Combined Application Of Urea Research Articles

Effects of nitrogen forms on nitrogen utilization, yield, and quality of two wheat varieties with different gluten characteristics

The assimilation and utilization of different nitrogen (N) forms in wheat are different. Therefore, supplying suitable forms of N may be an effective way to optimize yield, quality, and N use efficiency (NUE) synergistically. A two-year field trial was conducted with Jimai22 (JM22) and Jimai44 (JM44) wheat varieties at differential gluten characteristics, with N form treatments: no nitrogen (N0), and nitrogen supply (225 kg ha−1) as urea (U), ammonium nitrogen (ammonium chloride, A), nitrate nitrogen (calcium nitrate, NI), U + A (1:1, UA), U + N (1:1, UN), and N + A (1:1, NA). The results showed that different N forms significantly affected wheat yield, N utilization, and grain quality. Combined application of urea and nitrate nitrogen (UN) significantly increased the spike number by 3.5% on average over U (conventional fertilization), but with no statistical difference in grain yield. N and A treatments significantly increased the activity of N metabolism enzymes in flag leaves and grains at the early filling stage but rapidly declined at the middle and late filling stages. In contrast, UN treatment significantly increased nitrate reductase and glutamine synthetase activities of wheat flag leaves and grains within 7–28 d after anthesis, which facilitated N assimilation and significantly increased free amino acids content in the middle and late filling stages, thereby significantly promoting the accumulation of gliadin and glutenin in grains, resulting in the highest protein content and the best processing quality of JM22 and JM44. Except for N0, NUE, N uptake efficiency (NUPE), and N apparent recovery fraction (NARF) under UN were the highest, which were significantly increased by 4.3%, 5.8%, and 11.8% on average compared to the U treatment, respectively. Therefore, the combined application of urea and nitrate nitrogen could synergistically improve quality and nitrogen use efficiency while maintaining yield, which is important for the rational application of nitrogen fertilizer and achieving stable yield, high quality and efficient production of wheat.

Nitrogen transformation genes and ammonia emission from soil under biochar and urease inhibitor application

Ammonia (NH3) volatilization is the main pathway, by which nitrogen (N) losses from calcareous and alkaline soils occur, and is responsible for economic losses and environmental hazards. We hypothesize that the application of biochar and urease inhibitor (NBPT) can mitigate NH3 production from urea by reducing its hydrolysis and the abundance of related microbial genes. To clarify this hypothesis, soil N fluxes and the genes controlling hydrolysis and nitrification were investigated under the combined application of urea (0, 75, 150, 225 and 300 kg N ha−1), biochar (7.5 Mg ha−1) and NBPT (2 %) for maize under field conditions. Soil moisture, temperature, pH, mineral N, NH3, urease activity (UA) and N cycle related genes (ureC, amoB and amoA) were quantified each 6–17 days during two growing seasons. The combined application of NBPT and biochar reduced NH3 by 13% of the control, which is twofold higher than the separate additions. All investigated parameters were raised with increasing N rate except pH, which was reduced. Biochar and NBPT mediated these effects of N fertilizer by increasing the soil pH, genes abundance, ammonium and nitrate contents, and reducing urea hydrolysis. Biochar maximized the ammonium and nitrate contents one week and three weeks following the N urea application, respectively. Accordingly, NH3 and UA peaked directly after N fertilization; nevertheless, NBPT delayed the peaks for three weeks and reduced their intensity by 24 % and 36 %, respectively, under the addition of 300 kg N ha−1. NBPT reduced ureC and amoB genes abundance by 14 % and 8 %, respectively, and increased amoA by 3 %. Biochar increased amoA and amoB abundance and nitrate content, while reduced the ureC gene. Biochar and/or NBPT reduced the negative effects of the soil pH on ureC gene. NBPT mitigated the reduction effects of pH on the amoB and amoA genes. In conclusion, NBPT mitigated NH3 emission by decreasing the ureC gene and UA, whereas biochar had a synergistic effect with NBPT by increasing amoB and amoA abundance and accelerating nitrification.

