Emerald Harvest Grow Research Dossier

Emerald Harvest Grow

Give your crops what they need when they need it most, with Emerald Harvest Grow. The product supplies plants with precise nutrient formulations that deliver the right amounts of nitrogen, phosphorus and potassium throughout the crop lifecycle. In addition to regulating the amounts of N, P and K so that your high-yield plants flourish, the components present in this formula provides a rich mix of trace elements to accelerate growth.

Key Ingredients

Potassium Sulfate, Monopotassium Phosphate, Potassium Nitrate, Mono Ammonium Phosphate, Magnesium Nitrate, Ammonium Nitrate, Ammonium Sulfate, and Magnesium Sulfate.


Potassium Sulfate

  • Potassium has been shown to affect both flower number and fruit formation, giving the greatest number of flowers
  • Leaf area index increased with concurrent increase in potassium levels.

Mono Potassium Phosphate

  • Potassium affects flower formation
  • Higher female flower production.
  • Greater marketable fruit number.
  • Essential for root development
  • K deficient treatment significantly inhibited root length and the formation of lateral roots.
  • Reduced lateral roots mainly resulted from the shortened branched root zone

Potassium Nitrate

  • Critical during flower development, especially during flower opening
  • The increase in yields, dry weight.
  • N influenced yield by increasing leaf area duration which in turn increased mean tuber weight and hence tuber yield.
  • K controlled tuber yield via an increase in the proportion of dry matter diverted to the tubers and a rise in tuber number per
  • Growth in quality of produce
  • Increased sugar concentrations
  • Increases chlorophyll, photosynthesis, protects against oxidative stress
  • Increased seed yield

Mono Ammonium Phosphate

  • Allows energy to be available to plants
  • Glucose, sucrose and starch contents increased in all tissues of phosphate-deficient plants, showing that plants were unable to convert these molecules to make energy for their activities.
  • Phosphate deficiency increased activities of enzymes involved in sucrose synthesis in the leaves and root;
  • Promotes growth and enhances the number of flowers
  • Without phosphorus, there is a decrease in the number of flowers.
  • The amount of cytokinin activity decreases with a decrease in phosphorus concentration.

Magnesium Nitrate

  • Essential for proper growth of the plant
  • Shortage of Mg causes weak growth of chestnut trees, severe yield reduction, and lower nut caliber; nuts have lower levels of dry matter content and crude fat, but higher crude protein content
  • Nitrogen deficiency significantly reduces Chlorophyll content, and photosynthesis, resulting in lower biomass production.
  • Leaf area expansion was sensitive to lower leaf N followed by rates of stem elongation, node addition, and photosynthesis.
  • Higher shoot dry matter production
  • High nitrogen nutrition remarkably improved the photosynthetic CO2 assimilation (A) of the target leaves.
  • Transpiration rate (E) was increased in high-N grown plants

Ammonium Nitrate

  • Increased vegetative growth
  • Increases yield, dry matter. Maximum yield of dry matter was obtained at a concentration of 715 μM.
  • Increased sucrose synthesis activity by 20–200%.
  • Increase average fruit weight and size.

Magnesium Sulfate

  • Increases yield and quality
  • Without sulfur, the plant showed reduced dry weight, photosynthetic rate, chlorophyll content, and the total number of fruits.
  • Fertilization of deficient trees with magnesium sulfate resulted in increased height and growth
  • Essential for photosynthesis


Potassium Nitrate

Critical during flower development, especially during flower opening

Rose (Rosa hybrida L.) plants grown for cut-flower production in greenhouses produce flowers in flushes year-round. Crop models for this system must handle the cyclical nature of productivity, which is determined by the horticultural production methods.The aim of the current study was to measure uptake rates of nitrogen and potassium by roses, to be included in a production model. Rose plants var. ‘Kardinal’ were grown in the greenhouse in aero-hydroponics nutrient solution with 3 mM nitrate (NO3)-N and 1 mM potassium (K). After several flower growth/harvest cycles, the plants were transferred to a growth chamber in groups of three, every 10 days. The growth chamber provided 25 ◦C and 16 h day length. The nutrient solutions were sampled periodically while maintaining the volume constant at 5 l, and analyzed for NO3 and K concentrations reduction. The roots were harvested at the end of each depletion series, and their lengths measured. Influx of NO3 and K into roots was obtained by fitting a Michaelis–Menten function to the concentration depletion data. There was a cyclic rhythm of both the nutrients’ influx rates over time, with a decline in uptake after shoot harvest, and an increase during flower development, with maximal values towards flower opening. The results were incorporated in a simulation model for nutrient uptake by roses along successive flower-cutting cycles. This simulation assumes a constant number of identical flowering branches, which would be cut sequentially at flower maturity, and result in new shoot growth, assumed to follow a logistic function of time. Uptake rates of NO3 and K were assumed to follow the changes in leaf area and shoot nutrient percentage, to compensate for N and K demand by the shoot; There was a cyclic rhythm of both the nutrients’ influx rates over time, with a decline in uptake after shoot harvest, and increase during flower development, with maximal values towards flower opening.

M Silberbusha, b,  J.H Lietha, 2004. Nitrate and potassium uptake by greenhouse roses (Rosa hybrida) along successive flower-cut cycles: a model and its calibration. Scientia Horticulturae, Volume 101, Issues 1–2, Pages 127–141.

