前季施肥对玉-稻轮作养分吸收及土壤养分表观平衡的影响

Fertilization in Maize Season: Effects on Nutrient Uptake and Soil Nutrient Apparent Balance in Maize-rice Rotation System

玉米-晚稻水旱轮作是近年长江中游发展的新型种植模式,研究前季玉米施肥后养分周年动态及对后季晚稻的影响,对该模式周年合理施肥具有借鉴意义。本研究以玉米免耕复种晚稻为对象,设置了3个施肥处理,包括两季作物均不施肥(MR0)、玉米施肥晚稻不施肥(MR1)、两季作物均常规施肥(MR2)。与MR0处理相比,玉米收获时MR1、MR2土壤速效氮显著降低,速效磷含量显著升高,而速效钾含量没有显著变化。3个处理中氮、钾均表现为显著亏损;土壤磷素表现为MR2处理表观盈余,MR1处理表观平衡,MR0处理则明显亏缺。由于土壤氮、钾供应的限制,使得MR1晚稻干物质积累及产量与MR0差异不显著,且显著低于MR2处理。可见,玉米-晚稻水旱轮作下氮、钾肥要在作物当季施用,磷肥可考虑在玉米季多施,晚稻季则减少或不施用磷肥。

The maize-late rice rotation is a recently developed cropping system in the middle reaches of the Yangtze River. It is important to study the annual dynamics of soil nutrients after fertilization in maize season and their effect on late rice growth for optimization of annual fertilization in maize-rice system. The no-tillsystem of maize-rice rotation with three fertilization treatments was set up, including no fertilizer application inthe two crop seasons（MR0）, conventional fertilization in maize season and no fertilization in rice season（MR1）,conventional fertilization in both crop seasons（MR2）. Compared with MR0 treatment, soil available nitrogen（N） in MR1 and MR2 plots significantly decreased, while the soil available phosphorus（P） content significantlyincreased, and the content of available potassium（K） in the soil did not change significantly. N and K in maize-rice system showed obvious deficiency in the three treatments. However, the soil P was in apparent surplus in MR2 treatment, apparent equilibrium in MR1 treatment, and obvious deficit in MR0 treatment. Possibly due to the deficiency of soil available N and K, dry matter accumulation and yield of rice in MR1 treatment had nosignificant difference with those of MR0 treatment, and were significantly lower than those of MR2 treatment.Taken together, in the maize-late rice rotation system, N and K fertilizer should be applied in each crop season, while, P fertilizer should be applied more in maize season, and less or no in rice season.