Magnetic treatment of irrigation water: Its effects on vegetable crop yield and water productivity

This study examines whether there are any beneficial effects of magnetic treatment of different irrigation water types on water productivity and yield of snow pea, celery and pea plants. Replicated pot experiments involving magnetically treated and non-magnetically treated potable water (tap water), recycled water and saline water (500ppm and 1000ppm NaCl for snow peas; 1500ppm and 3000ppm for celery and peas) were conducted in glasshouse under controlled environmental conditions during April 2007 to December 2008 period at University of Western Sydney, Richmond Campus (Australia). A magnetic treatment device with its magnetic field in the range of 3.5-136mT was used for the magnetic treatment of irrigation water. The analysis of the data collected during the study suggests that the effects of magnetic treatment varied with plant type and the type of irrigation water used, and there were statistically significant increases in plant yield and water productivity (kg of fresh or dry produce per kL of water used). In particular, the magnetic treatment of recycled water and 3000ppm saline water respectively increased celery yield by 12% and 23% and water productivity by 12% and 24%. For snow peas, there were 7.8%, 5.9% and 6.0% increases in pod yield with magnetically treated potable water, recycled water and 1000ppm saline water, respectively. The water productivity of snow peas increased by 12%, 7.5% and 13% respectively for magnetically treated potable water, recycled water and 1000ppm saline water. On the other hand, there was no beneficial effect of magnetically treated irrigation water on the yield and water productivity of peas. There was also non-significant effect of magnetic treatment of water on the total water used by any of the three types of vegetable plants tested in this study. As to soil properties after plant harvest, the use of magnetically treated irrigation water reduced soil pH but increased soil EC and available P in celery and snow pea. Overall, the results indicate some beneficial effect of magnetically treated irrigation water, particularly for saline water and recycled water, on the yield and water productivity of celery and snow pea plants under controlled environmental conditions. While the findings of this glasshouse study are interesting, the potential of the magnetic treatment of irrigation water for crop production needs to be further tested under field conditions to demonstrate clearly its beneficial effects on the yield and water productivity.Magnetic treatment Water productivity Recycled water Salinity Snow pea Celery Pea plants

Dry matter production and uptake of zinc and phosphorus in two oilseed rape genotypes under differential rates of zinc and phosphorus supply

The effects of varied supply of zinc (Zn) (0, 0.1, 0.2, 1.0, and 10 mg Zn kg⁻¹ soil) and phosphorus (P) (low P: 50 mg P kg⁻¹ soil and high P: 150 mg P kg⁻¹ soil) on vegetative growth, plant tissue Zn and P concentration and their uptake were studied in six weeks old plants of two oilseed rape (Brassica napus) genotypes (92–13, a traditional genotype from China high in both erucic acid and glucosinolate, and Xinza‐2, a hybrid from China low in erucic acid and glucosinolate) grown in Laffer sand (low in Zn and P) under controlled environmental conditions. Two oilseed rape genotypes had a differential response to Zn application. Xinxa 2 responded significantly for shoot and root dry matter only up to 0.1 mg applied Zn kg⁻¹ soil, while 92–13 responded up to 0.2 mg Zn kg⁻¹ soil. Zinc at 10 mg kg⁻¹ soil slightly reduced shoot dry matter and drastically reduced root dry matter of both the genotypes. Shoot and root dry matter production at 0, 0.1, 0.2, and 1 mg Zn kg⁻¹ soil were significantly greater under high P supply compared with low P supply. High P supply did not accentuate Zn deficiency symptoms compared with low P supply even at nil Zn. Phosphorus concentration in plant parts was significantly higher at nil Zn compared with Zn application. An increase in P supply had a non‐significant effect on Zn concentration, but significantly increased the P concentration and P uptake in shoots. The results suggest that an increased supply of P at lower rates of Zn application was not detrimental for early vegetative growth and Zn uptake of two oilseed rape genotypes.Zhonggui Lu, Harsharn Singh Grewal & Robin D. Graha

Boron effects on rhizosphere acidification in canola

The original publication can be found at www.springerlink.comA root-box experiment was conducted under controlled environment conditions to investigate the effects of boron (B) on the degree of rhizosphere acidification by different cultivars of canola. Two cultivars, one B-efficient (Dunkeld) and another B-inefficient (Yickadee) were grown in a moderately B deficient soil at low and adequate B supply with NH₄⁺ as N source. Rhizosphere pH of both the tap and lateral roots was measured by an antimony microelectrode 21 days after sowing. Cultivars grown at adequate B supply acidified their rhizosphere by up to 2.5 pH units, with the cultivar Yickadee acidifying the rhizosphere more than Dunkeld. At low B supply, roots of both cultivars acidified the rhizosphere by up to an extra 1 pH unit and again Yickadee acidified its rhizosphere more than Dunkeld. These results indicate an effect of B at the root-soil interface but provide no evidence to support a role of rhizosphere acidification as a mechanism of B efficiency