{"title":"Investigation of mechanical properties of cotton stalk based on multi-component analyses","authors":"Wei-jun Zhao, Jianhua Xie, Zhenwei Wang, Qiming Gao, Mingjiang Chen","doi":"10.31545/intagr/152488","DOIUrl":"https://doi.org/10.31545/intagr/152488","url":null,"abstract":". A comprehensive understanding of the uprooting failure mechanism will likely require the accurate characterization of the mechanical properties of cotton stalk. Uprooting failure includes a fractured cotton stalk and peeled phloem sliding along the xylem. The modulus of elasticity of cotton stalk and its tissues (xylem and phloem) were measured using three different modes (tensile, compression and bending), and the reasons for the fractured cotton stalk and the peeled phloem sliding along the xylem were analysed from the perspective of composite mechanics. The results showed that the cotton stalk radially conforms to the properties of the composite with transverse anisotropy. The axial modulus of elasticity was significantly larger than the radial modulus of elasticity (axial modulus of elasticity: cotton stalk is 3181.79 MPa, xylem is 1093.91 MPa, phloem is 249.89 MPa, radial modulus of elasticity: is 91.04 MPa, xylem is 83.77 MPa, phloem is 77.01 MPa). Xylem is the backbone of the stalk that provides 96% of its compressive strength. The direct cause of fractured cotton stalk originated from the load force that exceeded its intrinsic compressive strength. Peeled phloem sliding along the xylem was related for the most part to the different radial modu lus of elasticity of the xylem and phloem, and the weak cohesion between these two tissues. Based on the results, some suggestions were provided for the design of a puller.","PeriodicalId":13959,"journal":{"name":"International Agrophysics","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2022-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44838347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Seasonal changes in dendrometer-derived stem variation in apple trees grown in temperate climate","authors":"Y. Rezaei, M. Zude-Sasse, W. Herppich","doi":"10.31545/intagr/152037","DOIUrl":"https://doi.org/10.31545/intagr/152037","url":null,"abstract":". Studies of daily changes in tree trunk diameter provide valuable information concerning growth patterns and their relationships with varying environmental conditions. To date, very few experiments with fruit trees evaluated the effects of climate variation on trunk shrinkage and the duration of the contraction and recovery phases and of growth. In this study, electronic dendrometers continuously monitored trunk diameter and trunk water storage dynamics of drip-irrigated ‘Gala’ apple trees ( Malus x domestica Borkh.) during three growing seasons, which differed significantly in temperature, precipitation, air humidity and solar irradiation. It was found that trunk diameter and meteorological variables were closely related, even when excluding the effects of soil water limitations. During each growing season, the durations of the daily contraction phase began to increase with increasing water vapour partial pressure deficit, and decreased again in autumn, when vapour partial pressure decreased. Throughout the season, the duration of the growth phase tended to change inversely to that of both contraction and recovery phase. The relationship between maximum trunk shrinkage and vapour partial pressure was higher post than preharvest for all years stud-ied. The duration of contraction, recovery, and growth phases may provide valuable information concerning seasonal changes and environmental drivers of water storage dynamics in apple trees.","PeriodicalId":13959,"journal":{"name":"International Agrophysics","volume":"1 1","pages":""},"PeriodicalIF":2.2,"publicationDate":"2022-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41379341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zeinab Heravizadeh, Morteza Sam Daliri, M. Moballeghi, Amir Abbas Mousavi Mirkalaei
{"title":"Effect of water stress on yield stability, water productivity, and canopy temperature of rice genotypes","authors":"Zeinab Heravizadeh, Morteza Sam Daliri, M. Moballeghi, Amir Abbas Mousavi Mirkalaei","doi":"10.31545/intagr/151642","DOIUrl":"https://doi.org/10.31545/intagr/151642","url":null,"abstract":". A field experiment was conducted to evaluate the performance and water productivity of 15 rice genotypes under non-stress and drought-stress conditions in a warm-temperate cli - mate. This study was laid out with a randomized complete block design at two research stations (Abbasabad and Katalom, Iran). Water deficit decreased the grain yield and increased the canopy temperature in all genotypes, but the response of water productiv - ity to drought stress was not the same for the different genotypes. The maximum water productivity in non-stress and stress condi - tions (0.50 and 0.53 kg m –3 , respectively) were found in landraces. The canopy temperature was a reliable indicator for identifying drought-tolerant genotypes of rice. With each degree increase in canopy temperature, the grain yield decreased by 1 942 kg ha –1 . The biplot analysis demonstrated that landraces were the most suitable genotypes for cultivation under drought-stress and no-stress conditions. A principal component analysis based on stress tolerance indices showed that Shastak and Sahel were the most tolerant genotypes to drought stress. Overall, Shastak with a max - imum grain yield (4 595 kg ha –1 ), the highest water productivity, and savings of irrigation water by as much as 54% under condi - tions of drought stress may be introduced as a superior genotype for cultivation under water scarcity conditions and used in future breeding programmes.","PeriodicalId":13959,"journal":{"name":"International Agrophysics","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2022-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49367648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Evaluation of the impact of freezing technique on pore-structure characteristics\u0000of highly decomposed peat using X-ray micro-computed tomography","authors":"H. Al Majou, A. Bruand, O. Rozenbaum, E. Le Trong","doi":"10.31545/intagr/152057","DOIUrl":"https://doi.org/10.31545/intagr/152057","url":null,"abstract":". The modelling of peatland functioning requires detailed knowledge of the peat structure. To this end, freezing is nowadays increasingly used to obtain X-ray micro comput ed tomography (X-ray -CT) images. The aim of this study was to analyze the structure of a peat material before freezing and post-defreezing using X-ray -CT and to look for possible alter ations in the structure by analyzing the air-filled porosity. A highly decomposed peat material close to water saturation was selected for study. Three samples were analyzed before freezing and post-defreezing using an X-ray -CT Nanotom 180NF. Results showed that the continuity and cross section of the air-filled tubu lar pores several hundreds to about one thousand micrometers in diameter were altered post-defreezing. Many much smaller air-filled pores not detected before freezing were also recorded post-defreezing. Detailed analysis showed a dramatic increase in the number of air-filled pores ranging between 1 voxel (216 10 3 µm 3 ) and 50 voxels (10.8 10 6 µm 3 ) in volume. The volume of these pores newly occupied by air using X-ray -CT and their total volume was found to be consistent with the one calculated as resulting from the increase in the specific volume of water when it turns into ice.","PeriodicalId":13959,"journal":{"name":"International Agrophysics","volume":" ","pages":""},"PeriodicalIF":2.2,"publicationDate":"2022-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47393293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}