Effects of phosphorus and iron on biomass production and nutrients partitioning in soybean cultivars under water stress condition

A pot experiment was conducted to investigate the effects of P and Fe application on the biomass production and nutrients partitioning of two soybeans (Glycine max. L. Merr) cultivars grown in carbonated chernoziom (low in Fe and P) under water stress conditions. P and Fe were applied at two levels (0 and 100 mg P kg-1 soil; 0 and 5 mg Fe kg-1 soil). Control plants were grown at 70% water holding capacity (WHC) while their counterparts were subjected to 35% WHC water stress at initial flowering stage for two weeks. Considerable variability was observed in leaves, roots dry mass accumulation and nodulation among the soybean cultivars (Zodiac, Licurici) at both P and Fe levels in relation to water regimes. The results showed that drought significantly reduced biomass production irrespective of nutrient supply and its adverse effect was more pronounced at low nutrient supply. Leaf development and nodules growth were the most sensitive to water deficit and insufficient nutrient supply. Adequate P and Fe supply increased dry matter production and nutrient concentrations for soybean cultivars. Phosphorus concentration in plant parts was significantly higher at nil Fe compared with Fe application. Phosphorus application decreased Fe allocation to the leaves. The experimental results demonstrated that there was a positive effect of P and Fe adequate nutrition on P use efficiency. Hence, the sufficient phosphorus and iron supply maintained growth at high level, improved P and Fe status and partially alleviated drought effect on soybean plants.

Regulation of Phosphorus Supply on Nodulation and Nitrogen Fixation in Soybean Plants with Dual-Root Systems

Phosphorus (P) is an important nutrient affecting nodulation and nitrogen fixation in soybeans. To further investigate the relationship of phosphorus with soybean nodulation and nitrogen fixation, the seedling grafting technique was applied in this study to prepare dual-root soybean systems for a sand culture experiment. From the unfolded cotyledon stage to the initial flowering stage, one side of each dual-root soybean system was irrigated with nutrient solution containing 1 mg/L, 31 mg/L, or 61 mg/L of phosphorus (phosphorus-application side), and the other side was irrigated with a phosphorus-free nutrient solution (phosphorus-free side), to study the effect of local phosphorus supply on nodulation and nitrogen fixation in soybean. The results are described as follows: (1) Increasing the phosphorus supply increased the nodules weight, nitrogenase activity, ureide content, number of bacteroids, number of infected cells, and relative expression levels of nodule nitrogen fixation key genes (GmEXPB2, GmSPX5, nifH, nifD, nifK, GmALN1, GmACP1, GmUR5, GmPUR5, and GmHIUH5) in root nodules on the phosphorus-application side. Although the phosphorus-application and phosphorus-free sides demonstrated similar changing trends, the phosphorus-induced increases were more prominent on the phosphorus-application side, which indicated that phosphorus supply systematically regulates nodulation and nitrogen fixation in soybean. (2) When the level of phosphorus supply was increased from 1 mg/L to 31 mg/L, the increase on the P– side root was significant, and nodule phosphorus content increased by 57.14–85.71% and 68.75–75.00%, respectively; ARA and SNA were 218.64–383.33% and 11.41–16.11%, respectively, while ureide content was 118.18–156.44%. When the level of phosphorus supply was increased from 31mg/L to 61mg/L, the increase in the regulation ability of root and nodule phosphorus content, ARA, SNA, and ureide content were low for roots, and the value for nodules was lower than when the phosphorus level increased from 1 mg/L to 31 mg/L. (3) A high-concentration phosphorus supply on one side of a dual-root soybean plant significantly increased the phosphorus content in the aboveground tissues, as well as the roots and nodules on both sides. In the roots on the phosphorus-free side, the nodules were prioritized for receiving the phosphorus transported from the aboveground tissues to maintain their phosphorus content and functionality.

