The amounts of litter produced and nutrients returned play a fundamental role in the productivity and biogeochemical and nutrient cycling of forest ecosystems.We monitored annual litterfall production, nutrient return...The amounts of litter produced and nutrients returned play a fundamental role in the productivity and biogeochemical and nutrient cycling of forest ecosystems.We monitored annual litterfall production, nutrient return,and monthly dynamics over a one-year period in Chinese fir plantations aged 10, 22, and 34 years. Our objective was to quantify litterfall and nutrient return over a complete harvest rotation of Chinese fir. Annual litterfall production increased with stand age and was recorded as（3,294.6 ± 360.4）,（3,733.9 ± 211.2）, and（4,876.1 ± 212.8） kg ha-1a-1in stands aged 10, 22 and 34 years, respectively. Total litter production was significantly greater in the stand aged34 years than in the stand aged 10 years（p ／ 0.05）. With the exception of miscellaneous components, needle litterfall constituted the highest proportion（27.5–43.6 %）, followed by branches/twigs（9.5–16.6 %）. In all three plantations,annual total nutrient return to soil was in the order of C（1,119.95–2,709.05 kg ha-1a-1） [ N（39.32–62.04 kg ha-1a-1） [ K（15.95–22.44 kg ha-1a-1） [ P（1.30–1.63 kg ha-1a-1）. C, N, K and P input to soil was significantly lower in the 10-year-old stand in comparison to the 22- and34-year-old stands（p ／ 0.05）. Litterfall production and nutrient return（C, N and K） followed similar patterns, and C and N input to soil was significantly related to litterfall production（needle, branch and total litterfall）. C, N, P and K input to soil and total litterfall production were mainly driven by needle litterfall.展开更多
Objective: The paper aims to analyze the dynamic characteristics of litter production and nutrient return of the forest ecosystems in subtropical areas, and provide a theoretical basis for the nutrient cycling study i...Objective: The paper aims to analyze the dynamic characteristics of litter production and nutrient return of the forest ecosystems in subtropical areas, and provide a theoretical basis for the nutrient cycling study in southwest Hubei Province and carbon sink function of the whole forest ecosystem. Methods: Three typical forest stands (Chinese fir plantation, Cryptomeria fortunei plantation and evergreen and deciduous broad-leaved mixed forest) in Golden Mountain Forest Farm in southwest Hubei Province were investigated and monitored continuously for the litter types and productivity and nutrient return. Results: The annual litter productivity of the three forest stands ranged from 161.77 to 396.26 kg·hm<sup>-2</sup>;Litters of branches, leaves and reproductive organs accounted for 14.14% - 20.85%, 33.26% - 78.33%, 7.52% - 42.18% of the total, respectively;The litter productivity and total litter productivity of each composition in the three forest stands show unimodal or bimodal changes over months, and the total litter productivity reached the highest value in January, April and October respectively. For different nutrient contents of the three forest stands, the common feature is C > N. The order of nutrient return amount from greatest to least is evergreen and deciduous broad-leaved mixed forest, Cryptomeria fortunei plantation and Chinese fir plantation. For different nutrient return amounts, the common feature is C > N, and the nutrient return amounts are 