Tomato (Solanum lycopersicum L.) is a high-value crop that has potential to enhance its P-use efficiency. While phosphorus (P) is an essential nutrient, supplies are finite and much of the P supply in agricultural soils is not bioavailable after application due to reactions such as soil adsorption, immobilization, or precipitation. Low-P bioavailability results in reduced growth, so plants may mobilize soil-bound P by altering root morphology, exuding root-derived compounds, or forming symbiosis with microorganisms. This review discusses (i) the significance of P in plants and agroecosystems, (ii) within-plant response to changing P bioavailabilities, and (iii) strategies to enhance P-acquisition efficiency (PAE). Phosphorus forms fluctuate in the soil and potential approaches to increase the bioavailable pool of P may focus on processes such as desorption, mineralization, or dissolving precipitated P-compounds. To enhance these processes, roots may alter their spatial arrangement, exude protons to acidify the rhizosphere, exude carboxylates to solubilize bound-P, exude phosphatase to mineralize organic P, or enhance symbiosis with native microbes. High PAE allows for use of accumulated soil P as opposed to relying on fertilizer application to meet crop demand.

Potato (Solanum tuberosum L.) has low phosphorus (P) use efficiency as compared with other vegetable crops. This study was conducted at two commercial chipping potato farms (A and B) in Northeast Florida to evaluate different P rates for potato production. Plot size was 0.62 and 0.49 hectares for Farms A and B, respectively. The total trial area was 13.32 hectares per growing season for three consecutive years from 2018 to 2020. The randomized complete block design (RCBD) was employed with four replications per P rate. The chipping potato variety, ‘Atlantic’ was cultivated with three P rates: 0, 24.5, and 48.9 kg P ha⁻¹ in 2018, and 12.2, 24.5, and 48.9 kg P ha⁻¹ in 2019 and 2020. The soil of Farm A contained 497 mg kg⁻¹ Mehlich-3 extractable P and 946 mg kg⁻¹ aluminum (Al), and that of Farm B had 220 mg kg⁻¹ Mehlich-3 extractable P and 253 mg kg⁻¹ Al. The results showed that a P rate of 48.9 kg P ha⁻¹ significantly improved tuber yield as compared to 0 in 2018 or 12.2 kg P ha⁻¹ in 2019 and 2020. Application of 48.9 kg P ha⁻¹ fertilizer P significantly increased the soil P level in 2018 and 2020, while the application of 24.5 kg P ha⁻¹ fertilizer P increased the soil P level significantly in 2018 only. Tubers with 48.9 kg P ha⁻¹ showed significantly lower external quality issues than 0 or 12.2 and 24.5 kg P ha⁻¹. However, there were no significant differences in specific gravity, internal tuber quality, and tuber size among the different P rates. The tuber yield data show that potato plants grown on soil with high legacy P still require approximately 50 kg ha⁻¹ P application for sustainable potato production in the area. This high P requirement results from the combination of high concentrations of active metals (Al and iron (Fe)) and a decrease in pH of one unit in the growing season. New P-fertilization programs with post-plant applications rather than with pre-plant application are urgently needed for minimizing P-immobilization by Al and Fe and improving P-use efficiency for potato production in the state.

This publication presents the fertilization recommendations for vegetable crops based on soil tests performed by the UF/IFAS Extension Soil Testing Laboratory (ESTL). It contains the basic information from which ESTL soil test reports and fertilization recommendations are generated. The audiences for this information include commercial and small farmers, crop advisers and consultants, state and local agencies, fertilizer industry, and any interested individuals interested in sustainable nutrient and environmental management. Major revision by Rao Mylavarapu, George Hochmuth, and Guodong Liu; 12 pp. https://edis.ifas.ufl.edu/cv002

China imports most of its potassium (K) requirements for crop production. The objective of this study was to evaluate indica rice hybrids for K‐use efficiency. Twenty‐eight indica rice hybrids were evaluated in nutrient solution. The K influx rate was greatest in genotype Weiyou 64 (684.9 nmol K⁺ plant⁻¹ h⁻¹) and least in genotype Xie A/909 (457.2 nmol K⁺ plant⁻¹ h⁻¹). The K‐use efficiency was greatest in genotype ShanA/909 [81.8 mg dry matter (DM) produced per mg K taken up] and least in genotype Shanyou 64 (55.9 mg mg⁻¹). The maximum biomass was produced by genotype Shan A/4663‐5 (100.8 mg DM per plant), and the least biomass was produced by genotype Xie A/4663‐4 (59.1 mg DM per plant). These results suggest that K shortage for rice production can be alleviated by using K‐efficient rice genotypes.