Interactive Effects of Water and Fertilizer on Yield, Soil Water and Nitrate Dynamics of Young Apple Tree in Semiarid Region of Northwest China

Exploring the interactive effect of water and fertilizer on yield, soil water and nitrate dynamics of young apple tree is of great importance to improve the management of irrigation and fertilization in the apple-growing region of semiarid northwest China. A two-year pot experiment was conducted in a mobile rainproof shelter of the water-saving irrigation experimental station in Northwest A&F University, and the investigation evaluated the response of soil water and fertilizer migration, crop water productivity (CWP), irrigation water use efficiency (IWUE), partial factor productivity (PFP) of young apple tree to different water and fertilizer regimes (four levels of soil water: 75%–85%, 65%–75%, 55%–65% and 45%–55% of field capacity, designated W1, W2, W3 and W4, respectively; three levels of N-P2O5-K2O fertilizer, 30-30-10, 20-20-10 and 10-10-10 g plant−1, designated F1, F2 and F3, respectively). Results showed that F1W1, F2W1 and F3W1 had the highest average soil water content at 0~90 cm compared with the other treatments. When fertilizer level was fixed, the average soil water content was gradually increased with increasing irrigation amount. For W1, W2, W3 and W4, high levels of water content were mainly distributed at 50~80 cm, 40~70 cm, 30~50 cm and 10~30 cm, respectively. There was no significant difference in soil water content at all fertilizer treatments. However, F1 and F2 significantly increased soil nitrate-N content by 146.3%~246.4% and 75.3%~151.5% compared with F3. The highest yield appeared at F1W1 treatment, but there was little difference between F1W1 and F2W2 treatment. F2W2treatment decreased yield by 7.5%, but increased IWUE by 11.2% compared with F1W1 treatment. Meanwhile, the highest CWP appeared at F2W2 treatment in the two years. Thus, F2W2 treatment (soil moisture was controlled in 65–75% of field capacity, N-P2O5-K2O were controlled at 20-20-10 g·tree−1) reached the best water and fertilizer coupling mode and it was the optimum combinations of water and fertilizer saving

Long-term manure and cropping systems effect on soil water vapour sorption characteristics is controlled by soil texture

Increasing studies indicate that long-term experiments (LTEs) involving manure application and optimal cropping systems can significantly improve soil physicochemical properties, which may also affect the soil water retention curve (WRC) in the wet region (pF 4.2) as well as the associated soil physicochemical properties. To overcome this knowledge gap, we investigated the effect of long-term manure application (24 to 177 years) and different cropping systems (71 to 82 years) on soil organic carbon (SOC) content, WSIs, hysteresis, and specific surface area (SSA). Soil samples were collected from five long-term manure experiments in Sweden, the United Kingdom, Spain, Germany, and Denmark, and two long-term cropping systems experiments in the United Kingdom. The five manure LTEs comprised three soil textures (silty clay, silt loam, and sandy loam) with one to four crops grown in the fields, including wheat, barley, maize, and grass/clover. The cropping system LTEs comprised silt loam and sandy loam including bare fallow (BF), arable rotation, ley–arable rotation, and permanent grass. Results showed that long-term manure application increased SOC content in each site, but it had little effect on the soil WSIs, hysteresis, and SSA in silty clay soils. The changes of soil WSIs, hysteresis, and SSA in silt loam and sandy loam arising from manure application largely depend on the crops grown in the field. For the long-term cropping systems experiments, permanent grass had the most significant effect in increasing SOC content, soil WSIs in silt loam and sandy loam, and hysteresis and SSA in silt loam compared to other treatments. Compared to BF, arable rotation and ley-arable rotation had no effect on SOC and soil WSIs in silt loam, and on hysteresis and SSA in silt loam and sandy loam. Multiple linear regression models including SOC, clay, and silt contents sufficiently explained the variabilities observed in the soil WSIs, hysteresis, and SSA for both manure and cropping systems LTEs

The Liver Tumor Segmentation Benchmark (LiTS)

In this work, we report the set-up and results of the Liver Tumor Segmentation Benchmark (LITS) organized in conjunction with the IEEE International Symposium on Biomedical Imaging (ISBI) 2016 and International Conference On Medical Image Computing Computer Assisted Intervention (MICCAI) 2017. Twenty four valid state-of-the-art liver and liver tumor segmentation algorithms were applied to a set of 131 computed tomography (CT) volumes with different types of tumor contrast levels (hyper-/hypo-intense), abnormalities in tissues (metastasectomie) size and varying amount of lesions. The submitted algorithms have been tested on 70 undisclosed volumes. The dataset is created in collaboration with seven hospitals and research institutions and manually reviewed by independent three radiologists. We found that not a single algorithm performed best for liver and tumors. The best liver segmentation algorithm achieved a Dice score of 0.96(MICCAI) whereas for tumor segmentation the best algorithm evaluated at 0.67(ISBI) and 0.70(MICCAI). The LITS image data and manual annotations continue to be publicly available through an online evaluation system as an ongoing benchmarking resource.Comment: conferenc