Increase in yields, dry weight

Two factorial fertilizer trials involving four levels of nitrogen and four levels of potassium were carried out on the sweet potato to gain a better understanding of the way in which fertilizer influences growth and yield. Under conditions of continuous cropping, nitrogen (N) had a greater influence on growth and yield than did potassium (K). N fertilization up to a rate of 225 kg N ha−1 increased tuber yield, mean tuber weight, total plant dry weight, dry weight of all plant components, leaf area index, leaf area duration, number of leaves per plant, mean leaf area per leaf, crop growth rate; and, for some periods, leaf area ratio (LAR) and relative growth rate. N reduced a number of tubers per plant early in the crop. K fertilization up to a rate of 375 kg K ha−1increased tuber yield, the number of tubers per plant, mean tuber weight, total plant dry weight, mean leaf area per leaf and harvest index. It reduced the percentage dry weight of tubers and LAR in Trial 2.

It is suggested that N influenced yield by increasing leaf area duration which in turn increased mean tuber weight and hence tuber yield. K controlled tuber yield via an increase in the proportion of dry matter diverted to the tubers and a rise in tuber number per plant. The effect of K occurred by seven weeks after planting, and it is suggested that K fertilizer is applied early in the crop life:

R.Michael Bourke, 1985. Influence of nitrogen and potassium fertilizer on growth of sweet potato (Ipomoea batatas) in Papua New Guinea. Field Crops Research, Volume 12, Pages 363–375.

Increase in quality of produce

Effects of potassium levels on fruit quality were evaluated on ‘Tiantian No. 1’ muskmelon (Cucumis melo, cv. reticulatus Naud.) in soilless medium culture under a greenhouse. Three potassium levels, K120(insufficient), K240 (suitable), and K360 (excessive) in the nutrient solution, which represent 120, 240, and 360 mg l−1 of potassium (K), respectively, were applied. At potassium level of 240 mg l−1, the concentrations of total sugar, total soluble solids, glutamic acid, aspartic acid, alanine, and volatile acetate components (n-amyl acetate, 2-butoxyethyl acetate) significantly increased in fruit flesh, which should improve the taste and aroma of muskmelon. However, no significant difference in fruit appearance or size was recorded among the treatments. Favorable quality of muskmelon in soilless medium culture were achieved when potassium level was adjusted to near 240 mg l−1 in nutrient solution:

Duo Lin1, Danfeng Huang, Shiping Wang, 2004. Effects of potassium levels on fruit quality of muskmelon in soilless medium culture. Scientia Horticulturae, Volume 102, Issue 1, Pages 53–60.

Increases chlorophyll, photosynthesis, protects against oxidative stress

Houttuynia cordata Thunb. is an edible herb with a variety of pharmacological activities, but only limited information is available about its response towards potassium supplementation. Sterile plantlets were cultured in media with different potassium levels, and parameters related to growth, foliar potassium, water and chlorophyll contents, photosynthesis, transpiration, H2O2 contents and antioxidative enzyme activities were determined after a month. Results showed that 1.28 mM potassium was the optimum for H. for data as highest values of dry weight, shoot height, root length and number were obtained at this concentration. The optimum potassium level resulted in the maximum net photosynthetic rate which could be associated with the highest chlorophyll content rather than limited stomatal conductance. The supply of surplus potassium resulted in a higher content of foliar potassium, but negatively correlated with the biomass. Both potassium starvation (0 mM) and high potassium (>1.28 mM) could lead to water loss through high transpiration rate and low water absorption, respectively, and resulted in H2O2 accumulation and increased activities of catalase and peroxidase, which suggested induction of oxidative stress. Moreover, H. cordata showed the minimum of H2O2 content and the maximum of superoxide dismutase activity on 1.28 mM potassium, implying its role in inducing tolerance against oxidative stress:

  1. Wen Xua, 1, Yu Ting Zoua, 1, Amjad M. Husainib, Jian Wei Zenga, Lin Liang Guana, Qian Liua, Wei Wua, 2011. Optimization of potassium for proper growth and physiological response of Houttuynia cordata Thunb. Environmental and Experimental Botany, Volume 71, Issue 2, Pages 292–297.

Increased seed yield

A 2-year field study was conducted to determine the effect of N fertilization on various aspects of linseed growth, including phenological stages, seed yield and yield components, the contribution of yield components to seed yield, biomass growth rate, and nitrogen uptake rate. Three different cultivars were used (Creola, Livia, and Lirina) and three rates of N fertilization were applied (0, 40 and 80 kg ha−1). N fertilization was found to increase seed yield by an average of 37% above the control rate over the 2-year study period. Application of N affected yield components, especially the seed weight per plant, the number of capsules per plant, the number of capsules m−2, and the number of seeds per plant, which were increased by an average of 54, 62, 45, and 56% respectively compared with the control. Phenological stages (time to reach flowering, seed maturity, and seed filling period) were also affected by N fertilization and the seed filling 10% increased period compared with the control. Plant height was also increased with N application, and cultivar height differences were also apparent. Biomass growth rate, economic growth rate, and seed growth rate were all increased with N application, but much higher increases were found in the N uptake rate, economic N rate, and seed N uptake rate. Seed yield was correlated with the yield components, seed filling period, biomass growth rate (BGR), economic growth rate (EGR), seed growth rate (SGR), and nitrogen uptake rate (NUR). Also, NUR was negatively correlated with the economic N uptake rate (ENUR) and seed N uptake rate (SNUR). In conclusion, the present study indicates that N fertilization promotes the growth of linseed, affecting the development and increasing the BGR, EGR, SGR, and also NUR, ENUR, and SNUR. These are important physiological determinants of seed yield that can be used as additional selection criteria for yield improvements:

Christos A. Dordas, 2010. Variation of physiological determinants of yield in linseed in response to nitrogen fertilization. Industrial Crops and Products, Volume 31, Issue 3, Pages 455–465.

