不同通风策略下大规模鸭粪堆肥的腐熟和光谱特征

[目的]鉴于鸭粪处理的固有挑战,有效的通风措施是鸭粪工业堆肥过程成功的关键。这项开创性的研究旨在评估来自鸭粪和蘑菇废弃物堆肥的腐熟度和稳定性。本研究进一步探讨了各种通风策略在促进堆肥过程中有机物分解和转化方面的有效性和效率。[方法]将鸭肥和蘑菇废弃物按干重比为2∶1(C/N约为21.15)混合进行堆肥试验。堆肥采用梯形桩,每桩体积5.6 m^(3),采用管道通风。堆肥试验包括4个通气时间处理,分别为10、20、30、60 min/d(分别记作C1、C2、C3和C4处理)。主要研究了堆肥过程中物理化学特性、紫外-可见光谱、X射线衍射(XRD)和红外光谱(IR)的变化特征。[结果]在堆肥第5天和第6天,堆肥进入嗜热期,持续17天,第15天达到50℃。在堆肥前5天,堆肥pH从8.5迅速上升到12.3,可能是由于鸭粪蛋白质的分解,然后在接下来的20天里逐渐下降,在28~30天急剧下降,之后逐渐下降。在高温期(第17天)后,堆肥C1、C2、C3和C4处理的含水量较堆肥初期分别减少了45.9%、46%、44.7%和43%。C3和C4处理的TC值远低于C1和C2。所有堆肥处理的紫外吸收均随波长的增加而降低。在X射线衍射图中存在部分纤维素特征峰(2θ=26.56°)。这些样品含有更多的结晶和“无定形”纤维素、木聚糖和其他多糖。在200~220 nm光谱范围内,硝酸盐和羧基类化学物质的吸收速度比芳香族或不饱和分子快。堆肥的吸收率随初始碳氮比和堆肥过程的持续时间而变化。相反,在460~480 nm处的吸光度表明有机材料的腐殖质化。Q2/6或Q4/6值越低,表明有机物腐殖化程度越高和越多的有机物缩合成芳香族化合物。在红外光谱中,整个堆肥过程中与有机或无机官能团相关的所有条带的强度都有明显的变化。红外光谱显示出一个宽峰,中心波数为3400 cm^(-1),表明存在与羟基(OH)基团和水分子相关的拉伸振动。在3000~2800 cm^(-1)的光谱范围内,可以观察到一个与有机化合物所表现出的疏水特性相关的现象。在2900~2850 cm^(-1)处存在的条带可以归因于C-H脂肪族基团和醛基基团(CHO)的伸缩振动。初始堆肥样品和C1、C2、C3、C4的红外光谱在堆肥过程中发生了显著变化。由于这些变化,红外光谱吸收带发生了显著的变化,表明相关的物质结构发生了变化。因此,C3和C4在堆肥过程中表现出较高程度的稳定性。[结论]65天的堆肥试验显示,在整个堆肥过程中,温度发生变化,通风60 min/d的堆肥最高温度高于通风10 min/d的堆肥。在堆肥过程中,随着通气量的增加,pH呈下降趋势,因此,日通风30~60 min的堆肥pH较低。堆肥过程中,堆料C/N逐渐降低,表明纤维素活性增加。XRD光谱显示峰值强度降低,反映了纤维素的分解。日通风30~60 min堆肥表现出较高的成熟度,突出了通风对成功堆肥的重要性。

Effect of seedling age and water depth on morphological and physiological aspects of transplanted rice under high temperature

To study the effect of high temperature, rice seedlings 20, 30, 40 and 50 d were kept at 5, 10, 15 and 20 cm water depth in a water pool. Meteorological findings indicated that water temperature varied up to 10 cm but became stable below this depth. Deep water inflicted higher tiller mortality, minimal increase in dry weight of aerial parts and leaf area, decrease in root length, and decrease in root dry weight especially at 20 cm water depth and produced an unbalanced T/R ratio (top versus root dry weight). However, deep water tended to increase plant length. These parameters, however, excel in shallow water. Older seedlings, with the exception of root dry weight, could not perform well compared to young seedlings in all physiological and morphological aspects. The study revealed that seedlings, particularly young ones, stand well in shallow water and can cope with high temperature.

