Research On Techniques Of Plant Population Configuration Under Maize/Soybean Relay-cropping System And Their Effects On Soybean

The experiments were carried out from 2005 to 2007,and consisted of five experiments, they were "effects of different planting width and tripe rate on relay-cropping soybean", "effects of sowing time and density of maize on relay-cropping soybean"," effects of different plant-type maize on relay-cropping soybean of different mature time","effects of different varieties and sowing time on the morphological characteristics and yield of relay-cropping soybean",and "effects of different density and population configuration on some morphological and physiological characteristics and yield of relay-cropping soybean". From the experiments we cleared the population configuration effect on the relay-cropping system,and the mechanism of good harvest,formed the technology system of high-yield of relay-cropping soybean whose core technology was colony configuration.The results were as follows:1 Appropriate planting width and tripe rate are beneficial to improve agronomic traits of relay-cropping soybean and increase the yield of the relay-cropping system.The results showed that large soybean bandwidth resulted in the short plant,thick main stem,large accumulation of dry matter,high LAI and SLM,and high yield of soybean.While small planting width and bandwidth led to the undergrowth of leaf and stem,over growth of plant,thin and lodging-susceptible stem,and low yield of soybean.The soluble sugar, starch,nitrogen content of leaf and stem at all growth stage were higher under the treatment of 1.17 m/0.83 m(soybean/maize,the same blow) than the treatment of 0.83 m/0.83 m,the values were 9.05%,8.39%;15%,32%;41%,30%respectively.The treatment of 1.17 m/0.83m had the highest yield of 2092.40 kg·hm^-2,while the treatment of 1 m/0.83 m had the lowest yield of 1101.52 kg·hm^-2,the former one was 90 percent higher than the latter one.It was concluded that relay planting soybean in a planting width and tripe rate of 1.17 m/0.83 m could be the best field combination in ensuring high yield and high efficiency all the year round.2 It is beneficial to improve the colony structure of relay-cropping soybean and to increase the yield,through regulation of sowing time and density of maize.The influences of different maize colony under relay-planting system of maize and soybean were investigated through the maize sowing date and density on agriculture character and yield. The results suggested that the treatment of sowing maize on March 26 to April 5(late) and under 48000-60000 plants per hm²(high density) was beneficial to improve the yield of maize.Maize sown on March 6(early)and under 36000 plants per hm²(low density) could decrease the height of soybean,increase the stem diameter,reduce the length of the 1st nodulation,improve number of branches,number of branch pods on 20-60 cm,number of main stem pods up 60 cm,grain yield of soybean was increased by 40.42%,as compared to the treatment of sowing on April 15(late) and increased by 35.79%,as compared with which was under the density of 60000 plants per hm²(high density).In conclusion,it was in favor improving the yield and output of the maize/soybean system,when seeds are sown on March 6 to March 26(appropriate early),and under the density of 48000 plant per hm² (moderate high density).3 The plant-type directly relates to improve agronomic traits and increase yield.With the expanding of maize plant-type,the relay-cropping soybean which resulted in the high plant height,thin main stem diameter and had higher ratio of loge and death seedling of soybean; The different genesis of soybean had a significant correlation,the increasing ratio of plant height of late mature-soybean was less than the middle-mature and early-mature,but its plant height,main stem diameter and the ratio of loge and death were prior to the other varieties.With the expanding of maize pant-type,the LAI and LAD of soybean decreased, and the value of seedling SPAD of soybean,the chlorophyll a,chlorophyll b and chlorophyll content of soybean after flowering were increased.There was no significant deviation among different soybean varieties in the seedling stage,but to the LAI,LAD and chlorophyll content of soybean during the other stages,the late-mature soybeans were best. The stem DR and leaf OR and leaf CR of soybean had a significant positive correlation with its DMA and Yield.The negative effect on the DMA,OR and CR of soybean were decreased by the expanding of maize plant-type.Because of the difference of soybean genesis,the OR,CR and DR of soybean were different.The stem of mid-mature and early-mature soybean about OR,CR and DR were higher than its leaves,but the late-mature soybean was opposite.This caused that the average DMA of the late-mature soybean was higher than the mid-mature and early-mature soybean,and it also had more effective pods per plant,effective seeds per pod and higher weight of 100-seed and less vacant seed.Example that the yield of late-mature soybean than the mid-mature and early-mature soybean4 Choose proper variety and sow at the appropriate time can coordinate the symbiotic period of maize and soybean,and it also can increase the yield of relay-cropping soybean. The yield among sowing dates was significantly different,the best sowing date was June 7.As the variety was different;its performance under different sowing dates was slightly different.The optimum sowing date of mid-maturing variety and late maturing variety was June 7,when their pods number per plant and seeds number per pod were much higher than other sowing dates;the optimum sowing date of early maturing variety was June 14, when its S pod number per plant,seed number per pod and seed weight was higher than other sowing dates.The yield among three varieties was the most significantly different, the yield of late maturing variety(Gongxuan No.1) was the highest,and that of mid-maturing variety(Ledou No.1) took second place that of early maturing variety (Zhechun No.3) was the lowest,compared with early maturing variety and mid-maturing variety,the nutritive growth period of the late maturing variety was longer,and it S symbiotic period of reproductive growth with maize was 0 day,and it's plant height was higher,stem diameter was wider by 0.13-0.16 cm,it's branch number increased 0.38-0.89, the number of stem node increased 4.47-7.12.The pod number per plant and seed number per pod was much higher.Therefore,the late maturing variety was suitable to relay-cropping.5 Proper density and reasonable configuration of row spacing can improve the dry matter production capacity of soybean.Under different density treatment,the plant height increased with the increase of the density,but the stem diameter and the branch numbers both decreased with the increasing of the density.With the photosynthetic production and dry matter accumulation transport from leaf and stem to the pod,the pod dry matter continuous increased,under different density treatment conditions,the value of the OR and DR in the leaf was higher than the value in the stem,and the OR and DR both decreased with the increase of the density.The DR in the pod at mature period was highest under the density of 180 000 plant per hm².And under different field collocation patterns the plant height increased with decline of the row spacing,the stem diameter and the branch numbers decreased with increase of the row spacing,the value of the OR and DR in the leaf and stem displayed rule of that 29 cm＞39 cm＞23 cm.The DR in the pod at mature period was highest under the row spacing of 29 cm.In the Yaan and Shehong different ecological regions,the result showed that:in different density and field distribution conditions,the effective pods per plant and the effective seeds per pod both decreased by the density increase,and the weight of 100-seeds was no significant with the density increase.This experiment showed that the appropriate groups density and field configuration could lead to high-yield which had the best of structure effective pods and effective seeds.Under different density treatment conditions,the yield increased with the density rise firstly and when the yield raised the threshold value,the yield become decrease. And under the different field distribution conditions the yield decreased with decrease of the row spacing.In the experiment,the factors effecting the yield of soybean present density＞row planting collocation＞density×row planting collocation.In the ecological regions of Yaan,the plant density should be in low-density,and in the Shehong ecological regions,the plant density should be higher than Yaan,so that the soybean can get better harvest.On the aspect of different field collocation patterns,the result shows that the bigger soybean row spacing can lead to higher yield of soybean,the treatment of 39 cm, plant 2～3 row can obtain better yield.