Uptake Of Sorghum Research Articles

Appropriate Use of Local Phosphate Rock Increases Phosphorus Use Efficiency and Grain Yield of Sorghum and Cowpea in the Sudan Savanna

Development of local P fertilizers using low-grade phosphate rock (PR) is expected to overcome the low-stagnated crop yield in Sub-Saharan Africa. Calcination and partial acidulation methods have been proposed to increase the phosphate (P) solubility of PRs. However, the effects of fertilization with calcinated PR (CPR) and partially acidulated PR (PAPR) on sorghum [Sorghum bicolor (L.)] and cowpea [Vigna unguiculata (L.) Walp.] cultivation are poorly understood. Therefore, we conducted a 2-year field experiment in Burkina Faso to identify the differences in sorghum and cowpea responses to CPR and PAPR application. The following eight treatments were applied with six replicates using a complete randomized block design: control without P fertilization, two types of CP (CPs), triple superphosphate (TSP) as a positive control for CPs, three types of PAPR with different degrees of acidulation (PAPRs), and single superphosphate (SSP) as a positive control for PAPRs. SSP mostly comprised of water-soluble P fraction (WP), TSP and PAPRs of WP and alkaline ammonium citrate-soluble P fraction (SP), and CPRs of SP and 2% citric acid-soluble P fraction (CP). Their solubility was in the order WP > SP > CP. The fertilization effects were evaluated by P use efficiency (PUE). In 2019, the biomass and P uptake of sorghum was decreased by the low available soil water at the early growth stage. On the contrary, cowpea survived the low available soil water because of its shorter growing period compared to sorghum. P fertilization significantly increased the grain yields. However, the effect size differed according to the crop and fertilizer types. The SP, along with WP, significantly contributed to the PUE and grain yield of sorghum, whereas only WP contributed to the PUE of cowpea. Therefore, CPs, mainly consisting of SP and CP, had a disadvantage compared to TSP, especially for cowpea. We thus concluded that PAPRs are effective for sorghum and would be effective for cowpea when the acidulation level is sufficiently high. We also conclude that the long growing period of sorghum is favorable for absorbing slow-release P, but is unfavorable for the variable rainfall often observed in this region.

Dates of Sowing and Residual Nitrogen Levels on Growth, Yield and Uptake in Sorghum under Zero-till Conditions in Coastal Belts of India

A field experiment was conducted during rabi seasons of 2017-18 and 2018-19 at College farm, Agricultural College, Bapatla, situated at 8 km away from the Bay of Bengal in the Krishna Agro-climatic Zone of Andhra Pradesh state of India to study the influence of dates of sowing and residue levels of nitrogen on growth, yield and uptake of sorghum under zero- till conditions in coastal rice fallows. The experiment was designed in RDB with factorial concept and replicated thrice. The treatments consisted of three dates of sowing (Factor-1): S1: 49 MW (5th December); S2: 50 MW (15th December); S3: 52 MW (25th December) and four residual nitrogen levels (Factor-2) applied to the previous rice crop: N1-60 kg, N2-80 kg, N3-100 kg and N4-120 kg N ha-1. Sorghum was grown as a residual crop under zero tillage in rice fallows. Significant higher improvement in drymatter (10395 and 10269 kg ha-1), length of spike (24.8 and 24.5 cm), grain (3839 and 3602 kg ha-1) and stover yields (7446 and 7298 kg ha-1) and nitrogen uptake by grain (51.9 and 42.9 kg N ha-1) and stover (42.0 and 39.9 kg N ha-1) was recorded in early date of sowing i.e. 49 MW in both the seasons 2017-18 and 2018-19, respectively, and among the residue nitrogen levels 120 kg N ha-1 showed highest drymatter (10661 and 10484 kg ha-1), length of spike (25.0 and 24.8 cm), grain (4078 and 3815 kg ha-1) and stover yields (7518 and 7443 kg ha-1) and nitrogen uptake by grain (54.6 and 46.6 kg N ha-1) and stover (44.3 and 42.1 kg N ha-1) compared to other nitrogen levels in both the seasons. Based on above results, early sowing of sorghum with high residue nitrogen levels could be recommended to small and marginal farmers in coastal belts of India for higher productivity.

