[Soil bacterial community characteristics and ecological function prediction of alfalfa and crop rotation systems in the Loess Plateau, Northwest China]. / 黄土高原苜蓿-粮食作物轮作下土壤细菌群落特征和生态功能预测.

In order to understand the effects of lucerne cropping rotation on the bacterial community of loess soil, a long-term field experiment was conducted in rain-fed agricultural area of Loess Plateau. The cropping systems included continuous lucerne (Medicago sativa, LC), lucerne removed and rotated with spring wheat (Triticum aestivum, LFW), lucerne removed and rotated with corn (Zea mays, LFC), lucerne removed and rotated with potato (Solanum tuberosum, LP), and lucerne removed and rotated with continuous millet (Panicum miliaceum, LM). Based on 16S rRNA high-throughput sequencing technology, we investigated soil bacterial community structure and diversity in different cropping systems, and predicted ecological function using PICRUSt method. The results showed that the dominant phyla of loess soil bacteria were Actinomycetes (20.3%-32.0%), Proteobacteria (19.2%-23.0%), Acidobacteria (12.4%-14.2%) and Chloroflexus (11.0%-12.7%). The dominant genus was Bacillus (1.9%) in lucerne-corn system and Pseudarthrobacter (2.5%) in other treatments. Rotation with annual crops decreased the relative abundance of Actinobacteria and increased that of Chloroflexi and Firmicutes. Redundancy analysis showed that the main soil factors driving soil bacterial community structure were nitrate, ammonium, and total nitrogen. PICRUSt function prediction results showed that metabolism (78.6%-79.1%) was the main function of soil bacterial communities in loess soil. Rotation with continued annual crops significantly decreased the abundance of soil bacterial carbohydrate metabolism functional genes, and significantly increased the abundance of functional genes for soil bacterial cofactors and vitamin metabolism, neurodegenerative diseases, and immune system. In conclusion, lucerne removed and rotated with continuous annual crops changed soil bacterial community structure and ecological functions. This study provided theoretical reference to explore succession characteristics of soil bacteria and to select succeeding crops for alfalfa in loess soil.

[Effects of the substitution of inorganic nitrogen by organic nitrogen fertilizer on maize grain yield and water and nitrogen use efficiency under plastic film fully mulched ridge-furrow in semi-arid area]. / æœ‰æœºæ°®æ›¿ä»£æ— æœºæ°®å¯¹æ—±ä½œå ¨è†œåŒåž„æ²Ÿæ’­çŽ‰ç±³äº§é‡å’Œæ°´æ°®åˆ©ç”¨æ•ˆçŽ‡çš„å½±å“.

To improve water and nitrogen (N) fertilizer use efficiency, increase sustainable agricultural production, and explore the appropriate substitution level of inorganic N fertilizer by organic fertilizer in the semi-arid region of the western Loess Plateau, a three-year field experiment was conducted at the Dingxi Agri-ecological Station in 2016-2018. We examined the effects of commercial organic fertilizer substitution on maize grain yield as well as the use efficiency of water and N fertilizer under plastic film fully mulched ridge-furrow in dryland. There were six fertilizer treatments: T1, N fertilizer without organic fertilizer; T2, substitution 50% inorganic-N with organic-N; T3, substitution 37.5% inorganic-N with organic-N; T4, substitution 25% inorganic-N with organic-N; T5, substitution 12.5% inorganic-N with organic-N; and CK, no N fertilizer. The results showed that treatments of commercial organic fertilizer substitution (T2-T5) had higher grain yield and water and N efficiency than that in T1 treatment in dry year under 200 kg N·hm-2. The changes in grain yield and water and N fertilizer efficiency had no significant difference in treatments of commercial organic fertilizer substitution compared to T1 treatment in wet year. T2 and T3 treatments increased grain yield by 15.6% and 18.2%, and with 35.1% and 27.0% enhancement in harvest index compared to T1. T2 and T3 treatments increased water use efficiency, rainfall use efficiency, N agrono-mic efficiency and partial productivity of N fertilizer by 17.4% and 22.3%, 15.7% and 17.7%, 15.6% and 18.0%, 155.2% and 179.3%. These results demonstrated that under the same N input level, 50% and 37.5% substitution inorganic-N with organic-N could be a suitable substitution rate under plastic film fully mulched ridge-furrow, which could be recommended as a fertilizer application pattern in this area.

[Effects of plastic film mulching patterns on maize grain yield, water use efficiency, and soil water balance in the farming system with one film used two years.] / 覆膜方式对一膜两年覆盖旱地玉米籽粒产量、水分利用效率和土壤水分平衡的影响.

