Quantitative study on the fate of residual soil nitrate in winter wheat based on a 15N-labeling method.

A considerable amount of surplus nitrogen (N), which primarily takes the form of nitrate, accumulates in the soil profile after harvesting crops from an intensive production system in the North China Plain. The residual soil nitrate (RSN) is a key factor that is included in the N recommendation algorithm. Quantifying the utilization and losses of RSN is a fundamental necessity for optimizing crop N management, improving N use efficiency, and reducing the impact derived from farmland N losses on the environment.

The nitrate leached below maize root zone is available for deep-rooted wheat in winter wheat-summer maize rotation in the North China Plain.

In winter wheat (Triticum aestivum L.)-summer maize (Zea mays L.) rotation system in the North China Plain, maize roots do not extend beyond 1.

[Studied of dry matter accumulation and echinacoside content of Cistanche tubulosa in Huabei plain].

Objective: To give some theory support of Cistanche tubulosa cultivation by searching dry matter accumulation and echinacoside content of C. tubulosa.

Method: Dry matter accumulation content of C.