Sulfur Nutrition Research Articles

Interactive effects of low phosphorus and elevated CO2 on root exudation and nutrient uptake in wheat is modified under sulphur nutrition

We investigated the influence of elevated CO2 concentration (e[CO2]) on the interaction of phosphorus (P) and sulphur (S) on nutrient uptake efficiency of wheat. Experiments were conducted on wheat varieties PDW-233 (Triticum durum) and PBW-396 (T. aestivum) under different levels of [CO2] (400 and 700 ppm) with low P (5 µM), low S (10 µM) or low P/S and control (P 500 µM and S 2000 µM). Results revealed an increased biomass accumulation under e[CO2] with low P or S as compared to ambient CO2 concentration (a[CO2]). The root biomass was doubled with higher belowground dry matter partitioning under low nutrient and e[CO2]. Low P and S restricted plant growth directly by reduction in biomass accumulation and limited exudation of total carboxylates from root, however e[CO2] helped to overcome these deficiencies. Interactive effects of e[CO2] and low P or low P/S resulted in increased root length, surface area, volume and number of lateral roots. Under limited P and e[CO2], S provided stability to enzymes involved in root exudation and accelerated mobilization of P and its uptake efficiency. The activity of enzymes viz., phosphoenolpyruvate carboxylase, citrate synthase, malate dehydrogenase and pyruvate kinase, involved in carboxylate synthesis showed significant increase under e[CO2]. Further, the concentration of P and S increased under e[CO2] in shoot and root tissues of both varieties. Under limited P and S supply, e[CO2] helped in modification of root morphology and higher root exudation, which improved nutrient uptake in both varieties.

Critical Sulfur Dilution Curve and Sulfur Nutrition Index in Maize

Core Ideas Critical S dilution curve was established for maize: S concentration = 2.13 × biomass−0.23. The S nutrition index successfully diagnosed S status at early crop stages (∼V6). Sulfur concentration and chlorophyll meter reading, both in the upper leaf, were good predictors of the S nutrition index. Sulfur (S) deficiency can severely limit maize (Zea mays L.) yield. This deficiency could be predicted by quantifying the S concentration (SC) in the shoot biomass (BM) and by calculating the S nutrition index (SNI = observed SC/critical SC). However, as shoot SC determination is laborious, alternative S diagnostic methods should be developed in maize. Thus, the objectives of our study were to: (i) determine and validate a critical S dilution curve, (ii) quantify the critical SNI, and (iii) explore the use of SC and chlorophyll meter reading (CMR), both determined in the uppermost developed leaf at vegetative growth stages, to predict SNI and for diagnosing S status in maize. Six field studies evaluating fertilizer S rates were executed, collecting maize shoot and uppermost developed leaf samples and determining Sc, CMR, yield, and SNI parameters. The main outcomes from our study were: (i) a maize critical S dilution curve was fitted (SC = 2.13BM−0.23) and validated with an independent dataset; (ii) a critical SNI threshold of 0.79 adequately diagnosed S status at ∼V6 stage; (iii) at V6, SNI was linearly related to SC (R2 = 0.65) and CMR (R2 = 0.85). As a result, a threshold value of 2.0 g S kg−1 for SC, 47.5 units for CMR, and 0.94 units for relative CMR can be used to successfully diagnose S deficiencies at early vegetative (∼V6) maize stages. Future studies testing S diagnostic tools for maize should be performed in environments with severe S deficiency and nutrient co‐limitations.

Enzymatic antioxidants—Relevant or not to protect the photosynthetic system against cadmium-induced stress in Massai grass supplied with sulfur?

