260 research outputs found
An alternative water-fertilizer-saving management practice for wheat-maize cropping system in the North China Plain: Based on a 4-year field study
No full textDeveloping an alternative water-fertilizer-saving management practice for winter wheat-summer maize double cropping system in the North China Plain (NCP) is urgent to address severe water scarcity and adverse envi ronmental impacts. A four-year field experiment in split plot design was conducted to evaluate the effects of supplemental drip irrigation on grain yield, water use efficiency (WUE), nitrogen use efficiency (NUE), nitrogen (N) loss and economic benefits, keeping three supplemental drip irrigation times (DI0, no irrigation after emergence; DI3, irrigation once at wheat jointing, once at maize seedling and once at maize jointing; DI5, irri gation once at wheat jointing, once at wheat anthesis, once at maize seedling, once at maize jointing and once at maize tasseling) in the main plots and three N fertilizer rates (N0, no N fertilizer; N60%, 60% of the localrec ommended N fertilizer rate, 272 kg N ha− 1 yr− 1; N100%, 100% of the local recommended N fertilizer rate, 453 kg N ha− 1 yr− 1) in the sub plots. The traditional surface irrigation regime was also conducted as control (CK) under local recommended N fertilizer at 453 kg N ha− 1 yr− 1. The results showed that DI5N60% achieved the highest WUE in wheat (1.93 kg m− 3) and maize (3.00 kg m− 3) on average, which was 3.0% and 25.3% higher compared to CK, respectively. The highest partial factor productivity from applied N (PEPN) in wheat and maize were also observed in DI5N60% (56.8 kg kg− 1 and 56.3 kg kg− 1, respectively) on average, which was 54.0% and 74.0% higher compared to CK, respectively. For winter wheat-summer maize double cropping system, DI5N60% can generally achieve similar crop yield and net income but reduce irrigation and N fertilizer use and N loss compared to CK. Therefore, DI5N60% was considered as an alternative water-fertilizer-saving management practice for winter wheat-summer maize double cropping system in the NCP. Moreover, the optimized combi nation of irrigation amount and N fertilizer rate corresponding simultaneously to higher crop yield, WUE and net income were determined by using the response surface methodology based on binary quadratic regression analysis, and the optimal irrigation amount were 165 mm and 90 mm, optimal N rates were 186 kg N ha− 1 and 185 kg N ha− 1 for winter wheat and summer maize, respectively
Developing nitrogen management strategies under drip fertigation for wheat and maize production in the North China Plain based on a 3-year field experiment
No full textThe intensive winter wheat (Triticum aestivum L.)–summer maize (Zea mays L.) cropping systems in the North China Plain (NCP) rely on the heavy use of mineral nitrogen (N) fertilizers. As the fertigated area of wheat and maize in the NCP has grown rapidly during recent years, developing N management strategies is required for sustainable wheat and maize production. Field experiments were conducted in Hebei Province during three consecutive growth seasons in 2012–2015 to assess the influence of different N fertigation rates on N uptake, yield, and nitrogen use efficiency [NUE: recovery efficiency (REN) and agronomic efficiency (AEN)]. Five levels of N application, 0 (FN0), 40 (FN40%), 70 (FN70%), 100 (FN100%), and 130% (FN130%) of the farmer practice rate (FP: 250 kg N ha−1and 205.5 kg N ha−1 for wheat and maize, respectively), corresponding to 0, 182.2, 318.9, 455.5, and 592.2 kg N ha−1 y−1, respectively, were tested. Nitrogen in the form of urea was dissolved in irrigation water and split into six and four applications for wheat and maize, respectively. In addition, the treatment “drip irrigation + 100% N conventional broadcasting” (DN100%) was also conducted. All treatments were arranged in a randomized complete block design with three replications. The results revealed the significant influence of both N fertigation rate and N application method on grain yield and NUE. Compared to DN100%, FN100% significantly increased the 3‐year averaged N recovery efficiency (REN) by 0.09 kg kg−1 and 0.04 kg kg−1, and the 3‐year averaged N agronomic efficiency (AEN) by 2.43 kg kg−1 and 1.62 kg kg−1 for wheat and maize, respectively. Among N fertigation rates, there was no significant increase in grain yield in response to N applied at a greater rate than 70% of FP due to excess N accumulation in vegetative tissues. Compared to FN70%, FN100%, and FN130%, FN40% increased the REN by 0.17–0.57 kg kg−1 and 0.03–0.34 kg kg−1and the AEN by 4.60–27.56 kg kg−1 and 2.40–10.62 kg kg−1 for wheat and maize, respectively. Based on a linear‐response relationship between the N fertigation rate and grain yield over three rotational periods it can be concluded that recommended N rates under drip fertigation with optimum split applications can be reduced to 46% (114.6 kg N ha−1) and 58% (116.6 kg N ha−1) of FP for wheat and maize, respectively, without negatively affecting grain yield, thereby increasing NUE
A New Method to Assess the Infiltration Rate in Large Commercial Complex in Beijing, China
No full textAbstractIn China, large commercial complex is a new type of building with complicated type of business and high energy consumption. The energy performance of building significantly depends on the ventilation, which is affected by air infiltration through the uncontrolled air leakage across the building envelope. It is important for improving the building energy performance and reducing the air conditioning load to learn the infiltration rate in a commercial complex. Currently, the testing method of infiltration rate commonly used in some cases fails to measure the infiltration rate in a large commercial building continuously for a period of time. In this paper, a new method using the principle of mass balance relationship between indoor and outdoor particles was put forward. Then a field testing was conducted in a commercial complex in Beijing, China and the calculation result of infiltration rate based on the measurement data using the new method was verified according to airflow mass balance in the whole building. This method makes it easier to assess the infiltration rate in a large commercial complex and learn the change of infiltration rate in a period time. It can also help find out the main sources of indoor particle and improve the indoor air quality
Certification of the ethical review for the experiment
No full textEthical review document on driver behavio
Apply the contour integral on multivalued function from the complex plane
No full textThis paper mainly intends to integrate the multivalued function on the complex plane by using contour integral. The improper integral of a single-valued function on the real plane is often difficult to solve directly. In addition to solving the integral itself, we also need to judge its convergence and divergence. In order to solve integral of this kind, this paper extends its domain onto the complex plane. Then, we can find that this kind of function may become a complex multivalued function on the complex plane. However, if we use the contour integral, we can deal with the complex-valued function efficiently and then obtain the solution of the integral. Using contour integral to solve the integral in the complex field is applied in many fields. Contour integral can be used to solve partial differential equations, which can be applied in electrodynamics, quantum mechanics, hydrodynamics, and other fields
Robust Exponential Stability of Impulsive Stochastic Neural Networks with Markovian Switching and Mixed Time-varying Delays
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