Abstract
Understanding the fates of soil hydrological processes and nitrogen (N) is essential for optimizing the water and N in a dryland crop system with the goal of obtaining a maximum yield. Few investigations have addressed the dynamics of dryland N and its association with the soil hydrological process in a freeze-thawing agricultural area. With the daily monitoring of soil water content and acquisition rates at 15, 30, 60 and 90 cm depths, the soil hydrological process with the influence of rainfall was identified. The temporal-vertical soil water storage analysis indicated the local albic soil texture provided a stable soil water condition for maize growth with the rainfall as the only water source. Soil storage water averages at 0–20, 20–40 and 40–60 cm were observed to be 490.2, 593.8, and 358 m3 ha−1, respectively, during the growing season. The evapo-transpiration (ET), rainfall, and water loss analysis demonstrated that these factors increased in same temporal pattern and provided necessary water conditions for maize growth in a short period. The dry weight and N concentration of maize organs (root, leaf, stem, tassel, and grain) demonstrated the N accumulation increased to a peak in the maturity period and that grain had the most N. The maximum N accumulative rate reached about 500 mg m−2d−1 in leaves and grain. Over the entire growing season, the soil nitrate N decreased by amounts ranging from 48.9 kg N ha−1 to 65.3 kg N ha−1 over the 90 cm profile and the loss of ammonia-N ranged from 9.79 to 12.69 kg N ha−1. With soil water loss and N balance calculation, the N usage efficiency (NUE) over the 0–90 cm soil profile was 43%. The soil hydrological process due to special soil texture and the temporal features of rainfall determined the maize growth in the freeze-thawing agricultural area.
Highlights
During the agricultural tillage management, the maximum crop production and minimum diffuse nitrogen (N) loading are the priority issues that need to be considered at the same time [1][2]
The field monitoring done in four stages as part of our study indicated that the temporal patterns of soil water (SW) content and acquisition rate closely followed the rainfall amount (Fig. 2)
The results of this study have shown that combined conditions of soil texture, soil hydrology and precipitation were basic factors for maize growth in the freeze-thawing area in Northeast China
Summary
During the agricultural tillage management, the maximum crop production and minimum diffuse nitrogen (N) loading are the priority issues that need to be considered at the same time [1][2]. It is essential to understand the fates of soil water (SW) and N in agricultural systems in order to attain higher crop yields and N usage efficiency [3]. The dryland agriculture in the Sanjian Plain, Northeast China, is a key food base and the most water limited agricultural zone in China [5]. In this freezethawing area, the soil N and water efficiency are the keys for dryland tillage sustainability due to the short growing season. There are few reports about the dryland soil hydrological process and N use efficiency in freeze-thawing agricultural areas [6]
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