Exposure to cadmium (Cd) can cause oxidative stress and injuries to the photosynthetic apparatus of plants. Otherwise, plant metabolism impaired by Cd toxicity can be aided by a proper sulfur (S) nutrition, since S is a component of antioxidants and photosynthetic systems. In this sense, our aim in this study was to evaluate the effect of S supply (0.1, 1.9 and 3.7 mmol L−1) on the antioxidant and photosynthetic systems of Massai grass exposed to Cd (0.0, 0.1 and 0.5 mmol L−1) as a prerequisite for studies of Cd phytoextraction. Plants supplied with 3.7 mmol L−1 S showed the lowest growth and the highest Cd concentrations when exposed to 0.5 mmol L−1 Cd. However, Massai grass grown without S deprivation showed the highest GSH + GSSG concentrations in all tissues and the lowest lipid peroxidation in stems and sheaths and roots. In general, the activities of SOD, CAT, APX, GPOX and GR did not increase in Massai grass exposed to Cd, even with proper S supply. Severe Cd exposure halted the photosynthetic system of Massai grass, although well-nourished plants with S exhibited greatest photosynthetic rate probably due to the action of GSH in the control of the oxidative stress.

Estimation of nitrogen and sulfur mineralization in soils amended with crop residues contributing to nitrogen and sulfur nutrition of crops in the North Central U.S

ABSTRACT Predicting nitrogen (N) and sulfur (S) mineralization of crop residues from the preceding crop might be a useful tool for forecasting soil N and S availability. Two soils from eastern North Dakota and three crop residues – corn, spring wheat, and soybean were used in an 8-week incubation study to estimate N and S mineralization from crop residues. The cumulative N and S mineralized were fit to a first-order kinetic model. Cumulative N mineralized ranged between 0.34 and 2.15 mg kg−1 and 0.45 to 3.41 mg kg−1 for the Glyndon and Fargo soils, respectively. Un-amended soils showed higher N mineralization than residue treated soils. For S, the highest mineralization occurred in un-amended Glyndon soil and in spring wheat-amended Fargo soil. This study indicates that crop residue additions can have a negative impact on plant available nutrients due to immobilization of N and S during the time when crops need the nutrients most.

Does Fe accumulation in durum wheat seeds benefit from improved whole-plant sulfur nutrition?

Sulfur and iron balanced supply is of paramount importance for plants, since Fe homoeostasis in plants has been shown to be strongly dependent on sulfate availability; vice versa the adaptation to Fe deficiency requires the adjustment of S uptake and assimilation rate. Interestingly, it has been demonstrated that providing S above adequate concentrations may enhance Fe use efficiency in wheat and this effect seems to be especially advantageous for plants grown under severe Fe shortage. Therefore, the investigation of sulfate effect on Fe uptake and allocation in crop could be of great significance.Aim of this study was to clarify in wheat at both leaf and seed level whether and to what extent the changes in S and Fe supply affect concentration and distribution of sulfate and also how different availability of S changes the mineral concentration and distribution in wheat adequately or poorly fed with Fe.Obtained results showed how plants recovered from Fe deficiency stress by means of a tuned S fertilization, without additional input of Fe fertilizers. Also, with decreasing Fe availability the Zn concentration of grains significantly increased, suggesting that a balanced crop Fe nutrition could allow a successful biofortification of wheat grains with Zn.

Effects of Selenium Supplementation on Glucosinolate Biosynthesis in Broccoli.

Selenium (Se)-enriched broccoli has health-beneficial selenium-containing compounds, but it may contain reduced amounts of chemopreventive glucosinolates. To investigate the basis by which Se treatment influences glucosinolate levels, we treated two broccoli cultivars with 25 μM Na2SeO4. We found that Se supplementation suppressed the accumulation of total glucosinolates, particularly glucoraphanin, the direct precursor of a potent anticancer compound, in broccoli florets and leaves. We showed that the suppression was not associated with plant sulfur nutrition. The levels of the glucosinolate precursors methionine and phenylalanine as well as the expression of genes involved in glucosinolate biosynthesis were greatly decreased following Se supplementation. Comparative proteomic analysis identified proteins in multiple metabolic and cellular processes that were greatly affected and detected an enzyme affecting methionine biosynthesis that was reduced in the Se-biofortified broccoli. These results indicate that Se-conferred glucosinolate reduction is associated with negative effects on precursor amino acid biosynthesis and glucosinolate-biosynthetic-gene expression and provide information for a better understanding of glucosinolate accumulation in response to Se supplementation in broccoli.