Optimal Drip Fertigation Regimes Improved Soil Micro-Environment, Root Growth and Grain Yield of Spring Maize in Arid Northwest China

Understanding the spatial distributions of soil water, temperature and nutrients as well as their effects on maize growth and grain yield is vital for optimizing drip fertigation regimes. In this study, a 2 year field experiment was conducted on drip-fertigated spring maize with plastic mulching in arid northwestern China in 2015 and 2016. Four irrigation levels were set: as I60 (60% ETc; ETc is crop evapotranspiration), I75 (75% ETc), I90 (90% ETc) and I105 (105% ETc) in 2015; and as I60 (60% ETc), I80 (80% ETc), I100 (100% ETc) and I120 (120% ETc) in 2016. Two fertilization rates of N-P2O5-K2O were set: as F180 (180-90-90) and F240 (240-120-120). The results showed that the average soil water content in the deeper soil layer (80–120 cm) increased with the increase in irrigation level, and the lowest average soil water content in the 0–80 cm soil layer occurred under I95 in 2015 and under I100 in 2016. The irrigation level more significantly influenced the soil temperature at 5 cm than at the other depths. With the decrease in the irrigation level and progression of the growth period, the soil temperature increased. The soil nitrate nitrogen content in the root zone decreased with increasing irrigation level. The largest soil nitrate nitrogen content at the 0–100 cm depth occurred under I60 in both 2015 and 2016. Significant differences were observed for root length density in the 0–20 cm soil layer at various lateral locations. In deeper (60–100 cm) soil layers, the root length density under I75 (2015) and I80 (2016) was greater than at other depths. Grain yield, water use efficiency (WUE) and partial factor productivity (PFP) increased with the increase in irrigation level in 2015, while it increased and then decreased in 2016. I105F180 achieved the maximum grain yield (18.81 t ha−1), WUE (3.32 kg m−3), and PFP (52.26 kg kg−1) in 2015, while I100F180 achieved the maximum grain yield (20.51 t ha−1), WUE (3.99 kg m−3), and PFP (57.02 kg kg−1) in 2016. The optimal drip fertigation regimes for spring maize in arid northwest China were recommended as 90–100% ETc and 180-90-90 (N-P2O5-K2O) kg hm−2

A marker-based watershed method for X-ray image segmentation

Digital X-ray images are the most frequent modality for both screening and diagnosis in hospitals. To facilitate subsequent analysis such as quantification and computer aided diagnosis (CAD), it is desirable to exclude image background. A marker-based watershed segmentation method was proposed to segment background of X-ray images. The method consisted of six modules: image preprocessing, gradient computation, marker extraction, watershed segmentation from markers, region merging and background extraction. One hundred clinical direct radiograph X-ray images were used to validate the method. Manual thresholding and multiscale gradient based watershed method were implemented for comparison. The proposed method yielded a dice coefficient of 0.964 ± 0.069, which was better than that of the manual thresholding (0.937 ± 0.119) and that of multiscale gradient based watershed method (0.942 ± 0.098). Special means were adopted to decrease the computational cost, including getting rid of few pixels with highest grayscale via percentile, calculation of gradient magnitude through simple operations, decreasing the number of markers by appropriate thresholding, and merging regions based on simple grayscale statistics. As a result, the processing time was at most 6 s even for a 3072 × 3072 image on a Pentium 4 PC with 2.4 GHz CPU (4 cores) and 2G RAM, which was more than one time faster than that of the multiscale gradient based watershed method. The proposed method could be a potential tool for diagnosis and quantification of X-ray images

Effects of Soil Water Deficit at Different Growth Stages on Maize Growth, Yield, and Water Use Efficiency under Alternate Partial Root-Zone Irrigation