Web Tension Regulation of Multispan Roll-to-Roll System using Integrated Active Dancer and Load Cells for Printed Electronics Applications

The mass production of primed electronics can be achieved by roll-to-roll（R2R） printing system, so highly accurate web tension is required that can minimize the register error and keep the thickness and roughness of printed devices in limits. The web tension of a R2R system is regulated by the use of integrated load cells and active dancer system for printed electronics applications using decentralized multi-input-single-output（MISO） regularized variable learning rate backpropagation artificial neural networks. The active dancer system is used before printing system to reduce disturbances in the web tension of process span. The classical PID control result in tension spikes with the change in roll diameter of winder and unwinder rolls. The presence of dancer in R2R system shows that improved web tension control in printing span and the web tension can be enhanced from 3.75 N to 4.75 N. The overshoot of system is less than ±2.5 N and steady state error is within ± 1 N where load cells have a signal noise of ±0.7 N. The integration of load cells and active dancer with self-adapting neural network control provide a solution to the web tension control of multispan roll-to-roll system.

Influence of rangeland protection and seasonal grazing on aboveground vegetation,forage quality and weight gain of small ruminants–a study in Thar Desert,Pakistan

The Thar Desert,Sindh,Pakistan is characterized by low productivity.Besides,economy is based on agriculture,livestock and mining,nevertheless,livestock graze freely on public and private land.The aim of this research was to determine biomass production and to evaluate the effects of continuous and seasonal grazing on protected and unprotected plots.A 45 ha protected rangeland area of Hurrabad in the Umerkot Thar desert was selected and divided into three blocks of 15 ha each.Blocks of the same size were also established in unprotected area.The data for vegetation biomass,canopy cover,forage nutrients and weight gain of animals in two seasons(spring and summer)was collected from both protected and unprotected sites.The results showed that biomass significantly increased in summer in both sites.However,the biomass values in protected sites were significantly higher.Similarly,the vegetation cover also seemed to increase in summer in both protected(90.7%±0.29%)and unprotected sites(39.2%±0.09%).The foliar concentrations of all nutrients varied significantly with season.The average final live-weight gain for does on the protected grazing sites during the 42-day period in spring and the 96 days after the monsoon was almost double that of does grazing on the unprotected site during 2016 and 2017(P<0.05).The study concludes that the protection of grazing lands during certain periods can lead to better production of vegetation and livestock and improve range conditions.

Impact of rangeland enclosure and seasonal grazing on protected and unprotected rangelands in Chakwal region, Pakistan

Scrub rangelands support livestock grazing and provide ecosystem services to their inhabitants. The present study was conducted in Chakwal, an important tract of the Pothwar Plateau,which sustains herds of small domestic and nomadic ruminants. Urbanization and uncontrolled grazing practices have reduced rangeland productivity and increased soil erosion and resulted in poor land conditions. This study assessed the influence of two years of rangeland protection on aboveground vegetation biomass and the chemical composition of plants and aimed to determine the influence of seasonal grazing on the live-weight gain of small ewes.Using the line intercept method, vegetation data from protected and unprotected plots in 2015 and 2016 were collected at two sites, Dhulli and Begal.Vegetation cover was assessed from images using VegMeasure. Results showed that protected study sites displayed higher vegetation biomass(834 and 690 kg ha^(-1)) compared to the unprotected study site(477 and 326 kg ha^(-1)) during April and August of both years. In the seasonal grazing trial, the experimental ewes that grazed on protected rangelands showed higher live-weight gain(33–63 g day^(-1)) compared to live weight of ewes(17–21 g day^(-1)) that grazed on unprotected rangelands during the experimental period of 127 days at both sites. The results suggest that the Chakwal rangeland has tremendous potential to improve vegetation productivity but modern livestock management and seasonal grazing practices are needed to improve carrying capacity and livestock productivity.

Erratum to:Impact of rangeland enclosure and seasonal grazing on protected and unprotected rangelands in Chakwal region,Pakistan

Erratum to:J.Mt.Sci.(2022)19(1):46-57 https://doi.org/10.1007/s11629-021-6761-z The article“Impact of rangeland enclosure and seasonal grazing on protected and unprotected rangelands in Chakwal region,Pakistan”,written by ISLAM Muhammad,RAZZAQ Abdul,ZUBAIR Muhammad,HASSAN Sawsan,AHMAD Sarfraz,GUL Shamim,RISCHKOWSKY Barbara and LOUHAICHI Mounir.