The aim of this study was to develop cost-saving and efficiency-improving technologies in whole plastic mulching and double ridge-furrow maize in semi-arid region of Loess Plateau. The objective was to investigate soil water balance in farming system with one film used two years. A field experiment was conducted to investigate the effects of different mulching and tillage patterns under one film used two years conditions on the yield, economic benefits, and water use efficiency of maize. There are four treatments: Ridge-furrow planting with complete plastic film mulching, F1M; flat-planting with complete plastic film mulching, F2M; flat-planting with half plastic film mulching, F3M; and flat-planting without mulching, F4M, the control. The results showed that the F1M and F2M treatments had significant effects on the improvement of the production and efficiency compared with the control. The F1M and F2M treatments improved biomass by 32.8% and 32.9%, enhanced grain yield by 60.0% and 51.7%. Water use efficiency and rainfall use efficiency in F1M and F2M treatments were increased by 59.8%, 35.9% and 87.6%, 64.4%, respectively. Furthermore, gross output value and input-output ratio of F1M and F2M treatments under every new plastic film mulched pattern were enhanced by 51.0%, 41.2% and 15.1%, 16.2%, respectively. The production pattern on cost-saving and efficiency-increasing of the system on double ridge-furrow and flat planting with one film used two years, this pattern increased gross output value by 40.8%, 42.2%, and increased input-output ratio by 40.3%, 42.2%, respectively. Under the condition of low precipitation (606.5 mm), total water consumption of ridge-furrow and flat planting under the system of one film used within two years was 731.3 mm and 746.8 mm, the soil moisture deficit was 124.8 mm and 140.3 mm, with enhancement of 22.7% and 38.0%, respectively. The total water consumption of ridge-furrow and flat planting treatments was reduced by 28.6% and 30.0%, and the fallow efficiency was improved by 178.9% and 148.3%. In conclusion, whole plastic mulching with double ridge-furrow and flat planting farming system had positive effects on yield and water use efficiency in semi-arid region of Loess Plateau. Combined with the technology of one film used within two years, this cropping system could be cost saving and efficiency increasing. However, the water deficit under low water condition should be seriously considered in practice.

[Soil dryness characteristics of alfalfa cropland and optimal growth years of alfalfa on the Loess Plateau of central Gansu, China].

This paper investigated soil moisture in alfalfa (Medicago sativa) cropland with different growth years (1, 3, 8, 12 and 14 years) and discussed the optimum growth years of alfalfa on the Loess Plateau of central Gansu. The results showed that the soil moisture along 0-300 cm soil profile of alfalfa croplands with different growth years was obviously lower than that of the local soil stable moisture. The soil water contents in croplands with alfalfa that had grown for 12 and 14 years were only 9.2% and 7.1% of local soil stable moisture, respectively, which were even lower than the lower limit of alfalfa growth. The average soil dryness indexes along 0-300 cm soil profile in 1, 3, 8, 12 and 14 years alfalfa croplands were 125.4%, 30.5%, 18.4%, -34.2% and -83.3% respectively. The results indicated that soil dryness occurred to varying degrees with different growth years except croplands with alfalfa grown for 1 year. With the increase of growth years of alfalfa, the soil dryness intensity increased and the soil dryness rate decreased. According to the soil moisture and alfalfa productivity results in this study, it could be concluded that the optimum growth years of alfalfa are 8-10 years in semiarid areas of the Loess Plateau.

[Differences between clinical response and pathologic response of breast cancer after neoadjuvant chemotherapy].

OBJECTIVE: to investigate the pathologic basis of the difference between clinical response and pathologic response of breast carcinoma after neoadjuvant chemotherapy. METHODS: two hundred and nine cases of breast cancer with neoadjuvant therapy were analyzed and clinical data were collected from June, 2005 to December, 2007. All patients had core needle biopsy taken before neoadjuvant chemotherapy and were operated within 4 weeks after neoadjuvant chemotherapy. Clinical examination, X-ray of breast and/or B ultrasonography of primary breast focus were taken before and after neoadjuvant chemotherapy. Clinical responses of breast primary focus were evaluated according to RECIST (response evaluation criteria in solid tumors) version 1.1.Pathologic responses of breast primary focus were evaluated according to Miller and Payne (MP) grading system. SPSS 15.0 software was used to statistical analysis. RESULTS: (1) Clinical responses basing on clinical examination showed complete response, partial response, stable disease and progressive response, in 33, 124, 41 and 11 cases respectively. (2) Eighty-seven cases had X-ray of breast taken before and after neoadjuvant chemotherapy. Clinical response basing on X-ray, showed complete response, partial response and stable disease in 8, 42 and 37 cases respectively. (3) Pathologic responses of breast primary focus were as MP1 (14 cases), MP2 (35 cases), MP3 (106 cases), MP4 (36 cases) and MP5 (18 cases). (4) The clinical response basing on clinical examination were related to the pathologic response (χ(2) = 33.668, P = 0.001); and the clinical response basing on X-ray of breast were also related to the pathologic response (χ(2) = 22.404, P = 0.004). (5) The pathologic basis of the difference between the pathologic response and the clinical response basing on X-ray of breast were: embolism of carcinoma, mucinous carcinoma, intraductal carcinoma with ossifying-type calcification, nodular fibrosis and others. CONCLUSIONS: the clinical response may be related to the pathologic response. The difference between the two may be caused by pathologic changes. Some benign and malignant pathologic changes may contribute to the under-estimation of clinical response over pathologic response; whereas embolism of carcinoma may contribute to the over-estimation of clinical response over pathologic response.

