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To explore the mechanism of increasing yield and benefit of millet-soybean intercropping in loess hilly and gully region, in this study, 5 treatments including SG(millet), SD(soybean), I22(millet-soybean row ratio 2∶2), I24(2∶4), and I42(4∶ 2) were set, the effects of different intercropping treatments on population photosynthetic characteristics, agronomic traits, and yield benefit were comprehensively analyzed. The results showed that net photosynthetic rate, transpiration rate, and stomatal conductance of millet in intercropping were generally higher than those in monoculture, and intercellular CO2 concentration in monoculture was higher than that in intercropping. The net photosynthetic rate, transpiration rate, and stomatal conductance of intercropping I24 at filling stage were significantly higher than those in I22 and I42. Net photosynthetic rate, transpiration rate, and stomatal conductance of soybean in monoculture were generally higher than those in intercropping. The average plant height, stem diameter, and dry matter accumulation in the entire growth period of millet in intercropping were higher than those in monoculture. The plant height at harvest stage of millet in I24 treatment were significantly higher than that in SG and I22 treatment at maturity, and the stem diameter was significantly higher than that in SG and I42 treatment, the dry matter accumulation was significantly higher than that in SG. The average plant height of soybean in intercropping was higher than that of monoculture, the stem diameter and dry matter accumulation in intercropping were lower than those in monoculture, and the agromic traits in I24 treatment were better than those in I22 and I42. The yield of millet in intercropping was higher than that in monoculture, and the yield in I24 was 45.17%, 13.14%, and 25.66% higher than that in SG, I22, and I42, respectively. The yield of soybean in intercropping was slightly lower than that in monoculture, without significant difference. The total yield in intercropping was higher than that in monoculture millet and monoculture soybean, with intercropping advantage, and the yield in I24 was significantly higher than that in other treatments, with the best economic benefit. [ABSTRACT FROM AUTHOR]

In order to clarify the irrigation system of high yield and high quality cultivation of Astragalus mongholicus in arid regions in northern Shaanxi, explore the influence of different irrigation amounts on the quality and yield of Astragalus mongholicus. In this study, with Astragalus mongholicus as the experimental material, six treatments of irrigation amounts including 5 240(W1), 4 190(W2), 3 140(W3), 2 090(W4), 1 040(W5), and 0(CK) m3 /ha were set, and the differences in soil water content, dry matter mass, root crown ratio, agronomic traits, yield, and quality of Astragalus mongholicus were analyzed. The results indicated that 0-60 cm, the soil water content in the treatments of W1, W2, W3, W4, and W5 increased by 50.1%, 30%, 19.8%, 19.6%, and 14.6%, respectively compared with CK. Root crown ratio at harvest stage in the treatments of W2, W3, and W5 increased by 61%, 38% and 36% compared with CK, respectively. The plant height, stem thickness and crown amplitude of Astragalus mongholicus increased with the increase of irrigation amount, the values reached the maximum at W2 treatment, then declined. Yield in the treatments of W2 increased by 53% compared with CK. In terms of the quality of Astragalus mongholicus, in treatment W3, the Astragalus methylside content was 0.131%, the Myislavone glucoside content was 0.22%, they were higher than those in other treatments. The correlation analysis found that root dry weight, root fresh weight, stem and leaf dry weight, and crown amplitude were siginificantly positively correlated with yield. In conclusion, the suitable irrigation amounts of high yield and high quality of Astragalus mongholicus planted in the arid regions in northern Shaanxi was 3 140-4 190 m³ /ha. [ABSTRACT FROM AUTHOR]

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To explore the best intercropping method of millet and soybean under interfilm cultivation conditions in the loess hilly-gully region of northern Shaanxi, a single-factor randomized block experimental design was used to set up 5 treatments,including 2 rows of millet with 2 rows of soybean intercropping(I22), 2 rows of millet with 4 rows of soybean intercropping(I24),4 rows of millet with 2 rows of soybean intercropping(I42), millet in single cropping（SG）, and soybean in single cropping（SD）.Characteristics such as dry matter accumulation and distribution, interspecific competitiveness, and their effects on the yield of millet and soybean under different intercropping patterns were analyzed. The results showed as follows. The dry matter accumulation of millet was significantly increased by the three intercropping treatments, and it was significantly higher in the I24treatment than that in the I42 treatment. At the booting stage, the dry matter allocation ratio to leaves was greater than that to stems. At the maturity stage, the dry matter allocation ratio to spikes was greater than that to leaves and stems. The dry matter allocation ratios of the three intercropping treatments were significantly higher than those of the single cropping, with I24 and I22treatments being significantly higher than the I42 treatment. The dry matter accumulation of soybean was significantly increased by the three intercropping treatments. At the flowering stage, the dry matter allocation ratio to leaves was greater than that to stems.At the maturity stage, the allocation ratio to pods was greater than that to the stems and leaves. Among the three intercropping treatments, the pod allocation ratios were significantly higher than those of the single cropping, with no significant differences observed among the intercropping treatments themselves. The land equivalent ratio for the I24 and I42 intercropping treatments was 1.10 and 1.06, respectively, increasing land productivity by 6%-10% and highlighting the benefits of intercropping. The I22intercropping treatment had a land equivalent ratio of 1.00, indicating no intercropping advantage. Under the intercropping treatments, millet demonstrated stronger interspecific competitiveness（AG＞0） and a higher yield nutrient competition ratio（CRG＞1） than soybean. The I24 treatment had significantly lower interspecific competition than the I42 and I22 treatments. In conclusion,the 2 rows of millet with 2 rows of soybean intercropping was the most effective millet soybean intercropping method in the loess hilly-gully region of northern Shaanxi. MoreReset [ABSTRACT FROM AUTHOR]

By the use of conventional meteorological and NCEP reanalysis data, the abnormal circulation and its effects on an extraordinary severe flood-causing rainstorm which occurred in the evening of August 21, 2016, along the Helan Mountain, was analyzed. Based on simulation of Weather Research and Forecasting model and sensitivity studies, the impacts of topography on rainstorm were explored. The results show that:the development of atmospheric circulation during midsummer appeared abnormal features after the strong El Niño. The South Asian high and subtropical high were abnormally strong in August. The eastern part of the Northwestern China was under the control of air with high temperature, high humidity and high energy. In this background, the rapid advance and retreat of the subtropical high, and the invasion of cold advection triggered the intense accumulation and rapid release of warm and wet unstable energy, which ultimately led to the outbreak of extraordinary severe rainstorm. The rainstorm occurred in the diversion area of high-level jet at 200hPa, which was correspond to the divergence zone, and in the southwest airflow region with high temperature and high humidity at middle atmosphere, in the strong warm advection area at the maximum bend of the left-side of the low-level south jet, and in the convergence zone at the south side of axis of easterly wind speed at 850hPa. The weather scale forcing of this rainstorm is relatively weak, with the combined action of the short wave trough at 500hPa, the low vortex shear at 700hPa and 850hPa, the southerly jet at 700hPa and easterly jet at 850hPa, and cyclonic shearing convergence line on the ground, played the main role in occurrence of this rainstorm. On the other hand, the terrain obstruction and forced uplift function of Helan Mountain promoted the intensify of vortex shear at low level, which enhanced the development of rainstorm, affected the precipitation range, strong precipitation area and central position through the influence of the weather system, etc. [ABSTRACT FROM AUTHOR]