| The Loess Plateau had less annual rainfall and varied largely among years and months, it also had uneven distribution, its altitude was higher than 2000 m and effective accumulated temperature was low, so they limited yield of crops. In order to improve yield, using double-ridges mulch with film technology to improve soil moisture and temperature were the best effective measure; To make crop planting structure perfect and use land resource fully was key way. Legume intercropping gramineae was the most successful combination in traditional intercropping, resonable close planting was an effective way to increase the yield per unit area in different planting structure. Studying corn sowing density and within- row- intercropping on land use, crop yield, soil water storage of 0~100 cm and fertility of 0~40 cm by controling corn density and pea density in intercropping, aimed at finding an optimal planting structure.A field experiment was conducted in 2014 and 2015 in the Loess Plateau semi-arid ecosystems experimental station of Lanzhou University, by using double-ridges mulching with film with ridge width of 40 cm and 70 cm, respectively, in which corn plants were sown along the rows with spacing 40, 50 and 60 cm, respectively, and one or two individual plants of peas were inserted between corn plants equidistantly, and also design peas monoculture with plant spacing 13.33, 16.67, 20, 25 and 30 cm respectively, so the experiment had fourteen treatments. Comparing synthetically moboculture and whith-row- intercropping in different corn plant spacing and the within-row- intercropping in the same corn spacing in which inserting one or two peas on the total aboveground biomass, the total grain yield, aboveground biomass and grain yield of corn and peas as well as aboveground biomass and grain yield of per plant of corn and pea; discussed the different treatments on the 0~20 cm, 20~60 cm and 60~100 cm soil water storage and 0~20 cm and 20~40 cm soil microbial carbon and nitrogen, nitrogen nitrate, total nitrogen and organic matter.The results showed that the land equivalent ratio(LER) of the within- row- intercropping were greater than 1, and the land equivalent ratio in within- row- intercropping that inserting two peas between two corns equidistantly was greater than inserting one pea. Corn spacing had great impact on yield, with spacing of corn increased, total aboveground biomass, the total grain yield, corn aboveground biomass and grain yield tended to decrease, and the yield of treatments when corn spacing was 40 cm and 50 cm was greater significantly than the yield of corn spacing was the 60 cm, M40 improved grain yield to 27.8% than M60 in 2014 in corn monoculture, increased 36.4% in 2015; M40P1 increased grain yield to 26.9% than M60P1 in 2014 in within-row-intercropping of inserting one pea, improved 55.5% than M60P1 and 25.6% than M50P1; M40P2 increased grain yield to 33.2% than M60P2 in 2014 in within-row- intercropping of inserting two peas, improved 26.6% than M60P2 and 19.7% than M50P2.There was significant increase in total seed yeild when two pea plants were inserted into the corn rows with spacing of both 40 cm and 50 cm(p < 0.05), while one pea plant inserting and one or two pea plants inserting with 60 cm row spacing had no significant effects on total seed yield(p > 0.05) compared to the corn monocultulre with the same plant spacings in 2014. In 2015, in contrast, when one or two pea plants were intercropped into the corn rows with plant spacings of 40 and 50 cm, no significant effects of intercropping peas and co rns were found even though there was an increasing trend in total seed yield(p > 0.05), total seed yield increased significantly only when two pea plants were intercrroped into the rows with spacing of 60 cm(p < 0.05).Aboveground biomass of one plant corn increased with corn plant spacing increased; The treatments of corn plant spacing was 60 cm in corn monoculture and within- row- intercropping of inserting one pea had higher grain yield of one plant corn than 40 cm. within-row-intercropping of inserting two peas had little effect on grain yield of one plant corn. Aboveground biomass and grain yield of peas in monoculture increased followed by plant spacing increased, and grain yield of one plant pea also had the same trend.In corn growth period soil water storage in 0~20 cm soil layer was less than 20~60 cm and 60~100 cm layer; the treatments of different corn spacing whose soil water storage had same trends in corn growth period; in corn maturity, the soil water storage in different layers had recovered, the trend of soil water storage in pea monoculture was less than corn monoculture and within-row-intercropping; after pea harvest the soil water storage relative to the treatments which contain the growth of corn planting changed little, but the trend was the same, they had ability to maintain soil moisture. The within-row-intercropping had effect on leaf area index(LAI) of corns and peas, it showed that LAI of corn and pea in within-row- intercropping in the growing season were less than corn and pea monoculture, corn in within- row- intercropping obstructed peas obsorbing sushine so made LAI of peas decrease, and the number of peas in within-row- intercropping also inhibited the increase in leaf area index of corn.In three determination of period, 0~20 cm and 20~40 cm soil microbial carbon and nitrogen, total nitrogen, organic carbon had an increasing trend and then decreasing in different treatments in 2014, while in 2015, it showed a slow upward trend. The soil nitrate content in 0~20 cm and 20~40 cm in 2014 and 2015 had shown similar trend, which was a decline then balance. Within-row intercropping which inserted one pea or two peas and different corn and pea plant spacing had no effect or had little effect on soil microbial carbon and nitrogen, total nitrogen, organic carbon. |
PDF Full Text Request