Why have a seminar day on the topic of soil supplements?
Dr. Shiri Freilich, A.R.O. Institute of Plant Sciences, Newe Ya‘arOrganic supplements derived from various sources are used on sustainable farms to improve soil health and fertility. Employment of such supplements is directed toward supporting soil fertility from the standpoints of improved soil physical characteristics and encouragement of optimal interactions within the soil for providing plants with nutrients and sustaining plant health. Such support is for beneficial organisms that, for example, facilitate the supply and uptake of nutrients by plants or, on the other hand, such soil treatments can act directly by suppressing undesirable interactions. Today, even with the various potential efficiencies, the main use of soil supplements is limited and focused on aspects of supplying nutrition and improving overall soil structure. The primary goal of this seminar day is to review leading practices in the field while addressing the latest challenges and opportunities.
Challenges in adopting sustainable-agriculture approaches in Israel: Developing a continuous soil cover
Dr. Gil Eshel, Laboratory for Soil Health and Sustainable Agriculture, Station for the Study of Erosion, Soil Maintenance and Drainage Branch, Ministry of Agriculture & Rural Development
The development of intensive agriculture and monoculture has been concomitant with exacerbated soil degradation, including accelerated soil erosion, loss of organic matter, salinzation and sodification, destruction of soil structure, and interference with agronomical balances including domination by weeds that are difficult to eradicate and outbreak of soil diseases and pests. Research in Israel and abroad has shown that changes in agricultural management by conservation of continuous soil coverage by plants are advantageous for slowing significantly soil erosion, improving soil structure, reduction of water loss due to evaporation from the soil surface, improved porosity of water in the soil, moderation of soil temperature fluctuations, increased biological diversity in the soil and overall increased resistance to outbreaks of diseases and pests, and rotation of nutrient elements among crops. All these have led to the development of conservation agriculture over time for health and functioning of the soil. In my presentation I will show the results of our research here in Israel and observations by growers who have adopted such principles, and will talk about the challenges before us in growing field crops for continuous plant cover resulting from the increased demand for plant biomass as animal feed.
Road map for the rehabilitation of the mesofauna soil food web
Dr. Eric Palevsky, A.R.O. Newe Ya‘ar Research Center
Species of soil predatory mites (SPMs) feed on a diverse diet making them excellent candidates for conservation biological control programs. Free living nematodes (FLNs) are commonly found in soils and serve as prey for many SPMs. Some species must feed on FLN to lay eggs and others will need them to complete immature development. Surprisingly, as far as we know, FLNs have never been used as alternative prey to enhance the efficacy of SPM for conservation biological control. Here we present results of two case studies where we provisioned the FLN Rhabditella axei as complementary prey for predatory mites. In the first study, we used the SPM Macrocheles embersoni for housefly control and in the second, the SPM Stratiolaelaps scimitus for the control of the root knot nematode Meloidogyne incognita. In both systems, the treatment including complementing the diet of predatory mites with FLNs resulted in higher predator abundance and better biological control, as compared with the negative treatment and the treatment of release of predators without FLNs. Future research will focus on manipulations of soil management and evaluating soil amendments to enhance the abundance and diversity of FLNs and predatory mites in cropping systems for enhanced conservation and biological control of soil pests.
Application of manures from various sources as a substitute for complex fertilizer: availability of phosphorus, nitrogen, and trace elements
Dr. Pinhas Fein, Institute of Soils, Water, and Environment, A.R.O. Volcani Center
Estimating the desirability of manure application as a substitue for mineral fertilizers on field crops is based on the differential between costs of mineral fertilizers versus costs of manure application in the field. We limited ourselves to comparing fertilizers with manures and among manures themselves, on the basis of loading application of any amount in cubic meters per unit area. Comparison is made here on the basis of changing loading applications but with a fixed amount of nitrogen of 500 kilograms of overall nitrogen per hectare. This comparison is based on laboratory and field investigations. As mineral fertilizer is supposed to contain amounts of loss and absorption of the supplemental fertilization, so do manure loads. There is a notable difference in manure dosage according to its overall contents of nutritional elements (and it does not matter which element is chosen) and its dosage according to contents (estimated) of components available to the plants of these elements. The relation between the available component to the overall differs with each type of manure and each nutrient element, and is highly affected also by soil and crop characteristics, crop growing regime, and conditions of the crop growing season. There is a need to take into account the overall manure components (including organic carbon) as a contribution to plant nutrition and soil health in the long term, but the goal here is to determine the economics of the application of common manures as a substitute for fertilizer, to be given prior to the upcoming growing season (in dual croppage). The quantities are 400 kg elemental N/ha (11 units) and 350 kg elemental K/ha (43 units), The contribution from the benefit of manure application was calculated according to availability of nitrogen in the manure (which was estimated in laboratory and field experiments) and according to the total actually absorbed of phosphorus and potassium in maize and wheat in the year following the application minus its costs, which are of the manure itself and its transport. The contribution of application of digested sludge (for example, from the city of Haifa) is 2000 New Israeli Sheqels (NIS)/ha, from pasteurized fattened cattle 300 NIS/ha, and from composted urban garbage 200 NIS/ha. Application of composted sludge and composted cattle manure will realize a loss of approximately 5000 and 4850 NIS/ha, respectively. In calculating according to overall composition of nutrient elements, the benefit, apparently, from each one of the manures is much greater. The advantage of digested sludge in field crops (up to the prohibition of its use) results from its being paid for entirely by the urban sector and the available amounts of nitrogen and phosphorus (but not potassium) in which it is highest. Sludge from Shafdan, a sewage treatment plant located in the city of Rishon LeZiyyon, which is of similar quality but is pasteurized, is sold to growers at 5–10 NIS/cubic meter, which reduces the benefit by 1500 to 2000 NIS/ha, but is still reasonable. It is notable that (a) the additional benefits of manures are not included in the calculation, such as the leftovers for successive years of nitrogen (small), potassium (an input which is usually a small part of the total absorbed in the field year), and phosphorus (availability of which fades quickly), as well as supply, sometimes critical, of trace elements and positive effect on soil structure; (b) as the marketing of the produce of field crops is local, application of sludge is exempt from limitations of Global G.A.P.; (c) for those crops having significant requirements of potassium, the application will be in accordance with the proportion of potassium and not according to the nitrogen, which would increase the relative value of fowl manure and cattle manure, of which the content and availability is especially high.
