处理植株氮磷钾含量的下降速度小于不施氮、磷、钾化学肥料的处理。处理N2P2K2的氮、磷、钾含量和积累量在各生育期均为最大,不施肥处理(N0P0K0)的氮、磷、钾含量和积累量在各生育期均为最小(P<0.05)。产量最高的是N2P3K2处理,为22 694.06 kg.hm-2,其次是N2P2K2处理,为21 417.87 kg.hm-2。【结论】木薯产量、氮磷钾养分积累及其在根冠间的分配,对施肥水平高度敏感,适当比例的氮磷钾肥配合施用既可以显著增加木薯植株的氮磷钾含量和积累量,又可以提高产量。在粤北坡岗地木薯生产中,氮素最重要,在氮素得到满足的条件下,磷素较钾素更重要。在本试验条件下,氮磷钾养分最佳用量为358.80 kgN.hm-2、89.10 kg P2O5.hm-2和187.50 kg K2O.hm-2。
基金Under the auspices of Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA05060300)
文摘The effects of reforestation on carbon （C） sequestration in China＇s Loess Plateau ecosystem have attracted much research attention in recent years. Black locust trees （Robinia pseudoacacia L.） are valued for their important use in reforestation and water and soil conservation efforts. This forest type is widespread across the Loess Plateau, and must he an essential component of any planning for C sequestration efforts in this fragile ecological region. The long-term effects of stand age on C accumulation and allocation after reforestation remains uncertain. We examined an age-sequence of black locust forest （5, 9, 20, 30, 38, and 56 yr since planting） on the Loess Plateau to evaluate C accumulation and allocation in plants （trees, shrubs, herbages, and leaf litter） and soil （0-100 cm）. Allometric equations were developed for estimating the biomass of tree components （leaf, branch, stem without bark, bark and root） with a de- structive sampling method. Our results demonstrated that black locust forest ecosystem accumulated C constantly, from 31.42 Mg C/ha （1 Mg = 106 g） at 5 yr to 79.44 Mg C/haat 38 yr. At the ＇old forest＇ stage （38 to 56 yr）, the amount of C in plant biomass significantly decreased （from 45.32 to 34.52 Mg C/ha） due to the high mortality of trees. However, old forest was able to accumulate C continuously in soil （from 33.66 to 41.00 Mg C/ha）. The C in shrub biomass increased with stand age, while the C stock in the herbage layer and leaf litter was age-independent. Reforestation resulted in C re-allocation in the forest soil. The topsoil （0-20 cm） C stock increased constantly with stand age. However, C storage in sub-top soil, in the 20-30, 30-50, 50-100, and 20-100 cm layers, was age-independent. These results suggest that succession, as a temporal factor, plays a key role in C accumulation and re-allocation in black locust forests and also in regional C dynamics in vegetation.