Effect of chemical and biological fertilizers on the morphology and yield of safflower and soybean under monoculture and intercropping

Intercropping and biofertilizers application are the most important agricultural methods for moving towards minimizing the risks of agricultural production and increasing production efficiency. Consequently, this experiment was conducted at one year and in 2019. A factorial set of treatments was arranged within randomized complete block design (RCBD) with three replications to investigate the effect of different planting ratios with safflower and soybean (sole cropping, 30:100 soybean to safflower ratio, 60:100 soybean to safflower ratio and 90:100 soybean to safflower ratio) and nutrient levels (100% urea fertilizer, 100% biofertilizer and the combined application of urea and biofertilizer) on growth and yield of these crops. The results of this study indicated that intercropping patterns had the highest plant height, number of grains per plant, biological and grain yields. In addition, the means of the number of heads per plant and the number of grains per head in safflower and the weight of 1000 grains in soybean were increased as intercrops were grown. Maximum of grain number per plant in safflower, leaf number per plan in soybean and biological and grain yields in both crops were attained in urea + biofertilizer. In all of intercropping patterns the values of LER (land equivalent ratio), RVT (relative value total) and RCC (relative crowding coefficient) was more than one, indicating an advantage from intercropping over sole crops.

Effects of mechanized deep placement of nitrogen fertilizer rate and type on rice yield and nitrogen use efficiency in Chuanxi Plain, China

This paper investigates the yield and nitrogen use efficiency (NUE) of machine-transplanted rice cultivated using mechanized deep placement of N fertilizer in the rice–wheat rotation region of Chuanxi Plain, China. It provides theoretical support for N-saving and improves quality and production efficiency of machine-transplanted rice. Using a single-factor complete randomized block design in field experiments in 2018 and 2019, seven N-fertilization treatments were applied, with the fertilizer being surface broadcast and/or mechanically placed beside the seedlings at (5.5±0.5) cm soil depth when transplanting. The treatments were: N0, no N fertilizer; U1, 180 kg N ha–1 as urea, surface broadcast manually before transplanting; U2, 108 kg N ha–1 as urea, surface broadcast manually before transplanting, and 72 kg N ha–1 as urea surface broadcast manually on the 10th d after transplanting, which is not only the local common fertilization method, but also the reference treatment; UD, 180 kg N ha–1 as urea, mechanically deep-placed when transplanting; M1, 81.6 kg N ha–1 as urea and 38.4 kg N ha–1 as controlled-release urea (CRU), mechanically deep-placed when transplanting; M2, 102 kg N ha–1 as urea and 48 kg N ha–1 as CRU, mechanically deep-placed when transplanting; M3, 122.4 kg N ha–1 as urea and 57.6 kg N ha–1 as CRU, mechanically deep-placed when transplanting. The effects of the N fertilizer treatments on rice yield and NUE were consistent in the 2 yr. With a N application rate of 180 kg ha–1, compared with U2, the N recovery efficiency (NRE), N agronomic use efficiency (NAE) and yield under the UD treatment were 20.6, 3.5 and 1.1% higher in 2018, and 4.6, 1.7 and 1.2% higher in 2019, respectively. Compared with urea alone (U1, U2 or UD), the NRE, NAE and yield achieved by M3 (combined application of urea and controlled-release urea) were higher by 9.2–73.3%, 18.6–61.5% and 6.5–16.5% (2018), and 22.2–65.2%, 25.6–75.0% and 5.9–13.9% (2019), respectively. Compared with M3, the lower-N treatments M1 and M2 significantly increased NRE by 4.0–7.8% in 2018 and 3.1–4.3% in 2019, respectively. Compared with urea surface application (U1 or U2), the yield under the M2 treatment was higher by 4.3–12.9% in 2018 and 3.6–10.1% in 2019, respectively. Compared with U2, the NRE and NAE under the M2 treatment was higher by 36.9 and 36.3% in 2018, and 33.2 and 37.4% in 2019, mainly because of higher N uptake. There was no significant difference in the concentration of nitrate in the top 0–20 cm soil under U1, U2 and M2 treatments during the full heading and maturity stages. During the full heading stage, U2 produced the highest concentration of nitrite in 0–20 cm and 20–40 cm soil among the N fertilizer treatments. In conclusion, mechanized deep placement of mixed urea and controlled-release urea (M2) at transplanting is a highly-efficient cultivation technology that enables increased yield of machine-transplanted rice and improved NUE, while reducing the amount of N-fertilization applied.