Response of root development and nutrient uptake of two chinese cultivars of hybrid rice to nitrogen and phosphorus fertilization in Sichuan Province, China

Background Chemical fertilization helped modern agriculture in grain yield improvement to ensure food security. The response of chemical fertilization for higher hybrid rice production is highly dependent on optimal fertilization management in paddy fields. To assess such responses, in the current work we examine the yield, root growth, and expression of related genes responsible for stress metabolism of nitrogen (N) and phosphorus (P) in two hybrid-rice cultivars Deyou4727 (D47) and Yixiangyou2115 (Y21). Methods and results The experiment followed four nitrogen (N) (N0, N60, N120, and N180 kg/ha) and phosphorus (P) (P0, P60, P90, and P120 kg/ha) fertilizer levels. The grain yield in D47 was more sensitive to nitrogen application, while Y21 was more sensitive to phosphorus application, which resulted in comparatively higher biomass and yield. Our findings were corroborated by gene expression studies of glutamine synthetase OsGS1;1 and OsGS1;2 and phosphate starvation-related genes PHR1 and SPX, confirming sensitivity to N and P application. The number of roots was less sensitive to nitrogen application in D47 between N0 and N60, but the overall nutrient response difference was significantly higher due to the deep rooting system as compared to Y21. Conclusions The higher yield, high N and P use efficiency, and versatile root growth of D47 make it suitable to reduce unproductive usage of N and P from paddy fields, improving hybrid rice productivity, and environmental safety in the Sichuan basin area of China.

Responses of Seed Yield Components to the Field Practices for Regulating Seed Yield of Smooth Bromegrass (Bromus inermis Leyss.)

Agronomic practices improve seed yield by regulating seed yield components, and the relationship between seed yield and seed yield components is still unclear in smooth bromegrass (Bromus inermis). To optimize seed production and yield in smooth bromegrass, a five-year field trial was designed with split-split-plot to study the combined effects of row spacing (30, 45, 60, and 75 cm), phosphorus (0, 60, 90, and 120 kg P ha−1) and nitrogen (0 and 100 kg N ha−1) on seed yield and seed yield components including fertile tillers m−2 (FTs), spikelets per fertile tiller (SFT), florets per spikelet (FS), and seeds per spikelet (SS). The results showed that FTs as a key factor had a positive effect to seed yield with the biggest pathway coefficient, while SS had a negative effect. Meanwhile, an interaction effect between FTs and SS was observed. FS and SS were increased with phosphorus application under the condition of sufficient nitrogen. In addition, sufficient precipitation at the non-growing season resulted in more FTs in the next year in rain-fed regions. Therefore, the optimum seed yield of smooth bromegrass can be obtained with row spacing (45 cm), nitrogen (100 kg N ha−1), and phosphorus application (60 kg P ha−1).

Optimizing Phosphorus Application Rate and the Mixed Inoculation of Arbuscular Mycorrhizal Fungi and Phosphate-solubilizing Bacteria Can Improve the Phosphatase Activity and Organic Acid Content in Alfalfa Soil

Alfalfa (Medicago sativa L.) is an important high-quality legume forage, and phosphorus is an important nutrient element for high-quality and high-yield of alfalfa. This study assessed the effects bacteria and phosphorus (P) use efficiency of alfalfa soil under different P applications. In this experiment, a two-factor complete randomized block design was used. Four bacterial treatments were as follows: Funneliformis mosseae (Fm), Bacillus megaterium (Bm), double inoculation (Fm × Bm) and no inoculation bacteria (CK). There are four levels of phosphorus treatment, namely: phosphorus application 0 (P0), 50 (P1), 100 (P2), 150 mgžkg-1 (P3). There were 16 treatments in total, and each treatment was repeated 6 times. The results showed that the effects of single inoculation and mixed inoculation were significantly higher than those of noninoculation (P < 0.05). With the increase in phosphorus application, each index increased first and then decreased. The alkaline phosphatase activity (AKP) and organic matter (SOM) content in soi lincreased with the increase of cutting times, and the content of organic matter in rhizosphere soil was higher than that in non-rhizosphere soil. Principal component analysis (PCA) shows that the top three treatments were J3P2 > J3P1 > J3P3. Therefore, when (P2O5) was 100 mgžkg-1, the mixed inoculation of Fm × Bm could improve the phosphatase activity in alfalfa soil, promote the secretion of organic acids in rhizosphere soil and then improve the content of soil fertility.

