| Maize is the core crop in the wheat/maize/soybean relay-intercropping system, so study on the effect of intercropping patterns and the application of N and P fertilizers on maize growth, nutrient absorption as well as the soil nutrient compared to the sole maize has a significant difference on developmenting and utilization of high yield and efficiency characteristics of the system. In the present study, the field experiment was carried out in 2013-2014 containing N fertilizer and P fertilizer applications in a wheat/maize/soybean relay-intercropping system and sole maize experiments.:in 2013 set up three nitrogen (N) rate:0,180,360 kg·hm-2 referred to as N0, N180, N360,2014 set four nitrogen (N) rate: 0,90,180,270 kg·hm-2, denoted N0, N90, N180, N270, two are located three phosphorus (P) rate:0,90,180 kg·hm-2 respectively denoted P0, P90, P180. We mainly tested the maize yield, dry matter accumulation translation, nutrient use efficiency and soil nutrient content diversification in these two intercropping patterns. The results showed that:(1)In the N0?N90 treatments, the maize yield in intercropping system was 20.5% and 7.5% lower than that of sole maize, respectively which showed a disadvantage. While in the N180?N270?N360 treatments, the maize yields had no significant difference in these two intercropping patterns.The biomass and N/P accumulation of maize in relay-intercropping system were significantly lower than that of sole, and the N transformation from the nutritional organs to the seeds was also lower than that of sole in the N0?N90 treatments. In the N180?N270?N360 treatments, the biomass and N/P accumulation of maize in the two intercropping patterns has no significant difference, while the N transformation rate in the cropping system was much higher than that of sole, and so was the N use efficiency. The soil NO3- content before the maize sowed in the intercropping system was 17.0% lower than that of sole maize. The former wheat significantly decreased the soil NO3- content, and this impact weakened with the increase of N fertilizer and the growth of maize. Therefore, we should add N fertilizer to the maize in the intercropping system to make up for the lack of soil N, so as to improve the N transformation. In the present, the best N application content was N180 (180 kg·hm-2).(2) In the P fertilizer experiment, maize in the two intercropping patterns had a similar situation. The relay-intercropping maize yield had averagely increased 5.0% in every P treatment than that of sole maize, and the relay-intercropping system had improved the P intake by plants with 15.1%,3.6%,1.6% higher than that of sole maize, respectively. The relay-intercropping system also promoted the P transformation from the nutritional organs to the seeds and the P fertilizer use efficiency. For all the P treatments, the PO treatment had a dominant advantage for the maize. All the growth period of the maize, the soil available P content in the relay-intercropping system was higher than that of sole one. Wheat and soybean provided maize with a much more beneficial soil available P, which was the origin of the advantage in the intercropping system.(3) The maize growth and nutrition absorption were similar in the two intercropping patterns, which showed a firstly slow growing then fast growing regulation. But in different growth periods, there was a difference between the two patterns:in the former periods, the maize growth and nutrition absorption in the relay-intercropping system were slower than that of sole while faster in the later periods. The maize intercropping pattern adjusted the growth and nutrition absorption of maize in different growth periods. For the soil nutrition dynamic, the soil NO3- content was the same in the two intercropping patterns except that the soil NO3- content and the available P had a smaller rangeability than that of sole-intercropping. And the soil available P content in the relay-intercropping system was totally higher than that of sole maize which provided a much more beneficial soil available environment for maize. In the low or no N environments, N fertilizer was the dominant limiting factor, so on this occasion the benefit of soil available P in the intercropping pattern could not be reflected. Thus, in the yield production, we should timely add enough N fertilizer to the maize in the nutrition growth periods to guarantee the normal growth and also make advantage the soil available P to stabilize the maize yield in the wheat/maize/soybean system.In all, the maize in the wheat/maize/soybean system should be provided with enough N fertilizer and low P fertilizer to decrease the bad effect of wheat on maize. And we should also make full use of the soil available P to stabilize the maize yield in the intercropping system to finalize the high production and high efficiency of the real production. |
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