Increased yield and quality of fruit

A fixed field experiment was designed to study the effects of nitrogen (N) and potassium (K) fertilizers applied to optimize the yield and quality of typical vegetable crops. Application of N and K fertilizers significantly increased the yields of a kidney bean. The largest yields were obtained in the first and second years after application of 1 500 kg N and 300 kg K2O ha−1. Maximum yields occurred when intermediate rates of N and K (750 kg N and 300 kg K2O ha−1) were applied. Application of K fertilizer was often associated with increased sugar concentrations:

Zhao-Hui LIU, Li-Hua JIANG, Xiao-Lin LI, R. HÄRDTER, Wen-Jun ZHANG, Yu-Lan ZHANG, Dong-Feng ZHENG, 2008. Effect of N and K Fertilizers on Yield and Quality of Greenhouse Vegetable Crops. Pedosphere, Volume 18, Issue 4, Pages 496–502.

Ammonium Nitrate

Increases growth, increased P, K and Ca uptake

A glasshouse experiment was carried out to study the effect of ammonium supply [0 and 1.5 mmol L‐1 in the nutrient solution, whereas total nitrogen (N) concentration, was 9.5 mmol L‐1] on nutrient uptake, leaves, and xylem sap composition and growth of bean plants in sand culture. Ammonium supply caused higher nitrogen, phosphorus (P), potassium (K), and calcium (Ca) uptake. However, K, Ca, and magnesium (Mg) concentrations in the plants (in xylem sap and leaves) were lower when ammonium was supplied. Plants vegetative growth was higher with ammonium supply than without it, especially after four weeks of cultivation:

  1. J. Sarro, J. M. Sánchez & J. M. Peñalosa, 1998. Influence of ammonium uptake on bean nutrition. Journal of Plant Nutrition, Volume 21, Issue 9, pages 1913-1920

Increases yield, dry matter

Soybean (Glycine max (L.) MERR. CV. ‘Amsoy’) plants were grown for 40 days in nutrient solution at various concentrations of ammonium. Maximum yield of dry matter was obtained at a concentration of 715 μM. Further increase in the concentration of ammonium resulted in a reduction in growth due to ammonium toxicity which affected both root and shoot development. The pattern of nitrogen accumulation in tops was consistent with the multiphasic uptake of ammonium and can be represented by 2 phases in the range 1.78 X 10-5-3.57 x X 10-3 M of ammonium:

  1. A. Joseph, Tang Van Hai and J. Lambert, 1976. Effect of ammonium concentration on growth and nitrogen accumulation by soybean grown in nutrient solution. BIOLOGIA PLANTARUM, Volume 18, 339-343

The growth and chemical composition of Ricinus communis cultivated hydroponically on 12 mol m – 3 NO3-N were compared with plants raised on a range of NH4+-N concentrations. At NH4+-N concentrations between 0.5 and 4.0 mol m-3, fresh- and dry weight yields of 62-d-old plants were not significantly different from those of the NO3-N controls. Growth was reduced at 0.2 mol m-3 NH4+-N and was associated with increased root. Shoot and C: organic N ratios, suggesting that the plants were N-limited. At 8.0 mol m-3 NH4+-N, growth was significantly restricted, and the plants exhibited symptoms of severe NH4+ toxicity’. Plants growing on NH4+-N showed marked acidification of the rooting medium, this effect being greatest on media supporting the highest growth rates. Shoot carboxylate content per unit dry weight was lower at most NH4+-N concentrations than in the NO3-N controls, although it increased at the lowest NH4+-N levels. Root carboxylate content was comparable to the two N sources, but also increased substantially at the lowest NH4+-N levels. N source had little effect on inorganic-cation content at the whole-plant level while NO3- and carboxylate were replaced by Clmultimap as the dominant anion in the NH4+-N plants. This was reflected in the ionic composition of the xylem and leaf-cell saps, the latter containing about 100 mol m-3 Cl- in plants on 8.0 mol m-3 NH4+. Xylem-sap organic-N concentration increased more than threefold with NH4+-N (with glutamine being the dominant compound irrespective of N source) while in leaf-cell sap it increased more than 12-fold on NH4+-N media (with arginine becoming the dominant species). In the phloem, N source had little or no effect on inorganic-cation, sucrose or organic-N concentrations or sap pH, but sap from NH4+-N plants contained high levels of Cl- and serine. Collectively, the results suggested that the toxic effects of high NH4+ concentrations were not the result of medium acidification, reduced inorganic cation or carboxylate levels, or restricted carbohydrate availability, as is commonly supposed. Rather, NH4+ toxicity in R. communis is probably the result of changes in protein N turnover and impairment of the photorespiratory N cycle:

Allen, S., and Smith, J A. C. 1986. Ammonium Nutrition in Ricinus communis: Its Effect on Plant Growth and the Chemical Composition of the Whole Plant, Xylem, and Phloem Saps. Journal of Experimental Botany, Volume: 37, Issue: 11, Publisher: Soc Experiment Biol, Pages: 1599-1610

The effects of ammonium on the activity of sucrose synthase (SS) in the roots of pea (Pisum sativum L.) plants were studied. On the medium containing 14.2 mM (NH4)2SO4, SS activity increased by 20–200% for 10–20 days of plant growth as compared to the roots of plants growing without nitrogen. Illuminance affected the degree of effects. Under natural illumination, ammonium changed SS activity not only in sunny days (up to 25 klx) but also in cloudy days (3–6 klx) but to a lower degree. Under stable low light (2.5 klx), ammonium did not affect SS activity. In the in vitro experiments, at (NH4)2SO4 concentrations from 0 to 1 mM, SS activity was suppressed (up to 10%), whereas 1–37.5 mM (NH4)2SO4, it was increased (up to 50%):

  1. Nikitin, R. Bruskova, T. Andreeva, S. Izmailovm,2010. Effect of ammonia on sucrose synthase in pea roots. Russian Journal of Plant Physiology, Vol. 57, No. 1. pp. 69-73

This work was carried out to study the effect of two nitrogen levels, 250 and 500 g of actual nitrogen per avocado tree per year. The nitrogen sources were calcium nitrate (as soil application) and urea (as foliage form).

Nitrogen fertilization gave a highly significant increase in tree yield (kg/tree) in most treatments. Moreover, urea sprays seemed to be more efficient on the yield than calcium nitrate added to the soil at the same nitrogen level. The 500 g nitrogen level of both sources gave a higher yield increase than 250 g nitrogen. Nitrogen fertilization gave a slight increase in mean avocado fruit weight and size while urea sprays seemed to be more efficient in increasing the average fruit weight and size. A small decrease in fresh oil content occurred as a result of nitrogen fertilization:

A.B.Abou Aziz, I. Desouki, M.M. El-Tanahy, 1975. Effect of nitrogen fertilization on yield and fruit oil content of avocado trees. Scientia Horticulturae, Volume 3, Issue 1, Pages 89–94.

Magnesium Nitrate

Three leafy vegetables, rape (Brassica campestris L.), Chinese cabbage (Brassica chinensis var. Oleifera Makino et Noto) and spinach (Spinacia oleracea L.), were grown in plastic pots with 5 kg soil per pot at five nitrate supply rates, 0.00 (N1), 0.15 (N2), 0.30 (N3), 0.45 (N4), and 0.60 (N5) g N kg−1 soil to investigate the effects of nitrate supply on plant growth, nitrate accumulation and nitrate reductase activity. (NRA) Nine weeks after sowing. The optimum yield appeared at N3, while above N4, a sharp decrease in plant growth occurred. The nitrate concentration increased with nitrate supply in the whole plant and the different organs except in roots where nitrate concentration at N5 decreased compared with N4. The nitrate concentration in both the metabolic pool (MP) and the storage pool (SP) of the leaf blades increased with nitrate supply. From N1 to N2, NRA grew most rapidly. The highest NRA occurred at N4. However, nitrate reductase (NR) activities were not significantly different between N3, N4, and N5, which imply that there is a threshold of nitrate concentration in MP (NMP) to induce NRA. The parameters of NR for nitrate were measured by the in vivo method. The Km values we obtained were similar to the reported values by the in vitro method, which confirms the feasibility of the anaerobic method for determining NRA and NMP. Finally, the effects of the posttranslational regulation of NR were discussed:

Bao-Ming Chen, Zhao-Hui Wang, Sheng-Xiu Li, Gen-Xuan Wang, Hai-Xing Song, Xi-Na Wang, 2004. Effects of nitrate supply on plant growth, nitrate accumulation, metabolic nitrate concentration and nitrate reductase activity in three leafy vegetables. Plant Science, Volume 167, Issue 3, Pages 635–643.

Under conditions of poor management, severe Mg deficiency is often observed in chestnut groves located on base-poor granites and schists, in NE Portugal. Many of the severe cases of Mg-deficiency are due to nutritional imbalances between Mg and a growth-stimulating nutrient, particularly nitrogen. In areas affected by Mg-deficiency sharp contrasts have been observed between chlorotic and symptom-free trees, particularly in young groves. A 20-years-old chestnut forest of a traditional Portuguese variety, Longal, was selected to study the influence of Mg-deficiency on several tree growth parameters, yield, and chestnut quality. Trees were classified according to the intercostal yellowing chlorosis of their leaves into three categories: symptom-free, slight chlorosis, and acute chlorosis. There is a strong negative correlation between severity of chlorosis and foliar Mg concentration, tree growth parameters, chestnut production and fruit quality. The mean Mg concentration in leaves of symptom-free trees was 1.2 g kg−1 and the lowest value in green leaves was 0.85 g kg−1. Severe intercostal chlorosis was observed when the Mg concentration in leaves was less than 0.55 g kg−1. The N/Mg ratios increase with the severity of the deficiency, reaching values higher than 40 in the leaves of trees with more acute deficiency. Shortage of Mg causes reduced growth of chestnut trees, severe yield reduction, and lower nut calibre; nuts have lower levels of dry matter content and crude fat, but higher crude protein content:

  1. Portela, J. Ferreira-Cardoso, M. Roboredo and M. Pimentel-Pereira, 1999. Influence of magnesium deficiency on Chestnut ( Castanea Sativa Mill.) yield and nut quality. IMPROVED CROP QUALITY BY NUTRIENT MANAGEMENT, Developments in Plant and Soil Sciences, Volume 86, 4, 153-156

An experiment was conducted under outdoor pot-culture conditions to determine effects of nitrogen (N) deficiency on sorghum growth, physiology, and leaf hyperspectral reflectance properties. Sorghum (cv. DK 44C) was seeded in 360 twelve-litre pots filled with fine sand. All pots were irrigated with half-strength Hoagland’s nutrient solution from emergence to 25 days after sowing (DAS). Thereafter, pots were separated into three identical groups and the following treatments were initiated: (1) the control (100% N) continued receiving the half-strength nutrient solution; (2) reduced N to 20% of the control (20% N), and (3) withheld N from the solution (0% N). Photosynthetic rate (Pn), chlorophyll (Chl) and N concentrations, and hyperspectral reflectance of the uppermost, fully expanded leaves were determined at 3- to 4-day-interval from 21 to 58 DAS during the N treatments. Plants were harvested 58 DAS to determine effects of N deficiency on leaf area (LA), biomass accumulation, and partitioning. Nitrogen deficiency significantly reduced LA, leaf Chl content, and Pn, resulting in lower biomass production. Decreased leaf Pn due to N deficiency was mainly associated with lower stomatal conductance rather than carboxylation capacity of leaf chemistry. Among plant components of dry weights, leaf dry weight had the greatest and root dry weight had the smallest decrease under N deficiency. Nitrogen-deficit stress mainly increased leaf reflectance at 555 (R555) and 715 nm (R715) and caused a red-edge shift to a shorter wavelength. Leaf N and Chl concentrations were linearly correlated with not only the reflectance ratios of R405/R715 (r2 = 0.68***) and R1075/R735 (r2 = 0.64***), respectively, but also the first derivatives of the reflectance (dR/dλ) in red edge centered 730 or 740 nm (r2 = 0.73–0.82***). These specific reflectance ratios or dR/dλ may be used for rapid and non-destructive estimation of sorghum leaf Chl and plant N status:

Duli Zhao, K. Raja Reddy, Vijaya Gopal Kakani, V.R. Reddy,2005. Nitrogen deficiency effects on plant growth, leaf photosynthesis, and hyperspectral reflectance properties of sorghum. European Journal of Agronomy, Volume 22, Issue 4, Pages 391–403..

Functional relationships between leaf nitrogen (N) and crop growth processes are not available in many vegetables including castor bean plant that is considered as a potential bioenergy crop. An outdoor pot culture experiment was conducted to determine N deficiency effects on castor bean plant growth and physiology. Castor bean, cv. ‘Hale,’ was seeded in 12-L pots filled with fine sand and irrigated with full-strength Hoagland’s nutrient solution from emergence. After 34 days of sowing (DAS), the treatments imposed were full-strength Hoagland’s nutrient solution (control, 100N), reduced N to 20% of the control (20N) and no N (0N) until final harvest, 66 DAS. Growth (plant height, leaf development, and leaf area), photosynthesis and leaf N were measured twice weekly and plant components biomass was measured, 66 DAS. Maximum growth and developmental rates were achieved at 7.0 g N kg−1, much higher than many other crops grown under similar nutrient conditions. Even though all growth rates declined with lower leaf N, leaf area expansion was more sensitive to leaf N followed by rates of stem elongation, node addition, and photosynthesis. Critical leaf N levels (90% of maximum) varied for various processes; 55.3 g N kg−1 for stem elongation, 63 g N kg−1 for node addition, 65.4 g N kg−1 for leaf area expansion, and 60.3 g N kg−1 for photosynthesis. Among the plant components, leaf dry weight had the greatest decrease while root/shoot ratio increased under N deficiency. The functional algorithms and critical leaf N levels for various growth processes will be useful for modeling, leaf N assessment and manage castor bean crop the in the field:

  1. Raja Reddy, Satyasai K. Matcha,2010. Quantifying nitrogen effects on castor bean (Ricinus communis L.) development, growth, and photosynthesis. Industrial Crops and Products, Volume 31, Issue 1, Pages 185–191.

The effects of nitrogen availability on growth and photosynthesis were followed in plants of sunflower (Helianthus annuus L., var. CATISSOL-01) grown in the greenhouse under natural photoperiod. The sunflower plants were grown in vermiculite under two contrasting nitrogen supply, with nitrogen supplied as ammonium nitrate. Higher nitrogen concentration resulted in higher shoot dry matter production per plant, and the effect was apparent from 29 days after sowing (DAS). The difference in dry matter production was mainly attributed to the effect of nitrogen on leaf production and individual leaf dry matter. The specific leaf weight (SLW) was not affected by the nitrogen supply. High nitrogen nutrition remarkably improved the photosynthetic CO2 assimilation (A) of the target leaves. However, irrespective of nitrogen supply, the decline in photosynthetic CO2 uptake occurred before the end of leaf growth. Although nitrogen did not change significantly stomatal conductance (gs), high-N grown plants had lower intercellular CO2 concentration (Ci) when compared with low-N grown plants. Transpiration rate (E) was increased in high-N mature plants only at the beginning of leaf growth. However, this not resulted in lower intrinsic water use efficiency (WUE):

Inês Cechin, Terezinha de Fátima Fumis, 2004. Effect of nitrogen supply on growth and photosynthesis of sunflower plants grown in the greenhouse. Plant Science. Volume 166, Issue 5, Pages 1379–1385.