The Impact of Nitrogen Fixers and Phosphate Solubilizing Microbes on Sorghum (Sorghum bicolor) Yield

Objective: The inoculants, mainly nitrogen fixers and phosphate solubilizing microbes, have an influence on plant growth attributes. The current study was conducted to assess the fertilizing activity of A. chroocaccum and B. megaterium strains on growth, yield parameters and nutrient uptake of Sorghum bicolor. Methods: The isolation and identification of the nitrogen-fixing bacterium- A. chroocaccum and phosphate solubilizing microbe- B. megaterium and the growth and yield parameters of Sorghum bicolor as well as NPK uptake levels were studied. Results: A. chroocaccum and B. megaterium exhibited the proliferation of microbial population in soil by synergistic interaction with plants, and the application increased the availability of NPK in the soil after harvest of the crop. These beneficial inoculants are also known to help in the uptake of some other nutrients. The maximum beneficial aspects of the plant were noticed in the plants inoculated with 100% Recommended Dose of Fertilizer (RDF)+ A. chroocaccum+ B. megaterium, and the least was noticed in the control plants at all growth stages and at the time of harvest. Conclusion: From this study, it can be concluded that the beneficial effect of A. chroocaccum and B. megaterium is observed in sorghum crop with improved yield and nutrient uptake. Therefore, this species can be used extensively for future inoculation of the sorghum crop for better growth and development and for good returns in an ecological way.

Efficacy of Supplemental Irrigation and Nitrogen Management on Enhancing Nitrogen Availability and Urease Activity in Soils with Sorghum Production

The soil nitrogen (N) availability and urease activity (UA) in a humid ecosystem with variable rainfall distribution and poor soil fertility are not well understood. A complete appreciation of N cycling in the soil–water–plant continuum is needed to better manage N and water in regions that will be strongly affected by climate change. A sorghum (Sorghum bicolor L.) study located in Florence, South Carolina, USA, was conducted using a variable-rate pivot system. We hypothesized that supplemental irrigation (SI) and N would enhance UA and N uptake while minimizing the concentration of N in porewater (TINW). The aim of the study was to assess the impact of SI (0, 50, and 100%) and N fertilization (0, 85, and 170 kg N ha−1) on: UA; total N (TNS); total inorganic N (TINS); TINW; and N uptake of sorghum. Results support our research hypothesis. The greatest UA was from 0% SI and 170 kg ha−1 (18.7 µg N g−1 ha−1). Porewater N (mg L−1), when averaged across SI and N showed a significantly lower concentration at lower soil depth (9.9 ± 0.7) than the upper depth (26.1 ± 2.4). The 100% SI had the greatest biomass N uptake (NUPB) of 67.9 ± 31.1 kg ha−1 and grain N uptake (NUG) of 52.7 ± 20.5 kg ha−1. The greatest NUPB (70.9 ± 30.3 kg ha−1) and NUG (55.3 ± 16.5 kg ha−1) was from the application of 170 kg N ha−1. Overall, results showed that proper use of water and N enhanced soil N dynamics, and improved biomass productivity and N uptake of sorghum.

Sugar Processing Residuals as an Iron Source for Grain Crops Grown in Calcareous Soil

ABSTRACT Iron (Fe) deficiency is common when grain crops are grown in calcareous soils. The study was conducted to determine if the DTPA-extractable Fe concentration and Fe uptake of sorghum and corn were greater when Fe fertilizers were co-applied with sugar processing residuals than without residuals. The glasshouse pot experiment was a 3 × 3 × 3 complete factorial with three Fe fertilizer sources (none, 5 mg Fe kg−1 of FeSO4, 5 mg Fe kg−1 of Fe-EDDHA (Fe-ethylene diamine-N,N’-bis (2-hydroxyphenylacetic acid)) combined with three residuals (filtercake, bagasse and sugar beet) that were applied at rates of 0, 1.5 and 3% (w/w) and cropped continuously with sorghum-sorghum-corn. Cumulative shoot Fe uptake was greater in pots amended with filtercake and sugar beet than bagasse. Application of 3% bagasse reduced the cumulative shoot Fe uptake by 36%, compared to the unamended control (P < .05). Application of Fe-EDDHA or FeSO4 increased cumulative shoot Fe uptake by 9%, compared to the unfertilized control. The DTPA-extractable Fe concentrations were consistently higher in soil amended with filtercake and Fe-EDDHA, and declined with time. Since co-application of Fe fertilizer and residuals did not increase Fe uptake, this practice is not expected to improve Fe availability in calcareous soils. Filtercake and sugar beet residuals are alternative Fe sources for grain crops in calcareous soils.

