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1.
The integrated nutrient management with organic manure and chemical fertilizers can improve rice (Oryza sativa L.) production, soil health, and fertility. Hence, this study aimed to evaluate the combined effects of organic manures and chemical fertilizers on the yield and nutrient content of wetland rice under field conditions. It was conducted in northern Iran in two consecutive years, 2015 and 2016 as a factorial experiment based on a randomized complete blocks design (RCBD) with three replications. Two local rice cultivars, Tarom Hashemi and Tarom Mahalli, were chosen as the first factor; mineral fertilizers in four levels: 100% recommended nitrogen-phosphorus-potassium (NPK), 75% recommended nitrogen with 100% phosphorus-potassium (PK), 75% recommended phosphorus with 100% nitrogen-potassium (NK), and 75% recommended potassium with 100% nitrogen-phosphorus (NP), were selected based on soil analysis and were arranged as the second factor; and three levels of organic manures, namely zero and eight tons of vermicompost per hectare, and 10 tons of rotted manure per hectare was the third factor. Results revealed that the highest paddy yield occurs with vermicompost and manure consumption for both cultivars. Moreover, the highest paddy yield (3962 kg ha?1) occurs with 100% recommended NPK and vermicompost consumption. For both cultivars, the most chlorophyll a and chlorophyll ab content was produced with application of 100% recommended NPK. The most grain nitrogen content, grain nitrogen uptake, protein content, and protein yield were observed with 100% recommended NPK applied with 10 tons of rotted manure and eight tons of vermicompost usage per hectare. Therefore, in view of the ever-increasing use of chemical fertilizers and irreversible damage thereby, the additional use of these compounds can benefit the environment and human health. The global attention to sustainable agricultural concepts and organic manure can, in addition to producing reasonable yields, be considered as an appropriate alternative to chemical fertilizers.  相似文献   
2.
We measured erodibility and mean weight diameter （MWD） of soil aggregates in different parts of a forest road. Samples of topsoil were collected from cutslope, fillslope, road surface and forest ground to assess the texture, bulk density, moisture, CaCO3 and organic matter. Soil aggregate stability was determined by wet sieving. Soil erodibility on the road surface was 2.3 and 1.3 times higher than on the fillslope and cutslope, respectively. The forest soil had the lowest erodibility. Aggregate stability of cutslope and road surface were low and very low, respectively. There was a significant negative relationship between cutslope erodibility with CaCO3 and sand content. Cutslope erodibility increased with increasing silt, clay and moisture content. On fillslopes, MWD increased with in-creasing rock fragment cover, plant cover, litter cover, organic matter and sand. There was a strong negative correlation between fillslope erodibility and organic matter, sand and MWD. There was no significant difference between erodibility of bare soil and soils beneathRubus hyrcanusL. and Philonotis marchica （Hedw.） Brid.  相似文献   
3.
Effects of moisture, porosity and soil bulk density properties, grubbing time and terrain side slopes on pc 220 komatsu hydraulic excavator productivity were investigated in Miana forests road construction project which located in the northern forest of Iran. Soil moisture and porosity determined by samples were taken from undisturbed soil. The elements of daily works were measured with a digital stop watch and video camera in 14 observations (days). The road length and cross section profiles after each 20 m were selected to estimate earthworks volume. Results showed that the mean production rates for the pc 220 komatsu excavators were 60.13 m3 h(-1) and earthwork 14.76 m h(-1) when the mean depth of excavation or cutting was 4.27 m3 m(-1), respectively. There was no significant effects (p = 0.5288) from the slope classes' treatments on productivity, whereas grubbing time, soil moisture, bulk density and porosity had significantly affected on excavator earthworks volume (p < 0.0001). Clear difference was showed between the earthwork length by slope classes (p = 0.0060). Grubbing time (p = 0.2180), soil moisture (p = 0.1622), bulk density (p = 0.2490) and porosity (p = 0.2159) had no significant effect on the excavator earthworks length.  相似文献   
4.
Journal of Plant Diseases and Protection - The honey bee (Apis mellifera), as one of the most important pollinating insects, plays a critical role in biodiversity conservation and global food...  相似文献   
5.
Abstract

In this study, moisture content (MC) images of subalpine fir (abies lasiocarpa Hook) boards were derived from near-infrared hyperspectral images in the 947–1637 nm range. One hundred and seven cubic samples with the size of 4 cm were prepared from 14 boards. All samples were dried to various MCs during several steps until being completely dried. Hyperspectral images and weight measurements were acquired over each sample at each drying step. The samples have MC ranging from 1% to 137% (dry basis). The images were first calibrated into reflectance. Then, bad pixels were found and replaced by a corrected value using a median filter. A modified version of the boxplot method was used to find abnormal spectra that were then removed. The remaining spectra were converted into absorbance spectra. They were then split into a calibration and a validation data-set according to the boards they were extracted from to build and validate a partial least squares (PLS) regression model between the near-infrared absorbance spectra and the measured MCs. The PLS model was applied first to the sample images, then to the whole board images in order to produce 2D images of MC.  相似文献   
6.
