Soil erosion modelling of burned and mulched soils following a Mediterranean forest wildfire

Soil erosion modelling applied to burned forests in different global regions can be unreliable because of a lack of verification data. Here, we evaluated the following three erosion models: (1) Water Erosion Prediction Project (WEPP), (2) Morgan-Morgan-Finney (MMF) and (3) Universal Soil Loss Equation-Modified (USLE-M). Using field plots that were either untreated or mulched with straw, this study involved observations of soil loss at the event scale at a burned pine forest in Central Eastern Spain. The erosion predictions of the three models were analysed for goodness-of-fit. Optimization of the MMF model with a new procedure to estimate the C-factor resulted in a satisfactory erosion prediction capacity in burned plots with or without the mulching treatment. The WEPP model underestimated erosion in the unburned areas and largely overestimated the soil loss in burned areas. The accuracy of soil loss estimation by the USLE-M model was also poor. Calibration of the curve numbers and C-factors did not improve the USLE-M model estimation. Therefore, we conclude that an optimized MMF model was the most accurate way to estimate soil loss and recommend this approach for in Mediterranean burned forests with or without postfire mulching. This study gives land managers insight about the choice of the most suitable model for erosion predictions in burned forests.     

Chemical speciation of copper and manganese in solution of a copper-contaminated soil and young grapevine growth with amendment application

Copper(Cu)-based fungicide application to control foliar diseases in grapevine(Vitis vinifera L.) can increase soil Cu availability. Brazilian soils have high natural Cu and manganese(Mn) concentrations, increasing the potential for toxicity to grapevine plants. Application of amendment substances can reduce the concentrations of toxic chemical species of Cu and Mn in soil solution, especially for the soils grown with young plants. We evaluated the chemical speciation of Cu and Mn in soil soluti...     

Poultry Residual Composts: Materials Balance and Crop Response

This paper discusses compost production yields as a percent of raw product mix using poultry litter, poultry processing plant dissolved air flotation skimmings, sawdust, wood chips and ground yard debris. Three different mixes were used and identified as Mixes 1, 2 and 3. Mixes 1 and 2 were produced using windrows and a windrow turner and Mix 3 was made using a covered in-channel compost turner. Mixes 1 and 2 were poultry litter compost with a screened mass yield of 80 and 77 percent, respectively. Mix 3 was a dissolved air flotation compost with a screened mass yield of 40 percent. Results from plant experiments show poultry litter compost can be used successfully in potting mixes for poinsettia and chrysanthemum production. A compost produced from dissolved air flotation skimmings, a poultry processing waste, can be used in field corn production but had little influence in the production of soybeans.     

A Comparison of Static Pile and Turned Windrow Methods for Poultry Litter Compost Production

Alternate technologies of compost manufactured from poultry litter (manure) were studied as a means of producing a value-added product for the landscape and nursery industry. Static pile and turned windrow technologies were investigated on a commercial scale with the composting of nearly 300 tons of material. The major difference between the technologies is the amount of energy and labor required. Static pile systems require less energy but more time than windrow turned systems. There was no process advantage found for passively aerated static piles over static piles but costs of passive aeration for pipes and labor were higher than for static piles. Machine turned windrows completed active temperature production within 100 days while portions of both the static and passively aerated piles continued to actively compost past 300 days. Process operational costs and compost quality were similar among the compost methods studied. Production operational cost is driven by the cost of compost ingredients and accounted for 60 to 70% of the cost in the pilot study. Ingredients were poultry litter, wood chips and sawdust. Screened compost was produced at an operational cost of $30 while unscreened compost could be produced for $20 per ton of compost. A production scheme where poultry litter is static pile composted on farms for later transport to regional processing centers appears feasible. This two-part composting procedure will eliminate the transport of raw litter and improve poultry biosecurity. Most likely, a private compost business would provide the expertise, on-farm compost procedures and operate the regional facility.     

