The combined application of organic and mineral fertilizers can be a proper way of nutrition management to increase the yield and quality and to mitigate environmental impacts of chemicals and the pertaining costs. Th...The combined application of organic and mineral fertilizers can be a proper way of nutrition management to increase the yield and quality and to mitigate environmental impacts of chemicals and the pertaining costs. The impact of different rates of sulfur-containing humic acid was studied on yield and nutrient uptake of the fruits of olive “Zard” three-year-old trees in a trial based on a Randomized Complete Block Design with three replications in Shariati College of Tehran, Iran. The studied treatment was sulfur-containing humic acid at four rates of 0, 20, 25 and 30 kg⋅ha−1, which was applied at two stages. The highest fresh weight, dry weight, chlorophyll b, carotenoid, N and Cu contents were related to humic acid rate of 20 kg⋅ha−1. The highest fruit length, chlorophyll a and total chlorophyll were observed in control. The highest K, Fe and Mn contents were obtained from plants treated with 30 kg⋅ha−1 humic acid. Plants treated with 25 kg⋅ha−1 exhibited the highest P and Zn contents. All in all, the application of sulfur-containing humic acid at different rates had favorable impacts on quantitative and qualitative traits of olive fruits.展开更多
Cranberry (Vaccinium macrocarpon Ait.) is an ammophilous plant grown on acid soils (pH 4.0 - 5.5). Elemental sulfur is commonly applied at a recommended rate of 1120 kg S ha<sup>−1</sup> per pH unit to aci...Cranberry (Vaccinium macrocarpon Ait.) is an ammophilous plant grown on acid soils (pH 4.0 - 5.5). Elemental sulfur is commonly applied at a recommended rate of 1120 kg S ha<sup>−1</sup> per pH unit to acidify cranberry soils, potentially impacting the plant mineral nutrition. The general recommendation may not fit all conditions encountered in the field. Our objective was to develop an equation to predict the sulfur requirement to reach pH<sub>water</sub> of 4.2 to tackle nitrification in acidic cranberry soils varying in initial pH values, and to measure the effect of elemental sulfur on the mineral nutrition and the performance of cranberry crops. A 3-yr experiment was designed to test the effect of elemental sulfur on soil and tissue tests and on berry yield and quality. Four S treatments (0, 250, 500 and 1000 kg S ha<sup>−1</sup>) were established on three duplicated sites during two consecutive years. We ran soil, foliar tissue, berry tissue tests, and measured berry yield, size, anthocyanin content (TAcy), Brix, and firmness. Nutrients were expressed as centered log ratios to reflect nutrient interactions. Results were analyzed using a mixed model. Soil Ca decreased while soil Mn and S increased significantly (p ≤ 0.05). Sulfur showed no significant effects on nutrient balances in uprights. The S impacted negatively berry B balance, and positively berry Mn and S balances. A linear regression model relating pH change to S dosage and elapsed time (R<sup>2</sup> = 0.53) showed that to reach pH<sub>water</sub> of 4.2 two years after S application, 250 - 1000 kg S ha<sup>−1</sup> could be applied depending on initial soil pH value. The stratification of surface-applied elemental S in the soil profile should be further examined in relation to plant rooting and nutrient leaching.展开更多
文摘The combined application of organic and mineral fertilizers can be a proper way of nutrition management to increase the yield and quality and to mitigate environmental impacts of chemicals and the pertaining costs. The impact of different rates of sulfur-containing humic acid was studied on yield and nutrient uptake of the fruits of olive “Zard” three-year-old trees in a trial based on a Randomized Complete Block Design with three replications in Shariati College of Tehran, Iran. The studied treatment was sulfur-containing humic acid at four rates of 0, 20, 25 and 30 kg⋅ha−1, which was applied at two stages. The highest fresh weight, dry weight, chlorophyll b, carotenoid, N and Cu contents were related to humic acid rate of 20 kg⋅ha−1. The highest fruit length, chlorophyll a and total chlorophyll were observed in control. The highest K, Fe and Mn contents were obtained from plants treated with 30 kg⋅ha−1 humic acid. Plants treated with 25 kg⋅ha−1 exhibited the highest P and Zn contents. All in all, the application of sulfur-containing humic acid at different rates had favorable impacts on quantitative and qualitative traits of olive fruits.
文摘Cranberry (Vaccinium macrocarpon Ait.) is an ammophilous plant grown on acid soils (pH 4.0 - 5.5). Elemental sulfur is commonly applied at a recommended rate of 1120 kg S ha<sup>−1</sup> per pH unit to acidify cranberry soils, potentially impacting the plant mineral nutrition. The general recommendation may not fit all conditions encountered in the field. Our objective was to develop an equation to predict the sulfur requirement to reach pH<sub>water</sub> of 4.2 to tackle nitrification in acidic cranberry soils varying in initial pH values, and to measure the effect of elemental sulfur on the mineral nutrition and the performance of cranberry crops. A 3-yr experiment was designed to test the effect of elemental sulfur on soil and tissue tests and on berry yield and quality. Four S treatments (0, 250, 500 and 1000 kg S ha<sup>−1</sup>) were established on three duplicated sites during two consecutive years. We ran soil, foliar tissue, berry tissue tests, and measured berry yield, size, anthocyanin content (TAcy), Brix, and firmness. Nutrients were expressed as centered log ratios to reflect nutrient interactions. Results were analyzed using a mixed model. Soil Ca decreased while soil Mn and S increased significantly (p ≤ 0.05). Sulfur showed no significant effects on nutrient balances in uprights. The S impacted negatively berry B balance, and positively berry Mn and S balances. A linear regression model relating pH change to S dosage and elapsed time (R<sup>2</sup> = 0.53) showed that to reach pH<sub>water</sub> of 4.2 two years after S application, 250 - 1000 kg S ha<sup>−1</sup> could be applied depending on initial soil pH value. The stratification of surface-applied elemental S in the soil profile should be further examined in relation to plant rooting and nutrient leaching.
