稻田免耕年限与复耕次数对土壤容重和水稻生长的影响

试验以免耕1~10年稻田和免耕3~6年后复耕1次、复耕2次、复耕3次稻田为对象,探索不同免耕年限与复耕次数对稻田土壤容重和水稻生长的影响,以期为因地制宜推广免耕技术提供科学依据。结果表明：无论土壤表层还是下层,免耕土壤容重总是大于翻耕土壤,且随着免耕时间的延长,其土壤容重逐渐加重,免耕3年及以后处理土壤容重显著大于翻耕处理(P<0.05),随着复耕次数的增加,土壤容重逐渐降低。连续免耕1~5年的田块,免耕栽培处理水稻最高苗和有效穗以及产量均表现为比翻耕栽培处理高,免耕6年处理表现相对平缓稳定,免耕7年及以后分蘖能力和产量明显下降。免耕3~5年后进行复耕处理水稻分蘖能力和产量总是低于对应的免耕4~6年处理,且随着复耕次数的增加差距逐渐扩大,免耕7年处理水稻分蘖能力和产量与免耕6年后进行复耕1次处理基本持平。结论为稻田免耕应以6年内为宜,当稻田连续免耕超过最适年限后,需要进行复耕作业,复耕1次即可。

Effects of No-tillage Years and Re-tillage Times on Soil Bulk Density and Rice Growth in Paddy Fields

To explore the effects of different no-tillage years and re-tillage times on soil bulk density and rice growth in paddy fields, the research includes no-tillage for 1 to 10 years of paddy field and re-tillage once, re-tillage twice and re-tillage 3 times after no-tillage for 3 to 6 years of paddy field. The results showed that the soil bulk density of no-tillage soil was always higher than that of conventional tillage soil at surface soil and sublayer soil, with the increase of no-tillage time, soil bulk density increased. The soil bulk density significantly increased after 3-year no-tillage compared to that of conventional tillage (P<0.05). With the increase of re-tillage time, soil bulk density gradually decreased. In the paddy fields with no-tillage for 1 to 5 years, the highest seedlings, effective panicles and yield of rice under no-tillage cultivation were higher than that of conventional tillage cultivation. The tillering ability and yield of rice treated with 6-year no-tillage were relatively flat and stable and that of rice treated after 7-year no-tillage decreased significantly. The tillering ability and yield of rice in paddy fields under the re-tillage treatment were always lower than that of the corresponding no-tillage treatment, and the gap gradually widened with the increase of re-tillage times. The tillering ability and yield of rice treated with no-tillage for 7 years were the same as that treated with the corresponding re-tillage once after no-tillage for 6 years. In summary, 6-year no-tillage treatment is the best measure for paddy production in the study area, when the continuous no-tillage of paddy fields exceeds the optimum years, it is necessary to re-tillage the paddy fields once.