76.51-180.69 kg·hm<sup>-2</sup> and 2.3 - 5.71 kg·hm<sup>-2</sup> respectively. Conclusion: The annual litter productivity and nutrient return amount of the evergreen and deciduous broad-leaved mixed forest are the highest among the three forest stands. Therefore, protecting the evergreen and deciduous broad-leaved mixed forest and studying the litter changes of Chinese fir plantation and Cryptomeria fortunei plantation are of far-reaching significance for the development of sustainable forest management in this region and the further improvement of the carbon sequestration function of the whole forest ecosystem.展开更多
Comparative analyses were conducted on the nutrient element content and returning amount of main fractional compositions of litter in Korean pine (KP), Mongolian Scots pine(MSP) and Dahurian larch (DL) plantations in ...Comparative analyses were conducted on the nutrient element content and returning amount of main fractional compositions of litter in Korean pine (KP), Mongolian Scots pine(MSP) and Dahurian larch (DL) plantations in Laoshan Plantation Experiment Station of Maoershan Experiment Forest Farm of Northeast Forestry University. The results are as follows: (1) The nutrient element content and returning amount in litter varies among different fractional compositions and tree species, the total returning amount of all nutrient elements and the returning amount of K, Ca, Mg, N and P are DL>MSP>KP, the returning amount of Cu is DL>KP>MSP, the returning amount of Fe and Mn are MSP>DL>KP, (2) To KP and DL plantations, the main nutrient element returned is dead needles; dead branches, bark scales and dead cones account for a little proportion; whereas to MSP plantation, besides dead needles,dead branches and bark scales also play an important role in the return of nutrient elements; (3)A little deal of dead leaves can provided a great deal of returning amount of nutrient elements.展开更多
A study concerning the throughfall and stemflow chemistry in the Castanopsis eyrei forest was conducted during 1993—1994. The results showed that the net throughfall nutrient fluxes showed consistent canopy effec...A study concerning the throughfall and stemflow chemistry in the Castanopsis eyrei forest was conducted during 1993—1994. The results showed that the net throughfall nutrient fluxes showed consistent canopy effects on precipitation chemistry. In general, potassium, calcium, magnesium, sodium and sulphur were added to precipitation by foliage, whereas the canopy absorbed nitrogen and phosphorus from precipitation. In stemflow, negative net deposition occurred for phosphorus only, and the rest nutrients were added to precipitation by tree stems and branches. The total net depositions of nutrients in both throughfall and stemflow followed the sequence of potassium>calcium>sodium>magnesium>sulphur, ranging between 2 56—52 54 kg/(hm 2·a). For potassium and calcium, net throughfall was the largest pathway, and the net throughfall contribution to the total yearly nutrient return to the forest soil was 54% and 42% respectively. Although the net stemflow contribution to the total yearly nutrient return was small (between 0 and 13%), stemflow represented the largest pathway of water and nutrient input to the stemflow zone of the forest floor in the C.eyrei forest ecosystem.展开更多
