摘要：
为提高我国南方丘陵地区旱地土壤作物种植的氮肥利用率,减少资源浪费和降低环境污染风险,通过采用田间小区定位试验进行土壤养分渗漏观测,研究比较了不施肥处理(T1)、普通尿素处理(T2)以及不同施氮量的控释氮肥处理(T3~T6)的TN、NO_3~--N和NH_4~+-N的流失浓度变化及其损失负荷特征。结果表明:在168~240 kg N/hm~2施氮水平变化内,渗漏水量在3 888~3 948L之间,即施肥量的增加或减少对渗漏体积的影响不显著(P>0.05);控释氮肥处理T3的TN、NO_3~--N和NH_4~+-N的平均流失浓度分别是32.66,29.41,0.26 mg/L,比等氮量施用的T2处理分别降低了24.99%(P<0.01), 25.56%(P<0.01)和25.71%(P<0.05);同样T3在损失负荷方面TN、NO_3~--N和NH_4~+-N分别为53.07,47.14,0.47 kg N/hm~2,较T2分别降低了24.10%(P<0.01),25.62%(P<0.01)和18.97%(P> 0.05)。当控释氮肥减氮10%,20%,30%时,其TN损失浓度为28.81,26.50,24.34 mg/L,较T3分别降低了11.79%(P>0.05),18.86%(P<0.05),25.47%(P<0.05);损失负荷为41.78,36.62,33.90 kg N/ hm~2,较T3分别降低了21.27%(P<0.01),31.00%(P<0.01),36.12(P<0.01)。NO_3~--N是渗漏氮素损失的关键成分,占TN损失负荷88.83%~92.75%,DON次之。控释氮肥在192 kg N/hm~2的投入下能够有效的减少氮素渗漏损失,降低环境污染风险,并且还可以增产增效。
摘要：
Sulfonamides (SAs) are applied widely as feed additives in the farming of livestock and poultry. It can lead to the excretion of large amounts of SAs in manure and result in persistent environmental pollution. We evaluated the fate of four SAs, sulfamerazine (SM1), sulfachloropyridazine (SCP), sulfadimoxine (SDM') and sulfaquinoxaline (SQ), from oral administration to excretion in urine and feces in pigs. The four SAs were added to homemade feed to make them reach the required concentration gradient, which were 0, 50 and 100 mg/kg (low, normal and high concentrations, respectively). In different treatments, excretions of the four SAs were 35.68-86.88 %. With regard to total excretion, the order was SQ > SCP > SM1 > SDM' for all treatments. The concentration of SAs in the feed had significant effects on the amount of the four SAs excreted every day. The concentration of SAs in feces and in the urine for different treatments was 15.03-26.55 and 14.54-69.22 %, respectively. In each treatment, excretions of SCP, SDM' and SQ in feces were lower than that in urine. The four SAs remained longer in urine than in feces. Excretions in urine and feces were lower if SAs were administered orally rather than by injection.
关键词：
Early ripening rapeseed;Controlled-release fertilizer;Yield;Nutrient uptake;Fertilizer usage efficiency
摘要：
Background: Nitrogen (N), phosphorous (P), and potassium (K) are critical nutrient elements necessary for crop plant growth and development. However, excessive inputs will lead to inefficient usage and cause excessive nutrient losses in the field environment, and also adversely affect the soil, water and air quality, human health, and biodiversity. Methods: Field experiments were conducted to study the effects of controlled-release fertilizer (CRF) on seed yield, plant growth, nutrient uptake, and fertilizer usage efficiency for early ripening rapeseed (Xiangzayou 1613) in the red-yellow soil of southern China during 2011–2013. It was grown using a soluble fertilizer (SF) and the same amounts of CRF, such as SF1/CRF1 (3750 kg/hm~2), SF2/CRF2 (3000 kg/hm~2), SF3/CRF3 (2250 kg/hm~2), SF4/CRF4 (1500 kg/hm~2), SF5/CRF5 (750 kg/hm~2), and also using no fertilizer (CK). Results: CRF gave higher seed yields than SF in both seasons by 14.51%. CRF4 and SF3 in each group achieved maximum seed yield (2066.97 and 1844.50 kg/hm~2, respectively), followed by CRF3 (1929.97 kg/hm~2) and SF4 (1839.40 kg/hm~2). There were no significant differences in seed yield among CK, SF1, and CRF1 (P>0.05). CRF4 had the highest profit (7126.4 CNY/hm~2) and showed an increase of 12.37% in seed yield, and it decreased by 11.01% in unit fertilizer rate compared with SF4. The branch number, pod number, and dry matter weight compared with SF increased significantly under the fertilization of CRF (P<0.05). The pod number per plant was the major contributor to seed yield. On the other hand, the N, P, and K uptakes increased at first and then decreased with increasing the fertilizer rate at maturity, and the N, P, and K usage efficiency decreased with increasing the fertilizer rate. The N, P, and K uptakes and usage efficiencies of the CRF were significantly higher than those of SF (P<0.05). The N accumulation and N usage efficiency of CRF increased by an average of 13.66% and 9.74 percentage points, respectively, compared to SF. In conclusion, CRF significantly promoted the growth of rapeseed with using total N as the base fertilizer, by providing sufficient N in the later growth stages, and last by reducing the residual N in the soil and increasing the N accumulation and N usage efficiency.
摘要：
In this article, Hafnium oxide (HfO2) overlayer was reported to be loaded on the surface of WO3 nanoparticles by a simple solvothermal method for the first time. HfO2 powders were dissolved in the concentrated sulfuric acid as raw material. The physicochemical properties of WO3 nanoparticles with and without HfO2 passivation layer were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). For the film electrode prepared with doctor-blade method, scanning electron microscopy (SEM) and UV–vis absorbance spectroscopy (UV–vis) were used to determine the morphological and optical properties. Meantime, the photoelectrochemical properties of two samples were evaluated by means of liner sweep voltammogram, electrochemical impedance spectroscopy (EIS), intensity modulated photocurrent spectrum (IMPS) and incident photon to current conversion efficiency (IPCE). The WO3 film with HfO2 passivation layer showed better photoelectrochemical performance which could be ascribed to the inhibition of the recombination of electron-holes.