Sulfur nutrition stimulates lead accumulation and alleviates its toxicity in Populus deltoides.

Sulfur (S) can modulate plant responses to toxic heavy metals, but the underlying physiological and transcriptional regulation mechanisms remain largely unknown. To investigate the effects of S supply on lead (Pb)-induced toxicity in poplars, Populus deltoides monilifera (Aiton) Eckenw. saplings were exposed to 0 or 50 μM Pb together with one of the three S concentrations (0 (low S), 100 (moderate S) or 1500 (high S) μM Na2SO4). Populus deltoides roots absorbed Pb and it was partially translocated to the aerial organs, thereby decreasing the CO2 assimilation rate and leaf growth. Lead accumulation in poplars caused the overproduction of O2- and H2O2 to induce higher levels of total thiols (T-SH) and glutathione (GSH). Lead uptake by the roots and its accumulation in the aerial organs were repressed by low S application, but stimulated by high S supply. Lead-induced O2- and H2O2 production were exacerbated by S limitation, but alleviated by high S supply. Moreover, the concentrations of S-containing antioxidants including T-SH and GSH were reduced in S-deficient poplars, but increased in high S-treated plants, which corresponded well to the changes in the activities of enzymes involved in S assimilation and GSH biosynthesis. The transcript levels of both genes encoding sulfate transporters, i.e., SULTR1.1 and SULTR2.2, were elevated by low S application or high S supply in the roots, and the transcriptional upregulation of both genes was more pronounced under Pb exposure. Furthermore, the mRNA levels of several genes involved in S assimilation and the biosynthesis of GSH and phytochelatins, i.e., ATPS1, ATPS3, GSHS1, GSHS2 and PCS1, were upregulated in poplar roots with high S supply, particularly under Pb exposure. These results indicate that a high S supply can stimulate Pb accumulation and reduce its toxicity in poplars by improving S assimilation and stimulating the biosynthesis of S-containing compounds including T-SH and GSH.

Effect of methods of irrigation and sulphur nutrition on seed yield, economic and bio-physical water productivity of two sunflower (Helianthus annuus L.) hybrids

A field experiment was conducted to find out the effect of methods of irrigation and sulphur nutrition on productivity of sunflower hybrids at Punjab Agricultural University, Ludhiana during spring season of 2016 and 2017. The experiment was laid out in randomized complete block design and treatments comprises combination of two hybrids (PSH 1962 and PSH 996), two methods of irrigation (drip and furrow irrigation) and four sulphur levels (0, 20, 40 and 60 kg S ha−1). PSH 1962 recorded 12.9% higher seed yield with 27.3% higher economic water productivity because of significantly superior yield attributing characters viz. capitulum diameter, capitulum weight, seeds per capitulum and 1000 seed weight than PSH-996. PSH 1962 recorded Rs 9393 ha−1 higher net returns along with 10.8 and 3.5% higher bio-physical water productivity (BPWP) and oil content than PSH 996, respectively. Drip irrigated crop produced significantly higher seed yield along with saving of 38.0% irrigation water and 32.6% higher water use efficiency as compared to furrow irrigated crop. Net returns, bio-physical and economic water productivity were also 32.7, 5.3 and 20.9% higher in drip than furrow irrigation, respectively. Seed yield increased successively and significantly with each increment in sulphur from 0 to 60 kg S ha−1. Sulphur nutrition with 60 kg ha−1 recorded 31.1, 18.8 and 8.0% higher seed yield than 0, 20 and 40 kg ha−1, respectively. Oil content increased to the tune of 3.2, 1.9 and 0.8% with 60 kg S ha−1 than 0, 20 and 40 kg S ha−1, respectively. Net returns were Rs 11,185 ha−1 higher from 60 kg S ha−1 than control (0 kg S ha−1) with 23.3% higher benefit: cost. Economic water productivity improved to the tune of Rs 2.32 with 60 kg S ha−1 over control (0 kg S ha−1) with each cubic metre of consumptive use (actual evapotranspiration). Drip irrigated crop produced 18.8, 12.2 and 11.3% higher seed yield than furrow irrigated with 20, 40 and 60 kg S ha−1. Drip irrigation also resulted in Rs 4.01, 2.49, 1.18 and 0.02 higher net returns with each cubic metre of consumptive use than furrow irrigation with 0, 20, 40, and 60 kg S ha−1, respectively.