The Litter nutrient concentrations of N, P, Ca, Mg, K and Na in mature leaves, twigs and reproductive parts and their relationship between senescent and young leaves were investigated in five forest species： Acacia n...The Litter nutrient concentrations of N, P, Ca, Mg, K and Na in mature leaves, twigs and reproductive parts and their relationship between senescent and young leaves were investigated in five forest species： Acacia nilotica, Acacia leucophloea. Tectona grandis, Miliusa tomentosa and Butea monosperma in Indian tropical dry deciduous forest in Western India.. Total dry matter of plant species was recorded and analyzed for N, P, Ca, Mg, K and Na. A. nilotica had the highest concentrations of N in leaf, while ,4. leucophloea had the highest concentrations of Ca and Mg in leaf. The highest concentrations of P in leaf were found in A. nilotica, A. leucophloea and B. monosperma where as lowest in T. grandis and M. tomentosa. No significant differences in K and Na were registered among the species. A marked seasonal variability was ob- served in the concentrations of N, P and K, except for Ca and Mg. Potas- sium is the single element that undergoes leaching and mobilization in all species. Resorped N and P can be used for the production of fresh leaf in the following annual cycle. Nutrient resorption and retranslocation from senescent leaves and litter supports the production of new foliage and increase the fertility of soil.展开更多
An experiment was conducted in three fallow paddy fields situated on the mid-tropical plain zone of a northeastern Indian state （Tripura） to provide rice fallow management options using leftover soil moisture and nu...An experiment was conducted in three fallow paddy fields situated on the mid-tropical plain zone of a northeastern Indian state （Tripura） to provide rice fallow management options using leftover soil moisture and nutrients. The three experimental fields were managed by growing rice under the system of rice intensification as the rainy season crop and then groundnut, lentil, rapeseed and potato as the post-rainy season crops. Fertilization under the integrated nutrient management system and lifesaving irrigation at critical stages of each post-rainy season crop were provided. Results showed that the field water use efficiency values were 5.93, 2.39, 2.37 and 59.76 kg/（hm2.mm） and that the yield of these crops increased by approximately 20%, 34%, 40% and 20% after applying two lifesaving irrigations in groundnut, lentil, rapeseed and potato, respectively. Therefore, fallow paddy field can provide possible profitable crops during the post-rainy season by utilizing the residual moisture and minimum supplemental irrigation under improved nutrient management practices.展开更多
【目的】探究秸秆不同还田方式对稻油轮作系统周年生产力及氮磷钾养分表观平衡的影响,为轮作系统秸秆资源的高效利用提供理论依据。【方法】田间定位试验位于湖北省武穴市,开始于2014年,设置秸秆不还田(NPK)、秸秆直接还田(NPK+St)和秸...【目的】探究秸秆不同还田方式对稻油轮作系统周年生产力及氮磷钾养分表观平衡的影响,为轮作系统秸秆资源的高效利用提供理论依据。【方法】田间定位试验位于湖北省武穴市,开始于2014年,设置秸秆不还田(NPK)、秸秆直接还田(NPK+St)和秸秆焚烧还田(NPK+Sb)3个处理,测定分析2014—2024年连续10年的水稻和油菜产量,氮、磷、钾养分吸收量及其表观平衡等相关指标。【结果】10年田间试验的平均结果表明,与NPK处理相比,NPK+St处理的水稻和油菜产量分别显著增加了7.7%和10.7%,NPK+Sb处理的油菜产量显著增加了5.2%,对水稻增产效果不显著;NPK+St和NPK+Sb处理的增产效果随着秸秆还田年限的增加而逐渐增强,在第6年达到显著水平,且秸秆直接和焚烧还田显著增加了水稻产量可持续性(23.6%—28.3%)。周年轮作养分积累特征表明,与NPK处理相比,NPK+St和NPK+Sb处理的平均周年氮、磷、钾积累量分别增加了11.6%和2.9%、11.9%和10.2%、55.8%和39.1%,秸秆直接还田显著提高了作物对氮、磷、钾养分吸收,而秸秆焚烧还田有效增加了作物对磷、钾养分吸收。秸秆不还田条件下,稻油轮作周年氮、磷、钾平均盈余量分别为101.3 kg N·hm^(-2)·a^(-1)、-8.9 kg P2O5·hm^(-2)·a^(-1)和-296.6 kg K_(2)O·hm^(-2)·a^(-1);秸秆直接还田条件下,稻油轮作周年氮平均盈余量达166.1 kg N·hm^(-2)·a^(-1),增幅为64.0%,秸秆直接和焚烧还田均实现了周年磷、钾养分盈余,盈余量分别为33.0和19.0 kg P2O5·hm^(-2)·a^(-1)、79.4和21.3 kg K_(2)O·hm^(-2)·a^(-1)。【结论】秸秆直接和焚烧还田通过维持稻油轮作系统养分平衡,显著提高作物产量与养分吸收,呈现水稻稳产和油菜增产的效果。秸秆直接还田较焚烧还田更有利于提高作物产量和实现养分收支平衡。因此,在农业生产过程中,建议推行秸秆直接还田方式处理农田秸秆,以充分发挥其增产稳产和养分平衡的优势,促进稻油轮作系统的可持续发展。展开更多
