Excessive use of agro-chemicals （such as mineral fertilizers） poses potential risks to soil quality. Application of organic amendments and reduction of inorganic fertilizer are economically feasible and environmenta...Excessive use of agro-chemicals （such as mineral fertilizers） poses potential risks to soil quality. Application of organic amendments and reduction of inorganic fertilizer are economically feasible and environmentally sound approaches to de- velop sustainable agriculture. This study investigated and evaluated the effects of mineral fertilizer reduction and partial substitution of organic amendment on soil fertility and heavy metal content in a 10-season continually planted vegetable field during 2009-2012. The experiment included four treatments： 100% chemical fertilizer （CF100）, 80% chemical fertilizer （CF80）, 60% chemical fertilizer and 20% organic fertilizer （CF60＋OM20）, and 40% chemical fertilizer and 40% organic fertilizer （CF40＋OM40）. Soil nutrients, enzyme activity and heavy metal content were determined. The results showed that single chemical fertilizer reduction （CF80） had no significant effect on soil organic matter content, soil catalase activity and soil heavy metal content, but slightly reduced soil available N, P, K, and soil urease activity, and significantly reduced soil acid phosphatase activity. Compared with CF100, 40 or 60% reduction of chemical fertilizer supplemented with organic fertilizer （CF60＋OM20, CF40＋OM40） significantly increased soil organic matter, soil catalase activity and urease activity especially in last several seasons, but reduced soil available P, K, and soil acid phosphatase activity. In addition, continu- ous application of organic fertilizer resulted in higher accumulation of Zn, Cd, and Cr in soil in the late stage of experiment, which may induce adverse effects on soil health and food safety.展开更多
Soil organic carbon （SOC） is one of the main carbon reservoirs in the terrestrial ecosystem. It is important to study SOC dynamics and effects of organic carbon amendments in paddy fields because of their vest expan...Soil organic carbon （SOC） is one of the main carbon reservoirs in the terrestrial ecosystem. It is important to study SOC dynamics and effects of organic carbon amendments in paddy fields because of their vest expansion in south China. A study was carried out to evaluate the relationship between the SOC content and organic carbon input under various organic amendments at a long-term fertilization experiment that was established on a red soil under a double rice cropping system in 1981. The treatments included non-fertilization （CK）, nitrogen-phosphorus-potassium fertilization in early rice only （NPK）, green manure （Astragalus sinicus L.） in early rice only （OM1）, high rate of green manure in early rice only （OM2）, combined green manure in early rice and farmyard manure in late rice （OM3）, combined green manure in early rice, farmyard manure in late rice and rice straw mulching in winter （OM4）, combined green manure in early rice and rice straw mulching in winter （OMS）. Our data showed that the SOC content was the highest under OM3 and OM4, followed by OM1, OM2 and OM5, then NPK fertilization, and the lowest under non-fertilization. However, our analyses in SOC stock indicated a significant difference between OM3 （33.9 t ha^-1） and OM4 （31.8 t ha^-1）, but no difference between NPK fertilization （27 t ha^-1） and nonfertilization （28.1 t ha^-1）. There was a significant linear increase in SOC over time for all treatments, and the slop of linear equation was greater in organic manure treatments （0.276-0.344 g kg-1 yr^-1） than in chemical fertilizer （0.216 g kg^-1 yr^-1） and no fertilizer （0.127 g kg^-1 yr^-1）.展开更多