Duckweed as an Agricultural Amendment: Nitrogen Mineralization, Leaching, and Sorghum Uptake.

Excessive N and P in surface waters can promote eutrophication (algae-dominated, low-O waters), which decreases water quality and aquatic life. Duckweed (Lemnaceae), a floating aquatic plant, rapidly absorbs N and P from water and its composition shows strong potential as a soil amendment. Therefore, it may be used to transfer N and P from eutrophic water bodies to agricultural fields. In this work, dried duckweed was incorporated into agricultural soil in microcosm, column, and field tests to evaluate biological N cycling, nutrient retention, and crop yield compared with compost, diammonium phosphate (DAP), and an amendment-free control. In microcosm tests, 25 ± 13% of duckweed N was mineralized, providing on average less mineral N than DAP (107 ± 21%), but more than compost (11 ± 12%). In columns, duckweed treatments leached only 2% of the N added, significantly less than DAP, which leached 60% of its N. Compared with the control, DAP leached significantly more phosphate (78%), whereas duckweed and compost treatments leached less (56 and 27%, respectively). Crop yield, as well as runoff N and P, were measured in field tests growing forage sorghum [ (L.) Moench.]. Although less total N was applied to duckweed plots than to DAP plots (75 vs. 130 kg ha, respectively), duckweed was found to retain 30% more total mineral N in a tilled agricultural field than DAP, while supporting a comparable yield. These tests indicate that duckweed may provide a sustainable source of N and P for agriculture.

Isolation, characterization and the effect of indigenous heavy metal-resistant plant growth-promoting bacteria on sorghum grown in acid mine drainage polluted soils.

The research purpose was the characterization of indigenous heavy metal-resistant plant growth-promoting bacteria (PGPB) from the farmlands located on the Le'an River basin contaminated by acid mine drainage and their effects on plant growth, nutrient uptake, antioxidant enzyme activities and metal accumulation. The plant growth-promoting (PGP) traits, including 1-aminocyclopropane-1-carboxylic acid deaminase, indoleacetic acid, siderophore, ammonia production and phosphate solubilization, as well as antibiotics, acid/alkali and salt resistance were determined. Ten isolates with relatively high PGP activities were identified to belong to the genera Burkholderia, Paraburkholderia, Cupriavidus, Pseudomonas and Ralstonia. The numerical classification based on bacterial resistant characteristics was mostly consistent with their phylogenetic positions. Burkholderia sp. strain S6-1 and Pseudomonas sp. strain S2-3 possessed both greater PGP activities and resistant characteristics in overall comparison. Compared with non-inoculated plants, strains S6-1 and S2-3 significantly increased the height, dry weight and N uptake of sorghum (Sorghum bicolor L.). The presence of S6-1 significantly increased Pb accumulation and enhanced the translocation of Zn from root to shoot in sorghum. Strain S2-3 helped sorghum to uptake Cu and Zn and improved the remediation effect of sorghum on Cu and Zn. Overall, indigenous PGPB did not show better advantages in improving plant growth than non-indigenous P. putida UW4. Nevertheless, indigenous PGPB can be used as better candidates in heavy metal phytoremediation to minimize the potential risks of introducing invasive microbial species into an agricultural ecosystem.

Soil organic carbon balance and nutrients (NPK) availability under treated wastewater irrigation for bioenergy sorghum production in an arid ecosystem

ABSTRACTThis column study evaluated the effects of irrigation with two water qualities (WW and FW) to produce bioenergy sorghum on SOC balance, nutrients availability and salt constituents in two soils (TX and NM) amended with gypsum & elemental sulfur (S) and un-amended. Study results indicated that SOC concentration was higher in freshwater irrigated columns (7.41 g kg−1) than wastewater irrigated soils (7.32 g kg−1) across growth year-soil type-amendments-depth. Soils amended with gypsum and sulfur registered significantly higher value of 7.52 and 7.41 g kg−1 compared to 7.30 and 7.23 g kg−1 in non-amended soils under fresh and wastewater irrigation, respectively. Lower SOC in WW irrigated columns could be due to the combined effects of increased salinity and priming effects. Although SOC content initially increased in gypsum and S amended soils to about 10g kg−1, at the end of the study SOC in all treatments decreased to levels significantly below the pre-study. WW irrigation added 2.00, 1.10 and 4.40 times the N, P and K added by fertilizers and was able to meet 65%, 87%, and 210% of bioenergy sorghum uptake of respective nutrients. Sulfates and chlorides of sodium and calcium were dominant salts, which significantly affected SOC and nutrients.Abbreviations: FW: freshwater; WW: treated wastewater; G + S: gypsum and elemental sulfur; NA: no amendment, TX: Texas soil and NM: New Mexico soil

