Monitoring of drinking water has shown an increase in nitrate-nitrogen (NO 3 − -N) concentration in groundwater in some areas of the Heihe River Basin, Northwest China. A combination of careful irrigation and nitrogen (N) management is needed to improve N uptake efficiency and to minimize fertilizer N loss. A 2-year experiment investigated the effects of different irrigation and N application rates on soil NO 3 − -N distribution and fertilizer N loss, wheat grain yield and N uptake on recently reclaimed sandy farmland. The experiment followed a completely randomized split-plot design, taking flood irrigation (0.6, 0.8 and 1.0 of the estimated evapotranspiration) as main plot treatment and N-supply as split-plot treatment (with five levels of 0, 79, 140, 221, 300 kgN ha −1 ). Fertilizer N loss was calculated according to N balance equation. Our results showed that, under deficit irrigation conditions, N fertilizer application at a rate of 300 kgha −1 promoted NO 3 − -N concentration in 0-200 cm depth soil profiles, and treatments with 221 kgN ha −1 also increased soil NO 3 − -N concentrations only in the surface layers. Fertilizer N rates of 70 and 140 kgha −1 did not increase NO 3 − -N concentration in the 0-200 cm soil profile remaining after the spring wheat growing season. The amount of residual NO 3 − -N in soil profiles decreased with the amount of Plant Soil (2010) 337:325-339irrigation. Compared with N 0 , the increases of fertilizer N loss, in N 79 , N 140 , N 221 and N 300 respectively, were 59.9, 104.6, 143.5 and 210.6 kg ha −1 over 2 years. Under these experimental conditions, a N rate of 221 kgha −1 obtained the highest values of grain yield (2775 kgha −1 ), above-ground dry matter (5310 kg ha −1 ) and plant N uptake (103.8 kgha −1 ) over 2 years. The results clearly showed that the relative high grain yield and irrigation water productivity, and relative low N loss were achieved with application of 221 kgN ha −1 and low irrigation, the recommendation should be for those farmers who use the upper range of the recommended 150-400 kgN ha −1 , that they can save about 45% of their N and 40% of their irrigation water application.

A field study was conducted to determine runoff efficiency and the effects of different ridge: furrow ratios and ridge-covering materials on tuber yield, soil moisture storage and water use efficiency (WUE) in the ridge and furrow micro-water harvesting system in a dry semi-arid region of China, during two consecutive years of 2002 and 2003. The average runoff efficiency of ridges with compacted soil (SR) was very low (24.6-28.8%) compared to that of ridges covered with plastic film (MR) (91.1-94.3%). The minimal rainfall necessary to produce runoff was 2.76-2.78 mm for SR, only 0.23-0.47 mm for MR. The field experiments using potato as an indicator crop showed that tuber yields in the MR system were significantly higher than that in the flat planting (control), with an average increase of 158.6-175.0% during 2 years. In the SR system, the average increase was valued of 14.9-28.4% during 2 years. Regression analysis between tuber yields and ridge widths indicated the optimum ridge: furrow ratio for MR was 39: 60 cm in 2002 and 48: 60 cm in 2003 respectively. The WUE values of potato in MR were 1.50 times greater than that of the controls in 2002 and 1.62 times greater than the controls in 2003. No differences were found in the WUE between the SR and the controls on average of 2 years. Due to the different runoff efficiency between two ridge-covering materials and absence of runoff occurrence in the controls, the soil water content in the MR was higher Water Resour Manage (than that in the SR, both of which were greater than the controls. With the soil crust development, the distribution of soil water at the bottom of the furrow, at the side of the furrow and at the top of the ridge, is similar between the SR and the MR.

Shape memory polymers (SMPs) have attracted significant attention from both industrial and academic researchers, due to their useful and fascinating functionality. One of the most common and studied external stimuli for SMPs is temperature; other stimuli include electric fields, light, magnetic fields, water, and irradiation. Solutions for SMPs have also been extensively studied in the past decade. In this research, we review, consolidate, and report the major efforts and findings documented in the SMP literature, according to different external stimuli. The corresponding mechanisms, constitutive models, and properties (i.e., mechanical, electrical, optical, shape, etc.) of the SMPs in response to different stimulus methods are then reviewed. Next, this research presents and categorizes up-to-date studies on the application of SMPs in dynamic building structures and components. Following this, we discuss the need for studying SMPs in terms of kinetic building applications, especially about building energy saving purposes, and review recent two-way SMPs and their potential for use in such applications. This review covers a number of current advances in SMPs, with a view towards applications in kinetic building engineering.

Salt stress is one of the key factors that limits the cultivation of Glycyrrhiza uralensis Fisch. (G. uralensis) in the northern part of China. In this study, three salt treatments (including 21, 42 and 63 ds/m NaCl/kg dry soil) and four Si (silicon) concentrations (including 0, 1.4, 2.8 and 4.2 ds/m SiO2/kg K2SiO3 in dry soil) were tested using G. uralensis as the plant material in a pot experiment with three replications. The results showed that the application of various concentrations of Si increased sucrose synthetase (SS), sucrose phosphate synthetase (SPS) and glutamine synthetase (GS), as well as nitrate reductase (NR) activities, and promoted carbon and nitrogen metabolism. Si application also increased the root dry weight of G. uralensis. Multilevel comparative analysis showed that the application of 2.8 ds/m SiO2 was the optimum rate for improved growth and yield of G. uralensis under different salt levels. This study provides important information that can form the basis for the cultivation of high-yielding and high-quality G. uralensis in saline soils.

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