The effects of phosphorus (P) nutrition on various aspects of photosynthetic metabolism have been examined for coffee plants (Coffea arabica) grown under greenhouse conditions. The experimental design was completely r...The effects of phosphorus (P) nutrition on various aspects of photosynthetic metabolism have been examined for coffee plants (Coffea arabica) grown under greenhouse conditions. The experimental design was completely randomized, and the treatments were carried out in a 2 × 5 factorial scheme: two P sources [Triple Superphosphate - TSP (46% P<sub>2</sub>O<sub>5</sub>) and Policote coated TSP - TSP + Policote (43.7% P<sub>2</sub>O<sub>5</sub>)] and five P rates (0;5;10;15 and 20 g P<sub>2</sub>O<sub>5</sub> plot<sup>-1</sup>), with three replications. The net photosynthetic rate (A), the leaf temperature (LT), the atmospheric CO<sub>2</sub> concentration (Ca), the stomatal conductance (gs), the transpiration rate (E), the substomatal CO<sub>2</sub> concentration (Ci) and carboxylation efficiency (Ce) were measured in the youngest fully expanded leaf, with the use of an infrared gas analyzer. All photosynthesis measurements were affected by P fertilization. P fertilization increased net photosynthetic rate, leaf temperature, substomatal CO<sub>2</sub> concentration, stomatal conductance, transpiration rate, and carboxylation efficiency. Policote coated P fertilizer resulted in a higher net photosynthetic rate, leaf temperature, stomatal conductance, and transpiration rate than conventional P fertilizer. The data indicated that Policote coated P fertilizer, a kind of enhanced efficiency P fertilizer (EEPF), alters the plant’s photosynthetic carbon metabolism, explaining higher crop development and yield resulted from this EEPF.展开更多
Phosphorus (P) plays a crucial role in plant growth by aiding in the development of strong roots, promoting flower and fruit formation, and aiding in photosynthesis. Studies to improve P fertilizers efficiency in coff...Phosphorus (P) plays a crucial role in plant growth by aiding in the development of strong roots, promoting flower and fruit formation, and aiding in photosynthesis. Studies to improve P fertilizers efficiency in coffee orchards are necessary due to the need for better efficiency and the lack of information on enhanced efficiency P fertilizers. This study aimed to investigate the effect of MAP coated with anionic polymers (Policote) on coffee orchard development. A coffee trial was carried out in a randomized block design with three replications. The treatments, applied at coffee planting, were arranged in an incomplete factorial (2 × 4) + 1, using two P sources (MAP and Policote coated MAP), four P rates (40, 80, 120, and 160 g P<sub>2</sub>O<sub>5</sub> plant<sup>-1</sup>) and control (without application of P fertilizer). Plant height was evaluated in the 2016/2017, 2017/2018, and 2018/2019 seasons, while coffee bean maturation, yield, and agronomic P efficiency use were evaluated in the last two seasons. P fertilization did not affect coffee bean maturation and increased coffee yield in 31-month-old plants when differences among P sources and rates were observed. Using Policote-coated P fertilizer resulted in higher yields at the same P rate, as well as similar yields at a lower P rate, compared to conventional fertilizer. Policote-coated P fertilizer can be used as an enhanced efficiency fertilizer and is an efficient way to deliver required P to plants. The target for reducing farm investment, increasing agricultural profits, preserving phosphatic rock reserves, and avoiding the overuse of phosphate fertilizer could be realized through the rational use of enhanced efficiency fertilizers.展开更多
文摘The effects of phosphorus (P) nutrition on various aspects of photosynthetic metabolism have been examined for coffee plants (Coffea arabica) grown under greenhouse conditions. The experimental design was completely randomized, and the treatments were carried out in a 2 × 5 factorial scheme: two P sources [Triple Superphosphate - TSP (46% P<sub>2</sub>O<sub>5</sub>) and Policote coated TSP - TSP + Policote (43.7% P<sub>2</sub>O<sub>5</sub>)] and five P rates (0;5;10;15 and 20 g P<sub>2</sub>O<sub>5</sub> plot<sup>-1</sup>), with three replications. The net photosynthetic rate (A), the leaf temperature (LT), the atmospheric CO<sub>2</sub> concentration (Ca), the stomatal conductance (gs), the transpiration rate (E), the substomatal CO<sub>2</sub> concentration (Ci) and carboxylation efficiency (Ce) were measured in the youngest fully expanded leaf, with the use of an infrared gas analyzer. All photosynthesis measurements were affected by P fertilization. P fertilization increased net photosynthetic rate, leaf temperature, substomatal CO<sub>2</sub> concentration, stomatal conductance, transpiration rate, and carboxylation efficiency. Policote coated P fertilizer resulted in a higher net photosynthetic rate, leaf temperature, stomatal conductance, and transpiration rate than conventional P fertilizer. The data indicated that Policote coated P fertilizer, a kind of enhanced efficiency P fertilizer (EEPF), alters the plant’s photosynthetic carbon metabolism, explaining higher crop development and yield resulted from this EEPF.
文摘Phosphorus (P) plays a crucial role in plant growth by aiding in the development of strong roots, promoting flower and fruit formation, and aiding in photosynthesis. Studies to improve P fertilizers efficiency in coffee orchards are necessary due to the need for better efficiency and the lack of information on enhanced efficiency P fertilizers. This study aimed to investigate the effect of MAP coated with anionic polymers (Policote) on coffee orchard development. A coffee trial was carried out in a randomized block design with three replications. The treatments, applied at coffee planting, were arranged in an incomplete factorial (2 × 4) + 1, using two P sources (MAP and Policote coated MAP), four P rates (40, 80, 120, and 160 g P<sub>2</sub>O<sub>5</sub> plant<sup>-1</sup>) and control (without application of P fertilizer). Plant height was evaluated in the 2016/2017, 2017/2018, and 2018/2019 seasons, while coffee bean maturation, yield, and agronomic P efficiency use were evaluated in the last two seasons. P fertilization did not affect coffee bean maturation and increased coffee yield in 31-month-old plants when differences among P sources and rates were observed. Using Policote-coated P fertilizer resulted in higher yields at the same P rate, as well as similar yields at a lower P rate, compared to conventional fertilizer. Policote-coated P fertilizer can be used as an enhanced efficiency fertilizer and is an efficient way to deliver required P to plants. The target for reducing farm investment, increasing agricultural profits, preserving phosphatic rock reserves, and avoiding the overuse of phosphate fertilizer could be realized through the rational use of enhanced efficiency fertilizers.
