Effects of spent mushroom substrates and inorganic fertilizer on the characteristics of a calcareous clayey‐loam soil and lettuce production

We evaluated the effects of the addition of two types of spent mushroom substrate (SMS), SMS from an Agaricus bisporus crop (SMS1) and a mixture of SMSs from an A. bisporus crop and a Pleurotus crop (50% v/v each) (SMS2), on the characteristics of a calcareous clayey‐loam soil and the yield and nutritional status of lettuce (Lactuca sativa L.), relative to crops receiving mineral fertilizer (M) and a control (C) without amendment. The application of SMS, especially SMS1, improved soil fertility compared with C and M soils. Moreover, the use of these organic substrates as soil amendments did not harm the plants and gave yields similar to that obtained with mineral fertilizer. The nutritional contents of the lettuce plants were greater than or similar to those of the plants from treatment C or M, except for the plant tissue concentrations of K, Fe and Zn, which were significantly reduced by SMS application. However, this latter fact did not reduce the lettuce yield in the amended soils. Therefore, the use of SMSs as organic amendments contributes to residue utilization, in an environmentally friendly way, and to improved soil fertility and crop yield.     

Short‐term releases of CO2 from newly mixed biochar and calcareous soil

The work aimed to quantify native organic C mobilized in one calcareous soil in the 21 days after addition of biochar at a range of large to very large applications. The experiment was carried out in unplanted microcosms, and CO₂ flux was used as a measure of net mineralization. A rapid methodological approach, which does not require ¹³C as a tracer, was used to assess any priming effects induced by the biochar. The amount of CO₂‐C mobilized was small relative to the amount of biochar C and proportional to the amount of the biochar added. The additional CO₂‐C was similar to the content of the water‐soluble organic carbon in the biochar added with each application. No interaction with native soil C, that is priming effect, was observed.     

Enhancing pedotransfer functions with environmental data for estimating bulk density and effective cation exchange capacity in a data‐sparse situation

Soil bulk density (BD) and effective cation exchange capacity (ECEC) are among the most important soil properties required for crop growth and environmental management. This study aimed to explore the combination of soil and environmental data in developing pedotransfer functions (PTFs) for BD and ECEC. Multiple linear regression (MLR) and random forest model (RFM) were employed in developing PTFs using three different data sets: soil data (PTF‐1), environmental data (PTF‐2) and the combination of soil and environmental data (PTF‐3). In developing the PTFs, three depth increments were also considered: all depth, topsoil (<0.40 m) and subsoil (>0.40 m). Results showed that PTF‐3 (R²; 0.29–0.69) outperformed both PTF‐1 (R²; 0.11–0.18) and PTF‐2 (R²; 0.22–0.59) in BD estimation. However, for ECEC estimation, PTF‐3 (R²; 0.61–0.86) performed comparably as PTF‐1 (R²; 0.58–0.76) with both PTFs out‐performing PTF‐2 (R²; 0.30–0.71). Also, grouping of data into different soil depth increments improves the estimation of BD with PTFs (especially PTF‐2 and PTF‐3) performing better at subsoils than topsoils. Generally, the most important predictors of BD are sand, silt, elevation, rainfall, temperature for estimation at topsoil while EVI, elevation, temperature and clay are the most important BD predictors in the subsoil. Also, clay, sand, pH, rainfall and SOC are the most important predictors of ECEC in the topsoil while pH, sand, clay, temperature and rainfall are the most important predictors of ECEC in the subsoil. Findings are important for overcoming the challenges of building national soil databases for large‐scale modelling in most data‐sparse countries, especially in the sub‐Saharan Africa (SSA).     

新型水土流失监测装置及其应用

测钎法是一种应用广泛的水土流失监测方法,但是传统测钎法难以适应复杂监测地形,缺乏专门测读装置,还会产生较大监测误差,需要对其加以改进.以颐和园万寿山山体为研究对象,针对其山体特征和文物分布状况,选定18块监测场地,发明单钎多点式测读装置,选用改进的测钎法对水土流失进行监测.结果表明:1)18块监测场地考虑了土壤、坡度、植被等因素的差异,可以全面反映万寿山水土流失状况;2)单钎多点式测读装置有效降低了测钎埋点环境条件、测读方式等客观和主观误差,提高了测钎法水土流失监测结果的准确性;3)监测期间,万寿山平均土壤流失值在-3 mm～ +1 mm范围内.说明新型水土流失监测装置是可行的,所用水土流失监测方法和数据处理方法,可供其他类似工程借鉴与应用.     

Nutrient availability and corn growth in a poultry litter biochar‐amended loam soil in a greenhouse experiment

Nutrient‐rich biochar produced from animal wastes, such as poultry litter, may increase plant growth and nutrient uptake although the role of direct and indirect mechanisms, such as stimulation of the activity of mycorrhizal fungi and plant infection, remains unclear. The effects of poultry litter biochar in combination with fertilizer on mycorrhizal infection, soil nutrient availability and corn (Zea mays L.) growth were investigated by growing corn in a loam soil in a greenhouse with biochar (0, 5 and 10 Mg/ha) and nitrogen (N) and phosphorus (P) fertilizer (0, half and full rates). Biochar did not affect microbial biomass C or N, mycorrhizal infection, or alkaline phosphomonoesterase activities, but acid phosphomonoesterase activities, water‐soluble P, Mehlich‐3 Mg, plant height, aboveground and root biomass, and root diameter were greater with 10 Mg/ha than with no biochar. Root length, volume, root tips and surface area were greatest in the fully fertilized soil receiving 10 Mg/ha biochar compared to all other treatments. The 10 Mg/ha biochar application may have improved plant access to soil nutrients by promoting plant growth and root structural features, rather than by enhancing mycorrhizal infection rates.     

