| Maize-soybean intercropping is development in Southwest China in recent years a dry land and new high in multiple cropping intercropping mode. In order to explore the different nodulation ability of soybean varieties and root interaction on crops growth, N uptake and N fixation in the system, and enrich maize-soybean intercropping cultivation system.This experiment was carried out by using pot method in 2013, with maize variety "Chuan dan 418", soybean varieties include strong nodulation cultivar" NTS 1007 "and weak nodulation cultivar "Nan dou 12" as research material, designed three different types of root barriers (no barrier, nylon barrier and plastic barrier). To measured and analyzed the agronomic characters, photosynthetic characteristics, biological yield and economic yield, plant N uptake and Nodule nitrogenase activity, with maize jointing stage, heading stage, maturity stage and soybean V3, R1, R4 and maturity stages in the maize-soybean intercropping system. The results showed that:1. In maize-soybean intercropping system, compared with the strong nodulation cultivar "NTS1007", the weak nodulation cultivar "Nan dou 12" advantageous to build the short plant morphology of soybean (Plant height was significantly decreased, the stem diameter increased, the length of first internode decreased), and the photosynthetic rate of maize (heading stage) and soybean (R4) increased by 5.99%?48.45% respectively, the yield of maize and soybean increased by 32.42% and 55.94%, respectively; Compared with no barrier, the nylon barrier increased the photosynthetic rate of maize and soybean by 16.10%and 8.18%, respectively. The aboveground biomass of stem, grain and tassel of maize were increased by 12.25%,16.60%,27.50% respectively, then the yield of maize was also increased 11.54%. However, the biomass yield and economic yield of soybean were decreased, compared with no barrier, the nylon barrier were decreased by 5.81%, 9.92%,19.82%, respectively. Observation from the interaction between varieties and root system, Maize and weak nodulation cultivar "Nandou 12" intercropping, compared with the strong nodulation cultivar "NTS1007" the nylon barrier increased the yield of maize and soybean by 34.88%,34.76%, respectively.2. Maize-soybean intercropping system, Compared with the strong nodulation soybean "NTS 1007", the weak nodulation soybean "Nan Dou 12" is beneficial to the absorption of nitrogen in maize, but its ability of nitrogen uptake was significantly reduced, and the difference was significant; Root interaction (non separation) significantly increased the uptake of nitrogen in maize and soybean, compared with the nylon barrier, the nitrogen uptake of stem, leaf, grain and tassel of maize were increased by 55.38%,10.95%,3.64% and 19.29% respectively, at soybean V3, R1 and R4 stage, the total N uptake were higher than the nylon barrier by 18.32%,7.53% and 9.73% respectively, and the soybean grains was increased by 7.64% compared with the nylon barrier.3. Maize-soybean intercropping system, The potential of N fixation of the strong nodulation cultivar "NTS 1007" was higher than the weak nodulation cultivar "NanDou 12", the activity of nitrogen fixing enzyme were increased 14.04% and 28.34% in the R1 and R4 stages, soybean plant nitrogen uptake and biomass were higher than that of "NanDou 12". After the harvest of maize, the number of nodules is larger than the weak nodulation soybean, but the single weight is smaller than the strong nodulation cultivar "NTS1007". The strong nodulation soybean cultivar "NTS1007" conducive to the accumulation of nitrogen in aboveground. However, the transfer efficiency of N and biomass of the weak nodulation "Nan Dou 12" was higher than "NTS 1007", the final economic yield of maize and soybean was higher than that of the strong nodulation "NTS 1007". Root interaction (no barrier), the activity of nitrogen fixing enzyme, the number of nodules and the weight of nodules were the highest in all growth stages of soybean, Although it is not conducive to the growth of seedling, however, the recovery of nitrogen fixation potential and the advantage of growth space in the soybean have been used to make the nitrogen uptake and utilization efficiency and yield increased. The nylon barrier can alleviate the pressure of nutrient competition in soybean seedling stages, but it is not conducive to the nutrient uptake of maize after harvest; root separation with nylon is not conducive to increase the nitrogen fixing potential of soybean. |
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