To investigate the effects of alternate partial root-zone irrigation (APRI) and water deficit at different growth stages on maize growth, physiological characteristics, the grain yield, and the water use efficiency (WUE), a pot experiment was conducted under a mobile automatic rain shelter. There were two irrigation methods, i.e., conventional irrigation (CI) and APRI; two irrigation levels, i.e., mild deficit irrigation (W1, 55%~70% FC, where FC is the field capacity) and serious deficit irrigation (W2, 40%~55% FC); and two deficit stages, i.e., the seedling (S) and milking stage (M). Sufficient irrigation (W0: 70%~85% FC) was applied throughout the growing season of maize as the control treatment (CK). The results indicated that APRI and CI decreased the total water consumption (ET) by 34.7% and 23.8% compared to CK, respectively. In comparison to CK, APRI and CI increased the yield-based water use efficiency (WUEY) by 41% and 7.7%, respectively. APRI increased the irrigation water efficiency (IWUE) and biomass-based water use efficiency (WUEB) by 8.8% and 25.5% compared to CK, respectively. Additionally, ASW1 had a similar grain yield to CK and the largest harvest index (HI). However, the chlorophyll and carotenoid contents were significantly reduced by 13.7% and 23.1% under CI, and by 11.3% and 20.3% under APRI, compared to CK, respectively. Deficit irrigation at the milking stage produced a longer tip length, resulting in a lower grain yield. Based on the entropy weight method and the technique for order preference by similarity to an ideal solution (TOPSIS) method, multi-objective optimization was obtained when mild deficit irrigation (55%~70% FC) occurred at the seedling stage under APRI

Water-use efficiency and physiological responses of maize under partial root-zone irrigation

Alternate partial root-zone irrigation (APRI) is a water-saving irrigation method but also can regulate crop physiological responses. This study investigated how water-use efficiency (WUE) and other physiological responses were regulated at different growth stages when maize plants were applied with APRI and how these responses were recovered to control levels when full irrigation was resumed. A pot experiment was carried out at two fertilization levels and with three irrigation methods at the jointing stage (29-38 days after sowing) or during the jointing and tasselling stages (29-77 days after sowing). The irrigation methods included the conventional irrigation (CI), APRI and fixed PRI (FPRI, watering was fixed to one side). Compared to the CI, APRI at the jointing stage for 10 days or during the jointing and tasselling stages for 49 days reduced water consumption by 10.6-12.9 and 31.7-32.4%, respectively, but did not reduce total dry mass accumulation significantly, thus increased canopy WUE by 10.4-13.6 and 41.2-41.8%, respectively. FPRI reduced the total dry mass significantly even though it also improved canopy WUE. APRI had slight effect on the leaf relative water content (RWC), chlorophyll (Chl), carotenoid (CAR), proline (Pro) and malondialdehyde (MDA) contents and superoxide dismutase (SOD) and peroxidase (POD) activities from jointing to tasselling stages but recovery to the levels of CI was rapid after receiving full watering. In comparison, FPRI treatment significantly reduced leaf RWC, Chl and CAR contents and SOD and POD activities and increased the Pro and MAD contents. After receiving full watering, the above-mentioned physiological indexes in FPRI could not recover fully to the levels of CI. High fertilization treatment only increased leaf Chl content significantly and contributed little to the total dry mass accumulation. Our result suggests that APRI can make plants use water and nutrients more efficiently with better drought tolerance.Water-use efficiency Biomass accumulation Soil fertilization Growth stage Maize (Zea mays)

Effects of Soil Water Deficit at Different Growth Stages on Maize Growth, Yield, and Water Use Efficiency under Alternate Partial Root-Zone Irrigation

To investigate the effects of alternate partial root-zone irrigation (APRI) and water deficit at different growth stages on maize growth, physiological characteristics, the grain yield, and the water use efficiency (WUE), a pot experiment was conducted under a mobile automatic rain shelter. There were two irrigation methods, i.e., conventional irrigation (CI) and APRI; two irrigation levels, i.e., mild deficit irrigation (W1, 55%~70% FC, where FC is the field capacity) and serious deficit irrigation (W2, 40%~55% FC); and two deficit stages, i.e., the seedling (S) and milking stage (M). Sufficient irrigation (W0: 70%~85% FC) was applied throughout the growing season of maize as the control treatment (CK). The results indicated that APRI and CI decreased the total water consumption (ET) by 34.7% and 23.8% compared to CK, respectively. In comparison to CK, APRI and CI increased the yield-based water use efficiency (WUEY) by 41% and 7.7%, respectively. APRI increased the irrigation water efficiency (IWUE) and biomass-based water use efficiency (WUEB) by 8.8% and 25.5% compared to CK, respectively. Additionally, ASW1 had a similar grain yield to CK and the largest harvest index (HI). However, the chlorophyll and carotenoid contents were significantly reduced by 13.7% and 23.1% under CI, and by 11.3% and 20.3% under APRI, compared to CK, respectively. Deficit irrigation at the milking stage produced a longer tip length, resulting in a lower grain yield. Based on the entropy weight method and the technique for order preference by similarity to an ideal solution (TOPSIS) method, multi-objective optimization was obtained when mild deficit irrigation (55%~70% FC) occurred at the seedling stage under APRI