Search

Soil health in terms of plant available nutrients is crucial to estimate the yield potential of agricultural land in an area. Based on the availability of soil health data, it is possible to set yield targets using various yield prediction models. This study was initiated to estimate the concentration of DTPA-extractable micronutrients in Tehsil Muzaffargarh and to develop a database that can be used to develop predictive models. Soil samples (n=11537) were collected from Muzaffargarh (0-15 cm depth). The latitude and longitude values of sampling points were recorded for the purpose of georeferencing the soil samples. Micronutrients such as zinc (Zn), copper (Cu), iron (Fe) and manganese (Mn) were extracted with diethylenetriamine penta-acetate (DTPA) extraction solution and their concentrations were determined with atomic absorption spectrophotometer. Water soluble boron (B) was determined spectrophotometrically using Azomethine-H as colour developing reagent. Critical limits established by the National Agricultural Research Center (NARC) Islamabad, Pakistan, were used as a benchmark for grading micronutrient status. The ordinary kriging technique was used to visualize the micronutrient status in the surveyed area and digital maps were prepared using Quantum Geographic Information System (QGIS) software. Results showed that the range of DTPA-extractable micronutrients Zn, Fe, Mn, and Cu ranged from 0.10-5.92, 0.01-12.51, 0.09-10.00 and 0.03-8.08 µg/g, respectively. Boron concentration ranged from 0.02-1.98µg/g. Most of the soils in the studied area had adequate levels of Zn (61.9%) and Cu (48.6%) while 45.8, 43.3 and 55.4 % of the soil samples fell into the marginal category in terms of Cu, Mn, and B, respectively. The results revealed the widespread deficiency of DTPA-extractable Fe (< 4.5mg kg-1 in 74% soil samples) in Tehsil Muzaffargarh. The digitized maps developed from this study would serve as primary source to locate micronutrient deficient areas and also set site-specific yield targets along with other biophysical factors. However, these maps need ground truthing after crop harvest each year. [ABSTRACT FROM AUTHOR]

Plant growth regulators are useful for promoting plant growth and their consumption in horticultural crops is increasing day by day. However, their quality and purity are most important characteristics to estimate their efficacy. In Pakistan, the determination and quality monitoring of naphthyl acetic acid (NAA) in commercial plant growth regulator formulations by using HPLC technique is very limited. For the purpose of registration of plant growth regulators (PGRs) for marketing and for post-registration quality monitoring, a robust, simple, and accurate analytical method is needed. In this study, a high performance liquid chromatography (HPLC) method for the determination of NAA in commercial PGR samples was validated under the laboratory conditions and available resources of Provincial Reference Fertilizer Testing Laboratory (PRFTL) Raiwind, Lahore. The guidelines and values set by Collaborative International Pesticides Analytical Council (CIPAC) were considered as standard for method evaluation. The chromatographic conditions of HPLC method under study are comprised of (i) mobile phase; mixture of acetonitrile: water (30:70,v/v); (ii) C8 column; (iii) UV detection at 255nm; (iv) Flow rate of 1.0mL / minute; (v) and injection volume of 10 µL. The method demonstrated clear response linearity with correlation coefficient (r) of 0.999. In order to determine the precision, an interlaboratory comparison of NAA was conducted and percent relative standard deviation (RSD) was calculated from results received from eight (8) participating laboratories. The Horwitz equation was followed to evaluate precision of method. The experimental inter-laboratory RSD (RSDR =0.168) was within the Horwitz acceptable limit of RSDR (2.097). Method accuracy was evaluated by calculating percent recovery of analytical standard of NAA obtained from Sigma Aldrich along with its certificate of analysis. The recovery of NAA standard ranged between 99.96 to 100%. The results revealed that aforementioned HPLC method fulfilled the validation criteria of CIPAC and can be followed under laboratory conditions of PRFTL, Raiwind, Lahore for routine analysis of NAA in commercial PGRs. Additionally, the quality of commercial NAA samples marketed by different companies was assessed by following aforesaid validated HPLC method. Ten samples of NAA were collected from market and were analyzed. The results were tested for fit or unfit and compared with the company/manufacturers' claim considering the decision rule followed by the Agriculture Department, Government of Punjab, Pakistan. The NAA contents in samples ranged from 4.20 ± 0.10 to 5.13 ± 0.05%. The results showed that all the samples were fit, and it can be inferred that presently the quality of commercial NAA marketed in district Lahore is satisfactory. [ABSTRACT FROM AUTHOR]

A significant increase in food production, approximately 70%, is needed to feed the estimated 9.1 billion world population by 2050. Site-specific nutrient management through adoption of Precision Agriculture (PA) technologies can potentially increase crop productivity while keeping the use of chemical fertilizers at its minimum required level. In this study, agricultural land of tehsil Chunian was delineated into management zones using georeferenced soil attributes database developed by Soil Fertility Research Institute (SFRI), Punjab. Appropriate number of zones was determined after conducting fuzzy c -means unsupervised clustering analysis by using Management Zone Analyst (MZA) software and finally Quantum Geographic Information System (QGIS) was used to differentiate study area into five zones. Analysis of variance was performed to verify whether these defined zones reflect soil attributes. We concluded that tehsil Chunian could be categorized into five statistically different management zones based on soil electrical conductivity (EC), pH, soil organic matter (SOM), available potassium and available phosphorus levels. The highest crop yield was predicted in southeastern parts of tehsil Chunian represented by management zone-2 (4.4 t ha-1) followed by zone-1 (4.3 t ha-1). Whereas, northern and northwest areas were predicted with decreasing trend of wheat yield (zone-5, 3.7 t ha-1; zone-4, 4.0 t ha-1), respectively. We found that MZA and QGIS software could be used as supportive tools for making informed-decisions and the database of soil attributes developed by SFRI would serve as primary source of information for adoption of PA technology in coming years. [ABSTRACT FROM AUTHOR]