Effects of sulfur fertilization and short-term high temperature on wheat grain production and wheat flour proteins

The content of wheat flour proteins affects the quality of wheat flour. Sulfur nutrition in wheat can change the protein content of the flour. The inconsistency and instability of wheat grain quality during grain filling under high temperature stress (HTS) are a major challenge to the production of high-quality wheat. The effects of sulfur fertilization and HTS on wheat flour protein and its components are unknown. In this study, treatments varying two factors: sulfur fertilization and exposure to short-term HTS, at 20days post-anthesis, were applied to two wheat cultivars with differing gluten types. Plants of a strong-gluten wheat (Gaoyou 2018) and a medium-gluten wheat (Zhongmai 8) were grown in pots in Beijing in 2015–2017. HTS significantly increased the contents of total protein, albumin, gliadin, glutenin, Cys, and Met in wheat kernels, but reduced grain yield, grain weight, protein yield, globulin content, and total starch accumulation. The HTS-induced increase in total protein amount was closely associated with nitrate reductase (NR) and glutamine synthetase (GS) activities in flag leaves. Sulfur fertilization increased grain and protein yields; grain weight; total protein, albumin, gliadin, glutenin, and globulin contents; protein yield; total starch; Cys, Met; and NR and GS activities. HTS and sulfur fertilization had larger effects on the strong- than on the medium-gluten cultivar. Sulfur fertilization also alleviated the negative effects of HTS on grain yield, protein yield, and starch content. Thus, growing wheat with additional soil sulfur can improve the quality of the flour.

Effect of nitrogen and sulphur nutrition on storage protein quality in soybean [Glycine max (L.) Merrill

The relative availabilities of nitrogen and sulphur can modulate seed storage protein composition in grain legumes and cereals. Soybean contains two major seed storage proteins, glycinins and ?-conglycinins that account for approximately 70% of total protein and their composition is affected by nitrogen and sulphur supplies. The present study demonstrated the effect of sulphur (Gypsum @ 20 kg S ha-1 ) and recommended a dose of nitrogen (Urea @ 31.25 kg N ha-1 ) alone or in combination on accumulation patterns of various protein fractions and protein quality in soybean seeds under agro-climatic conditions of Punjab. Application of nitrogen or sulphur alone decreased the relative proportion of ?-subunit of purified ?-conglycinin fraction than control. The acidic polypeptides of glycinin fraction of globulin and 11S/7S ratio were increased in all the treatments in comparison to control, and the maximum increase was reported in the combined application of gypsum with the recommended dose of urea. The lower proportion of total 7S, increased acidic polypeptides and improved 11S:7S ratio by combined treatment of nitrogen and sulphur suggests that gypsum @ 20 kg S ha-1 can be beneficial when applied along the recommended nitrogen dose to improve soybean protein quality.

