Nitrogen and Phosphorus Addition to Soil Improves Seed Yield, Foliar Stomatal Conductance, and the Photosynthetic Response of Rapeseed (Brassica napus L.)

Abstract

The effects of nitrogen and phosphorus levels on the physiological traits, yield, and seed yield of rapeseed (Brassica napus L.), were studied in a farm research project of Zanjan University. Three levels of nitrogen (0, 100, and 200 kg/ha) and three levels of phosphorus (0, 75, and 150 kg/ha) were considered. The results showed that an increase in nitrogen level caused an increase in the leaf chlorophyll content so that the application of 200 kg/ha of nitrogen increased the chlorophyll content of the leaves until the mid-grain filling stage. Nitrogen application lowered leaf stomatal conductance in the early flowering stage whereas the stomatal conductance was increased during the late flowering stage. Nitrogen application (100 and 200 kg/ha) also increased the quantum yield of photosystem II. On the other hand, with the application of 150 kg/ha and 75 kg/ha of phosphorus, the leaf stomatal conductance and the quantum yield of photosystem II in the early flowering stage increased respectively. The results showed that the application of 200 kg/ha of nitrogen and 75 kg/ha of phosphorus significantly increased seed and oil yield compared to the control. In addition, the number of siliques per plant and the weight of 1000 seeds showed an increasing trend that was affected by nitrogen and phosphorus levels. This study demonstrated that nitrogen enhanced the chlorophyll content, leaf area, and consequently, the quantum yield of photosystem II. Nitrogen also augmented the seed filling duration, seed yield, and oil yield by increasing gas exchange. As a result, the application of 100 kg/ha of nitrogen together with 75 kg/ha phosphorus showed the greatest effect on the qualitative and quantitative yield of rapeseed. However, the application of 200 kg/ha of nitrogen alone or in combination with different levels of phosphorus did not significantly increase many of the studied traits.

Lime and Manure Amendment Improve Soil Fertility, Productivity and Nutrient Uptake of Rice-Mustard-Rice Cropping Pattern in an Acidic Terrace Soil

“…Liming has also been linked to an increase in crop yields [52,53]. In addition, interactive effects of N and P fertilizers increases chlorophyll content, stomatal conductance and quantum yield of photosystem II resulting in higher yield of crops [54]. Crop yields of straw likewise followed a similar pattern.…”

Anthropic Effects on the Biodiversity of the Habitats of Ferula gummosa

“…The results of soil samples analysis of the natural habitats of FG in the Zanjan Province are presented in Table 4. Soil texture characteristics (amount of clay, sand and silt) and elements concentration in the soil (amount of potassium and nitrogen) are important and influential factors on FG distribution as observed by other authors [22,24,26]. The structure of the soil with its vegetation influences the amount of humidity and plant elements available, the water retention capacity and permeability of the soil, the organic matter present, the nutrient cycle of the soil and the depth of rooting of the plants.…”

“…The distribution of plant species in rangeland ecosystems is not accidental; rather, environmental factors such as climate, soil, topography and human activities play an important role in the expansion of plants [17,18]. Some authors have shown that the establishment of plant communities in mountainous areas is mainly affected by climate factors, and in low-lying areas and rolling hills by soil factors [19][20][21][22][23]. Therefore, it seems that regarding the establishment of FG in the highlands, climatic factors have the greatest role in the distribution and establishment of this plant.…”

Release of Nitrogen from Granulate Mineral and Organic Fertilizers and Its Effect on Selected Chemical Parameters of Soil

“…The implementation of practices such as split application and sowing fertilization can increase the efficiency of nitrogen use by up to 16-17% in calcareous soils [50]. A higher level of available nitrogen in calcareous soil results in a higher yield of plants, even in semi-dry soil conditions [51]. The small granules of U-PSf can be recommended for these conditions with a high dissolving capacity.…”