Effect of Hairy Vetch Incorporated as Green Manure on Growth and N Uptake of Sorghum Crop

Hairy vetch (Vicia villosa Roth) has the potentials for preventing soil erosion and suppressing weed growth as a winter cover crop. We evaluated the additional N supplied by this crop harvested at different growing stages to the succeeding sorghum in pot experiments. Hairy vetch was grown in 1/5000a Wagner pot, and shoots (S) and roots (R) were mixed separately or together (S+R) into the soil on 30 March, 18 April and 2 May. After incorporation of the plants, seeds of sorghum were sown in the pots. Dry weight and N content of hairy vetch increased throughout the growing period. The value of nitrogenase activity in root nodules peaked on 18 April and then drastically declined. When hairy vetch was harvested on 30 March, N content of sorghum in the S pots was definitely less than that in the R and S+R pots. When hairy vetch harvested on 2 May, however, the N content in the S pots was similar to that in the S+R pots, and it was significantly higher than that in the R pots. Although N input from hairy vetch was higher in the S pots than in the R pots, N uptake by sorghum was not reflected in those values. The belowground parts of hairy vetch may have a considerable effect on N uptake of sorghum when using this plant species as green manures.

Effect of nutrient supply on the green mass, dry matter accumulation and nutrient uptake of silage sorghum (Sorghum bicolor L./Moench/)

The results of the experiments can be summarized as follows: 80kgNha−1 dose of fertilizer resulted in a serious growth of green crop and dry matter yield, but by the further increase of the dose the available extra yield was less and less. The nutrient uptake of sorghum per unit of dry matter yield: N: 11.8 kgt−1; P: 2.5 kgt−1 and K: 15.0 kgt−1.

Estimates of Dry Matter Yield and Nitrogen Uptake in Sorghum Grown on Saline and Non-Saline Soils Manured with Dhaincha Plant Residues

A pot experiment was conducted to determine the effects of manuring with three types of plant residues (roots, shoots and roots plus shoots) of dhaincha (Sesbania aculeata Pers.) on growth of sorghum (Sorghum bicolor L.) grown on saline and non-saline soils. The objectives of this experiment were (1) to determine the effects of adding different plant residues of dhaincha on dry matter yield and nitrogen (N) uptake of sorghum; (2) to estimate the percentages and amounts of N derived from various N sources; (3) to estimate N recoveries from sesbania residues; (4) to make comparison between the direct and indirect 15N tracer techniques for estimating sorghum N uptake from sesbania residues; and (5) to test feasibility of using the non-isotopic technique (N-difference) for estimating N derived from plant residues. For measuring N uptake from various sources, two isotopic dilution techniques were utilized by adding to these soils either 15N-labelled inorganic N fertilizer (indirect method) or 15N-labelled sesbania leaves (direct method). For the indirect method, both soils manured with each type of sesbania residue, received four split applications of 15N-labelled ammonium sulfate. Results indicated that each type of sesbania residue, applied as green manure, resulted in significant increases in both dry matter yield and N uptake of sorghum as compared with the unmanured control. In addition, sesbania residues decreased the harmful effect of salinity on plant growth. Percentages of N derived from residues (%Ndfr) in sorghum grown in non-saline soil ranged between 3.9 and 33%, whereas in saline soil the observed values ranged between 4.9 and 19.8%. The N recoveries in sorghum grown in non-saline soil were 61, 45 and 37% of the total amount contained in sesbania root, shoot and root plus shoot, whereas the values in sorghum grown in saline soils were 48, 14.8 and 15.7%, respectively. The beneficial effects of sesbania residues are attributed not only to the additional N availability to the plants, but also to its effects on the enhancement of soil N uptake. Percentages and amounts of Ndfr calculated using the indirect method were not significantly different from those obtained by the direct method indicating that the indirect method used herein is feasible and simple for measuring N release from organic residues. The findings suggest that the use of Sesbania aculeata residues, particularly the shoots, as green manure, can provide a substantial portion of total N in sorghum. Moreover, the use of sesbania green manure in saline soils, as a bio-reclaiming material, can be a promising approach for enhancing plant growth on a sustainable basis.