Effect of Elemental Sulfur as Fertilizer Ingredient on the Mobilization of Iron from the Iron Pools of a Calcareous Soil Cultivated with Durum Wheat and the Crop’s Iron and Sulfur Nutrition

The granules of conventional fertilizers have been enriched recently with 2% elemental sulfur (S0) via a binding material of organic nature and such fertilizers are suitable for large scale agriculture. In a previous work, we demonstrated that a durum wheat crop that received the enriched fertilization scheme (FBS0-crop) accumulated a higher amount of Fe compared to the durum wheat crop fertilized by the corresponding conventional fertilization scheme (F-crop). In this study, we investigated the effect of S0 on the contingent mobilization of iron from the iron pools of the calcareous field that affiliated the durum wheat crop and the corresponding effect on the crop’s iron nutrition and sulfur nutrition. A sequential extraction of Fe from root zone soil (rhizosoil) was applied and the fluctuations of these fractions during crop development were monitored. The fertilization with FBS0 at sowing affected the iron fractions of the rhizosoil towards iron mobilization, thus providing more iron to the crop, which apart from the iron nutrition fortified the crop’s sulfur nutrition, too. No iron was found as iron attached to carbonates of the rhizosoil. Fluctuations of the iron pool, bound or adsorbed to the organic matter, were exactly the opposite to those of the iron pool associated with the clay particles in both treatments, suggesting iron exchange between the two pools. Replenishment of the F-crop’s Fe content and a deficit in the FBS0-crop’s Fe content in the rhizosoil were found at the end of the cultivation period. Furthermore, the initiation of the fast stem elongation stage (day 125) constituted a turning point. Before day 125, the use of FBS0 increased the iron concentration in the main stems and this was an early fortification effect, followed by an increase in the organic S concentration. Following day 125, the FBS0-crop consisted of plants with higher main stems and less tillers. A late fortification effect was observed in the iron concentration of the main stems and their heads after the stage of complete flowering. Prior to harvesting in the FBS0-crop, all plant parts were heavier, with more iron and organic sulfur accumulated in these plant parts, and the obtained commercial yield of the FBS0-crop was higher by 27.3%.

Response of soybean to potassium and sulphur nutrition grown in foothills of Nagaland

Response of soybean to potassium and sulphur nutrition grown in foothills of Nagaland

Molecular regulation of aluminum resistance and sulfur nutrition during root growth

Aluminum toxicity and sulfate deprivation both regulate microRNA395 expression, repressing its low-affinity sulfate transporter ( SULTR2;1 ) target. Sulfate deprivation also induces the high-affinity sulfate transporter gene ( SULTR12 ), allowing enhanced sulfate uptake. Few studies about the relationships between sulfate, a plant nutrient, and aluminum, a toxic ion, are available; hence, the molecular and physiological processes underpinning this interaction are poorly understood. The Al-sulfate interaction occurs in acidic soils, whereby relatively high concentrations of trivalent toxic aluminum (Al3+) may hamper root growth, limiting uptake of nutrients, including sulfur (S). On the other side, Al3+ may be detoxified by complexation with sulfate in the acid soil solution as well as in the root-cell vacuoles. In this review, we focus on recent insights into the mechanisms governing plant responses to Al toxicity and its relationship with sulfur nutrition, emphasizing the role of phytohormones, microRNAs, and ion transporters in higher plants. It is known that Al3+ disturbs gene expression and enzymes involved in biosynthesis of S-containing cysteine in root cells. On the other hand, Al3+ may induce ethylene biosynthesis, enhance reactive oxygen species production, alter phytohormone transport, trigger root growth inhibition and promote sulfate uptake under S deficiency. MicroRNA395, regulated by both Al toxicity and sulfate deprivation, represses its low-affinity Sulfate Transporter 2;1 (SULTR2;1) target. In addition, sulfate deprivation induces High Affinity Sulfate Transporters (HAST; SULTR1;2), improving sulfate uptake from low-sulfate soil solutions. Identification of new microRNAs and cloning of their target genes are necessary for a better understanding of the role of molecular regulation of plant resistance to Al stress and sulfate deprivation.

