Precision Farming
R. Azadnia; A. Rajabipour; B. Jamshidi; M. Omid
Abstract
IntroductionApple is one of the most frequently consumed fruits in the world. It is a source of minerals, fiber, various biological compounds such as vitamin C, and phenolic compounds (natural antioxidants). The amount of nutrients plays a significant role in the growth, reproduction, and performance ...
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IntroductionApple is one of the most frequently consumed fruits in the world. It is a source of minerals, fiber, various biological compounds such as vitamin C, and phenolic compounds (natural antioxidants). The amount of nutrients plays a significant role in the growth, reproduction, and performance of agricultural products and plants. Chemical inputs can be accurately managed by predicting these elements. Thus, timely and accurate monitoring and managing the status of crop nutrition is crucial for adjusting fertilization, increasing the yield, and improving the quality. This approach minimizes the application of chemical fertilizers and reduces the risk of environmental degradation. In crop plants, leaf samples are typically analyzed to diagnose nutrient deficiencies and imbalances, as well as to evaluate the effectiveness of the current nutrient management system. Therefore, the main aim of this study is to estimate the level of Nitrogen (N), Phosphorus (P), and Potassium (K) elements in the leaves of the apple tree using the non-destructive method of Visible/Near-infrared (Vis/NIR) spectroscopy at the wavelength range of 500 to 1000 nm coupled with chemometrics analysis.Materials and MethodsThis research investigated the potential of the Vis/NIR spectroscopy coupled with chemometrics analysis for predicting NPK nutrient levels of apple trees. In this study, 80 leaf samples of apple trees were randomly picked and transferred to the laboratory for spectral measurement. The Green-Wave spectrometer (StellarNet Inc, Florida, USA) was utilized to collect the spectral data. In the next step, the spectral data were transferred to the laptop using the Spectra Wiz software (StellarNet Inc, Florida, USA). For this purpose, spectroscopy of the leaf samples was done in interactance mode. Ten random points were selected on each leaf to capture reflectance spectra and the averaged spectrum was used to determine the reflectance (R). The data was then transformed into absorbance (log 1/R) for chemometrics analysis. Following the spectroscopy measurements, the NPK contents were measured using reference methods. Afterward, Partial Least Square (PLS) multivariate calibration models were developed based on the reference measurements and spectral information using different pre-processing techniques. To remove the unwanted effects, various pre-processing methods were utilized to obtain an accurate calibration model. To evaluate the proposed models, the Root Mean Square Error of calibration and prediction sets (RMSEC and RMSEP), as well as the correlation coefficient of calibration and prediction sets (rc and rp), and Residual Predictive Deviation (RPD) were calculated.Results and DiscussionThe statistical metrics were calculated for the evaluation of PLS models and the results indicated that the PLS models could efficiently predict the NPK contents with satisfactory accuracy. The model with the best performance for nitrogen prediction was based on the standard normal variate pre-processing method in combination with the second derivative (SNV+D2) and resulted in rc= 0.988, RMSEC=0.028%, rp=0.978, RMSEP=0.034%, and RPD of 7.47. The best model for P content prediction resulted in rc= 0.967, RMSEC=0.0051%, rp=0.958, RMSEP=0.0057%, and RPD of 5.96. Additionally, the PLS model based on MSC+D2 pre-processing method resulted in rc= 0.984, RMSEC=0.017%, rp=0.976, RMSEP=0.021%, and RPD of 7.10, indicating the high potential of PLSR model in predicting K content. Moreover, the weakest performing model was related to the estimation of P content without pre-processing with rc = 0.774, RMSEC = 0.013%, rp = 0.685, RMSEP = 0.018%, and RPD value of 1.87. Based on the obtained results, the proposed PLS models coupled with suitable pre-processing methods were able to predict the nutrient content with high precision.ConclusionField spectroscopy has recently gained popularity due to its portability, ease of use, and low cost. Consequently, the use of a portable system for estimating nutrient levels in the field can significantly save time and lower laboratory expenses. Therefore, due to the accuracy of the Vis/NIR spectroscopy technique and according to the obtained results, this method can be used to actualize a portable system based on Vis/NIR spectroscopy to estimate the nutrient elements needed by the apple trees in the orchards and to increase the productivity of the orchards.
M. Mohammad Shafie; A. Rajabipour; H. Mobli; M. Khanali
Abstract
Introduction: The pomegranate journey from orchard to supermarket is very complex and pomegranates are subjected to the variety of static and dynamic loads that could result in this damage and bruise occurring. Bruise area and bruise volume are the most important parameters to evaluate fruit damage occurred ...
