Effects Of Different Cropping Patterns Of Soybean And Maize Seedlings On Root Zone Soil Carbon And Nitrogen Mineralization

Through the pot experiment, three planting patterns of soybean and maize continuous,rotation and mixed cropping was simulated. The effects of different cropping patterns ofsoybean and maize seedlings on root zone soil urease, catalase, polyphenol oxidase, invertase,alkaline phosphatase activities, DOM, carbon and nitrogen mineralization were studied, anddry matter, nitrogen, phosphorus and potassium accumulation of soybean and maizeseedlings in different cropping patterns were determined at the same time. Nine treatmentswere set, and soybean, maize and soy-maize mixed cropping were planted in pots filled withcropped soils of soybean, maize or mixed cropping, respectively. Results showed that:1. Soy-maize rotation could improve soil urease and polyphenol oxidation activities atroot zone in various degree. Soybean and maize continuous cropping decreased soil ureaseactivity and increased invertase activity at root zone compared with mixed cropping.Monocropping of maize could improve soil alkaline phosphatase activity at root zone. Soilcatalase activity was higher in the soil of cropped maize and the mixed than that of thesoybean soil. The root zone soil enzyme activity had a significant correlation not only withDOM, carbon and nitrogen mineralization indicators, but also with dry matter, nitrogen,phosphorus and potassium accumulation of soybean and maize shoot at the same time. Soilenzyme activity of root zone in different cropping patterns showed different variation, soy-maize rotation and mixed cropping had obvious advantages compared with soybean andmaize continuous cropping.2. The size order of the root zone soil DOC content on different cropping patterns wasas follows: maize continuous> soybean continuous> soy-maize rotation> soy-maize mixedcropping. Rotation and mixed cropping increased the content of reducing sugar in root zonesoil compared with soybean continuous, but soy-maize mixed cropping decreased the contentof reducing sugar in the soil of cropped maize or mixed. Monocropping of maize couldimprove the content of phenolic compounds compared with monocropping of soybean andmixed cropping, and that of monocropping of maize in the soil of cropped soybean was muchsignificant. 3. Mixed cropping increased the content of soil MBC and MBN at root zone in the soilof cropped maize. Soybean and maize continuous increased the content of MBC, MBN andinorganic nitrogen in root zone soil compared with soy-maize rotation. The accumulation ofsoil inorganic nitrogen in the soil of cropped soy-maize mixed was significantly higher thanthat of other soils.4. The effects of different cropping patterns of soybean shoot seedlings on dry matteraccumulation, nitrogen, phosphorus and potassium absorption and that of maize shootseedlings on dry matter accumulation, phosphorus and potassium absorption wereinsignificant. Dry matter accumulation, nitrogen, phosphorus and potassium accumulation ofsoybean and maize shoot between soil enzyme activities at root zone, soil DOM, carbon andnitrogen mineralization indicators showed a significant or very significant correlation.