Magnesium is required in significant amounts as it is needed everywhere inside and outside plant cells. The reason plants are green is because of magnesium; this metal is at the centre of every chlorophyll molecule, the green pigment in plants. Without the magnesium, the chlorophyll molecule falls apart, and light energy is not captured in photosynthesis. Thus, plants cannot make their food and grow.

Magnesium also is involved where ever phosphorus is being used to transfer cellular energy; Mg stabilizes high-energy phosphates wherever they are being carried by molecules such as adenosine triphosphate (ATP), or guanosine triphosphate GTP.

In the entire range of iron supply used, low iron levels depressed the chlorophyll content in pea leaves, the depression being marked and statistically significant at 15, 30 and 45 days growth:

Plant and Soil, 1978. 49, 343-353.

Magnesium Sulphate

Magnesium is required in significant amounts as it is needed everywhere inside and outside plant cells. The reason plants are green is because of magnesium; this metal is at the centre of every chlorophyll molecule, the green pigment in plants. Without the magnesium, the chlorophyll molecule falls apart, and light energy is not captured in photosynthesis. Thus plants cannot make their food and grow.

Magnesium also is involved where ever phosphorus is being used to transfer cellular energy; Mg stabilizes high-energy phosphates where ever they are being carried by molecules such as adenosine triphosphate (ATP), or guanosine triphosphate GTP.

The Role of Magnesium, Pyrophosphate, and Their Complexes as Substrates and Activators of the Vacuolar H+-Pumping Inorganic Pyrophosphatase (Studies Using Ligand Protection from Covalent  Inhibitors) Plant Physiology, 199. 111(1) 195-202

In soilless culture systems, recycling the nutrient solution causes an accumulation of sulphate ions, which can generate nutrient imbalances affecting crop yield. This study determined the effects of four sulphate concentrations in the nutrient solution on growth, foliar mineral composition, physiology and yield of greenhouse tomatoes. Ten days after transplanting, young tomato plants (Lycopersicon esculentum Mill, cultivar ‘Trust’) grown in rock wool were subjected to four sulphate concentrations (S0 = 0, S1 = 5.2 (control), S2 = 10.4 and S4 = 20.8 mmol L−1) in the nutrient solution. The S0 reduced plant dry weight, photosynthetic rate, chlorophyll content, and the total number of fruits. The S0 treatment was associated with high concentrations of P, Ca and Mg, but low levels of S in the leaves. The largest concentration of sulphates in the nutrient solution did not reduce shoot dry weight, photosynthesis, crop yield and fruit quality, although it decreased Mg, Ca and P content in the leaves. Consequently, tomato plants appeared prone to sulphate deficiency but tolerated sulphate concentrations up to 20.8 mmol l−1 in the nutrient solution with no apparent detrimental effects on yield and fruit quality over a short cropping period:


Javier Lopez, Nicolas Tremblay, Wim Voogt, Sylvain Dubé, André Gosselin,1996. Effects of varying sulfate concentrations on growth, physiology and yield of the greenhouse tomato. Scientia horticulture, Volume 67, Issues 3–4, pages 207–217.

Studies of S deficiency, a problem in certain crops in Africa, have yielded inconclusive and incomplete information. There is little information on the S status of soil in the forest-savanna zone.

Field trials were carried out with maize (Zea mays L.) at six locations in the forest and savanna areas of western Nigeria. Sulfur was applied at 0, 7.5, 15.0, 30.0, and 60.0 kg S/ha. Significant yield increases were observed with rates of S application from 7.5 to 30 kg S/ha. The response was more distinctly evident in the savanna than in the forest zone. The silking percentage was enhanced and grain quality improved with S application. No significant residual effect of the applied S was observed in the savanna zone, which was probably due to heavy leaching of the applied S. On these soils S response was observed where the amount of extractable S, extracted with either KH2PO4, Ca(H2PO4)2, or NH4C2H3O2 was below 4 ppm S. There was no response to S when extractable S levels were equal to or greater than 8.5, 10.0, and 12.0 ppm when soils were extracted with Ca(H2PO4)2, NH4C2H30, and KH2PO4, respectively. The critical S level in the ear leaf was estimated at 0.14% S. Although there was a strong correlation between % N and % S in the ear leaf, the N:S ratio was not related to critical S levels in plants:

  1. T. Kang and O. A. Osiname,1975. Sulfur response of maize in western Nigeria. Agronomy Journal, vol. 68 no. 2, p. 333-336


Potassium Sulphate

A field experiment was conducted at Central Cotton Research Institute, Multan, Pakistan to study the effects of potassium nutrition on leaf area index in cotton (Gossypium hirsutum L.) The treatments consisted of four cotton cultivars (CIM-448, CIM-1100, Karishma, S-12), four potassium-rates (0, 62.5, 125.0, 250.0 kg K ha-1) and two sources of potassium fertilizer [potassium chloride (KCl), potassium sulphate (K2SO4)]. During the early part of the season, leaf area index progressed slowly and required 60 days to reach at 1.5 and then it reached at 4.02 within next 30 days. After that, it declined gradually to minimums of 0.62 at maturity. Cultivar CIM-1100 maintained the highest leaf area index compared to other cultivars. Leaf area index increased with concurrent increase in potassium levels. The regression analysis indicated a highly significant relationship (r = 0.94**) between potassium levels and leaf area index. The addition of potassium fertilizer in the form of potassium sulfate showed an edge over potassium chloride. There were highly significant (p<0.01) relationships between leaf area index and number of total fruit, number of bolls per plant, plant height, total dry weights and leaf dry weights:


Potassium has been shown to affect both flower number and fruit formation, giving the greatest number of flowers until the 43rd day after cotyledon expansion. (Effect of potassium nutrition on tomato plant growth and fruit development.