【目的】明确长期秸秆还田对稻稻油轮作作物产量和土壤肥力的影响,为稻稻油轮作秸秆资源高效利用与化肥减量技术提供科学依据。【方法】从2007年早稻开始至2022年,进行连续15年的稻稻油三熟制秸秆还田定位试验,试验设置常规施肥+秸秆不...【目的】明确长期秸秆还田对稻稻油轮作作物产量和土壤肥力的影响,为稻稻油轮作秸秆资源高效利用与化肥减量技术提供科学依据。【方法】从2007年早稻开始至2022年,进行连续15年的稻稻油三熟制秸秆还田定位试验,试验设置常规施肥+秸秆不还田(100%F)、常规施肥+秸秆还田(100%F+St)和化肥减量20%+秸秆还田(80%F+St)3个处理,分析作物产量、氮磷钾养分积累量与土壤理化性质,评估稻稻油轮作周年养分表观平衡与土壤综合肥力指数。【结果】长期秸秆还田提高了稻稻油轮作作物产量、产量稳定性与可持续性,其中油菜季产量增幅最为显著。与2007—2010年相比,100%F+St处理2019—2022年晚稻、油菜的平均产量分别增加28.9%、58.7%。与100%F处理相比,100%F+St处理早稻、晚稻与油菜产量分别平均增加7.2%、6.9%、13.4%,其中2019—2022年晚稻季100%F+St处理产量稳定性与可持续性平均增加23.6%、12.5%。连续4年秸秆还田配合化肥减量20%(80%F+St)后,早稻、晚稻、油菜产量均维持稳定或高于常规施肥。与100%F处理相比,2019—2022年80%F+St处理的早稻、晚稻分别增产5.3%、3.1%。100%F+St处理提升了作物氮磷钾养分积累量与周年养分盈余,80%F+St与100%F+St处理相比,轮作周年氮磷钾盈余分别减少54.0 kg N·hm^(-2)、13.7 kg P2O5·hm^(-2)、48.6 kg K_(2)O·hm^(-2)。分析长期秸秆还田后油菜季和水稻季土壤综合肥力指数(IFI)发现,100%F+St处理在油菜季、水稻季IFI分别为1.44、1.51,较100%F处理分别显著提高6.4%、4.3%。油菜季IFI增幅高于水稻季。与100%F处理相比,80%F+St处理在水稻季、油菜季均无显著差异,土壤IFI分别为1.29、1.45。100%F+St处理IFI提高主要依赖于油菜季有机质、全氮、速效钾含量分别提升22.8%、20.5%、13.7%,水稻季有机质、全氮、有效磷含量分别提升14.1%、1.7%、19.0%。【结论】长期秸秆还田可提高稻稻油轮作作物产量、氮磷钾养分积累量及土壤综合肥力指数,且随着还田年限的增加,作物产量稳定性与可持续性提高。秸秆还田配合化肥减量20%能有效保障作物产量与养分积累量维持或高于常规施肥水平,且水稻季产量的可持续性与稳定性高于油菜季。因此在水稻季化肥减量20%能够保障稻稻油轮作体系的稳产高效。展开更多
基金supported by National Natural Science Foundation of China(Grant Nos.31370619 and 31100472)Doctoral Program of Higher Education of Ministry of Education of China(Grant No.20113515110009)+2 种基金Forestry Public Benefit Research Projects of National Forestry Administration(Grant No.201304303)Science and Technology Major Project of the Fujian Province(Grant No.2012NZ0001–1)Training Program Foundation for University Distinguished Young Talents of Fujian Province,P.R.China(Grant No.JA 12091)
文摘The amounts of litter produced and nutrients returned play a fundamental role in the productivity and biogeochemical and nutrient cycling of forest ecosystems.We monitored annual litterfall production, nutrient return,and monthly dynamics over a one-year period in Chinese fir plantations aged 10, 22, and 34 years. Our objective was to quantify litterfall and nutrient return over a complete harvest rotation of Chinese fir. Annual litterfall production increased with stand age and was recorded as（3,294.6 ± 360.4）,（3,733.9 ± 211.2）, and（4,876.1 ± 212.8） kg ha-1a-1in stands aged 10, 22 and 34 years, respectively. Total litter production was significantly greater in the stand aged34 years than in the stand aged 10 years（p ／ 0.05）. With the exception of miscellaneous components, needle litterfall constituted the highest proportion（27.5–43.6 %）, followed by branches/twigs（9.5–16.6 %）. In all three plantations,annual total nutrient return to soil was in the order of C（1,119.95–2,709.05 kg ha-1a-1） [ N（39.32–62.04 kg ha-1a-1） [ K（15.95–22.44 kg ha-1a-1） [ P（1.30–1.63 kg ha-1a-1）. C, N, K and P input to soil was significantly lower in the 10-year-old stand in comparison to the 22- and34-year-old stands（p ／ 0.05）. Litterfall production and nutrient return（C, N and K） followed similar patterns, and C and N input to soil was significantly related to litterfall production（needle, branch and total litterfall）. C, N, P and K input to soil and total litterfall production were mainly driven by needle litterfall.
