From 1990,over 17 years field experiment was carried out in paddy field cultivated from infertile upland to evaluate the response of rice productivity,soil organic carbon（SOC）,and total N to long-term NPK fertilizat...From 1990,over 17 years field experiment was carried out in paddy field cultivated from infertile upland to evaluate the response of rice productivity,soil organic carbon（SOC）,and total N to long-term NPK fertilization or NPK combined with organic amendments.The field trials included NPK（N,P,K fertilizer）,NPKRS（NPK combined with rice straw）,NPK2RS（NPK combined with double amount of rice straw）,NPKPM（NPK combined with pig manure） and NPKGM（NPK combined with green manure） and the cropping system was rice-rice（Oryza sativa L.） rotation.Annual rice yield,straw biomass,and harvesting index increased steadily with cultivation time in all treatments.Average annual rice yield from 1991 to 2006 was ranged from 7 795 to 8 572 kg ha-1 among treatments.Rice yields in treatments with organic amendments were usually higher than that in treatment with NPK.Contents of SOC and total N also increased gradually in the cultivation years and reached the level of 7.82 to 9.45 and 0.85 to 1.03 g kg-1,respectively,in 2006.Soil fertilities in treatments with chemical fertilization combined with organic amendments were relatively appropriate than those in treatment with NPK.There was obvious discrepancy between cumulative characters of rice yield and soil organic fertility in newly formed paddy field.Compared with relatively high rate of crop productivity improvement,cumulative rates of SOC and total N were much lower in our study.SOC and total N contents were still less than half of those in local highly productive paddy soils after 17 years cultivation in subtropical China.Present work helps to better understand the development of infertile paddy soils and to estimate the potential of yield improvement in this region.展开更多
Field experiments with medicinal rice Njavara were conducted at Cropping Systems Research Centre, Karamana, Thiruvananthapuram, Kerala during summer of 2007 and 2008. The experimental design was split plot with three ...Field experiments with medicinal rice Njavara were conducted at Cropping Systems Research Centre, Karamana, Thiruvananthapuram, Kerala during summer of 2007 and 2008. The experimental design was split plot with three replications. The treatments consisted of four establishment techniques viz., System of Rice Intensification SRI (M1), Integrated Crop Establishment Method (ICM) (M2), Package of practices (PoP) (M3) of Kerala Agricultural University and Conventional Management Practices (CMP) (M4) in main plot. Three nutrient sources viz., (1) organic, 2) integrated use of organic and inorganic, 3) chemical fertilizers only) were used under different establishment techniques. Root dry matter production was determined at weekly intervals and plant nutrients uptake was determined by calculating from the product of dry matter, straw dry weight, grain yield and percentage of nutrients. Results revealed that at early stages (4-6 WAT/WAS) (Weeks after transplanting/Weeks after sowing), root dry matter production hill-1 was in the order of SRI > ICM > CMP > PoP which changed to SRI > ICM > PoP > CMP from 7th week onwards. Maximum root dry matter (at 9th WAS/WAT) was recorded in SRI (0.51/0.50 g.hill-1 in 2007/2008). The total nutrients uptake (N, P, K, Fe, Mn and Zn) in conventional management practices was significantly higher than other establishment techniques. Among the nutrient sources, higher total (N, P, K, Fe, Mn and Zn) uptake by crop was recorded under integrated nutrient source than organic and inorganic sources.展开更多
基金supported by the National Basic Research Program of China (2007CB109301)the National Natural Science Foundation of China (40871122) the National Key Technology R&D Program of China (2009BADC6B03)
文摘From 1990,over 17 years field experiment was carried out in paddy field cultivated from infertile upland to evaluate the response of rice productivity,soil organic carbon（SOC）,and total N to long-term NPK fertilization or NPK combined with organic amendments.The field trials included NPK（N,P,K fertilizer）,NPKRS（NPK combined with rice straw）,NPK2RS（NPK combined with double amount of rice straw）,NPKPM（NPK combined with pig manure） and NPKGM（NPK combined with green manure） and the cropping system was rice-rice（Oryza sativa L.） rotation.Annual rice yield,straw biomass,and harvesting index increased steadily with cultivation time in all treatments.Average annual rice yield from 1991 to 2006 was ranged from 7 795 to 8 572 kg ha-1 among treatments.Rice yields in treatments with organic amendments were usually higher than that in treatment with NPK.Contents of SOC and total N also increased gradually in the cultivation years and reached the level of 7.82 to 9.45 and 0.85 to 1.03 g kg-1,respectively,in 2006.Soil fertilities in treatments with chemical fertilization combined with organic amendments were relatively appropriate than those in treatment with NPK.There was obvious discrepancy between cumulative characters of rice yield and soil organic fertility in newly formed paddy field.Compared with relatively high rate of crop productivity improvement,cumulative rates of SOC and total N were much lower in our study.SOC and total N contents were still less than half of those in local highly productive paddy soils after 17 years cultivation in subtropical China.Present work helps to better understand the development of infertile paddy soils and to estimate the potential of yield improvement in this region.
文摘Field experiments with medicinal rice Njavara were conducted at Cropping Systems Research Centre, Karamana, Thiruvananthapuram, Kerala during summer of 2007 and 2008. The experimental design was split plot with three replications. The treatments consisted of four establishment techniques viz., System of Rice Intensification SRI (M1), Integrated Crop Establishment Method (ICM) (M2), Package of practices (PoP) (M3) of Kerala Agricultural University and Conventional Management Practices (CMP) (M4) in main plot. Three nutrient sources viz., (1) organic, 2) integrated use of organic and inorganic, 3) chemical fertilizers only) were used under different establishment techniques. Root dry matter production was determined at weekly intervals and plant nutrients uptake was determined by calculating from the product of dry matter, straw dry weight, grain yield and percentage of nutrients. Results revealed that at early stages (4-6 WAT/WAS) (Weeks after transplanting/Weeks after sowing), root dry matter production hill-1 was in the order of SRI > ICM > CMP > PoP which changed to SRI > ICM > PoP > CMP from 7th week onwards. Maximum root dry matter (at 9th WAS/WAT) was recorded in SRI (0.51/0.50 g.hill-1 in 2007/2008). The total nutrients uptake (N, P, K, Fe, Mn and Zn) in conventional management practices was significantly higher than other establishment techniques. Among the nutrient sources, higher total (N, P, K, Fe, Mn and Zn) uptake by crop was recorded under integrated nutrient source than organic and inorganic sources.