Plant and Soil. 1975. 42, 395-412.

In the cytoplasm, K has a major role in providing the correct ionic environment for metabolic processes. The ionic requirements of protein synthesis seem to be particularly important in determining the composition of the cytoplasm. Potassium salts in the vacuole are involved in the generation of turgor.

In another study, cotton plants receiving K fertilization yielded more than plants that did not receive K. The cotton yield increased an average of 9% during these two yrs. This larger ball mass was due to more seed per boll, greater seed weight, and more lint/seed. Thus, K addition showed an overall increase in yield of cotton.

Relationships between Insufficient Potassium and Crop Maturity in Cotton – Cotton. Agronomy Journal. (2003). 95, 1323-1329.

Traynor, J. “Making ‘K’ Pay in your Vinyard: Dripping Potassium Carbonate into the System.” BeeSource. 2002.

The influence of the level of potassium supply on the incorporation of labelled nitrogen (15N) was studied in young tobacco plants. During a 4-h period the plants, which were well supplied with potassium, absorbed a greater amount of labelled nitrogen and utilisation of this nitrogen for the synthesis of organic nitrogen compounds occurred more rapidly. The results clearly indicate that in the plants with lower K supply soluble amino acids accumulated whereas in the “+K” plants the incorporation of amino nitrogen into the protein fraction was accelerated:

Klaus Koch, Konrad Mengel, May 1974. The influence of the level of potassium supply to young tobacco plants (Nicotiana tabacum L.) on short-term uptake and utilization of nitrate nitrogen (15N). Journal of the Science of Food and Agriculture, Volume 25, Issue 5, pages 465–471.

Monopotassium Phosphate

Bare-root, vegetatively propagated plants (average 15-cm leaf spread) of a white-flowered Phalaenopsis Taisuco Kochdian clone were imported in late May and planted either in a mix consisting of three parts medium-grade Douglas fir bark and one part each of perlite and coarse Canadian sphagnum peat (by volume) or in Chilean sphagnum moss.All plants were given 200 mg L each of nitrogen and phosphorus, 100 mg L calcium, and 50 mg L magnesium at each irrigation with 0, 50, 100, 200, 300, 400, or 500 mg L potassium (K). After eight months, K concentration did not alter the number of new leaves on plants in either medium. In moss, plants had longer and wider top leaves increasingly as K concentration increased. The lower leaves on plants in the bark mix lacking or receiving 50 mg L K showed symptoms of yellowing, irregular purple spots, and necrosis after spiking and flowering, respectively. Symptoms became more severe during flower stem development and flowering. All of the plants lacking K were dead by the end of flowering. K at 50 mg L greatly reduced and 100 mg L completely alleviated the symptoms of K deficiency at the time of flowering. However, by the end of flowering, plants receiving 50 or 100 mg L K had yellowing on one or two lower leaves. Plants grown in moss and lacking K showed limited signs of K deficiency. All plants in the bark mix bloomed, whereas none in sphagnum moss receiving 0 mg L K produced flowers. For both media, as K concentration increased, flower count and diameter increased. Flower stems on plants in either medium became longer and thicker with increasing K concentration. To obtain top-quality Phalaenopsis with the greatest leaf length, highest flower count, largest flowers, and most interminable inflorescences, it is recommended that 300 mg L K be applied under high N and high P conditions regardless of the medium:

Yin-Tung Wang, 2007. Potassium Nutrition Affects Phalaenopsis Growth and Flowering. Hortscience, 42(7), pp. 1563–1567.

In experiments, the efficiency of fruit setting, i.e. the percentage of the total number of flowers which produced fruit, fell significantly in conditions of potassium deficiency and was less than 66 percent when the nutrient feed contained concentrations less than 2.3 me K+/1. Since both the final flower number and fruit setting efficiency were reduced under these conditions, the number of fruit produced per plant was also lower at the lower potassium treatments. The total yield of fruit per plant reached a maximum with the 5.03 and 10.23 me K+/1 treatments.  Maximum fruit yield without the production of excessive foliage was associated with 5.2 i 0.8 g K+/100 g dry weight in the whole leaf (3.8 ± 0.6 and 8.1 =h 1.1 in the laminae and petioles, respectively):

  1. T. Besfordand G. A. Maw, 1975. Effect of Potassium Nutrition on Tomato Plant Growth and Fruit” in Plant and Soil, 42, pp 395-412

