Water sensitive paper  in agricultural  applications

الورق الحساس للماء في التطبيقات الزراعية

ا.د. مرتضى جليل المعموري

رئيس قسم الجغرافية التطبيقية / كلية التربية للعلوم الانسانية / جامعة كربلاء

WSP has been used in different sciences and applications both in the field and laboratory. To demonstrate its significance, summaries of some of researchers conducted using WSP are presented here. Previous research has shown that there is just 1% difference between two methods being used to estimate the volume and number median diameter, these being visual microscopic classification and a computer program .However, it was noted that the microscopic method was slower than that using a computer program. In other work, three imaging systems (USDA-ARS, Swath Kit camera-based system and the Droplet Scan scanner-based system) were described and the results compared with those of two sets of WSP. There was a high correlation for the three image systems used for droplet spectral parameters of DV0.1, DV0.5, and DV0.9, but less consistent results relative to the span measurements. These outcomes gave the researchers confidence in using WSP to compare their results using the software package . 

The relative performance of eight image processing software programs, both commercial and experimental, used in analyzing results obtained using WSP (Gotas, Stain Master, Stain Analysis, Agro Scan, Droplet Scan and Spray_imageI and II) was compared. The results showed that Spray-imageII with its overlapped feature provided the highest accuracy for coverage and droplet size spectrum measurement, when compared to the other software tested . A strong relation between the values of the measured diameter and volume of droplets emerged from using four different software programs (CIR, e- Sprinkle, DepositScan and Conta-Gotas) and manual analysis. However, there were great differences between the numerical values measured for the same test paper . Experiments to determine the droplet characteristics of seven agriculture spray nozzles were carried out, with the purpose of the study being to develop a practical alternative to the conventional approach of Spot Elimination (SE) from WSP surfaces. The results gave a linear relationship between the minimum SR (Spot Roundness) value and volume median diameter of the droplets. Moreover, it was determined that the spot roundness values can be employed for an elimination procedure of overlapped spots as well as for non-circular spots on a WSP surface . 

A method to determine the amount of sprayed liquid for several commercial orchard sprays with different types of air discharge systems (conventional, cross flow and directional spouts) was presented, with both WSP and blotting paper being used. The experimental results indicated that the former was suitable for the proposed technique, because it could generate the spray distribution, spot density, spot size and a histogram of spot size as well as the distance between spots, although it has to be acknowledged that in practice it is very hard to adjust a sprayer used on trees that are characterised by their randomness . A fully automatic methodology based on image processing was used to evaluate the quality of spray application sampled by several WSPs. The experimental data obtained indicated that one with appropriate scanning resolutions can provide good results, not only in terms of stains, size and spectra factors, but also, in relation to the homogeneity of coverage . 

The software package Image J for image processing results obtained using WSP was used to estimate the spray characteristics of different types. The results indicated that there is a close relationship between the simulated superficial coverage and the computed form, thus showing that this relationship is independent of the type of spraying system used. This means it is easy to estimate the overlap between the droplets and certain spraying characteristics, such as: the volume median diameter (VMD), the coefficient of variation (CV), impact density, the degree of uniform deposition as well as the coverage surface area as WSP can now be analyzed electronically . WSP was used to determine pesticide performance on the cotton plant. Specifically, for a fixed area of spray coverage, every part of the used WSP . 

الخلاصة :

تطبيقات الورق الحساس للماء , هي واحدة من الاستعمالات المهمة في مجال الفيزياء والهندسة اضافة الى مجال الهندسة الزراعية. التي تعد هذه التطبيقات هي من صلبها. الفكرة الاساس بها تاتي في كيفية حساب احجام قطرات الماء او أي سائل اخر لغرض دراسة سلوكية هذه القطيرات اثناء تولدها من مصدر انتشارها مثال ذلك المرشات التي تستخدم في توليد رذاذ متناثر من السوائل . مثلا تناثر البنزين وتحويله  الى غرفة الوقود لغرض توليد طاقة حرارية وحركية . وكذلك  تناثر القطرات الناتجة من تذري المادة الكيمائية الى قطرات صغيرة تنتشر على جسم النبات لغرض معالجة الحشرات . وتستخدم هذه الاوراق  الحساسة للماء مبدئيا في تحديد واختيار حجوم القطيرات المطلوبة لتحقيق هدف المكافحة كما هو معمول بالري الكهربائي الذي ثبت كفاءة في اصابة الهدف ( مكافحة الآفات) وتقليل التلوث الذي يعد العامل الاكثر اهمية في مجالات التطبيقات الحديثة لتقليل التلوث.