Flowability,moisture sorption and thermal properties of tef [Eragrostis tef (Zucc.) Trotter] grain flours

Recently tef is attracting the attention of the modern food industry since it is a gluten-free grain encompassing highly appreciated nutritional advaxntages. As a relatively new raw material, little information on its handling and processing properties is available. Flowability, water sorption characteristics and thermal properties of flours from three Ethiopian tef varieties were studied. Wheat (whole and refined) and rice flours were included as references. Tef flours were less flowable than the reference flours and their flow properties were more sensitive to water activity changes. Tef flours led to sigmoidal sorption isotherms with estimated monolayer water content of 0.053 (BET model) and 0.057 (GAB model) g water/g dry solids. No significant differences among the three tef varieties were observed on their gelatinization enthalpies that were higher than that of wheat and similar to rice. The amylopectin recrystallization extent after 7 days of storage at 4 °C was significantly higher in tef than in wheat flour.     

丘陵红黄壤区施用399对“一种两收”再生稻根系和产量的影响

[目的]研究399对"一种两收"再生稻的影响。[方法]以适宜丘陵红黄壤种植的丰两优香1号、准两优527、宜优673再生稻品种为材料,分别设置喷施399和不喷施399(CK)2种处理,研究各处理对再生稻根系和产量的影响。[结果]结果表明:施用399使水稻在生育期上延缓成熟,且施后再生稻的总根系数量、白根数量、根鲜重、根干重、根体积大幅度增加,同时在两季总产量上准两优527、丰两优香1号和宜优673品种分别比对照增产6.39%、4.86%、5.94%。[结论]施用399有利于准两优527、丰两优香1号和宜优673再生稻品种再生根的发生。     

不同施肥处理对油茶生长及土壤肥力的影响

为探究不同施肥处理对油茶生长及土壤肥力的影响,连续3年在广西柳州市对5年生油茶人工林进行施肥试验研究。结果表明,施肥后,处理Ⅱ的树高、地径和冠幅的增长量明显高于其它处理,即有机—无机复混肥料直接施入油茶林地最有利于营养生长,而处理CK(不施肥)各项生长指标的增长量最低。不同施肥处理对油茶林地土壤养分各指标的影响差异较大,经灰色关联度法分析得出土壤综合肥力的高低顺序,其中处理Ⅲ(即无纺布包装有机—无机复混肥)施肥后对油茶林地土壤综合肥力的提高最显著,其次为处理Ⅰ(即有机栽培肥料),不施肥处理CK的土壤综合肥力则显著降低,土壤质量退化严重。     

Environmental performances of giant reed (Arundo donax L.) cultivated in fertile and marginal lands: A case study in the Mediterranean

Perennial rhizomatous grasses (PRGs) tend to have a high yield combined with a low environmental impact. Cultivation in marginal or poorly cultivated land is recommended in order not to compromise food security and to overcome land use controversies. However, the environmental impacts of using different types of soil are still unclear. We thus assessed the environmental impact of two giant reed (GR) systems cultivated in a fertile soil (FS) and in a marginal soil (MS) through a cradle-to-plant gate LCA. We analyzed energy balance, GHG emissions (including LUC, not including iLUC), and the main impacts on air, water and soil quality. In both systems the annualized soil carbon sequestration was more than twofold the total GHG emitted, equal to −6464 kg CO₂eq ha⁻¹ in FS and −5757 kg CO₂eq ha⁻¹ in MS. Overall, soil characteristics affected not only GR yield level, but also its environmental impact, which seems to be higher in the MS system both on a hectare and tonne basis. The production of GR biomass in marginal soil could thus lead to higher environmental impacts and a more extensive land requirement.     

The installation of underground pipelines: effects on soil properties

Since the 1970s a network of underground pipes, up to 1200 mm diameter, has been installed in the UK to transmit crude oil to refineries and gas from onshore terminals for distribution. Chosen routes are subject to significant constraints. Current techniques for pipe installation involve topsoil removal and storage. Trench depth is set to allow a cover of 1200 mm overburden after pipes have been installed. The heavy machinery involved results in severe compaction of exposed subsoil. Subsoil is loosened comprehensively and topsoil replaced. Existing field drains are reconnected, and, if necessary, new drains with gravel backfill installed. Pipe installation usually takes place between April and October. Preventative measures to limit compaction during installation are not a practical option. If subsequent arable crops or grass are poorer or drainage more defective than before disturbance, the loss is assessed and compensation paid. To determine the cause of the loss >60, investigations have been made throughout the UK. Soil physical properties were assessed in an open trench using visual and tactile methods. Consistently, severe compaction in the subsoil was identified as the cause of poor crop growth or drainage; it was not observed in the topsoil. Specific recommendations for remedial action were made based on location, depth and severity of the compaction. These included the installation of additional land drains, increasing the amount of gravel above the drains, or further subsoil loosening orientated to cross gravel backfill. After appropriate remedial action, net compensation for crop losses was frequently small or negligible.