关键词: 异色瓢虫, 异色瓢虫, 光波, 光源距离, 温度, 趋光性

Abstract: To study the rational N, P, K application rate and propose a scientific fertilization ratio for open field broccoli, the authors investigated the effects of different N, P, and K supplying levels on yield of open field broccoli and N, P, K uptake and accumulation in its overground part in the Yellow River irrigation region of Ningxia, and evaluated fertilizer use efficiency. The results showed that the yield of broccoli significantly increased by the application of N and P fertilizer, however, there was no significant difference among different K fertilizer treatments. Compared with N0 and P0 treatment, there was 23.6%-36.2% and 7.6%-11.5% of economic yield increment by N and P fertilizer application, respectively. N, P, K accumulation amount in overground part of broccoli also significantly increased with rational N, P, K fertilizer application. Fertilizer using efficiency, agronomy efficiency and partial fertilizer productivity all decreased with the increase of fertilizer application amount. Application of 1 kg N, P2O5 and K2O produced 50.9-184.7, 89.3-369.1 and 53.9- 220.2 kg economic broccoli yield, respectively, and the yield significantly decreased with the increase of fertilizer application amount. Both economic broccoli yield and N (R2=0.886), P (R2=0.906) and K (R2=0.794) application rate could be described by quadratic curve relations. With overall consideration of economic yield, nutrients accumulation and fertilizer use efficiency of the vegetable, the N, P2O5, K2O application rate could be proposed as 189.8- 200.0, 79.8- 86.8 and 80.2- 112.5 kg/hm2 for open field broccoli in the Yellow River irrigation region of Ningxia, respectively, and the suitable fertilization ratio ranged from 1:0.42-0.43:0.42-0.56.