Comparison of crop yield, soil microbial C, N and P, N-fixation, nodulation and mycorrhizal infection in inoculated and non-inoculated sorghum and chickpea crops

A field experiment was conducted on a clay loam soil to assess the response of crops to inoculation and inorganic and organic fertilizers. Microbial biomass C, N and P under sorghum ( Sorghum bicolor L.) and chickpea ( Cicer arietinum L.) were significantly higher ( r=0.641–0.735, P<0.01) when a combination of Azospirillum brasilense or Rhizobium, Bacillus megaterium and Glomus fasciculatum were used, and was maximum with 50% recommended fertilizers (40 kg N ha −1 and 8.73 kg P ha −1 for sorghum; 10 kg N ha −1 and 8.73 kg P ha −1 for chickpea) along with bioinoculants. Biomass C, N and P in the rhizosphere soil of sorghum–chickpea sequences were greater after 30 days and decreased subsequently (at 60 days or at harvest). A strong correlation ( P<0.01) of biomass C, N and P was observed with N and P uptake of sorghum and chickpea indicating the role of microorganisms in crop response. Azospirillum population in the rhizosphere improved significantly from 38.0 cfu g −1 under recommended fertilizer to 176.8 cfu g −1 under farm yard manure (FYM) and bioinoculants. Nodule dry weight and acetylene reduction activity (ARA) were significantly higher in the treatments receiving Rhizobium inoculation. Vesicular arbuscular mycorrhizal (VAM) infectivity was also improved significantly with combined inoculants and FYM compared to sole application of FYM or fertilizers (N and P). Application of fertilizer nutrients along with FYM, use of nitrogen fixers, phosphate solubilizers and VAM significantly increased grain ( r=0.618, P<0.05) and straw yields ( r=0.602, P<0.05) and, in general, decreased C:N and C:P ratio. The results suggested that for maximum crop yield only 50% of the required fertilizer might be supplied along with bioinoculants.

Nitrogen uptake of sorghum (Sorghum bicolor L.) from tree mulch and mineral fertilizer under high leaching conditions estimated by nitrogen-15 enrichment

The effects of applying either inorganic fertilizer or leaf mulch of Acacia saligna (Labill.) H.L. Wend. on yields of Sorghum bicolor (L.) were compared with an unfertilized control under the high leaching conditions of runoff irrigation in a dry tropical environment. The N use efficiency and transfer from 15N-labelled (NH4)2SO4 or acacia leaves to the sorghum differed in quantity and quality. Only 6% of the applied mulch N was retrieved in the crop, in contrast to 21% of the fertilizer N. The proportions of N in the crop derived from the fertilizers were small, amounting to 7% and 28%, respectively, in the mineral fertilizer and mulch treatments. However, the application of inorganic fertilizer and mulch significantly increased crop grain yield (P<0.05 and P<0.1, respectively), biomass production and foliar N contents (P<0.05). The inorganic fertilizer improved crop yields to a larger extent than mulching. At the same time, more N was lost by applying (NH4)2 SO4 than leaf mulch: only 37% of the N of applied (NH4)2 SO4 was found in the crop and the soil (0–0.3 m), but 99% of the mulched N. High NO3 – contents in the topsoil of the inorganic fertilized sorghum treatments indicated the risk of N leaching. However, more important may have been gaseous N losses of surface-applied NH4 +. From a nutrient conservation point of view, mulches should be given preferance to inorganic fertilizers under high soil pH and leaching conditions, but larger improvements of crop yields could be achieved with mineral fertilizers.

Yield and Green‐Manure Benefits of Interseeded Legumes in a High Desert Environment