Estimation of above-ground biomass is vital for understanding ecological processes. Since direct measurement of above-ground biomass is destructive, time consuming and labor intensive, canopy cover can be considered as a predictor if a significant correlation between the two variables exists. In this study, relationship between canopy cover and above-ground biomass was investigated by a general linear regression model. To do so, canopy cover and above-ground biomass were measured at 5 sub-life forms(defined as life forms grouped in the same height classes) using 380 quadrats, which is systematic-randomly laid out along a 10-km transect, during four sampling periods(May, June, August, and September) in an arid rangeland of Marjan, Iran. To reveal whether obtained canopy cover and above-ground biomass of different sampling periods can be lumped together or not, we applied a general linear model(GLM). In this model, above-ground biomass was considered as a dependent or response variable, canopy cover as an independent covariate or predictor factor and sub-life forms as well as sampling periods as fixed factors. Moreover, we compared the estimated above-ground biomass derived from remotely sensed images of Landsat-8 using NDVI(normalized difference vegetation index), after finding the best regression line between predictor(measured canopy cover in the field) and response variable(above-ground biomass) to test the robustness of the induced model. Results show that above-ground biomass(response variable) of all vegetative forms and periods can be accurately predicted by canopy cover(predictor), although sub-life forms and sampling periods significantly affect the results. The best regression fit was found for short forbs in September and shrubs in May, June and August with R~2 values of 0.96, 0.93 and 0.91, respectively, whilst the least significant was found for short grasses in June, tall grasses in August and tall forbs in June with R~2 values of 0.71, 0.73 and 0.75, respectively. Even though the estimated above-ground biomass by NDVI is also convincing(R~2=0.57), the canopy cover is a more reliable predictor of above-ground biomass due to the higher R~2 values(from 0.75 to 0.96). We conclude that canopy cover can be regarded as a reliable predictor of above-ground biomass if sub-life forms and sampling periods(during growing season) are taken into account. Since,(1) plant canopy cover is not distinguishable by remotely sensed images at the sub-life form level, especially in sparse vegetation of arid and semi-arid regions, and(2) remotely sensed-based prediction of above-ground biomass shows a less significant relationship(R~2=0.57) than that of canopy cover(R~2 ranging from 0.75 to 0.96), which suggests estimating of plant biomass by canopy cover instead of cut and weighting method is highly recommended. Furthermore, this fast, nondestructive and robust method that does not endanger rare species, gives a trustworthy prediction of above-ground biomass in arid rangelands.  相似文献   
7.
The importance of knowledge sharing, as an integral part of decision making, has been highly acknowledged by many authors. However, the process in which knowledge sharing should be conducted has remained a debatable issue. In this study, changes in experts’ attitudes, as a result of the knowledge-sharing process, in the context of rangeland management were assessed. We demonstrated a three-step knowledge-sharing process while recognizing collaborative knowledge sharing systems, which involves knowledge-sharing tools including face-to-face and virtual approaches. The process was applied to explore experts’ attitudes regarding livelihood alternatives in the Bazoft region of southwestern Iran. Sixty experts were selected from three groups categorized as key local stakeholders, practitioners, and scientists. First, the experts were independently given the task of ranking livelihood alternatives. Next, for a better understanding of alternatives and enhancing their view, additional knowledge and information were provided. Thereafter, their attitudes in the final step were assessed. According to the findings, change in the experts’ attitudes could take place, which eventually resulted in the prioritization of livelihood alternatives to approach sustainable rangeland management (SRM). The synergy of experts’ knowledge, which can be realized through a collaborative knowledge sharing process, can be further pursued by devising a workable policy framework to approach SRM.  相似文献   
8.
研究伞伐更新法对赫卡尼亚森林系统中森林再生和林分结构的影响。在伊朗北部优势种为山毛榉（Fagus orientalisLipsky）的硬木林,采取伞伐更新法和非伞伐更新法方法设计实验区。结果表明,在山毛榉（F orientalis Lipsky）林中采用伞伐更新法处理,明显影响林下草本植物种的频度和密度。伞伐更新法处理后,林堇菜（Viola silvestris Lam.）、车叶草（Asperula odorata L.）、苔草（Carex spp.）和悬钩子（Rubushyrcanus Juz）的种频度明显增加。在对照区,树种的胸高直径（57.50&#177;2.15cm）大于被处理区（50.67&#177;1.88cm）的树种的胸高直径（50.67&#177;1.88 cm）,但对照区和处理区的树种的高度值相似。在1995-2005年间,波斯铁木（Parrotia persica）苗木数量增加到13.2%,而山毛榉（F orientalis）和欧洲鹅耳枥（Carpinus betulus）的苗木数量却明显减少。总之,应该利用其它育林方法,如,带状择伐作业,而不是伞伐更新法培育赫卡尼亚森林中山毛榉林。  相似文献   
9.
Abstract

Wood density (ρMC) and basic specific gravity (BSG) are important properties in several forest products manufacturing processes. In this study, near-infrared hyperspectral images were tested to produce two-dimensional (2D) ρMC and BSG images of subalpine fir (Abies lasiocarpa Hook) board. A total of 107 cubic samples with the size of 4 cm were prepared from 14 boards. All samples were dried to various moisture contents (MCs) during several steps until being completely dried. The resulting MCs ranged from 1% to 137% (dry basis). After the last drying step, the samples were soaked in water to determine BSG. Hyperspectral images and weight measurements were acquired over each sample at each drying step. ρMC was also estimated at each MC level. Partial least squares (PLS) models were developed for estimating both ρMC and BSG from the near-infrared hyperspectral imaging (NIR-HSI) system absorbance spectra acquired over all the samples during each drying step. The ρMC model provides a reasonable accuracy with the validation data-set (R2 = 0.81, RMSE = 39 kg/m3, and RPD = 2.3). For BSG, only models built with samples having MC of less than 12% are significant. The calibration data-set provides similar accuracy as the ρMC model (RMSE = 0.004, R2 = 0.82, and RPD = 2.28), but the accuracy is lower with the validation data-set (RMSE = 0.007, R2 = 0.53, and RPD = 1.39). Our data-set has BSG values varying only from 0.326 to 0.374, and further work is needed to apply these methods to a data-set that includes a more extended range of BSG variations for improving estimation accuracy.  相似文献   
10.
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