Effects Of Film Mulching, Nitrogen Application And Planting Density On The Yield And Nitrate Nitrogen Of Dryland Spring Maize

The Loess Plateau has a typical semi-arid monsoon climate, in which maize(Zea mays L.) is one of the most common grain crops; however, low air temperatures and drought during the early crop growth stage in the spring, low efficiency of light and heat resource use due to low plant density and poor fertilizer management often result in poor crop yield. To solve the main problem of maize production in the Loess Plateau dryland region, on the basis of previous studies, a field experiment was conducted to explore mulching, planting density and nitrogen(N) application on the yield and mineral nitrogen of spring maize, thus providing a theoretical basis and practical guidance for the corn production in arid regions. The main results were showed as follow:1. In each treatment, the soil nitrate mainly distributed in the 0-40 cm soil profile, with the increasing of N application, soil nitrate content increased. While in the 0-200 cm soil profile, soil nitrate content decreased with the depth of soil layers increasing. The whole film double furrow cultivation patterns can significantly increase grain yield, N uptake and nitrogen use efficiency(NUE), and reduce the accumulation of nitrate in the soil. While the NUE of traditional planting cultivation was low, it could easily lead to a lot of accumulation of residual nitrate in the soil, even to the extent that nitrate migrating to the depth that difficult for crops to use, resulting in nitrate leaching losses. Considering the production and NUE, the whole film double furrow planting pattern was suitable for the Loess Plateau dryland farming.2. Under the whole film double furrow conditions, when planting density was constant, corn yield, N uptake increased with the N application increasing, while the NUE increased first then decreased. Suitable N fertilizer could increase grain yield, but too much N fertilizer would reduce the NUE, increase the apparent loss of N, resulting in a waste of resources. The study showed that in the 0-230 kg/hm2 nitrogen application range, the amount of nitrogen fertilizer 200 kg/hm2 was more appropriate.3. Under the whole film double furrow conditions, when N application was constant, and planting density between 50000-80000 plants/hm2, the corn yield, N uptake and NUE increased with the planting density increasing, while the nitrate accumulation in 0-200 cm soil profile had an opponent trend. The study showed that 80000 plants/hm2 was the best.4. As a whole, the whole film double furrow planting pattern was suitable for the Loess Plateau dryland farming, and the suitable N application rate was 200 kg/hm2, the suitable planting density was 80000 plants/hm2.