Effects of Fertilizer Type and Grass Species on Agronomic Performances and Chemical Composition in Gozamin District, East Gojjam Zone, Ethiopia

The field experiment was conducted in rainy season to evaluate the effects of fertilizer type and grass species on agronomic performances and nutritive value of grass. The study was conducted 3x4 factorial arrangements with 3 grass species (Buffel, Setaria and Desho) and 4 four fertilizer type (Ft); Ft1 (control), Ft2 (50 kg urea+60 quintal of compost/ha), Ft3 (100 kg urea/ha) and Ft4 (120 quintal of compost/ha) with 3 replications was used. The data were collected agronomic performances such as plant height, number tillers per plant, number leaves per plant, leaf length and dry matter yield (DMY). Chemical analysis was conducted for dry matter (DM %), Ash, crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) was quantified. Results indicated that the agronomic performances and dry matter yield were significantly affected by fertilizer types, grass species and their interactions while interactions had no significant (P>0.05) effect on chemical analysis. Only chemical analysis no significantly (P>0.05) affected by grass species was crude protein (CP). However, fertilizer type was significantly (P<0.01) affected CP, NDF and ADL as well as ADF and Ash content (P<0.001), but non-significant (P>0.05) effect on DM %. The highest dry matter yield (DMY), crude protein (CP) and Ash content were obtained at received Ft2 (50 kg urea+ 60 quintal of compost/ha, whereas Ft1 (control) lowest in parameter. Higher NDF, ADF and ADL were recorded for unfertilized group. It could be concluded that, combined application of urea and compost showed a positive result on agronomic performance and forage quality. It could be suggested that Desho grass can be cultivated with 50 kg urea+ 60 quintal of compost/ha is important for maximize production with forage quality and sustainability of animal production in Gozamen district.

Impact of urea and farm yard manure on nitrate concentration in soil profile and productivity of wheat crop

During the last century, concerns about nitrate presence in the groundwater have tremendously increased worldwide, mainly because of its detrimental consequences on environment and human health. There are different factors contributing their past in nitrate pollution, farm manure is given due consideration. Knowing above facts, a field study was performed to check the effect of different farm yard manure (FYM) levels with urea on nitrate distribution in the soil profile and yield of wheat crop. The experiment was set out in a randomized complete block design, consisted of application of nitrogen at 125 kg ha−1 from urea, 80 kg ha−1 of N from urea +10 tons FYM ha−1 and 20 tons FYM ha−1 with three replications. Wheat (cultivar S7ehar-2006) was sown as test crop. Soil samples were examined to measure the nitrate concentration from four different depths (0–25, 25–50, 50–75, and 75–100 cm) after harvesting. Results showed that the straw yield, total biomass, spike length, and number of grains per spike and 1000-grain weight were significantly influenced by fertilizer strategies. All manure treatments significantly affected the infiltration rate and concentration of nitrate at different depths of the soil profile. Farm yard manure showed greater nitrate concentration up to 50 cm depth as compared to alone urea and combined application, while at the depth of 100 cm, combined application of urea and FYM showed a minimum concentration of nitrates than alone application of either urea or FYM.

Modeling the impacts of alternative fertilization methods on nitrogen loading in rice production in Shanghai

Nitrogen (N) loss from paddy fields is an important source of agricultural non-point source pollution that leads to eutrophication of water bodies and degradation of water quality. The impacts of alternative N fertilizer management practices on N loading (N loss through runoff and leaching) from paddy fields in Shanghai were assessed using a process-based biogeochemical model, DNDC. The results indicated that the current fertilization rate in paddy fields of Shanghai (300kgN/ha) exceeds the actual rice demand and has led to substantial N loading of 1142±276kg. The combined application of urea at 150kgN/ha and organic manure at 100kgN/ha was identified as the best fertilization method for rice cultivation in Shanghai; this application maintained optimal rice yields and significantly reduced N loading to 714±151kg in comparison with the current fertilization rate. A sensitivity test was conducted with various input parameters, and the results indicated that fertilization, precipitation and soil properties were the most sensitive factors that regulate N loss from paddy fields. The variability of soil properties, especially SOC led to high uncertainties in the simulated results. Therefore, the local climate conditions and soil properties should be taken into account in the identification of the best management practice (BMP) for rice cultivation, given the high spatially heterogeneous N loading values across all towns used in the simulation. The DNDC model is an effective approach for simulating and predicting N loading in paddy fields under alternative agricultural management practices.