A glimpse into the symplastic and apoplastic Cd uptake by Massai grass modulated by sulfur nutrition: Plants well-nourished with S as a strategy for phytoextraction

To date, there have been no studies demonstrating the influence of sulfur (S) on the cadmium (Cd) uptake kinetics, which limits the understanding of mechanisms involved in the uptake of this element. Therefore, this study was carried out in order to quantify the contribution of symplastic and apoplastic uptakes of Cd (0.1 and 0.5 mmol L−1) by Massai grass (Panicum maximum cv. Massai) grown under low and adequate S-supply (0.1 and 1.9 mmol L−1) by measuring Cd concentration in the nutrient solution (Vmax, Km, and Cmin) along the plant's exposure time (108 h) and determining Cd concentration in root symplast and apoplast. The Vmax of Cd influx in Massai grass exposed to higher Cd and S concentrations was 38% higher than that plants supplied with lower S concentration. The Km and Cmin of plants exposed to the highest Cd concentration was higher than that plants subjected to the lowest Cd concentration, although values were not affected by S supply. Symplastic influx of Cd in plants subjected to the lower Cd and S concentrations was 20% higher as compared to plants supplied with the higher concentration of S, whereas the apoplastic influx of Cd was higher when there was a higher supply S, regardless of Cd concentration in the solution. This result indicates that an adequate supply of S decreases the contribution of the symplastic Cd uptake and increases the contribution of the apoplastic Cd uptake when the toxicity caused by Cd is lower.

Higher Novel L-Cys Degradation Activity Results in Lower Organic-S and Biomass in Sarcocornia than the Related Saltwort, Salicornia

Salicornia and Sarcocornia are almost identical halophytes whose edible succulent shoots hold promise for commercial production in saline water. Enhanced sulfur nutrition may be beneficial to crops naturally grown on high sulfate. However, little is known about sulfate nutrition in halophytes. Here we show that Salicornia europaea (ecotype RN) exhibits a significant increase in biomass and organic-S accumulation in response to supplemental sulfate, whereas Sarcocornia fruticosa (ecotype VM) does not, instead exhibiting increased sulfate accumulation. We investigated the role of two pathways on organic-S and biomass accumulation in Salicornia and Sarcoconia: the sulfate reductive pathway that generates Cys and l-Cys desulfhydrase that degrades Cys to H2S, NH3, and pyruvate. The major function of O-acetyl-Ser-(thiol) lyase (OAS-TL; EC 2.5.1.47) is the formation of l-Cys, but our study shows that the OAS-TL A and OAS-TL B of both halophytes are enzymes that also degrade l-Cys to H2S. This activity was significantly higher in Sarcocornia than in Salicornia, especially upon sulfate supplementation. The activity of the sulfate reductive pathway key enzyme, adenosine 5'-phosphosulfate reductase (APR, EC 1.8.99.2), was significantly higher in Salicornia than in Sarcocornia These results suggest that the low organic-S level in Sarcocornia is the result of high l-Cys degradation rate by OAS-TLs, whereas the greater organic-S and biomass accumulation in Salicornia is the result of higher APR activity and low l-Cys degradation rate, resulting in higher net Cys biosynthesis. These results present an initial road map for halophyte growers to attain better growth rates and nutritional value of Salicornia and Sarcocornia.

Sulphur Nutrition and its Effect on Yield and Oil Content of Oilseed Rape (Brassica Napus L.)

