不同耕作制对水田土壤有效硅的影响

人工模拟试验结果表明,耕型旱地红壤改为不同稻作制后有效硅下降,其顺序为冬油>冬绿>冬泡,淹水植稻期间是前期明显增加,到分蘖末期达峰值,孕穗至始穗期显著下降,以后缓慢继续降低,到黄熟期降到最低值;早、晚稻期间比较,晚稻期明显减少,而不同耕作制相比,则冬泡制高于冬种制,另外,施用有机肥能使有效硅提高,且随用量增加而加大。

EFFECTS OF CROPPING SYSTEMS AND GREEN MANURE APPLICATION ON SOIL AVAILABLE SILICA

A modelling experiment was conducted to study the silica supply-ing ability of paddy soil reclaimated from red earth. When arable red earth was flooded to plant rice crop, soil available silica varied with previous cropping systems. In order of decreasing silica they were winter rap crop, Winter green manure and winter flooding. During the early stage of rice plant growth, soil available silica increased greatly and peaked during the late tillering stage.Howe-vet, it decreased significantly from the booting stage to the initial panicle stage and the decrease continued slowly after that stage until it got to the lowest co-ntent at yellow maturation stage. Soil available silica content during the gro-wth stage of late rice was much lower than that of early rice,while soil availa-ble silica under the systems of winter rape and winter green manure was lower than that of winter flooding. In addition,soil available silica increased with the increase of green manure application.