More rice with less water – evaluation of yield and resource use efficiency in ground cover rice production system with transplanting

Adoption of the innovative water-saving ground cover rice production system (GCRPS) based on transplanting of rice seedlings under high soil moisture conditions, resulted in an overall increase in grain yield compared to previous reports on GCRPS employing direct seeding. However, there is a lack of quantitative information on water and nitrogen use efficiency as affected by water and nitrogen management in GCRPS-transplanting. To close this knowledge gap, we conducted a two-year field experiment with traditional paddy rice (Paddy) and GCRPS-transplanting under two soil moisture conditions (GCRPSsat and GCRPS80%), combined with 3 nitrogen fertilizer management regimes (0, 150kg urea-N/ha as basal fertilizer for Paddy and GCRPS, 150kg urea-N/ha in 3 splits for Paddy or 75kg urea-N/ha plus 75kg N/ha as chicken manure for GCRPS). Grain yield, water and nitrogen use efficiency, stable isotope 13C of plant shoots and yield components were evaluated.The study showed: (1) compared to Paddy, both GCRPSsat and GCRPS80% produced significantly more grain yield, while no significant difference in grain yield was found between both GCRPS treatments. (2) Irrigation water use efficiency was increased by 140% in GCRPSsat and >500% in GCRPS80%, while total water use efficiency was improved by 52–96% as compared to Paddy. (3) δ13C of plant shoots was significantly higher in GCRPS than in Paddy, and showed significant positive correlations with total and irrigation water use efficiencies. (4) Compared to Paddy, agronomic N use efficiency was significantly higher in both forms of GCRPS. However, N recovery rates were only significantly higher in GCRPS than in Paddy when all urea nitrogen was applied as basal fertilizer before transplanting. With improved fertilizer N management, i.e., split N application in Paddy or combined application of urea and chicken manure in GCRPS, there were no significant differences. Overall, this quantitative evaluation of water use efficiency highlights that the use of GCRPS involving transplanting of seedlings has a great potential to reduce irrigation water input, increase grain yield and resource use efficiency.

Effect of urea and certain NPK fertilizers on the cereal cyst nematode (Heterodera avenae) on wheat

Two outdoor pot experiments were conducted in two consecutive years under outdoor conditions during the wheat growing season in Saudi Arabia to determine the effects of urea and certain compound fertilizers (NPK), compared to the effects of the nematicide fenamiphos on the cereal cyst nematode (CCN), Heterodera avenae, and wheat growth. The results showed that all of the treatments, except the fertilizer diammonium phosphate (DAP), reduced the number of nematode cysts/root system and increased (P⩽0.05) the dry weight of nematode-infected wheat plants. Fenamiphos and urea resulted in the best control, followed by the NPK fertilizers. The combined application of urea and fenamiphos resulted in the most significant effect in decreasing (P⩽0.05) the number of cysts/root system and increasing (P⩽0.05) the growth of nematode-infected wheat plants.

In an Ecuadorian pasture soil the growth of Setaria sphacelata, but not of soil microorganisms, is co-limited by N and P

In the mountain rainforest region of southern Ecuador, soils of active pastures, established after slash-and-burn of the forest, are characterized by improved quantity and quality of soil organic matter favoring microbial conditions. However, these beneficial conditions decrease with increasing pasture age and burning frequency. As a consequence, rates of soil nutrient cycling decrease, supporting the infestation of bracken fern and, in turn, causing further decreases in pasture productivity. Finally, farmers are forced to abandon the degraded pastures and to establish new ones by continuous deforestation. To investigate whether an application of N and/or P nutrients to an extensively grazed pasture (active pasture) can improve grass productivity and maintain soil fertility, a pasture fertilization experiment was conducted. On an active pasture site, planted with Setaria sphacelata, moderate rates of urea (50kgNha−1a−1), rock phosphate (10kgPha−1a−1), and a combination of both were applied. It was examined whether soil mineralization (gross and net N mineralization, SOC mineralization) and microbial community structure (PLFA-analysis), as well as quantity and quality of the grass biomass, were affected by fertilization. Furthermore, the impact of fertilization on in situ soil respiration rates was studied. The combined application of urea and rock phosphate increased the pasture yield by 2Mgha−1a−1 most efficiently, indicating a co-limitation of growth. Additionally, the fodder quality was improved by a 67% higher content of P and by a 7% higher content of Ca in the grass biomass compared to the control. While carbon, nitrogen, and phosphorus in the microbial biomass remained unaffected and the microbial activity increased only temporarily, the relative abundance of fungi (18:2n6,9) increased significantly due to fertilizer addition. Urea addition induced a short-lived increase in the in situ soil CO2-C effluxes, assuming a positive priming effect due to an activation of soil microbes. In total, plots amended with urea emitted 0.8MgCO2-Cha−1a−1 more than the control. Results reveal that already moderate fertilization significantly improved pasture productivity and maintained soil quality. However, it is expected that higher loads of NP fertilizer will increase pasture productivity at the expense of soil organic carbon sequestration due to enhanced soil CO2-C losses. Hence, to establish a sustainable pasture management in the study region, the soil C management must also be carefully considered.