天津市农业节水灌溉现状及发展方向

根据天津市农业节水灌溉的现状,分析了目前存在的农业节水工程建设速度缓慢、建设标准不高,管理体制和用水机制不健全,先进的节水技术和管理机制发展不平衡、不普及、不深入等主要问题,并根据山丘区、井灌区、混灌区和旱作区等不同节水类型区域,提出各类型区域发展节水灌溉的重点。     

我国节水灌溉技术及其模式和发展趋势

综述了我国水资源的现状及节水灌溉技术与模式的研究和应用,并展望了我国节水灌溉技术的发展趋势。     

醋酸铅对体外培养大鼠大脑皮质神经细胞形态的影响

为了观察醋酸铅对神经细胞的形态学影响,通过建立体外培养大鼠大脑皮质神经细胞模型,应用不同浓度醋酸铅(0,50,100,200,400μmol/L)与神经细胞分别培养3、6、12、24 h,倒置相差显微镜观察细胞形态变化.结果显示,醋酸铅与神经细胞共同培养12~24 h,细胞密度降低,胞体变小,突起缩短;随醋酸铅浓度递增,细胞形态较对照组差异愈加显著(P<0.05).表明染铅浓度与神经细胞形态变化存在剂量效应与时间效应关系.     

肉牛冬季舍饲日粮配方优化筛选试验

选择不同日粮类型肉牛养殖户14户,参试生长母牛48头,参照肉牛营养需要和饲养标准,设计不同饲粮组合类型及日粮配方.随机分为5个试验组和1个对照组,试验Ⅰ组、Ⅱ组和Ⅲ组按规范化全株玉米青贮十氨化麦草等多元化日粮进行科学饲养,Ⅳ组、Ⅴ组和Ⅵ组(对照)按传统的"有啥喂啥"方法饲喂,同期进行饲养试验研究.结果表明,试验Ⅰ组、Ⅱ组和Ⅲ组平均头日增重效果均比Ⅳ组、Ⅴ组和Ⅵ组(对照)有明显提高(P＜0.05,P≤0.01),显示了肉牛标准化科学饲养的优势效益.试验Ⅰ组、Ⅱ组、Ⅲ组饲粮组成类型及日粮配方为较理想的肉牛繁殖母牛日粮优化配方.     

Rainfall Interception by Singleleaf Piñon and Utah Juniper: Implications for Stand-Level Effective Precipitation

The expansion of piñon and juniper trees into sagebrush steppe and the infilling of historic woodlands has caused a reduction in the cover and density of the understory vegetation. Water is the limiting factor in these systems; therefore, quantifying redistribution of water resources by tree species is critical to understanding the dynamics of these formerly sagebrush-dominated rangelands. Tree canopy interception may have a significant role in reducing the amount of rainfall that reaches the ground beneath the tree, thereby reducing the amount of available soil moisture. We measured canopy interception of rainfall by singleleaf piñon (Pinus monophylla Torr. & Frém.) and Utah juniper (Juniperus osteosperma [Torr.] Little) across a gradient of storm sizes. Simulated rainfall was used to quantify interception and effective precipitation during 130 rainfall events ranging in size from 2.2 to 25.9 mm hr^? 1 on 19 trees of each species. Effective precipitation was defined as the sum of throughfall and stemflow beneath tree canopies. Canopy interception averaged 44.6% (± 27.0%) with no significant difference between the two species. Tree allometrics including height, diameter at breast height, stump diameter, canopy area, live crown height, and width were measured and used as predictor variables. The best fit predictive model of effective precipitation under canopy was described by stump diameter and gross precipitation (R² = 0.744, P < 0.0001). An alternative management model based on canopy area and gross precipitation predicted effective precipitation with similar accuracy (R² = 0.741, P < 0.0001). Canopy area can be derived from various remote sensing techniques, allowing these results to be extrapolated to larger spatial scales to quantify the effect of increasing tree canopy cover on rainfall interception loss and potential implications for the water budget.