AbstractRelay intercropping legumes into vegetable crops provides cover and green‐manure benefits to subsequent crops, but has not been adequately researched in high desert regions. This study evaluated the dry matter, N yield, effect on a subsequent forage sorghum [Sorghum bicolor (L.) Moench] crop, and estimated fertilizer‐replacement value (FRV) of several legumes interseeded into sweet corn (Zea mays L.). The study took place under furrow irrigation in north‐central New Mexico (study site elevation, 1737 m) on a Fruitland sandy loam (coarse‐loamy, mixed, calcareous, mesic Typic Torriorthent). Five legumes (hairy vetch, Vicia villosa Roth; barrel medic, Medicago truncatula Gaertn.; alfalfa, Medicago sativa L.; black lentil, Lens culinaris Medik.; and red clover, Trifolium pratense L.) were interseeded into sweet corn at last cultivation or blister stage in 1993 and 1994. Corn ears and stover were harvested in August. The following spring, plots were plowed and seeded to forage sorghum. Estimated FRV for the legumes were calculated from regression equations for sorghum dry matter yield as a function of N fertilizer rate. Herbage N yields in the fall were greatest for hairy vetch and barrel medic and, averaged across interseeding dates, ranged from 55 to 64 kg ha−1 in 1993 and 100 to 108 kg ha−1 in 1994. Whole‐plant N yields (herbage + roots + crowns) in May were greatest for hairy vetch, 205 kg ha−1 in 1994 and 172 kg ha−1 in 1995. Seasonal dry matter yield and N uptake of sorghum were greatest following hairy vetch in 1994, and hairy vetch and alfalfa in 1995. Based on seasonal sorghum yield, hairy vetch and alfalfa had the highest FRV, ranging from 78 to 140 kg ha−1 N.

Effects of Va mycorrhizae on growth and mineral uptake of sorghum grown at varied levels of soil acidity

Abstract The effects of the vesicular‐arbuscular mycorrhizal (VAM) fungus Glomus deserticola (Trappe, Bloss, and Menge) on growth and mineral element uptake of sorghum [Sorghum bicolor (L.) Moench] were investigated in greenhouse experiments with acid Cecil sandy clay loam (clayey, kaolinitic, thermic, Typic Hapludults) at five pH values (4.1 to 5.8). Control experiments consisted of sterile VAM inocula. Dry matter yields and mineral element uptake were markedly depressed at pH 4.1, were relatively high at pH 4.5, and remained fairly constant from pH 4.5 to 5.8 in mycorrhizal plants. Dry matter yields, root lengths, and mineral element contents of nonmycorrhizal plants increased as soil pH increased, and these characteristics were similar to mycorrhizal plants only after the soil was above pH 5.0 to 5.5. Mycorrhizal plants had higher total and efficiency uptake of mineral elements (shoot element content/root dry matter ratio) than nonmycorrhizal plants. Available Al in acid soils may have been detrimental...

Nitrate/ammonium ratio effects on nutrient solution pH, dry matter yield, and nitrogen uptake of sorghum1

Abstract Sorghum [Sorghum bicolor (L.) Moench] seedlings were grown in nutrient solutions in a growth chamber to investigate the effects of different ratios of NO3 – and NH4 + on nutrient solution pH, dry matter yield, and N uptake. Nutrient solutions and plant tissues were assayed throughout the time plants grew in the nutrient solutions. Nutrient solution pH depended on source of N. The pH rose to near 8 with NO3 – as the sole source of N and decreased to near or below 4 with NH4 + added to the solutions. Upon depletion of NH4 + from solution, pH values rose abruptly to near 8 and remained near this value throughout the duration of the experiments. Dry matter yield was generally higher for plants grown with some NH4 + compared to plants grown with NO3 – alone. Nitrogen uptake was generally higher in plants grown with the higher proportions of NH4 +. Nitrogen concentrations remained unchanged with plant age as NO3 –/ NH4 + ratio varied. For solutions low in NH4 +, N concentrations in roots increased with...

Interactions of gamma‐irradiated sewage, nitrogen and phosphorus for Sorghum on a calcareous soil

Abstract The interaction of gamma‐irradiated sewage sludge, nitrogen and phosphorus fertilizers on dry matter production, phosphorus concentration and phosphorus uptake of sorghum was examined. Three crops of sorghum were grown in the greenhouse in 19 1 plastic buckets. The phosphorus and sludge treatments were applied at the initiation of the experiment only. Nitrogen was applied to the corresponding nitrogen treatment pots before each of the three croppings. There was a significant nitrogen x sewage interaction for dry matter production, phosphorus concentration and phosphorus uptake in each harvest. There was a significant phosphorus sewage sludge interaction in the first harvest for phosphorus uptake. All other possible interactions were not statistically significant. The 67 metric ton/ha sludge rate produced nearly the same yield as the nitrogen treatment. In the first harvest, sludge significantly increased plant phosphorus uptake from the fertilizer phosphorus. The phosphorus uptake in sorghum from...