Effects of field rainwater harvesting by plastic mulch and complement irrigation on soil water and yield of winter wheat

Based on the field experiment conducted in year 2005-2006 at Changping District, Beijing, the effects of field rainwater harvesting by plastic mulch and the complementary irrigation on the soil moisture and yield of winter wheat were studied. Results showed that under the complementary irrigation treatment, soil moisture was improved significantly and water consumption increased by 45.8% in contrast to the control, while by 29%-39% in contrast to the treatment of rainwater harvesting by plastic mulch for the soil profile with depth of 1.6 m. Meanwhile, the yield was 1.63-1.95 times to the control, while increased by 32%-58% in contrast to the treatment of field rainwater harvesting by plastic mulch. In addition, for the treatment of combination with plastic mulch and irrigation, the corresponding yield almost changed nothing. Under the condition of the rainfall closed to the half of normal level and plastic mulch area reached 40% of the total planting area, soil moisture within profile of 1.6 m depth was improved and water consumption increased by 3.68%-12.23%, while, the deep soil water utilization was 1.55-1.69 times to the control, and the yield of winter wheat increase by 63%-95%. The water production efficiency in the soil profile with depth of 1 m increased by 55.8%-73.8%. For the same consideration of plastic mulch, spring top-dressing had the better effect for keeping the soil water content at seeding stage than fall fertilizer and basal fertilizer. In conclusion, both spring top-dressing with plastic mulch during irrigation and complementary irrigation can greatly increase yield, and improve capacity of drought resistance. So it is worth expanding in drought area of North China.