以砂姜黑土长期施肥试验为平台,研究砂姜黑土冬小麦—夏大豆轮作系统下作物钾素吸收量、钾素回收率、土壤钾素盈亏量和速效钾含量的演变特征,探明土壤速效钾与外源钾投入、土壤累积钾盈亏的响应关系,分析不施肥(CK)、常规化肥(CF)、化肥...以砂姜黑土长期施肥试验为平台,研究砂姜黑土冬小麦—夏大豆轮作系统下作物钾素吸收量、钾素回收率、土壤钾素盈亏量和速效钾含量的演变特征,探明土壤速效钾与外源钾投入、土壤累积钾盈亏的响应关系,分析不施肥(CK)、常规化肥(CF)、化肥+麦秆(SCF)、化肥+猪粪(PCF)、化肥+牛粪(CCF)等施肥方式对土壤钾素利用及盈亏的影响,以期探寻砂姜黑土地区高产高效的施钾方式。结果表明:29 a作物钾素平均回收率在55.1%~66.1%,高低顺序为CCF>PCF>SCF>CF。土壤累积钾盈亏与土壤速效钾增量呈显著线性关系(p<0.05),土壤中钾素每盈余100 kg hm-2,CF、SCF、PCF和CCF处理土壤速效钾含量分别增加1.4、1.8、2.3和15.8 mg kg-1;土壤钾素投入量与速效钾含量呈显著线性关系(p<0.05),CF处理每投入钾100 kg hm-2,土壤速效钾含量增加0.4 mg kg-1,而SCF、PCF和CCF处理每投入钾100 kg hm-2,土壤速效钾含量分别增加0.5、0.6和4.3 mg kg-1,这说明适当增施有机肥可提升土壤钾素的供应能力。综上所述,投入有机物料是影响土壤钾素利用的重要调控措施,长期增施有机肥可提高作物钾素回收率以及土壤中盈余的钾素向速效钾的转化能力,本试验条件下以增施牛粪效果最好,猪粪和秸秆次之。因此,砂姜黑土小麦—大豆轮作系统下秸秆养畜过腹还田是实现作物高产高效的一种推荐施钾方式。展开更多
Ploughing and fertilization practices in rice-wheat system have deteriorated the soil carbon (C) pools. Conservation agriculture (CA) based management approaches have proven to enhance C sequestration and reverse the ...Ploughing and fertilization practices in rice-wheat system have deteriorated the soil carbon (C) pools. Conservation agriculture (CA) based management approaches have proven to enhance C sequestration and reverse the loss of soil-organic-carbon (SOC), which further enhances soil fertility. Different fractions of SOC pools react to the alterations in management practices and indicate changes in SOC dynamics as compared to total C in the soil. Higher SOC levels in soil have been observed in case of reduced/no-till (NT) practices than conventional tillage (CT). However, between CT and zero tillage/NT, total SOC stocks diminished with an increase in soil depth, which demonstrated that the benefits of SOC are more pronounced in the topsoil under NT. Soil aggregation provides physical protection to C associated with different-sized particles, thus, the improvement in soil aggregation through CA is an effective way to mitigate soil C loss. Along with less soil disturbance, residual management, suitable crop rotation, rational application of manures and fertilizers, and integrated nutrient management have been found to be effective in not only improving soil C stock but also enhancing the soil health and productivity. Thus, CA can be considered as a potential method in the build-up of SOC of soil in rice-wheat system.展开更多
基金financially supported by grants of the Key Projects in the Key Technologies R&D Program of China during the 12th Five-Year Plan period(2012BAD14B00)the Guangdong Provincial Science and Technology Plan Key Project,China(2012A020100003,2015A050502043)
文摘Excessive use of agro-chemicals （such as mineral fertilizers） poses potential risks to soil quality. Application of organic amendments and reduction of inorganic fertilizer are economically feasible and environmentally sound approaches to de- velop sustainable agriculture. This study investigated and evaluated the effects of mineral fertilizer reduction and partial substitution of organic amendment on soil fertility and heavy metal content in a 10-season continually planted vegetable field during 2009-2012. The experiment included four treatments： 100% chemical fertilizer （CF100）, 80% chemical fertilizer （CF80）, 60% chemical fertilizer and 20% organic fertilizer （CF60＋OM20）, and 40% chemical fertilizer and 40% organic fertilizer （CF40＋OM40）. Soil nutrients, enzyme activity and heavy metal content were determined. The results showed that single chemical fertilizer reduction （CF80） had no significant effect on soil organic matter content, soil catalase activity and soil heavy metal content, but slightly reduced soil available N, P, K, and soil urease activity, and significantly reduced soil acid phosphatase activity. Compared with CF100, 40 or 60% reduction of chemical fertilizer supplemented with organic fertilizer （CF60＋OM20, CF40＋OM40） significantly increased soil organic matter, soil catalase activity and urease activity especially in last several seasons, but reduced soil available P, K, and soil acid phosphatase activity. In addition, continu- ous application of organic fertilizer resulted in higher accumulation of Zn, Cd, and Cr in soil in the late stage of experiment, which may induce adverse effects on soil health and food safety.