Suppression of soil-borne diseases using compost
Dr. Anat Yogev, Project Leader of Innovation, Plant Substrates
In this research we developed composts from plant wastes and cattle manure that efficiently suppressed four species of Fusarium and the bacterium Clavibacter michiganensis ssp. michiganensis in artificial media. Fusarium wilt suppression in melon was also observed in organic commercial production fields in which compost was applied each year. The observations show the great potential that composts have to suppress plant diseases, a potential which is not yet put to good use on a large scale. The mechanism of action of the compost is connected with the microorganisms that it contains, that affect the pathogen both directly (suppressing the pathogen population) and inducing resistance of the plant to the pathogen. Supplementing the growing medium with compost, like solarization treatment, has long-term advantages that cannot be obtained by chemical treatments. The suppression that is obtained affects not only the pathogens occurring in the medium but also on those that can contaminate it over the course of the crop season and in subsequent croppings. Compost production from plant remains is a solution to recycling plant waste whilst preventing the spread of pathogens and weed seeds to the environment.
Soil Fertility from an Organic-Agriculture Point-of-View
Uri Adler, Extension Agent for Organic Agriculture, the Organic Agriculture Association and Plant Council
Fertile soil is the central component of organic agriculture as well as from the overall point-of-view of organic agriculture. A fertile soil is one the provides nutrients to plants and protects them from damage. Fertile soil holds moisture better while at the same time providing aeration to the root system, as well as being more stable, less liable to erosion. Soil fertility is achieved by crop rotation, green manuring, and cover crops. In Israel, the principle supplement that improves soil fertility is quality, finished compost. In addition, if the soil is not optimally fertile and composting is unable to provide all of the needs of the crop, nutrient supplements such as pasteurized fowl manure, guano, seabird droppings, or liquid fertilizers that are a product of biological breakdown of various wastes can be added. However, improved fertility and improved soil can also be attained with biological supplements that are not fertilizers but instead materials that affect the microbiological composition of the soil, such as beneficial bacteria, compost tea, humic acids, algae, and others. Ultimately, the crop regime is dependent on the situation as regards fertility and the amount of time the soil is treated organically but the result is a stable soil that provides the crop with nutrients and some resistance to soil-borne pathogens.
Controlling Soil Fertility as a Biologically Dynamic Process, Insights from Israel and Abroad
Liron Yisra’eli, Advisor and Extension Agent for Dynamic Organic Agriculture, Ph.D. Student, Tel Aviv University in Cooperation with the A.R.O. Volcani Center
A biodynamic crop regime was recorded in 1924 and established itself as a quality symbol for agricultural produce in 1927 under the brand name Demeter. Its process of development was conducted in parallel by a number of growers and scientists in Germany, the U.S.A., and Australia. The base of this regime places stress on three components of soil health: (1) Optimal tillage for absorption of oxygen and water, (2) use of organic nutrients including controlled-heat compost and a variety of green manures, (3) breeding within-soil interactions using rotations and “contaminating” the soil with biodynamic preparations. The results of long-term agricltural investigations under this regime have shown an increase in microbial activity in the soil and an increase in organic matter. From deployment of this regime, quenching of greenhouse gases, variation in resistance to pests, climate changes, and improved soil structure and root development have also been reported. The epistimology of this regime rests on induction and less so on deductive processes, for which the common modern approach to agricultural research not well-suited. However, as this regime is based on practical experience with growers and researchers, it suggests practical insights to designing sustainable-agriculture systems. Regarding organic supplements: Accumulated experience with this regime stresses the importance of locally occurring nutrient matierals within the regime itself, developing the humic component in the materials, and importance of managing the entire agricultural system, its abiotic, biotic, and interactive conditions.
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