文摘Objective: The paper aims to analyze the dynamic characteristics of litter production and nutrient return of the forest ecosystems in subtropical areas, and provide a theoretical basis for the nutrient cycling study in southwest Hubei Province and carbon sink function of the whole forest ecosystem. Methods: Three typical forest stands (Chinese fir plantation, Cryptomeria fortunei plantation and evergreen and deciduous broad-leaved mixed forest) in Golden Mountain Forest Farm in southwest Hubei Province were investigated and monitored continuously for the litter types and productivity and nutrient return. Results: The annual litter productivity of the three forest stands ranged from 161.77 to 396.26 kg·hm<sup>-2</sup>;Litters of branches, leaves and reproductive organs accounted for 14.14% - 20.85%, 33.26% - 78.33%, 7.52% - 42.18% of the total, respectively;The litter productivity and total litter productivity of each composition in the three forest stands show unimodal or bimodal changes over months, and the total litter productivity reached the highest value in January, April and October respectively. For different nutrient contents of the three forest stands, the common feature is C > N. The order of nutrient return amount from greatest to least is evergreen and deciduous broad-leaved mixed forest, Cryptomeria fortunei plantation and Chinese fir plantation. For different nutrient return amounts, the common feature is C > N, and the nutrient return amounts are 76.51-180.69 kg·hm<sup>-2</sup> and 2.3 - 5.71 kg·hm<sup>-2</sup> respectively. Conclusion: The annual litter productivity and nutrient return amount of the evergreen and deciduous broad-leaved mixed forest are the highest among the three forest stands. Therefore, protecting the evergreen and deciduous broad-leaved mixed forest and studying the litter changes of Chinese fir plantation and Cryptomeria fortunei plantation are of far-reaching significance for the development of sustainable forest management in this region and the further improvement of the carbon sequestration function of the whole forest ecosystem.
文摘Comparative analyses were conducted on the nutrient element content and returning amount of main fractional compositions of litter in Korean pine (KP), Mongolian Scots pine(MSP) and Dahurian larch (DL) plantations in Laoshan Plantation Experiment Station of Maoershan Experiment Forest Farm of Northeast Forestry University. The results are as follows: (1) The nutrient element content and returning amount in litter varies among different fractional compositions and tree species, the total returning amount of all nutrient elements and the returning amount of K, Ca, Mg, N and P are DL>MSP>KP, the returning amount of Cu is DL>KP>MSP, the returning amount of Fe and Mn are MSP>DL>KP, (2) To KP and DL plantations, the main nutrient element returned is dead needles; dead branches, bark scales and dead cones account for a little proportion; whereas to MSP plantation, besides dead needles,dead branches and bark scales also play an important role in the return of nutrient elements; (3)A little deal of dead leaves can provided a great deal of returning amount of nutrient elements.
文摘A study concerning the throughfall and stemflow chemistry in the Castanopsis eyrei forest was conducted during 1993—1994. The results showed that the net throughfall nutrient fluxes showed consistent canopy effects on precipitation chemistry. In general, potassium, calcium, magnesium, sodium and sulphur were added to precipitation by foliage, whereas the canopy absorbed nitrogen and phosphorus from precipitation. In stemflow, negative net deposition occurred for phosphorus only, and the rest nutrients were added to precipitation by tree stems and branches. The total net depositions of nutrients in both throughfall and stemflow followed the sequence of potassium>calcium>sodium>magnesium>sulphur, ranging between 2 56—52 54 kg/(hm 2·a). For potassium and calcium, net throughfall was the largest pathway, and the net throughfall contribution to the total yearly nutrient return to the forest soil was 54% and 42% respectively. Although the net stemflow contribution to the total yearly nutrient return was small (between 0 and 13%), stemflow represented the largest pathway of water and nutrient input to the stemflow zone of the forest floor in the C.eyrei forest ecosystem.