基金supported by the Special Fund for Agroscientific Research in the Public Interest (201203030 and 201003016)the National Basic Research Program of China (973 Program, 2011CB100501-S06)the National Natural Science Foundation of China (41301269)
文摘Soil organic carbon （SOC） is one of the main carbon reservoirs in the terrestrial ecosystem. It is important to study SOC dynamics and effects of organic carbon amendments in paddy fields because of their vest expansion in south China. A study was carried out to evaluate the relationship between the SOC content and organic carbon input under various organic amendments at a long-term fertilization experiment that was established on a red soil under a double rice cropping system in 1981. The treatments included non-fertilization （CK）, nitrogen-phosphorus-potassium fertilization in early rice only （NPK）, green manure （Astragalus sinicus L.） in early rice only （OM1）, high rate of green manure in early rice only （OM2）, combined green manure in early rice and farmyard manure in late rice （OM3）, combined green manure in early rice, farmyard manure in late rice and rice straw mulching in winter （OM4）, combined green manure in early rice and rice straw mulching in winter （OMS）. Our data showed that the SOC content was the highest under OM3 and OM4, followed by OM1, OM2 and OM5, then NPK fertilization, and the lowest under non-fertilization. However, our analyses in SOC stock indicated a significant difference between OM3 （33.9 t ha^-1） and OM4 （31.8 t ha^-1）, but no difference between NPK fertilization （27 t ha^-1） and nonfertilization （28.1 t ha^-1）. There was a significant linear increase in SOC over time for all treatments, and the slop of linear equation was greater in organic manure treatments （0.276-0.344 g kg-1 yr^-1） than in chemical fertilizer （0.216 g kg^-1 yr^-1） and no fertilizer （0.127 g kg^-1 yr^-1）.
文摘以砂姜黑土长期施肥试验为平台,研究砂姜黑土冬小麦—夏大豆轮作系统下作物钾素吸收量、钾素回收率、土壤钾素盈亏量和速效钾含量的演变特征,探明土壤速效钾与外源钾投入、土壤累积钾盈亏的响应关系,分析不施肥(CK)、常规化肥(CF)、化肥+麦秆(SCF)、化肥+猪粪(PCF)、化肥+牛粪(CCF)等施肥方式对土壤钾素利用及盈亏的影响,以期探寻砂姜黑土地区高产高效的施钾方式。结果表明:29 a作物钾素平均回收率在55.1%~66.1%,高低顺序为CCF>PCF>SCF>CF。土壤累积钾盈亏与土壤速效钾增量呈显著线性关系(p<0.05),土壤中钾素每盈余100 kg hm-2,CF、SCF、PCF和CCF处理土壤速效钾含量分别增加1.4、1.8、2.3和15.8 mg kg-1;土壤钾素投入量与速效钾含量呈显著线性关系(p<0.05),CF处理每投入钾100 kg hm-2,土壤速效钾含量增加0.4 mg kg-1,而SCF、PCF和CCF处理每投入钾100 kg hm-2,土壤速效钾含量分别增加0.5、0.6和4.3 mg kg-1,这说明适当增施有机肥可提升土壤钾素的供应能力。综上所述,投入有机物料是影响土壤钾素利用的重要调控措施,长期增施有机肥可提高作物钾素回收率以及土壤中盈余的钾素向速效钾的转化能力,本试验条件下以增施牛粪效果最好,猪粪和秸秆次之。因此,砂姜黑土小麦—大豆轮作系统下秸秆养畜过腹还田是实现作物高产高效的一种推荐施钾方式。
文摘Ploughing and fertilization practices in rice-wheat system have deteriorated the soil carbon (C) pools. Conservation agriculture (CA) based management approaches have proven to enhance C sequestration and reverse the loss of soil-organic-carbon (SOC), which further enhances soil fertility. Different fractions of SOC pools react to the alterations in management practices and indicate changes in SOC dynamics as compared to total C in the soil. Higher SOC levels in soil have been observed in case of reduced/no-till (NT) practices than conventional tillage (CT). However, between CT and zero tillage/NT, total SOC stocks diminished with an increase in soil depth, which demonstrated that the benefits of SOC are more pronounced in the topsoil under NT. Soil aggregation provides physical protection to C associated with different-sized particles, thus, the improvement in soil aggregation through CA is an effective way to mitigate soil C loss. Along with less soil disturbance, residual management, suitable crop rotation, rational application of manures and fertilizers, and integrated nutrient management have been found to be effective in not only improving soil C stock but also enhancing the soil health and productivity. Thus, CA can be considered as a potential method in the build-up of SOC of soil in rice-wheat system.