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Introduction: The pomegranate journey from orchard to supermarket is very complex and pomegranates are subjected to the variety of static and dynamic loads that could result in this damage and bruise occurring. Bruise area and bruise volume are the most important parameters to evaluate fruit damage occurred in harvest and postharvest stages. The bruising is defined as damage to fruit flesh usually with no abrasion of the peel. The two different types of dynamic loading which can physically cause fruit bruising are impact and vibration. The impact and vibration loadings may occur during picking or sorting as the pomegranates are dropped into storage bins and during transportation. The focus of this work was on the impact loading as this appeared to be the most prevalent. In view of the limitations of conventional testing methods (ASTM D3332 Standard Test Methods for Mechanical Shock Fragility of Products), the method and procedure for determining dropping bruise boundary of fruit were also established by adapting free-fall dropping tests.
Materials and Methods: After the ‘Malas-e-Saveh’ pomegranates had been selected, they were numbered, and the weight and dimension of each sample were measured and recorded. Firmness in cheek region of each fruit was also measured. Fruit firmness was determined by measuring the maximum force during perforating the sample to a depth of 10 mm at a velocity of 100 mm min-1 with an 8 mm diameter cylindrical penetrometer mounted onto a STM-5 Universal Testing Machine (SANTAM, Design CO. LTD., England). Free-fall dropping tests with a series of drop heights (6, 7, 10, 15, 30 and 60 cm) were conducted on fresh ‘Malas-e-Saveh’ pomegranates. Three samples were used for each dropping height, and each sample was subjected to impact on two different positions. Before the test was started, it was necessary to control the sample's drop position. The cheek of sample was placed on the fruit holder. An aluminum plate mounted on upper part of the piezoelectric force sensor was the dropping impact surface of the device. After dropping impact, the sample was caught by hand to prevent a second impact due to sample rebound. After impact, the samples were stored at room temperature for 48h, during which time bruise tissues and arils turned brown. The bruise area and bruise volume of each sample were calculated according to equations (1 and 2).
Results and Discussion: Dropping impact acceleration versus time curves for the typical samples at ten drop heights are shown in figure 5. Drop height notably affected the impact acceleration. The peak force increased while contact times decreased with increasing drop height, which resulted in an increase of peak acceleration. Figure 6 shows the dropping impact velocity change during contact by theoretical calculation. The results showed that the velocities at the beginning of contact and the rebound velocities of the samples increased with increasing the drop height. Critical drop height of pomegranate in certain bruise area was determined and linear relationship between drop height and bruise volume for ‘Malas-e-Saveh’ pomegranates were obtained. It is clear that there were obvious differences between dropping bruise boundaries of pomegranates and the conventional damage boundary of products (as shown in figure 9). For the conventional damage boundary, the vertical line, critical velocity (Vc), represents the velocity change below which no damage occurs, regardless of the peak pulse acceleration. The horizontal line, critical acceleration (AC), represents the acceleration at which the product will be damaged if velocity exceeds VC. At the same time, for a conventional product, there is only one damage boundary at one shock condition. However, for fruit, a change in drop height (velocity) will lead to a change in bruise ratio. A series of bruise boundaries can be determined for different bruise ratios. Moreover, even if the velocity approaches zero, the fruit can still be bruised if its acceleration exceeds a certain value. These relationships provide an effective basis to predict and control drop bruising, which may be achieved through the design of reasonable cushioning packaging for fruit.
Conclusions: This research applied the concept of dropping bruise for pomegranate fruits. Because of the limitations in using conventional testing methods to test product of a viscoelastic nature, such as fruit, free fall dropping tests were adapted to determine dropping bruise fragility and bruise boundary for ‘Malas-e-Saveh’ pomegranates at different drop heights. For viscoelastic products such as fruit, even if the dropping impact velocity approached zero, the fruit could be bruised as long as the impact acceleration exceeded a certain value (critical acceleration). A series of bruise boundaries can be established for different levels of bruise ratios, i.e., a contour of constant bruise ratio can be drawn on the velocity acceleration plane.
M. R. Bayati; A. Rajabipour; H. Mobli; A. Eyvani; F. Badii
Abstract
Introduction: Apple fruit (Mauls domestica Borkh, Rosaceae) after citrus fruits, grape and banana, is the fourth important fruit in the world and is considered the most important fruit of temperate regions. In terms of trade volume, Iran is fourth producer and 17th exporter in the world. Among Iranian ...
