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The effect of swine manure application on nitrate nitrogen leaching was investigated in the Yellow River irrigation area of Ningxia. The field experiment was conducted with 3 Treatments: Traditional fertilization 225 kg N kg.hm-2 without swine manure (CK), traditional fertilization with swine manure 4500 kg . hm-2 ( T1 ) and traditional fertilization with swine manure 9000 kg.hm-2 (T2). Nitrate nitrogen leaching rates were measured for 30, 60, 90 cm depth soil layers with a resin core absorption method. The results indicated that the nitrate leaching losses of T1 and T2 treatments ranged from 9.33 to 14. 04 kg.hm-2 (pure nitrogen), which accounted for 4. 2% - 6. 2% of applied nitrogen fertilizer. Compared to CK, the nitrate leaching losses of T1 and T2 increased by 2. 6% and 2. 1% at 30 cm depth, increased by 1. 5% and decreased by 1. 3% at 60 cm depth, decreased by 8. 7% and increased by 4. 0% at 90 cm depth, respectively. The difference did not reach statistical significance among CK and T1 and T2 in nitrate leaching loss at 30, 60 and 90 cm depths. However, there was a declining trend of nitrate leaching at deep soil layers of treatments. The key period of nitrate leaching loss was from spring reviving to early filling stage, which had a higher daily leaching loss than the average of the whole growth period, and accounted for 58. 7% -75. 3% of total leaching loss. Compared with CK, the yields of T1 and T2 increased by 9.3% and 12. 5%, respectively. [ABSTRACT FROM AUTHOR]

A field experiment was conducted in a winter wheat field in Weibei dry highland region of Loess Plateau to study the effects of different mulching and fertilization treatments on soil moisture regime. The treatments were 1) no fertilization, 2) conventional fertilization, 3) recommended fertilization, 4) recommended fertilization + manure, 5) recommended fertilization + plastic mulch on soil ridges, 6) recommended fertilization + plastic mulch on soil ridges and straw mulch in furrows, and 7) recommended fertilization + straw mulch on entire plot. Soil moisture content was determined regularly with a neutron probe. Among the treatments, recommended fertilization plus plastic mulch on soil ridges and straw mulch in furrows in dry season (spring) resulted in the greatest increase of soil water storage and maintained the storage to the critical stage crops needed, followed by recommended fertilization plus plastic mulch on soil ridges. These two treatments could store more precipitation in field, and would benefit the development of rainfed agriculture in dry highland region of Loess Plateau. As for recommended fertilization plus manure, it had the least increase of soil water storage, with a difference of 48.2 mm to the recommended fertilization plus plastic mulch on soil ridges and straw mulch in furrows in dry season. [ABSTRACT FROM AUTHOR]