| Manure |
USD 15–28 per ton |
Long-term manure application improves crop yield (most of the crops and vegetables). |
Improves soil organic matter, soil organic carbon, water retention, soil microbial biomass. |
Long-term application of manure has the potential to cause water contamination and phosphorus leaching. |
[38,76] |
| Greensand |
USD 33 per 50 lbs |
Availability is limited to a few garden studies found on independent websites. It is primarily used as a soil conditioner for flower beds, gardens, and lawns. |
It improves water retention and microbial growth, promotes plant root growth by loosening clay soil, and helps bind sandy soil. |
None to report due to limited studies. |
[66,99] |
| Rock Phosphate |
USD 35 per 50 lbs |
It improves crop yield but varies based on soil types and nutrient profiles. |
Improve carbon sequestration and accumulation by increasing soil exchangeable calcium and magnesium cations. |
Overapplication of rock phosphate can lead to water pollution and accumulation of cadmium, which is harmful to the environment. |
[100,101] |
| Lime |
USD 12 per 50 lbs |
Liming can significantly enhance the effectiveness of fertilizers by reducing soil acidity, potentially leading to yield increases of 20% or more in crops such as corn and soybean. For alfalfa, the yield improvement can be 35% or greater. |
Liming increases soil pH, which stimulates microbial activity and enhances soil organic matter. This process can significantly impact the dynamics of carbon pools in the soil. By lowering soil acidity, liming not only improves crop yield but also enhances the soil’s water retention capacity. |
Over-liming can add excess calcium, which can lead to deficiencies in nutrients like magnesium and potassium. |
[102,103,104,105,106] |
| Bone Meal |
USD 40 per 50 lbs |
Improves protein content in spring and winter wheat; crude fat yield in rapeseed; and yield in sweet corn and perennial grass. |
Increases soil pH and improves total and mineral nitrogen, total phosphorus, and dissolved organic carbon. |
Reduces the bioavailability of lead, zinc, and cadmium in polluted soils. |
[107,108,109,110,111] |
| Blood Meal |
USD 60–100 per 50 lbs |
Reduce chemical fertilizer dependency for cereals, oilseed rape, and sweet corn; contradictory, one study also reported a potential inhibitory effect on maize establishment. |
Increases soil organic matter and fertility; improves the availability of iron and micronutrients for plant growth and development. |
Potential risk of water contamination and heavy metal pollution. |
[60,61] |
| Fish Emulsion |
USD 20 per gallon |
Improves crop yield in tomato and rice. |
Positive impact on disease suppression and plant growth. |
Fish can accumulate heavy metals in their marine environment, which can then be transferred to soil and plants; high nitrogen content can lead to nutrient runoff if overapplied. |
[112,113,114,115] |
| Seaweed Extracts |
USD 25 per quart |
Improves yield in tomato. |
Improving soil nitrogen, soil fertility, and microbial activity enhances plant growth and yield; additionally, it improves water retention and nutrient uptake and provides plants with resistance to both abiotic and biotic stress environments. |
Unsustainable harvesting of seaweed can disrupt marine ecosystems and biodiversity; the production and processing of seaweed extract may contribute to greenhouse gas emissions, depending on the method; the heavy metals accumulated by seaweed may get transferred to the soil. |
[116,117,118,119,120] |
| Alfalfa Meal |
USD 30–60 per 50 lbs |
While there is a lack of specific scientific reports, several independent websites have dmonstrated that alfalfa meal contributes to an increase in organic matter, trace minerals, and NPK levels. Additionally, when used as mulch, alfalfa can help in weed reduction. It is also noteworthy that alfalfa contains triacontanol, a natural plant growth stimulator, which has been reported to enhance yield in vegetable crops. |
Alfalfa meal enhances soil microbial biomass and nitrogen levels, decomposes quickly, and positively impacts soil tilth and water retention. |
Producing alfalfa meal requires careful consideration of water and land usage, particularly in environments with water scarcity. Additionally, if the alfalfa is treated with pesticides, there is a potential risk of transferring residues to both the soil and the plants. |
[121,122] |
| Biosolids |
USD 50–125 per dry ton |
Biosolids improve crop yield in winter wheat and corn |
Improves soil organic carbon and potentially mineralizable nitrogen, soil organic matter, water retention capacity, and water infiltration rate. |
Biosolids can contain heavy metals, pathogens, and residual pharmaceuticals, posing a risk to water quality and human health. |
[123,124,125,126,127,128] |
