深耕改善砂姜黑土理化性状提高小麦产量

为探明砂姜黑土农田适宜的耕作方式,进一步挖掘砂姜黑土生产潜力,发挥地域资源优势,以周麦27为试验材料,在大田条件下设置免耕、旋耕(15 cm)、深耕(30 cm)3种耕作方式,研究了耕作方式对砂姜黑土农田土壤容重、有机碳含量、无机氮含量以及小麦籽粒产量的影响。结果表明,在小麦苗期和成熟期,3种耕作方式处理间0~10 cm土层土壤容重差异不显著(P0.05),但深耕处理显著降低10~30 cm土层土壤容重(P0.05)。在小麦苗期、越冬期、拔节期、开花期和成熟期,3种耕作方式对0~20 cm土层土壤有机碳含量的影响规律不明显,但深耕处理明显增加20~40 cm土层土壤有机碳含量;20~40 cm土层土壤铵态氮含量均为深耕旋耕免耕。与免耕处理相比,深耕处理通过增加小麦穗粒数和千粒质量,最终促使籽粒产量增加16.33%。综上所述,在该试验条件下,在秸秆还田的基础上,小麦季30 cm深耕处理可以降低土壤容重,增加土壤有机碳含量,进而提高小麦籽粒产量,可作为砂姜黑土农田适宜的耕作方式。

Deep tillage improving physical and chemical properties of soil and increasing grain yield of winter wheat in lime concretion black soil farmland

At present, rotary tillage is a conventional farming method in wheat-maize rotation system in North China Plain, however, under the rotary tillage year after year, plough pan tends to become shallow and harden, which results in poor ventilation and drainage, and also is hard to increase grain production, especially in the farmland of lime concretion black soil. Using 'Zhoumai27' as the test material, the field experiment was conducted to research the effects of 3 tillage practices (no tillage, rotary tillage and deep tillage) on grain yield of winter wheat, soil bulk density, soil organic carbon and soil inorganic nitrogen, in order to select the appropriate tillage practices and further improve the potential of grain production in the farmland of lime concretion black soil. The results showed: 1) In terms of soil bulk density, there were no significant differences among 3 tillage treatments in 0-10 cm soil layer during wheat growth period, and also no differences at maturity period of wheat in >30-40 cm soil layer, but deep tillage practice could significantly decrease (P<0.05) soil bulk density in >10-30 cm soil layer compared with no tillage. 2) There were no significant differences among 3 tillage practices in 0-20 cm soil layer, but deep tillage could increase (P<0.05) the content of soil organic carbon in >20-40 cm soil layer compared with no tillage. 3) In 0-20 cm soil layer, compared with no tillage or deep tillage, rotary tillage significantly increased (P<0.05) the contents of nitrate nitrogen in the seedling, wintering and anthesis period of winter wheat. However, the content of nitrate nitrogen at jointing stage did not reach significant difference among 3 treatments, and was significantly higher (P<0.05) under no tillage than under rotary tillage and deep tillage at maturity of wheat. In >20-40 cm soil layer, the higher content of nitrate nitrogen was detected in rotary tillage in seedling and anthesis period, and no tillage was higher at other growth stages of winter wheat. 4) In terms of the content of ammonium nitrogen in soil, in 0-20 cm soil layer, during the seedling, wintering and anthesis period of winter wheat there were no significant differences between rotary tillage and deep tillage, but no tillage showed higher values. At jointing stage, the order of the content of ammonium nitrogen was rotary tillage > deep tillage > no tillage, and also there was significant differences among 3 tillage treatments (P<0.05), but at maturity stage, the content of ammonium nitrogen in 3 treatments did not reach significant differences. In >20-40 cm soil layer, the order of the content of ammonium nitrogen was deep tillage > rotary tillage > no tillage during the whole growth period of winter wheat. 5) Compared with no tillage, deep tillage could significantly increase (P<0.05) grain yield of winter wheat mainly, for deep tillage increased 1000-grain weight and grain number. To sum up, under the condition of our field experiment, deep tillage could decrease soil bulk density in >10-30 cm soil layer, improve the content of organic carbon and ammonium nitrogen in >20-40 cm soil layers, and also increase grain yield of winter wheat in the end. Therefore, deep tillage practice should be selected as an appropriate tillage practice in the farmland of lime concretion black soil.