ORGANIC FARMING: VEGETABLE CROPS

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Horace Edwards
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1 ORGANIC FARMING: VEGETABLE CROPS

2 In oganic farming the product is not the mere sum of some productive input it is the interaction of several factors within a system with its equilibrium It is based on an appropriate agronomic system that accounts for the pedoclimatic characteristcs harmonize with the natural processes activates favourable (positive) synergies in this environment. Agronomic practices addressed to the maximum utilization of resources available (biotic and abiotic) The system has an internal equilibrium, to maintain which it is possible and necessary to limit the external intervention

3 Agroecosistem The mainteinance and enhancement of natural equilibrium in the agro-ecosystem is fundamental in organic vegetable production. To reach this goal: Protection from any unbalance (landslip, erosion, water logging, loss of organic matter and loss of fertility) suitable hydraulic soil arrangements, taking care of their maintainance in suitable efficiency in time. Promotion and enhancement of biodiversity, with hedges, group of plants and/or bushes Presence of hedges to protect from polluting sources and from climatic adversity Keyrole is played by carefully planned crop rotations

4 Crop rotations Never have any crop follow itself. Valid principle even in common agronomic practice, but it becomes of primary importance in organic farming. The goals of crop rotation are: protect and increase the soil fertility level preventive control of pest and disease limitation of weeds populations control of the self toxicity of root exudates It is crucial to abandon the concept of farm specialized in vegetable crops need to insert fallow: cropping of nonvegetable crops

5 Criterion for choosing crop rotation In relation to the influence on the agro-ecosystem, any crop can be defined either: exploiting soil fertility, if it leaves the soil in a worse state than before (as wheat) improving soil fertility if it leaves the soil in a better state than before (as leguminous crops) prepararing soil fertility, if it leaves the soil in a good fertility state not because of internal characteristics, but for the crop agronomic techniques to which it has undergone (hoed crops) A good practice should plan an alternance among the categories above mentioned, in such a way to recuperate with inproving plants the impoverishing effects of those crops that deplete soil soil fertility.

6 In horticulture the principle is to alternate A. Plant s with deep roots (tomato) with plants with shallow root system (lettuce) B. Plants grown for roots or tubers (potato, carrot) with those grown for fruits or shoot (pepper, broccoli, lettuce) To protect soil structure C. Plants with very extent root system (cereals) with plant with more modest root system (lettuce)

7 C. Plants with extended above-ground part (eggplant) with plants showing a restricted shoot (lettuce, onion, garlic) D. Plants with accurate and intense soil tillage and crop agronomic practice (tomato, artichokes) with plants less requiring (crogettes, cerals) To contrast weeds

8 F. N-fixing plants (leguminous) with N- requiring plants (potato) G. Bonificating the soil, modifying ph reaction, with plants suitable for healthy soils To save and improve soil chemical fertility H. Plants more vulnerable to a certain pathogen with others that are less sensitive To prevent possible insect pest&disease

9 Rotations with Vegetable Crops Crop rotation is the most effective technique to protect and enhance soil fertility besides preventing uncontrollex explosion of pest&disease + weeds Basic criteria to decide a crop rotation Crop rotation and soil fertility Cultivar with short cropping cycle Rotation and plant health state Rotation and soil phisical characteristics Rotation and weed control Favourable and unfavourable crop rotation A correct planning of the crop rotation will determine all the effect of this practice on all the agroecosystem With the crop rotation it is possible to protect and increase the organic matter content in the soil, and N availability Permit the rational use of water resources, soil fertility, allow inserting fallow crops in the crop rotation, and reduce the possibility of infections from insects and diseases Rotating more crops on a soil is the most effective mean to control and restrict the spreading of pest&diseases Crop rotation exert a beneficial effect on soil structure Rotation is the most importants practice to prevent uncontrolled weed development Every crop can be ascribed to a crop position in the rotation, it is therefore possible to list what are the most adviced crops to precede it

10 The choice of cultivars In an organic farm oriented to vegatable crops, the choice of cultivars, together with an adequate crop rotation and an adequate plant density represents a crucial mean to: prevent problems in agronomic management, reduce inputs (fertilizers, plant protection actions, irrigation) obtain products with high qualitative standards

11 Prefer Cultivar adapted to pedoclimatic conditions and suitable to the market requests Cultivar resistent to main biotic and abiotic adversities of the area of cultivation Cultivar with short cropping cycle Choice of cultivar Reasons Express the highest use efficiency because they benefit from all the natural reasources Reduce all the plant health problems Permit the rational use of water resources, soil fertility, allow inserting fallow crops in the crop rotation, and reduce the possibility of infections from insects and diseases