Effects of transgenic Bt cotton on soil fertility and biology under field conditions in subtropical inceptisol

Although there is large-scale adoption of Bt cotton by the farmers because of immediate financial gain, there is concern that Bt crops release Bt toxins into the soil environment which reduces soil chemical and biological activities. However, the majorities of such studies were mainly performed under pot experiments, relatively little research has examined the direct and indirect effects of associated cover crop of peanut with fertilization by combined application of organic and inorganic sources of nitrogen under field conditions. We compared soil chemical and biological parameters of Bt cotton with pure crop of peanut to arrive on a valid conclusion. Significantly higher dehydrogenase enzyme activity and KMnO(4)-N content of soil were observed in Bt cotton with cover crop of peanut over pure Bt cotton followed by pure peanut at all the crop growth stages. However, higher microbial population was maintained by pure peanut over intercropped Bt cotton, but these differences were related to the presence of high amount of KMnO(4)-N content of soil. By growing cover crop of peanut between Bt cotton rows, bacteria, fungi, and actinomycetes population increased by 60%, 14%, and 10%, respectively, over Bt cotton alone. Bt cotton fertilized by combined application of urea and farm yard manure (FYM) maintained higher dehydrogenase enzyme activity, KMnO(4)-N content of soil and microbial population over urea alone. Significant positive correlations were observed for dry matter accumulation, dehydrogenase enzyme activity, KMnO(4)-N content, and microbial population of soil of Bt cotton, which indicates no harmful effects of Bt cotton on soil biological parameters and associated cover crop. Our results suggest that inclusion of cover crop of peanut and FYM in Bt cotton enhanced soil chemical and biological parameters which can mask any negative effect of the Bt toxin on microbial activity and thus on enzymatic activities.

Mineral nitrogen in a rhizosphere soil and in standing water during rice (Oryza sativa L.) growth: effect of hydroquinone and dicyandiamide

Inhibitors are applied to improve the efficiency of N fertilizer use and to reduce N losses from the soil. However, little information is available on the effects of a urease inhibitor, hydroquinone (HQ), and a nitrification inhibitor, dicyandiamide (DCD), on urea-derived mineral N in the rhizosphere of rice plants and in the standing water. Furthermore, this is important to understand the contribution of rice plants to gaseous N losses in the presence of inhibitor(s). A rhizobox was used to simultaneously study urea-derived mineral N in the soil at increasing distances from rice roots, and the effect of growing plants on the behavior of fertilizer-N in soil. The combined application of urea (U) with DCD showed a significantly positive effect on rice growth. The redox potentials in the rhizosphere soil were higher in the presence than in the absence of DCD, especially when rice plants entered their vigorous growth stage. During the entire experimental period, NH 4 + –N concentrations in the rhizosphere of rice plants were smaller in the U + DCD and U + HQ + DCD treatments than in the U and U + HQ treatments. On days 20 and 60 after fertilization, the U + DCD and U + HQ + DCD treatments showed a smaller concentration of (NO 3 − + NO 2 − )–N in soil less than 0.5 cm from the rhizobox, compared to the U treatment. During the early period of rice growth, the NH 4 + –N concentration of the standing water was higher in the presence than in the absence of DCD. However, there were no significant differences in NH 4 + –N among all treatments after 20 days. In the absence of rice plants, also, the application of DCD and especially DCD and HQ, always increased the level of NH 4 + –N and pH in the standing water. Thus, rice plants might reduce potential gaseous N losses from a urea-fertilized, flooded soil, due to the stimulating effect on rice growth in the presence of DCD or DCD + HQ. The N 2 O emissions from the urea-fertilized, rice-planted soil significantly decreased when DCD or DCD + HQ was used. From the results obtained, we conclude that DCD and DCD + HQ together with U can be an effective tool to improving crop growth and reducing N loss as N 2 O in rice cultivation, and that the use of a rhizobox is useful to study the interaction between plant uptake and the behavior of fertilizer-N in soil.