The aim of the experiment was to study the importance of sulphur in oilseed rape (Brassica napus L.) nutrition as well as the effect of rising doses of sulphur in combination with nitrogen on yield, oiliness, oil production, nutrients content in seed and nutrients uptake by rapeseed. The plot–scale experiment was established in years 2013/14 and 2014/15 within the agricultural cooperative in Mojmírovce. There were four fertilization treatments on 600 m2 experimental plots in three replications in this experiment. The first treatment was unfertilized control. Other three treatments were fertilized by the same nitrogen dose of 160 kg.ha−1 and by increasing doses of sulphur. The second treatment was fertilized by a dose of 15 kg.ha−1 S, the third by a dose of 40 kg.ha−1 and a dose of 65 kg.ha−1 S was applied at the fourth treatment. The highest average yield 3.96 t.ha-1 was found when a dose of 40 kg.ha−1 S was applied. The application of sulphur in a dose of 65 kg.ha−1 was accompanied by a yield decrease by 11.4 % as compared to the treatment where a sulphur dose of 40 kg.ha−1 was used. An average oil content of 45.1, 45.5, and 44.0 % was found in treatments in which the doses of sulphur of 15, 40 and 65 kg.ha−1 were applied. No significant difference among the treatments fertilized by sulphur was found. The average oil production reached 1809, 1802 and 1595 kg.ha−1 in cases of treatments fertilized by sulphur doses of 15, 40 and 65 kg.ha−1.

Response of Sulphur Nutrition and Mulching on Indian mustard (Brassica napes L.)

Field experiment was conducted to study the effect of sulphur nutrition and mulching on Indian mustard (Brassica napes L.) at Rajeev Gandhi South Campus (Banaras Hindu University), Mirzapur, Uttar Pradesh during rainy season of 2013. Three levels of sulphur 20 kg ha-1 S (S1), 40 kg ha-1 S (S2), 60 kg ha-1 S (S3) and five levels of mulching, Zero mulch (M0), paddy straw @ 4 t ha-1 (M1), wheat straw @ 6 t ha-1 (M2), legume straw @ 5 t ha-1 (M3), and green weed mulch @ 12 t ha-1 (M4) were included in the experiments. Variety named ‘PT-303’ was selected for experimental study which was suitable for soils of Vindhyan region. Results showed that, plant height (98.9 cm), plant dry weight (32.1 g), length of siliquae (6.20 cm), seed siliquae-1(16.5), test weight (3.07 gm) were recorded highest in S2×M1 treatment combination as well as changes in soil physical, and chemical properties. Significantly the highest results were recorded in S2 (S40 kg ha-1) along with M1 paddy straw @ 4 ha-1 (S2×M1) in growth as well as yield attributing characters of Indian Mustard. In terms of nutrient uptake highest nitrogen as well as sulphur uptake noticed in S2M1. Soil samples collected after harvesting of mustard crop showed the highest nitrogen 223.90 N kg ha‑1, phosphorus 26.90 kg ha-1, organic carbon 0.410% and water holding capacity 43.60% in S2M3 treatment combination. The combined application of 40 kg ha-1 with paddy straw was superior all over the treatments combinations.

N:P:S stoichiometry in grains and physiological attributes associated with grain yield in maize as affected by phosphorus and sulfur nutrition