12 The choice of cultivar Prefer Cultivar adapted to pedoclimatic conditions and suitable to the market requests Cultivar resistent to main biotic and abiotic adversities of the area of cultivation Cultivar with short cropping cycle Reasons Express the highest use efficiency because they benefit from all the natural reasources Reduce all the plant health problems Permit the rational use of water resources, soil fertility, allow inserting fallow crops in the crop rotation, and reduce the possibility of infections from insects and diseases

13 Other critera to follow regard: suitability to product processing production of non-soft fruits, resistent to breakage and to mechanical damaging Early ripening, full process and contemporary Good resistence to over-ripening Some morphologic characteristics Smell and flavour characteristics

14 Sowing technique Planting technique exerts its influence on microclimate conditions and therefore on the presence of parassite, on natural plant community (weeds), management of water resources and soil fertility management. For these reasons it is important, after choosing the specie to cultivate in function of the pedoclimatic vocation of the area, to use planting techniques, altering the least possible tenendo presente i punti su citati, alterino il meno possibile the equilibrium of the habitat, allowing to adopt preventive measures instead of curative.

15 Sowing Preferable for fast growing species or for those that cannot be transplanted. Provides the advantage for the plant of being less vulnerable to water stress (>> deepening of root system). Advisable: utilize healthy seed with good germination % (deriving from organic production if possible) wait till the soil has reached a suitable temperature to ensure a quick seedling emergence don t use to dense plant densities don t sow too deep (emergence would be slowed)

16 Transplanting This technique provides the following advantages : little plants escape pest&disease attacks more easily seedlings can be planted earlier in the season escaping weed competition lower waste of water and fertility resources NO plants thinning soil can be used for other crops (es. cover crop) we can choose strong healthy seedlings early production more contemporary production

17 Plant density In organic farming it is preferable to have more loose plant stands, thus lowering plant density, both in case of sowing and of transplanting This allows: easier control of spontaneous plants (weeds) with mechanic means more ventilation among plants (<< parassitic attacks), better quality and health conditions of the products more vigorous plants less vulnerable to fungal desease&parassites in fruit species (tomato, pepper, crogettes), an adequate fruit size, early yield and fruit contemporary ripening.

18 Propagation material From Jan 1st 1998 growers should use when transplanting only organically produced seedlings (certified). From Jan 1st 2000 for seeds and all vegetative produced materials (bulbs, tubers, stolones, rizomes, grafted or micropropagated seedlings)

19 Management of soil fertility in vegetable farming In Italy organic farm is usually small in size and often, to meet market needs and farm economy tends to specialize, short crop rotations (implying the exclusion from crop rotations of cereal crops and animal husbandry). In these conditions maintaing or increasing natural soil fertility is a difficult task because there is a limited amount of crop residues whose composting does not compensate for the bulk of nutrients taken up and gone with the product

20 Each agronomic technique is performed to ensure and adequate mineral nutrients abundance in the soil, its availability for the crop, and the fact that they are not leached in the soil deeper layers This implyes that nutrients, safeguarded with suitable crop rotations, green manures, and in general with organic matter contributions, must little by little become available through their slow mineralization, thus being available for the crop nutrition.

21 Stable organic matter improves soil fertility (physic characteristics of the soil), contributing to improving the soil ability to house plants (for example by providing better porosity), and also by enhancing water storage capacity (very important feature of soil fertility).

22 For a correct management: we need to know soil chemical, physic, microbic characteristics (that means soil fertility) performm suitable crop rotations that can maintain and/or inprove humus and nutrients balance utilize crop residues as far as possible, because in horticulture most of the plant is the product, and it is thus taken away (i.e. lettuce) utilize green manures apply suitable tillage, protecting organic matter from quick mineralization and not disturbing microorganism transforming soil O.M. in humus careful water resources management apply supplemental fertilizers

23 Soil tillage In farming vegetable crops, an adequate mangement of soil tillage is a powerful tool to improve the agro-ecosystem, to create the ideal conditions for crop growth Soil tillage directly and indirectly affect soil characteristics: by acting Effects of tillage on soil chemicalphysical on O.M. supply and on nutrients characteristics supply, on temperature, on soil moisture, on structure and on porosity The choice of soil tillage depth Tillage operations Deep tillage are always discouraged: one should carefully balance out crop nutritional requirements and soil fetrility maintainance Some operations are more suitable to preserve soil fertility features

24 In organic farming, due to the need to perform in one year several crop cycle, tillage operations can be numerous: if irrationally cumulated this can lead to: loss of soil structure impoverish soil Organic Matter content, increase of erosion Dangerous aspects

25 Tillage operation allow: to adequately preparare seed bed thus favouring a vigorous plant growth to encourage roots penetration and optimise their activity: this concept is crucial in root crops (like carrot, potato, onion etc.) to increase soil layer explored by roots, thus optimizing soil water and nutrient use to increase the quantity of water stored in the most rainy periods, less need for supplemental irrigation