Yield of Spring Grown Chickpea (Cicer arietinum L.) under Different Doses of Soil Applied Phosphorus in An Agroecology of Semi-arid Highlands with Mediterranean Climate

Background: This study was carried out to determine the effects of different phosphorus doses on the flowering, yield and yield components of spring grown chickpea crop under the ecological conditions of Siirt province in the experimental field of Siirt University, Faculty of Agriculture, Field Crops Department during two seasons in 2018 and 2019. Methods: The study was carried out in randomized complete blocks design with three replications. Before planting, 140 kg ha-1 of DAP fertilizer (18.46.0) was spreaded and incorporated into the soil with a rake. Following emergence of plants, TSP fertilizer (0.42.0) was spreaded to the plots at doses of 0, 30, 60, 90 kg ha-1 P2O5 into the mellow humid soil. Result: All observed parameters were effected from phosphorus application doses. Based on different P doses, two years’ average plant height, first pod height; main branch number, flower number per plant, pod number per plant, grain number per plant, 100 grain weight and grain yield values were determined as 51,25-55,91 cm; 29,17-35,98 cm; 2,10-2,97 piece plant-1; 39,00-57,86 piece plant-1; 18,87-27,92 piece plant-1; 18,00-27,33 piece plant-1; 29,92-33,41 g and 969-1565 kg ha-1, respectively. Highest values for all parameters were obtained from 60 kg ha-1 P2O5 but further dose (60 kg ha-1 P2O5) resulted with reduction from top values for all parameters.

Agronomic Efficiency of Phosphorus Fertilizers With Associate Technology in Soy Crop in Cerrado Soil

For commercial soybean production, the presence of phosphorus in the soil is essential, not only to increase productivity but also because it affects basic functions in plant metabolism. Phosphate fertilizers have low efficiency in Cerrado soils. For this reason, the use of technologies associated with phosphate fertilizers is important to increase their efficiency in the soil. The experiment was conducted at Fazenda Rio Brilhante in Coromandel, MG. The experiment was laid out in a randomized block design in a 4 &times; 4 + 1 factorial arrangement. Treatments consisted of four phosphate fertilizer sources (MAPCONVENCIONAL, MAPpol 1, MAPpol 2, and FOM), four P2O5 doses (40, 80, 120, and 160 kg ha-1), and the control treatment (no phosphorus application). The soybean cultivar RK8115 IPRO with a plant population of 340 thousand plants per hectare was used. The experimental plots consisted of five planting lines with a spacing of 0.5 meters and a length of 7 meters. In the experiment, phosphorus leaf, morphological evaluation of plant height, stem diameter, number of stems, and pods were measured. For plant biomass, the dry matter of leaves, stems, and pods were determined. For yield evaluation, the calculation of productivity and RAE was compared with MAPCONVENCIONAL. For sources, data were subjected to analysis of variance, and means were separated by Tukey&rsquo;s rate test (p &lt; 0.05). For P2O5 doses, regression model fitting was performed using the ExpDes.pt package of R Studio software. Morphological assessments responded linearly to P doses, except for DPM. Leaves and pods P content and yield were affected by P dosage and P sources, with a quadratic response to P dosage. Maximum yield efficiency was achieved at P2O5 doses of 122.73; 145.07; 112.03; and 94.71 kg ha-1, with yields of 3818.30; 4064.67; 4089.03; and 3952.63 kg ha-1 for MAPCONVENCIONAL, MAPpol 2, MAPpol 1, and FOM, respectively. However, MAPpol 1 and FOM provided a dose reduction of 26 and 15 compared to the maximum yield of MAPCONVENCIONAL, respectively.