Organic Spray + Biofertilizer: What works better for Sweet Pepper (Study & Results)

Sweet pepper (Capsicum annuum L.) is a valuable vegetable crop from the nightshade family, and this greenhouse study looked at a practical question many growers care about: can organic nutrient sprays and biofertilizer improve the nutrient status of pepper leaves?

The experiment compared three organic nutrient spray levels, 0, 2, and 4 g/L, with three biofertilizer levels, 0, 2, and 4 mL/L. The strongest results came from the highest rates. Organic nutrient spraying at 4 g/L gave leaf nitrogen of 2.643%, phosphorus of 0.5900%, and potassium of 2.0067%. Biofertilizer at 4 mL/L also significantly improved the same nutrients, giving nitrogen of 2.113%, phosphorus of 0.5133%, and potassium of 1.8478% compared with the control.

Sweet pepper is important because it is widely grown, highly consumed, and nutritionally rich. According to the article, every 100 grams of fresh pepper fruit contains about 1.2 g protein, 4.8 g carbohydrates, 2.6 g fiber, 0.8 g fat, 29 mg calcium, 2.6 mg iron, and 61 mg phosphorus. The fruit is also an important source of vitamin C, which supports bone formation, protein metabolism, appetite, and resistance to inflammation. It also contains vitamins B1, B2, and A, which are known antioxidants.

Sweet pepper grows best in a moderate climate that leans warm, with an optimal growth temperature of about 21-27 ºC. The study notes that peppers can grow successfully under unheated protected cultivation in some regions when early varieties are used.

Seeds were sown in plastic trays with one seed per cell, then kept in a shaded area covered with green saran cloth. Seedlings received uniform agricultural care before being transplanted into the greenhouse field. The first nutrient and biofertilizer application was carried out six weeks after planting, and the second was applied 15 days later.

Five homogeneous plants were randomly selected from each experimental unit in all replications. The researchers focused on the percentage of nitrogen, phosphorus, and potassium in the leaves. A dry, ground leaf sample of 0.2 g was digested using sulfuric acid and perchloric acid before nutrient measurement.

The study found that both the organic nutrient spray and the biofertilizer had a significant effect on leaf nutrient content. The most effective single rate of organic nutrient was 4 g/L, while the most effective single biofertilizer rate was 4 mL/L.

The best interaction was also clear. When 4 g/L organic nutrient was combined with 4 mL/L biofertilizer, the leaf nutrient levels reached the highest recorded values for the combined treatment: 2.910% nitrogen, 0.6833% phosphorus, and 2.7967% potassium.

In simple terms, the plants receiving both inputs at the highest tested levels showed much better nutrient concentration in their leaves than plants that received neither input.

The organic nutrient treatment at 4 g/L produced the highest average nitrogen percentage in leaves, reaching 2.643%. The control treatment had the lowest nitrogen percentage at 0.599%. Biofertilizer also had a significant effect: 4 mL/L gave the highest nitrogen percentage of 2.113%, compared with 1.263% in the control.

The organic nutrient treatment at 4 g/L gave the highest phosphorus percentage in leaves at 0.5900%, while the control recorded the lowest value of 0.2900%. Biofertilizer at 4 mL/L also significantly increased phosphorus to 0.5133%, compared with 0.3700% in the control.

The organic nutrient treatment at 4 g/L significantly outperformed the control and gave the highest average potassium percentage in leaves at 2.0067%. The control gave 1.4249%. Biofertilizer at 4 mL/L also recorded the highest potassium percentage at 1.8478%, compared with 1.5797% in the control.

The article explains that organic nutrients can help provide essential elements such as N, P, and K and reduce visible deficiency symptoms. Organic materials may improve the availability of both macronutrients and micronutrients in leaves. Humic acid, according to Mikkelsen (2005), can affect carbon assimilation efficiency, increase cell membrane permeability, and enhance phosphorus absorption. Singer et al. (1998) also noted that humic acid can make nutrients more available and encourage uptake of potassium, phosphorus, and calcium.

Biofertilizer performance is linked to microorganisms that help plants access nutrients. These organisms can fix nitrogen and solubilize phosphorus and potassium. They may also secrete growth regulators, organic acids, and chelating compounds, which can increase nutrient availability around plant roots and improve absorption.

• ✅ Organic nutrient spray at 4 g/L significantly improved nitrogen, phosphorus, and potassium percentages in sweet pepper leaves.
• ✅ Biofertilizer at 4 mL/L also significantly increased N, P, and K compared with the control.
• ✅ The strongest combined treatment was 4 g/L organic nutrient plus 4 mL/L biofertilizer.
• ✅ The experiment used a reliable RCBD factorial design, three replications, GenStat analysis, and LSD testing at the 0.05 level.
• ✅ For growers, the results support using biological and organic inputs as part of a balanced sweet pepper nutrition plan.

The study cited works by Abu Rayan (2010), Al-Rawi and Khalaf Allah (2000), Al-Marjani (2011), Al-Naemi (1999), Hassan (2001), Zidan and Hamad (2016), Othman (2007), Asli and Neumann (2010), Mawgoud et al. (2010), Cresser and Parsons (1979), Denis (1979), Grubben and Mohamed (2004), Magdoff and Weil (2005), Mikkelsen (2005), Page et al. (1982), and Singer (1998). These references covered organic agriculture, agricultural experiment design, pepper production, organic fertilizers, humic substances, plant digestion methods, soil organic matter, and nutrient analysis.