Atom8, SM-10 Soil and Bio-Fertiliser Tests on Potato Seed and Seedling Production
Introduction
There was an opportunity to improve Potato Seed Productions’ greenhouses and seedlings, mainly lettuce, quality, yield and cost management just outside Lydenburg. Potatoes are one of most important crops in the world alongside maize, wheat, and rice. As such the seed industry within South Africa is extremely important and regulated, yet as with most of the farming industry, fertiliser costs go up and quality seems to gradually lower, with the rising costs of chemical fertilisers, it’s effect on soil health and the challenges surrounding effective organic fertilisers and its place within the agricultural sector as a whole we we’re able to start trials within an important farm and it’s facilities towards the larger industry.
Methodology
- Medium samples and quality were taken.
- Sterilization of growing media is conducted.
- A clear nutrient plan for growth was set forth.
- Sap samples were taken procedurally for any necessary adjustments.
- Lettuce seedlings and Potato seedlings were monitored in growth and quality.
- Lettuce received a growing mixture of primarily 2:3:5 and 3:1:6 at 500ml/200L. An EC of 0,6 to 0,8.
- Potato seedlings from In Vitro labs received 2:3:5 at a dose of 1l/100L. An effective EC dosage of 1,6. After which a foliar formulation was sprayed weekly at 500ml/100L, an EC of 1.2 and could be doubled to 1L/100L for an EC of 3.2 without any leaf stress or damage.
Figure 1: Location of Potato Seed Production (PSP)
Potato Production Soils
Most soils in the Mpumalanga, Lydenburg area are classified as sand, varying from coarse sands with low clay (<4%) and silt (<0.05%) content to soils with higher clay (>8%), silt (>5%) and fine sand (>16%) content. Coarse soils have lower water-holding capacity and may require more frequent irrigation than finer textured soils.
Variation in soil texture may affect fertiliser requirements but soil testing is used to ascertain the nutrient status of the soil before planting. Test your plants to evaluate the effectiveness of the fertiliser program on the growing crop.
Potatoes generally tolerate low soil pH but if pHw (in water) is less than 5.5 soil and plant aluminium levels may increase and limit yield. Soil pH should be adjusted with limes such as dolomite or lime sand. Soil pH can influence the level of +potato scab diseases so if amendments are needed, manage them to prevent increase in scab risk. Only apply enough lime to increase soil pHw to 6.0. Soil pH measured in CaCl2 rather than water is on average 0.8 of a unit lower than the pHw values.
Soil Selection
Potatoes can be produced on a wide range of soils but avoid waterlogged, compacted, saline or rocky/gravelly soils. Rocky or gravelly soils are difficult to till and cropping these soils may result in bruising of tubers during harvest. Lydenburg has large areas of well drained soils with low EC (1:5 H2O<13mS/m or 0.13dS/m) and no gravel so selecting suitable soils should not be a problem.
Herbicide residues from the previous crop can limit potato yield and quality. Follow label directions to minimize the impact of herbicide residues applied to other crops on the potato crop.
Plant Health and Integrated Pest Management
Potato seed crops are at high risk of invasion by aphid virus and different types of blight such as Alternaria alternata, Alternaria solani and Phytophthora infestans in summer. The greenhouses where the generation 0 seed are produced tend to get Botrytis as well. SM10 proved to reduce all blight infections significantly as well as secondary infections of Botrytis. SM10 has anti-bacterial, anti-fungal and anti-viral qualities that keep plants free of pests and diseases. This works extremely well in conjunction with current pesticide and fungicides spraying programs for better IPM structures.
Figure 3: Control spray program  |
Figure 2: Atom-8 added to spray program  |
Land Preparation
A properly prepared seed bed is required. Sandy soils are easier to cultivate than heavier soils and may require less cultivation. Cultivation also provides opportunity to control weeds prior to planting by using irrigation and shallow cultivation to stimulate germination and then cultivation to kill the weeds when small. A proper soil analysis must be taken to enhance soil with the right SM10 formulation for the right nutrient balance.
For the hydroponic trial the seedlings were planted with 2:3:5 super mix. This ensures effective root formation and growth first whilst still supplying nutrients for the vegetative cycle. After 4 weeks a 6:1:6 or 3:1:6 mix can be applied depending on nutrient requirements within soil or media planted. Whether soil applied or hydroponically grown, the foliar mix ensured a weekly additive to keep nutrient levels high without causing phytotoxicity. Within the hydroponic application using Atom-8 in supplemental manner as a drench and weekly nutrient spray a maximum of 17% increase on yield had been observed in some instances as well as a 50% lower cost to spraying foliar nutrients.
Post-planting and Fertilising Plan
Post-plant SM-10 was designed to apply N-P-K if pre-plant soil N and K are low, depending on soil type, with higher rates of Potassium for more sandy soils. Depending on nutrient samples spray the weekly additive foliar SM-10.
On processing potatoes, apply K as sulphide or nitrate because muriate of potash has been shown to lower the specific gravity (dry matter %) of tubers compared with other forms of potassium fertiliser.
Seed crops often require less N than non-seed crops, as they may grow for a shorter period, especially if the plan is to maximize the yield of small round seed. Tuber size in some varieties is very sensitive to applied N and high rates may result in low yields of small round seed and high yields of oversize tubers. Excess N may also increase tuber disorders such as hollow heart in sensitive varieties.
Monitoring Fertiliser Program with Plant Testing
The effectiveness of the fertiliser program was monitored by using plant foliar sap samples for tissue testing. This ensures understanding which nutrients are translocating and available for use within the younger new growth leaves and older leaves instead of only checking dry matter content. This method was developed in the Netherlands to good results.
Quality and Yield Improvements
After harvesting the seeds, an increase in tuber size was observed as shown in the photo below. In the left box we can observe the quantity and quality of the yield. The box on the right side was conducted as the control without any SM-10 applications. Within the left box the tuber size leaned more to larger than smaller and if replicated within open fields could promote higher ton/ha yields.
Figure 4: Atom-8 left and Control right
Lettuce and Seedling Production
Trials were done on lettuce seedlings, the growth of seedlings were constant and healthy, these lettuces are produced by strict GAP standards. The seedlings grew exceptionally well and reduced input costs of fetiliser by 28%. Butternut, tomato, and pumpkin seedlings were also grown with great quality.
Along with growing seedlings trials to grow and protect in cold and frost conditions were conducted. Results were exemplary.
Conclusion
In this experiment we found conclusive evidence that our new SM10 bio-fertilisers has an excellent performance. By improving soil health, nutrient availability, uptake and reducing salt levels contributed to this performance. Costs of chemical fertilizer and soil health is becoming an increasingly faster growing problem. It’s our belief that bio-fertilisers will play a much more important role in agriculture. We also have other tests done or busy with on wheat, tomatoes, strawberries, cannabis etc. with similar results.
Acknowledgement
- Jakkie Mellet MD of Potato Seed Production
- Werner Schutte Manager of Potato Seed Production
- Personal of Potato Seed Production
- Project monitoring team
- Contact details: 084 802 6303
- David Wei of HENAN CHUFANG AGRICULTURE IMPORT&EXPORT CO., LTD