基金Foundationfor Ecological Security,Anand,Gujarat for financial assistance of this research project
文摘The Litter nutrient concentrations of N, P, Ca, Mg, K and Na in mature leaves, twigs and reproductive parts and their relationship between senescent and young leaves were investigated in five forest species： Acacia nilotica, Acacia leucophloea. Tectona grandis, Miliusa tomentosa and Butea monosperma in Indian tropical dry deciduous forest in Western India.. Total dry matter of plant species was recorded and analyzed for N, P, Ca, Mg, K and Na. A. nilotica had the highest concentrations of N in leaf, while ,4. leucophloea had the highest concentrations of Ca and Mg in leaf. The highest concentrations of P in leaf were found in A. nilotica, A. leucophloea and B. monosperma where as lowest in T. grandis and M. tomentosa. No significant differences in K and Na were registered among the species. A marked seasonal variability was ob- served in the concentrations of N, P and K, except for Ca and Mg. Potas- sium is the single element that undergoes leaching and mobilization in all species. Resorped N and P can be used for the production of fresh leaf in the following annual cycle. Nutrient resorption and retranslocation from senescent leaves and litter supports the production of new foliage and increase the fertility of soil.
文摘An experiment was conducted in three fallow paddy fields situated on the mid-tropical plain zone of a northeastern Indian state （Tripura） to provide rice fallow management options using leftover soil moisture and nutrients. The three experimental fields were managed by growing rice under the system of rice intensification as the rainy season crop and then groundnut, lentil, rapeseed and potato as the post-rainy season crops. Fertilization under the integrated nutrient management system and lifesaving irrigation at critical stages of each post-rainy season crop were provided. Results showed that the field water use efficiency values were 5.93, 2.39, 2.37 and 59.76 kg/（hm2.mm） and that the yield of these crops increased by approximately 20%, 34%, 40% and 20% after applying two lifesaving irrigations in groundnut, lentil, rapeseed and potato, respectively. Therefore, fallow paddy field can provide possible profitable crops during the post-rainy season by utilizing the residual moisture and minimum supplemental irrigation under improved nutrient management practices.