Balanced nutrition is necessary to reduce yield gaps in maize. Simultaneous phosphorus (P) and sulfur (S) deficiencies may be present in soils, so a P×S interaction is expected. In maize, yield is closely related to grain number (GN); thus, nutrient deficiencies impacting crop growth during GN formation can consequently impact yields. Grain nutrient concentration may reflect soil supplying capacity, and nutrient stoichiometry in grains can be used as an indirect indicator of nutrient deficiency for a retrospective diagnosis of sites responsive to P or S fertilization. The objectives of this study were to: i) determine maize response to increasing S fertilizer rates and to P addition; ii) analyze the effects of P, S, and their interaction on mechanisms involved in yield determination of maize; and iii) evaluate the effects of P and S shortage on stoichiometric relationships among N, P, and S content in maize grains. Two fertilization experiments were conducted on-farming conditions in 19 sites-year (SY) for analyzing grain yield response to increasing S fertilizer rates (E1), and studying the interaction between P and S fertilization on grain yield and physiological attributes associated with grain yield determination (E2), i.e. CGRCP, IPARCP, RUECP and biomass at R6. Also N (%N), S (%S) and P (%P) concentration in grains were determined. Stoichiometric relationships among N, P and S in both P or S fertilized and unfertilized treatments in all SY were analyzed. Average grain yield response due to S and P addition was ca. 13 and 20%, respectively. Grain yield increased up to S fertilizer rates around 10kgSha−1. P addition increased CGRCP by 15–60% in 8 SY while S addition 12–16% in 2 SY. Both, RUECP and IPARCP were positively associated with biomass production. P fertilization increased IPARCP by 4%, but no S effect was observed. Before silking, P addition boosted cumulated radiation by 7%, but after silking no P or S effects were observed. A significant P×S interaction was observed for RUECP, since S fertilization increased RUECP by 14% only when P was not added. Independently of P or S shortage, grain N content scaled almost isometrically with grain S content, while N:P and P:S showed allometric relationships. Phosphorus deficiency did not modify N:S, N:P nor P:S stoichiometry. Likewise, S addition did not modify the N:P or N:S stoichiometry. A significant change in the intercept of the P:S relationship was observed in response to fertilization and may be used as a tool for identifying S responsive sites using grain nutrient analysis.

Effect of Sulfur and Boron Nutrition on Yield and Quality of Soybean (Glycine max L.) Grown in an Acid Soil

ABSTRACTSoybean (Glycine max L.), being a leguminous oilseed crop, requires relatively higher amount of sulfur (S) and boron (B) for optimum yield and quality. A field experiment was conducted to evaluate the effect of S and B application on growth, yield, and quality of soybean, and to find out their optimum doses for the best crop performance in acidic soils of northeast India. The treatments comprised four levels of S (0, 20, 40, and 60 kg/ha) and four levels of B (0, 0.5, 1.0, and 1.5 kg/ha) in factorial combination. In general, application of S and B, either alone or in combination, significantly increased the growth, yield, and quality of soybean. When applied alone, S resulted in best yield (1767 kg/ha) at S40, which was 21.2% higher than the yield at control (1458 kg/ha), while B produced maximum yield (1578 kg/ha) at B1.5 (8.23% higher than control). Interestingly, 57.4% yield improvement over control was recorded with combined application of S40 and B1.5, which shows their synergistic effect on crop performance. Similarly, with concurrent application of S40 and B1.5, a 28% increase in protein and 33% increase in oil content of soybean were recorded relative to control. In general, S40 + B1.5 also resulted in the highest nutrient nitrogen, phosphorus, potassium sulfur, and boron (NPKSB) uptake by soybean. Based on these results, we recommend the conjunctive use of 40 kg S and 1.5 kg B/ha for the best yield and quality of soybean on acidic soils of northeast India and other regions with similar soils.

Nutrient uptake by clusterbean as influenced by weed management and sulphur nutrition

A field experiment was carried out during two consecutive seasons of Kharif 2013 and 2014 to evaluate effect of weed management and sulphur nutrition on the nutrient uptake by weeds and crop in clusterbean [Cyamopsis tetragonoloba (L.) Taub.]. Minimum weed dry matter of narrow-leaved (239 kg/ha), broad-leaved (285 kg/ha) and total dry weight (524 kg/ha) was observed under hand weeding at 20 and 40 days after sowing (DAS), which was closely followed by the sequential application of preemergence application of pendimethalin 0.75 kg/ha followed by (fb) imazethapyr 0.075 kg/ha as postemergence. The highest seed (1.22 t/ha), haulm (2.44 t/ha) and biological yields (3.66 t/ha) was registered in hand weeded twice, which was statistically at par to pendimethalin fb imazethapyr. Hand weeding twice and pendimethalin fb imazethapyr, with non-significant difference between these two, saved N and P uptake by 56, 47 and 55, 46%, respectively, compared to weedy check in combined uptake of nutrient both by weeds and crop.