EFFECT OF COMBINED USE OF UREA AND GOAT DUNG MANURE ON CELOSIA

Three field experiments were conducted to investigate the separate and combined effects of urea and goat dung manure on leaf nutrient contents, growth and yield of Celosia argentea in southwest Nigeria. Each experiment involved 7 treatments namely: no treatment, 10t/ha goat dung, 125 kg/ha urea, 125 kg/ha urea + 2t/ha goat dung, 125 kg/ha urea + 4 t/ha goat dung, 125 kg/ha urea + 6t/ha goat dung and 125 kg/ha urea + 8 t/ha goat dung, replicated three times using a randomised complete block design. Goat manure increased height, number of leaves, stem girth, root length, stem and leaf weight of celosia and leaf N, P, K, Ca and Mg contents. Compared with urea or goat dung alone, combined application of urea and goat dung increased growth and yield of celosia and leaf nutrients contents. Addition of goat manure to urea increased leaf P, K, Mg status. Leaf P and K increased with increasing amount of goat manure. Compared with no treatment, 10t/ha goat dung, 125 t/ha urea and 125 t/ha urea + 6t/ha goat dung increased fresh matter yield by 66, 273 and 974% respectively. [Niger Agric. J. 34 (2003): 87-90]

Urea as an organic nitrogen source for hydroponically grown tomatoes in comparison with inorganic nitrogen sources

Tomato (Lycopersicon esculentum Mill., cv. Momotaro) plants were grown in nutrient solutions with several levels of urea, nitrate, and ammonium alone or in combination to evaluate the role of urea as an organic nitrogen source compared with that of nitrate and/or ammonium as inorganic nitrogen sources. Nitrogen deficiency and excess symptoms were detected in the urea-fed plants at lower (28 mg N L-1) and higher nitrogen levels (336, 504 mg N L-1), respectively. The effect of urea on plant growth and leaf elemental composition was intermediate between that of nitrate and ammonium. Solution pH under urea nutrition slightly increased or remained stable. When plants were cultured with the solution containing 168 mg N L-1, the total dry weight of the plants which received urea+nitrate was significantly higher than that of the plant which received urea and was almost equal to that of the plants which received nitrate or nitrate+ammonium. Both absorption and utilization of nitrogen in the plants fed with urea decreased compared with those of the plants fed with nitrate or ammonium. The insufficient absorption and utilization of nitrogen were estimated to be the main factors associated with the growth reduction of tomato plants under urea nutrition. However, combined application of urea and nitrate is useful for adequate plant growth without a reduction of the cation absorption in tomato while maintaining a stable solution pH.

Ammonia volatilization from urea as affected by the addition of iron pyrites and method of application

Laboratory incubations were conducted to determine the ammonia (NH3) loss from urea as affected by the addition of coarse and ground (fine) pyrites at 1:1, 1:2 and 1:5 urea: pyrite (w/w) ratios and methods of application (surfaceapplication, incorporation and placement). Coarse pyrites (>-2mm) were not effective in reducing NH3 loss from urea when surface applied even at the highest ratio of pyrite (15.9% vs 18.7% without pyrite). Ground pyrites (0.1–0.25 mm), in 1:1 ratio, had about 5% less NH3 loss than the urea alone treatment. Higher ratios of pyrites reduced NH3 loss much more. Ammonia losses were the most with surface-applied urea (18.9%) and the least (13.5%) when placed (2.5 cm) below the soil surface. Addition of ground pyrite to surface-applied urea (1:1 ratio) decreased the loss to 13.2%. Urea+pyrite placed below the soil surface had the least loss (9.8%). Results indicate that combined application of urea and fine pyrite could reduce NH3 loss.

Effect of algal inoculation on the yield and vitamin C content of two varieties of tomato

Two varieties of tomato (Pusa Rubi and Selection 120) positively responded to algal inoculation in terms of the yield of fruits and shoots, but there was no significant effect on the vitamin C content of the fruits. A combined application of urea and algae was more effective than the application of urea alone.

The effect of Calothrix inoculation on vegetable crops

The inoculation of the soil with the nitrogen fixing blue-green alga,Calothrix anomala had a positive effect onCapsicum annum andLactuca sativa, in terms of yield and percentage nitrogen. A combined application of urea and alga was more effective than their individual applications.