文摘【目的】探究秸秆不同还田方式对稻油轮作系统周年生产力及氮磷钾养分表观平衡的影响,为轮作系统秸秆资源的高效利用提供理论依据。【方法】田间定位试验位于湖北省武穴市,开始于2014年,设置秸秆不还田(NPK)、秸秆直接还田(NPK+St)和秸秆焚烧还田(NPK+Sb)3个处理,测定分析2014—2024年连续10年的水稻和油菜产量,氮、磷、钾养分吸收量及其表观平衡等相关指标。【结果】10年田间试验的平均结果表明,与NPK处理相比,NPK+St处理的水稻和油菜产量分别显著增加了7.7%和10.7%,NPK+Sb处理的油菜产量显著增加了5.2%,对水稻增产效果不显著;NPK+St和NPK+Sb处理的增产效果随着秸秆还田年限的增加而逐渐增强,在第6年达到显著水平,且秸秆直接和焚烧还田显著增加了水稻产量可持续性(23.6%—28.3%)。周年轮作养分积累特征表明,与NPK处理相比,NPK+St和NPK+Sb处理的平均周年氮、磷、钾积累量分别增加了11.6%和2.9%、11.9%和10.2%、55.8%和39.1%,秸秆直接还田显著提高了作物对氮、磷、钾养分吸收,而秸秆焚烧还田有效增加了作物对磷、钾养分吸收。秸秆不还田条件下,稻油轮作周年氮、磷、钾平均盈余量分别为101.3 kg N·hm^(-2)·a^(-1)、-8.9 kg P2O5·hm^(-2)·a^(-1)和-296.6 kg K_(2)O·hm^(-2)·a^(-1);秸秆直接还田条件下,稻油轮作周年氮平均盈余量达166.1 kg N·hm^(-2)·a^(-1),增幅为64.0%,秸秆直接和焚烧还田均实现了周年磷、钾养分盈余,盈余量分别为33.0和19.0 kg P2O5·hm^(-2)·a^(-1)、79.4和21.3 kg K_(2)O·hm^(-2)·a^(-1)。【结论】秸秆直接和焚烧还田通过维持稻油轮作系统养分平衡,显著提高作物产量与养分吸收,呈现水稻稳产和油菜增产的效果。秸秆直接还田较焚烧还田更有利于提高作物产量和实现养分收支平衡。因此,在农业生产过程中,建议推行秸秆直接还田方式处理农田秸秆,以充分发挥其增产稳产和养分平衡的优势,促进稻油轮作系统的可持续发展。
文摘【目的】明确长期秸秆还田对稻稻油轮作作物产量和土壤肥力的影响,为稻稻油轮作秸秆资源高效利用与化肥减量技术提供科学依据。【方法】从2007年早稻开始至2022年,进行连续15年的稻稻油三熟制秸秆还田定位试验,试验设置常规施肥+秸秆不还田(100%F)、常规施肥+秸秆还田(100%F+St)和化肥减量20%+秸秆还田(80%F+St)3个处理,分析作物产量、氮磷钾养分积累量与土壤理化性质,评估稻稻油轮作周年养分表观平衡与土壤综合肥力指数。【结果】长期秸秆还田提高了稻稻油轮作作物产量、产量稳定性与可持续性,其中油菜季产量增幅最为显著。与2007—2010年相比,100%F+St处理2019—2022年晚稻、油菜的平均产量分别增加28.9%、58.7%。与100%F处理相比,100%F+St处理早稻、晚稻与油菜产量分别平均增加7.2%、6.9%、13.4%,其中2019—2022年晚稻季100%F+St处理产量稳定性与可持续性平均增加23.6%、12.5%。连续4年秸秆还田配合化肥减量20%(80%F+St)后,早稻、晚稻、油菜产量均维持稳定或高于常规施肥。与100%F处理相比,2019—2022年80%F+St处理的早稻、晚稻分别增产5.3%、3.1%。100%F+St处理提升了作物氮磷钾养分积累量与周年养分盈余,80%F+St与100%F+St处理相比,轮作周年氮磷钾盈余分别减少54.0 kg N·hm^(-2)、13.7 kg P2O5·hm^(-2)、48.6 kg K_(2)O·hm^(-2)。分析长期秸秆还田后油菜季和水稻季土壤综合肥力指数(IFI)发现,100%F+St处理在油菜季、水稻季IFI分别为1.44、1.51,较100%F处理分别显著提高6.4%、4.3%。油菜季IFI增幅高于水稻季。与100%F处理相比,80%F+St处理在水稻季、油菜季均无显著差异,土壤IFI分别为1.29、1.45。100%F+St处理IFI提高主要依赖于油菜季有机质、全氮、速效钾含量分别提升22.8%、20.5%、13.7%,水稻季有机质、全氮、有效磷含量分别提升14.1%、1.7%、19.0%。【结论】长期秸秆还田可提高稻稻油轮作作物产量、氮磷钾养分积累量及土壤综合肥力指数,且随着还田年限的增加,作物产量稳定性与可持续性提高。秸秆还田配合化肥减量20%能有效保障作物产量与养分积累量维持或高于常规施肥水平,且水稻季产量的可持续性与稳定性高于油菜季。因此在水稻季化肥减量20%能够保障稻稻油轮作体系的稳产高效。
