Abstract:
Two treatments, Zizania latifolia co cropping and crayfish (ZC) and Zizania latifolia monoculture (Z), were set up to study the effects of Zizania latifolia co cropping and crayfish on soil nitrogen and phosphorus content, Zizania latifolia yield, dry matter accumulation and N, P, K absorption and distribution of Zizania latifolia, so as to provide a theoretical basis for rational fertilization and further promotion of Zizania latifolia planting and breeding mode. The results of two years of research indicate that the Zizania latifolia and crayfish co cropping mode increased the content of total nitrogen, total phosphorus, and available phosphorus in the soil during the harvesting period by 5.45% to 38.89% compared to the Zizania latifolia single cropping mode, increase the net Zizania latifolia yield by 5.10% to 19.54%, and increase the dry matter accumulation of Zizania latifolia stems, leaves, and net Zizania latifolia during the harvest period by 10.28% to 21.45% compared to the Zizania latifolia single cropping mode. As for the content of nitrogen, phosphorus and potassium, in 2021,the nitrogen content in the leaves of Zizania latifolia and crayfish co-cropping mode was significantly increased by 25.74% than that of Zizania latifolia monoculture mode in the harvest stage, but the phosphorus content in the stem was significantly reduced by 16.76% during the pregnancy period of Zizania latifolia;In 2022, under the reduction of nitrogen fertilizer and reduced feeding, the Zizania latifolia and crayfish co cultivation mode significantly reduced the nitrogen content of the stem by 23.75% during the pregnancy stage and the phosphorus content of the leaves by 12.08% during the tillering stage compared to the Zizania latifolia single cropping mode. The potassium content of the same organ during the entire two-year growth period was not significantly different between the two modes. With regard to nutrient accumulation, in 2021,the nitrogen, phosphorus and potassium accumulation in leaves of Zizania latifolia and crayfish co-cropping mode was significantly reduced by 26.0% to 27.27% compared to the Zizania latifolia monoculture mode at tillering stage, however, during the harvesting period, the accumulation of nitrogen and potassium in the stem and nitrogen and phosphorus in the leaves significantly increased by 18.80% to 38.41% and 35.71% to 44.77%, respectively, compared to the single cropping mode of Zizania latifolia; Under the reduction of nitrogen fertilizer and reduced feeding in 2022, the phosphorus accumulation in the leaves and potassium accumulation in the stems of the Zizania latifolia and crayfish co-cropping mode significantly increased by 30.0% and 30.77% compared to the Zizania latifolia monoculture mode during the harvesting period. With regard to nutrient distribution, the nitrogen distribution of the two modes of Zizania latifolia in the pregnancy and harvest stages is mainly stem and leaf, while the distribution of phosphorus and potassium is mainly stem, with the proportion of stem distribution between 42% and 66%. As for nutrient transport, in 2021,the roots, stems, and leaves of the two modes of Zizania latifolia represented mostly "sink" organs in nitrogen and phosphorus transport, while most of them represented "source" organs in potassium transport; Under the reduction of nitrogen fertilizer and reduced feeding in 2022, the roots, stems, and leaves of Zizania latifolia in the two modes mostly represented "source" organs in nitrogen, phosphorus, and potassium transport. Therefore, appropriately reducing the input of fertilizer and feed in the Zizania latifolia and crayfish co-cropping mode can promote the formation of a reasonable source sink relationship, which is conducive to the formation of yield.