Study On The Material Production, Nutrient Accumulation And Economic Benefit In Maize-soybean Relay Strip Intercropping System

In recent years, the relay strip intercropping of maize and soybean has been developing very quickly, to explore the differences in the physical output, nutrient absorption and utilization, economic benefit in relay strip intercropping as compared to the traditional relay intercropping and monoculture, four planting patterns were established as maize-soybean relay strip intercropping, maize-soybean equal line spacing intercropping, maize monoculture and soybean monoculture at the Ya’an, Renshou and Lezhi in 2012-2013. We studied the dry matter accumulation, nutrient accumulation, yield of maize and soybean, nutrient accumulation and economic benefits of system. The main results showed as follows:1 The intercropping had no significant influence on the dry matter accumulation of maize. Dry matter of whole plant and every organs of soybean in relay strip intercropping were significantly lower than those in cropping soybean, but significantly more than those in equal line spacing intercropping. The strip intercropping and equal line spacing intercropping decreased the root-shoot ratio of soybean, but increased the harvest index. The total dry matter of system in strip intercropping was 20929.3 in 2012 and 22206.3 kg/hm2 in 2013, respectively, both which were much higher than those of equal line spacing intercropping, maize monoculture and soybean monoculture. Its BLER was 1.64-1.74 which was significantly higher than equal line spacing intercropping.2 The intercropping had no significant influence on yield and yield composition of maize. The yield of soybean in relay strip intercropping and equal line spacing intercropping were 15.4% and 50.9%, respectively, which was significantly lower than that in monoculture respectively, however, the yield of soybean in relay strip intercropping was 72.4% higher than that in equal line spacing intercropping. Effective strains and pods per plant of soybean in relay strip intercropping were lower than those in monoculture but higher than that in equal line spacing intercropping. The grain yield of system in strip intercropping were 8598.5kg/hm2 in 2012 and 9726.9kg/hm2 in 2013, which were significantly higher than those in equal line spacing intercropping and monoculture. Its LER was 1.78-1.88, which was significantly higher than that in equal line spacing intercropping.3 The strip intercropping had no significant influence on the nitrogen accumulation in maize, there was no significant influence on the phosphorus and potassium accumulation when compact-type maize intercropped with soybean, but that were lower than monoculture when semi-compact-type maize intercropped with soybean. Nitrogen, phosphorus and potassium accumulation in the whole plant and in each organ of soybean in the strip intercropping were significantly lower than those in soybean monoculture, but significantly higher than those in equal line spacing intercropping. The distribution ratio of nitrogen, phosphorus and potassium in the grains of soybean in strip intercropping was higher than that in sole cropping. Accumulation of nitrogen, phosphorus and potassium in relay strip intercropping system was higher than that in equal line spacing intercropping, maize monoculture or soybean monoculture. P input-output of soil-crop system in relay strip intercropping can keep balance, but N and K of soil-crop system are in the state of deficit. The grain production efficiency of nutrient in relay strip intercropping was lower than that in maize monoculture, but higher in soybean monoculture. There was no significant difference between relay strip intercropping and equal line spacing intercropping.4 The partial factor productivity of fertilizer in relay strip intercropping was lower than that in maize monoculture, however, there was no significant difference in their fertilizer use efficiency. The partial factor productivity of fertilizer and fertilizer use efficiency in relay strip intercropping were significantly higher than those in soybean monoculture. The partial factor productivity of fertilizer of relay strip intercropping had no significant difference from equal line spacing intercropping, while the fertilizer use efficiency was higher than that in equal line spacing intercropping.5 The total expense of the strip intercropping was 32.0% or 100.8% higher than that of maize monoculture or soybean monoculture, respectively, but it had no significant difference from equal line spacing intercropping. Output value of relay strip intercropping was 24801.4 yuan/hm2 in 2012 and 28658.2 yuan/hm2 in 2013, and economic benefit of strip intercropping was 11551.2 and 15408.1 yuan/hm2, which were significant higher than that of equal line spacing intercropping and monoculture. There were also no significant difference in input-output-ratio and labor productivity between relay strip intercropping and maize monoculture, whereas investment output ratio of relay strip intercropping was lower than that of maize monoculture. The input-output-ratio, labor productivity and investment output ratio of relay strip intercropping had no significant difference from equal line spacing intercropping, however, all of them were significant higher than soybean monoculture. Additionally, benefit per labor force of relay strip intercropping was significant higher than equal line spacing intercropping and soybean monoculture.In a word, maize-soybean relay strip intercropping have advantages over maize-soybean equal line spacing intercropping, maize monoculture and soybean monoculture on material product, nutrients accumulation and utilization, and economic benefit. It has important meaning for raising land utilization efficiency and helping farmers to increase both production and income, which is worth to be widely used and promoted heavily.