[Effects of different tillage measures on upland soil respiration in Loess Plateau].

A field experiment was conducted in Lijiabu Town of Dingxi City, Gansu Province to study the soil respiration and its relations with the canopy temperature and soil moisture content in a rotation system with spring wheat and pea under effects of different tillage measures. Six treatments were installed, i.e., tillage with no straw- or plastic mulch (conventional tillage, T), tillage with straw mulch (TS), tillage with plastic mulch (TP), no-tillage (NT), no-tillage with straw mulch (NTS), and no-tillage with plastic mulch (NTP). During the growth periods of spring wheat and pea, soil respiration had different change patterns, with the peaks appeared at the early jointing, grain-filling, and maturing stages of spring wheat, and at the 5-leaf, silking, flowering and poding, in spring wheat field between treatments NTS and T, and the soil respiration rate was significantlyand maturing stages of pea. There was an obvious difference in the diurnal change of soil respiration lower in NTS than in T; while the soil respiration in pea field had less diurnal chan ge. Soil respiration rate had a significant linear relationship with the canopy temperature of both spring wheat andpea, the correlation coefficient being the highest at booting stage of spring wheat and at flowering and poding stage of pea, followed by at grain-filling stage of spring wheat and at branching stage of pea. There was also a significant parabola relationship between soil respiration rate and soil moisture content, the correlation coefficient being higher under conservation tillage than under conventional tillage, with the highest under NTS. The moisture content in 10-30 cm soil layer of spring wheat field and that in 5-10 cm soil layer of pea field had the greatest effects on soil respiration. Comparing with conventional tillage, all the five conservation tillage measures decreased soil respiration, with the best effects of no-tillage with straw mulch.

[Animal community structure in greenhouse soils with different planting years in Shouguang City].

By the methods of hand-sorting, Tullgren's and Baermann's, the animal community structure in greenhouse soils with different planting years in Shouguang City of Shandong Province was investigated from March 2006 to April 2007. A total of 20966 soil animals belonging to 3 phylums and 12 classes were obtained. Collembola, Nematoda, Acariformes and Oribatida were the dominant groups, accounting for 82.3% of the total individuals. The soil animals had an obvious vertical distribution pattern, with most of them assembled in surface soil and occupying 75.4% and 14.6% of the total at the depths of 0-5 cm and 5-10 cm, respectively. The animals' amount in greenhouse soils was the highest from March to May and from October to December, and the lowest in August; while that in open field soils was the highest from July to September, and the lowest in January. The animal community in greenhouse soils in this region had a high diversity, but the density of dominant groups increased obviously with increasing planting years, resulting in a decrease of diversity index.

[Leaf water potential of spring wheat and field pea under different tillage patterns and its relationships with environmental factors].

Based on a long-term experiment, the leaf water potential of spring wheat and field pea, its relationships with environmental factors, and the diurnal variations of leaf relative water content and water saturation deficient under different tillage patterns were studied. The results showed that during whole growth period, field pea had an obviously higher leaf water potential than spring wheat, but the two crops had similar diurnal variation trend of their leaf water potential, i.e., the highest in early morning, followed by a descent, and a gradual ascent after the descent. For spring wheat, the maximum leaf water potential appeared at its jointing and heading stages, followed by at booting and flowering stages, and the minimum appeared at filling stage. For field pea, the maximum leaf water potential achieved at squaring stage, followed by at branching and flowering stages, and the minimum was at podding stage. The leaf relative water content of spring wheat was the highest at heading stage, followed by at jointing and flowering stages, and achieved the minimum at filling stage; while the water saturation deficient was just in adverse. With the growth of field pea, its leaf relative water content decreased, but leaf water saturation deficient increased. The leaf water potential of both spring wheat and field pea had significant correlations with environmental factors, including soil water content, air temperature, solar radiation, relative air humidity, and air water potential. Path analysis showed that the meteorological factor which had the strongest effect on the diurnal variation of spring wheat' s and field pea' s leaf water potential was air water potential and air temperature, respectively. Compared with conventional tillage, the protective tillage patterns no-till, no-till plus straw mulching, and conventional tillage plus straw returning increased the leaf water potential and relative water content of test crops, and the effect of no-till plus straw mulching was most significant.