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Introduction: Apple fruit (Mauls domestica Borkh, Rosaceae) after citrus fruits, grape and banana, is the fourth important fruit in the world and is considered the most important fruit of temperate regions. In terms of trade volume, Iran is fourth producer and 17th exporter in the world. Among Iranian cultivars of apple fruit, known as “Golab apple”. Golab apple is one of the fragrant and tasty varieties and meanwhile is very sensitive and also its period of the postharvest shelf life is very short. In a study, the firmness of pear fruit during 4 weeks of storage was monitored using non-destructive impulse response (I-R) and destructive Magness-Taylor (M-T) puncture tests. The results of this study showed that the dominant frequency, stiffness coefficient and elasticity coefficient as a function of time could be expressed as a decreasing linear function (Gómez et al., 2005). Tiplica et al., (2010), showed that acoustic measurement can be a useful tool to discriminate different apple batches with a low error rate. Starting from the spectrum of the signal recorded by a microphone after the impact of a small hammer on the fruit, 18 key features were identified and used for the classification of apples belonging to 10 different varieties. The study aimed to evaluate apple firmness measured using both the penetrometer and acoustic methods. The methodologies were applied to Royal Gaya and Golden Smoothee apples harvested from 12 different orchards in Catalonia (Spain), on six different dates, and over three seasons. The results obtained showed a noticeable correlation between Magness Taylor firmness and acoustic measurements in Royal Gala, but no correlation was found for Golden Smoothee. In this study, also, acoustic measurements seemed to be a good tool for evaluating changes in tissue firmness during long-term storage (Molina-Delgado et al., 2009). In another study, it was presented a novel approach based on the simultaneous profiling of the mechanical and acoustic response of the flesh tissue to compression, using a texture analyzer coupled with an acoustic device. The methodology was applied to a 86 different apple cultivars, measured after two months postharvest cold storage and characterised by 16 acoustic and mechanical parameters. The results demonstrate the good performance of our combined acoustic-mechanical strategy in measuring apple crispness as it is perceived by human senses (costa et al, 2011). Hence, present study was about postharvest durability evaluation of this apple in cold storage and effect of methylcellulose coating on durability of this sensitive apple for both intact and damaged ones.
Materials and Methods: After obtaining Golab apples, from one of the gardens of Karaj (Alborz province, Iran), 240 of them were selected. Our aim in this study was to evaluate the firmness of apples with two methods: penetration (destructive) and acoustic (non destructive). The tests were performed in Agricultural Engineering Research Institute in Karaj. Firmness is one of the fruit characteristics that changes during storage. In present study, this characteristic of the apple fruit was assessed by two mentioned methods. Half of the apples were damaged with identified and controlled impact. In the next stage, another half of apples in both groups (the intact apples and the bruised apples) were coated with methylcellulose. Effect storage on apple in four groups, including: Intact and uncoated apples, intact and coated (with methylcellulose) apples, bruised and uncoated apples and bruised and coated apples during about ten weeks of cold storage at 2˚C and 85% RH was studied by the acoustic and the penetration tests. Acoustic parameters including: natural frequency, firmness index, elasticity coefficient were measured by recording audio signals resulting from non destructive impacts of a pendulum using a sound analyzer microphone and then the conversion of those parameters were performed from the time domain to the frequency domain by the corresponding formulas and software. Penetration test measurements were performed using a texture analyzer and its software. The tests were carried out every week. Statistical analysis of the results was carried out using Excel 2007 and SPSS 16 software and the significance of the results was determined using Duncan's test at the 5% confidence level.
Results and Discussion: Analysis of variance showed effect of independent variables including: effects of coating, impact and time and also interaction effects on dependent variables including: natural frequency, acoustic index and modulus of elasticity and penetration index on the tested apples. Effects of coating and time were significant at the 5% confidence levelon all dependent variables. But the impact and interaction effect were not significant on dependent variables (Table 1). In general, bruise and lack of coating on the apples during the 10 weeks of storage, were reduced acoustic parameters. In the penetration test, changes were similar to acoustic test (Table 2). In this test, all curves have downward trend and combination of independent variables: coated and intact apples were reasons of more penetration resistance of apples in all of the groups. The condition was continued until the end of storage time, despite of the downwards slopped curves in all groups. In penetration test, coated apples keep more firmness than other groups (groups of apples without coating) and thus the apple's quality would stay better, too (Fig.7).
Conclusions: In general, the following results were obtained from this research: The results showed that the acoustic and penetration parameter were decreased during 10 weeks of storage. Reduction of these parameters continued until the end of storage period, but this reduction was significant only up to eighth week. Also at this time, the acoustic parameters (natural frequency, firmness index, elasticity coefficient) and penetration firmness in intact and coated apples were 14.26%, 4.11%, 14% and 40% respectively higher compared to other apples. Due to the more tangible acoustic parameters changes, especially acoustic index and modulus of elasticity (having the more slope than the penetration firmness). One could use acoustic tests for more accurate evaluation of apples firmness and quality changes. Finding correlation between acoustic parameters and penetration parameter showed that, correlation between acoustic parameters in each case is greater than correlation between these parameters with penetration parameter.
