Changes of soil nitrogen supply and production of upland forage crops by cattle manure during conversion from paddy to upland condition in paddy field.

摘要

The effect of cattle manure applied at rates of 2 and 4 tonnes 10a-1 for winter rye and summer maize cultivation, respectively, on dry matter (DM) yield and nitrogen (N) uptake were investigated during successive three-year conversion period from paddy to upland condition in paddy field in Korea Republic. The changes in soil properties and soil N supplying capacity during repetitive manure application were also examined. Growth and DM yield of upland forage crops, especially winter rye were hindered highly by poor soil condition in the first year after conversion from paddy to upland condition, so apparent recovery of cattle manure N by crops was very low in the first conversion year. But, DM yield and N uptake of upland forage crops were increased linearly by accumulative input of cattle manure along with mineral N enrichment in soil, which also increased apparent recovery of cattle manure-N. It seemed that those increases were mainly due to the improvement of soil properties such as soil mineral N, soil organic matter (soil carbon), potentially mineralizable N and bulk density by accumulative input of cattle manure rather than the increase of soil N supply according to accumulative conversion period from paddy to upland condition. It was derived that conversion period from paddy to upland condition over 2 years is needed to obtain proper DM yield in paddy field and accumulative inputs of cattle manure during the conversion period is more influential to the continuous increment of DM yield and N uptake of upland crop as well as of potential N supplying capacity of soil..