A field experiment was conducted to investigate the effects of paclobutrazol on ear characteristics and grain yield by regulating root growth and root-bleeding sap of maize crop. Seed-soaking at rate of 0 (CK1), 200 (S1), 300 (S2), and 400 (S3) mg L−1, and seed-dressing at rate of 0 (CK2), 1.5 (D1), 2.5 (D2), and 3.5 (D3) g kg−1 were used. Our results showed that paclobutrazol improved the ear characteristics and grain yield, and were consistently higher than control during 2015–2016. The average grain yield of S1, S2 and S3 were 18.9%, 61.3%, and 45.9% higher, while for D1, D2 and D3 were 20.2%, 33.3%, and 45.2%, compared to CK, respectively. Moreover, paclobutrazol-treated maize had improved root-length density (RLD), root-surface area density (RSD) and root-weight density (RWD) at most of the soil profiles (0–70 cm for seed-soaking, 0–60 cm for seed-dressing) and was attributed to enhancing the grain yield. In addition, root-activity, root-bleeding sap, root dry weight, diameter and root/shoot ratio increased by paclobutrazol, with highest values achieved in S2 and D3 treatments, across the whole growth stages in 2015–2016. Our results suggested that paclobutrazol could efficiently be used to enhance root-physiological and morphological characteristics, resulting in higher grain yield.
Building stock modeling can predict stock energy consumption and carbon emissions for both current and future conditions to inform building design and retrofitting policies. A 'bottom-up' engineering approach for building stock energy modeling is attractive to built environment energy researchers because of its capacity for detailed energy analysis. However, such studies in China have been very limited to date. The aim of this research is to develop a modeling approach to residential building stock energy consumption for space heating and cooling. A holistic four-step approach of archetype configurations; building performance simulation; stock floor area estimation and local weather adjustment is presented. The Chongqing municipality was chosen to demonstrate the approach. The results show that adopting the northern China standard pattern of central space heating for Chongqing's urban residential stock is not feasible because it dramatically increases primary energy consumption and therefore carbon dioxide emissions from space heating usage. By applying energy conservation retrofit measures to the Chongqing urban residential stock, the total energy consumption for space heating and cooling and resulting carbon dioxide emissions can be significantly reduced, with estimated reductions of 57.6% to 60.7% in 2020 and 55.3% to 57.2% in 2050. The method described can provide useful information and guidance for policymakers contemplating energy retrofit schemes.
The soil water supply is the main factor that limits dryland crop production in China. In a three-year field experiment at a dryland farming experimental station, we evaluated the effects of various straw mulch practices on soil water storage, grain yield, and water use efficiency (WUE) of winter wheat (Triticum aestivum). Field experiments were conducted with six different mulch combinations (two different mulch durations and three different mulch amounts): high (SM1; 9000 kg ha−1), medium (SM2; 6000 kg ha−1), and low (SM3; 3000 kg ha−1) straw mulch treatments for the whole period; and high (SM4), medium (SM5) and low (SM6) straw mulch treatments during the growth period only, where the control was the whole period without mulch (CK). Throughout the whole growth period of the three-year experiment, the average soil water content in the 0–200 cm soil layer increased by 0.7–22.5% compared with CK, while the WUE increased significantly by 30.6%, 32.7% and 24.2% with SM1, SM2, and SM3, respectively (P < 0.05). The yield increased by 13.3–23.0% when mulch was provided during the growth period, while the WUE increased by 15.2%, 17.2% and 18.0% with SM4, SM5, and SM6, respectively, compared with CK.
The problem of designing sliding mode controllers investigated the feasibility of the sliding surface combined for a class of linear systems with uncertainties and both input with a predictor to compensate for the input delay of the and time state delays is investigated. A particular linear system. Robust integral sliding mode control for uncertain transformation is defined to transform the time-delay system into stochastic systems with time-varying delay was researched by a delay-free form first. Then, the sliding mode controller is Niu and Ho [9]. designed based on the transformed system. Optimal control The study of uncertain systems with either state-delay or theory is adopted to construct the optimal sliding manifold with a quadratic performance index minimized. The selected control nput-delay has been pad much attention in the past decade law can ensure the existence of the sliding mode and alleviate[7]-[1O]. However, with regard to the control of system chattering effectively in the sliding motion. About the featuring both state and input delays, only a few studies have uncertainties, the cases of matched condition and unmatched been reported in the literature. In this paper, based on SMC, a condition are studied respectively. Furthermore, a sufficient class of linear uncertain systems with both input delay and condition that guarantees the global asymptotic stability of the state delay are investigated. A novel systematic SMC system original system is derived. Finally, a numerical example is given design methodology is proposed. to illustrate the proposed approach.This paper is organized as follows. The next section describes the system that will be studied. In Section III a linear Index Terms -Sliding mode control, uncertain systems, timetransformation is defined to map the original system into a delay systems, optimal control. delay-free form. Section IV presents the design of the sliding I. INTRODUCTION mode controller in detail. The optimal sliding manifold design based on optimal control theory is presented in Section A. Time delay is quite common in various engineering systemsThe design of the control law that consists of a continuous such as chemical processes, hydraulic systems, biological control action and a discontinuous control action is carried out systems and economic systems. Compared to the systems in Section B. A sufficient condition for the asymptotic without delay, the presence of delay makes it more difficult to stability of the original system with the proposed control law achieve the satisfactory performance of the systems. Another is given in Section C. Section V performs a simulation major problem in real-world systems is the robust control to example to verify the effectiveness of the proposed scheme. minimize the effects of uncertainties. In recent years, there is II. PROBLEM STATEMENTS an increasing interest in the development of robust control systems for processes having time delays and uncertainties.Consider the uncertain retarded system described by Many approaches have be...
The ridge and furrow rainwater harvesting (RFRH) system is a promising water-saving planting technique for dryland farming, but we lack a full understanding of the effects of different fertilizer rates (N:P) on plant nutrient uptake and nutrient use efficiency (NuUE) in foxtail millet using this planting method, as well as the available nutrient residues in the soil. We conducted field studies (Loess Plateau, China) comparing RFRH planting (R) and traditional flat planting (T) at four different fertilizer rates to determine suitable fertilizer application rates for R during 2013–2015. Compared with T, R improved the soil moisture and the utilization of rainwater and fertilizer, thereby enhancing the grain yield, water use efficiency (WUE), grain nutrient uptake, and NUE in a dry year, but with no improvements in a rainy year. The grain yield and WUE exhibited parabolic increasing trends as the fertilizer application rate increased over three years, but no significant increase was found when the fertilizer rate exceeded 189:96 kg N:P ha−1 under R, which significantly reduced the NuUE and might waste nutrients. Therefore, we recommend R combined with 189:96 kg N:P ha−1 as a promising planting strategy for foxtail millet in semiarid areas.
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