“Summer squash” (Cucurbita maxima var. zapallito (Carr.) Millán) is a monoecious species and the reproductive stage starts with female flowering. A male to female flower ratio lower than 10:1 results in greater fruit setting and yield. This relation is controlled by environmental factors, growth hormones, and nutrients. The aim of this study was to evaluate the effect of the N: K ratio of sex expression, fruit setting, earliness and yield on the summer squash. Before emergence 50 kg P ha -1 was applied, after that N and K were used to get the following relations: 50N:0K, 50N:50K, 50N:100K. The number of flowers was greater for the relations 50N:50K and 50N:100K than for 50N:0K. The increment in the K fertilization did not affect the number of male flowers but decreased the male to female flower ratio due to higher female flower production. The number of fruit set was lower at 50N:0K, without significant differences between 50N:50K and 50N:100K. The highest early yield was obtained with 50N:50K and 50N:100K, on 50N:0K. The highest marketable yield was obtained with 50N:100K because of a greater commercial fruit number since there was no significant fruit weight difference with fertilization:

De Grazia, Javier; Tittonell, Pablo; Perniola, Omar Salvador; Caruso, Ariel & Chiesa, Angel, 2003. “Summer Squash (Cucurbita maxima var. zapallito (Carr.) Millán) Earliness and Yield as Affected by the Nitrogen: Potassium Ratio”. Agricultura Tecnica, 63(4), pp 428-435

Eight cultivars  of gladiolus namely Deciso, Hong Kong, Jessica, Jester  Ruffled,Madonna, Peters Pears, Rose Supreme and White Friendship were used to study the influence of potassium levels (0, 100 and 200kg K ha-1). All growth parameters except plants corm-1 studied during the experiment were significantly affected by the two experimental years. Plants emergence (Sprouting), spike emergence, first floret and full spike opening were earlier in the first year. A number of plants corm-1 was more in the first year whereas plant height was higher in the second year (2004-05). Potassium levels significantly affected days to spike emergence and first florets opening. Spike appearance was earlier at 100kg ha-1 and first floret opening was delayed with an increase in potassium levels. Cultivars irrespective of years and potassium levels were significantly different in pre flowering growth characteristics. Similarly years X cultivars interaction resulted in significant differences in pre flowering growth characteristics. Cultivars  X potassium interaction significantly influenced spike emergence and days to first florets opening. Days to peak emergence were significantly affected by an interaction among years, phosphorus levels, and cultivars. Rose Supreme andJessica and potassium@100kg are recommended for commercial cultivation of gladiolus in Peshawar, Pakistan:

For the purpose of dissecting the mechanism of root growth in response to potassium (K) deficiency in cotton (Gossypium hirsutum L.), young seedlings of NuCOTN99B grown in half-strength modified Hoagland’s solution with low K nutrient (0.05 mmol L−1) were investigated for the root configuration, content of endogenous free indole acetic acid (IAA), and amount of ethylene released from the roots 4 d after treatment. Compared with the treatment with moderate K nutrient (0.50 mmol L−1, control), the K deficient treatment significantly inhibited root length and the formation of lateral roots. The reduced lateral roots mainly resulted from the shortened branched root zone, and there was no change in the lateral root density. Under K deficient condition, the greatest reductions in root length, total root surface area, and root volume occurred in fine roots (0.05 mm ≤ diameter < 0.20 mm), followed by the coarse roots (diameter [.tau] 0.45 mm) and the middle roots (0.25 mm ≤ diameter < 0.45 mm). The fine roots were more important in nutrient uptake than the middle and the coarse roots. Thus, the K starving damage was greater in cotton seedlings than the growth inhibition of roots. When the cotton seedlings exposed to K deficient media for 4 d and 10 d, the total root length and the total root surface area were 35.7–38.0% and 47.7–50.6% of the values of the control plants; whereas the K accumulation was approximately 25% and 16% of the control values, respectively. As expected, the endogenous free IAA content in the roots grown in K-deficient media reduced by 50%, whereas the amount of ethylene released from roots increased by nearly 6-fold, which partially explained the inhibition of lateral root formation and root elongation by K deficiency:

Zhi-Yong ZHANG, Qing-Lian WANG, Zhao-Hu LI, Liu-Sheng DUAN, Xiao-Li TIAN, 2009. Effects of Potassium Deficiency on Root Growth of Cotton Seedlings and Its Physiological Mechanisms. Acta Agronomica Sinica, Volume 35, Issue 4, Pages 718–723.

Phosphorus plays a vital role in virtually every plant process that involves energy transfer.  High-energy phosphate, held as a part of the chemical structures of adenosine diphosphate (ADP) and adenosine triphosphate (ATP), is the source of energy that drives the huge number of chemical reactions within the plant. (1999). Better Crops, 83(1).

Without phosphorus, there is a decrease in the number of flowers. Cytokinins which are crucial growth hormones are also implicated in this pathway, and the amount of cytokinin activity decreases with a decrease in phosphorus values. “When P is limiting, the most striking effects are a reduction in leaf expansion and leaf surface area, as well as the number of leaves. Shoot growth is more affected than root growth, which leads to a decrease in the shoot-root dry weight ratio. Nonetheless, root growth is also reduced by P deficiency, leading to less root mass to reach water and nutrients.”

Better Crops.  1999.  83(1)


Emerald Harvest Grow supplies plants with precise nutrient formulations that deliver the right amount of macro and micronutrients throughout the crop cycle. The formulation is hand mixed to ensure quality and help maximize the genetic potential of high-yield crops.

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