26 to interrupt capillary rise, thus limiting water loss through evaporation to decrease the occurring of waterlogging, that are cause of growth ralented, and cause lots of insect&disease development, to limit the action conveying water running, because it can cause erosion (easy cause of soil impoverishment) to limit expansion of weed population and of any pest&disease to plaugh crop residues or the O.M. distributed to the field (i.e. farmyard manure)

27 Choice of main tillage depth Choice of main tillage depth One of the most inportant problems In general tillage operation must be performed only on top layers, and in limited number, to: safeguard soil structure reduce soil compactation avoid quick OM oxidation with consequent loss of soil fertility better manage soil water reservoir, in that evaporation is hindered prevent the emergence of weed seed bank, easily germination if superficial cut down the energy cost

28 Tillage depth must increase only in case: crop has deep root system the part commercially grown is below ground (tuber, tap root) In any case the depth of normal root layer should never be exceeded, and crop rotation must be carefully organized, to separate crops requiring deep tillage (i.e. tomato, potato, carrot, melon etc.). In particular, after growing a specie requiring accurate soil tillage (i.e. tomato), a crop like lettuce or broccoli should be planned, because requiring more shallow tillage.

29 Tillage depth Shallow Medium Deep Broccoli, Cauliflower, Cabbage, Savoy cabbage, Strawberry, Lettuce, Garlic Beet, Bean, Carrot, Cucumber, Eggplant, Peas, Pepper, Courgette, Leak Asparagus, Artichoke, Watermelon, Melon, Tomato, Squash

30 SOUTH ITALY: TRIENNAL ROTATION Year Crop Growing period Begin End 1 Cauliflower/Cabbage Oct Mar Tomato Apr Aug 2 Cereal Nov Jun Cowpea Jul Oct 3 Courgette Apr Jun SOLARIZATION Jul-Sept It is also reccommended to distribute an organic ammendment, after growing cauliflower or cabbage.

31 Solarization

32 Solarization

33 SOUTH ITALY: 3Year/4Year ROTATION Year Crop Growing period Begin End 1 Early potato Nov May Cawpea Jun Oct 2 Cereal Nov Jun Fennel Aug-Sept Dec 3 Green manure Jan Apr Tomato Apr Ago SOLARIZATION Jul-Sept 4 carrot Sept May lettuce Sept Nov Potato planting, anticipated to Nov in areas with no danger of frost, allows to benefit from rainy period optimal management of water availability

34 SOUTH ITALY: 4Year ROTATION Growing period Year Crop Begin End 1 Cowpea Apr Oct 2 Early Potato Dec May 3 Cereal Nov Jun Lettuce Sept Nov 4 Fava/Pea Nov-Feb Jun Fennel (traspl) Sept Dec SOLARIZATION July-Sept

35 SOUTH ITALY: 4 YEAR ROTATION Year Crop Growing period Begin End 1 Tomato Apr Aug Lettuce Sept Dec 2 Green Bean Apr Aug 3 Cereal Nov Jun 4 Cauliflower/Cabbage Sept Dec-Feb SOLARIZATION July-Sept Cauliflower or cabage can be planted with a shallow plowingonly on the rows where transplanting will occurr,and no tillage on the rest cereal strow have mulching effect.

36 SOUTH ITALY: 4 Year ROTATION Year Crop Growing period Begin End 1 Onion Nov May 2 Carrot Sept May Lettuce Sept Nov 3 Early potato Nov May 4 Cereal Nov Jun SOLARIZATION July-Sept Potato planting, anticipated to Nov in areas with no danger of frost, allows to benefit from rainy period optimal management of water availability.

37 SOUTH ITALY: 5Year ROTATION Year Crop Growing period Begin End 1 Early tomato Nov May Bean (or Solarization) Jun-Jul Sept 2 Catch crop Oct Apr Courgette Apr Aug 3 Cereal Nov Jun 4 Cauliflwer/Cabbage Sept-Oct Dec-Feb 5 Cowpea Apr Oct Cauliflower or cabage can be planted with a shallow plowing only on the rows where transplanting will occurr, and no tillage on the rest cereal strow have mulching effect.

38 NORTH ITALY (VENETO): 2 YEARS CROP ROTATION Year Crop Growing period Begin End 1 Wheat Oct-Nov Jun-Jul Chicory Jul-Aug Oct-Feb 2 Potato Mar Jul Traditional of north Italy. Organic amendment after Chicory is reccomanded

39 NORTH ITALY (VENETO): 3 YEARS CROP ROTATION Year Crop Growing period Begin End 1 Carrot Oct-Nov (Feb) May-Jun (Jun-Jul) Chicory Jul-Aug Sept-Mar 2 Potato Mar Jul Courgette Aug Oct 3 Onion (or Leak) Mar Jun-Jul Cauliflower Aug Dec Quite specialized rotation, to be performed only if farmyard manure is available Organic amendment after Chicory and Courgette

40 NORTH ITALY (VENETO):3 YEARS CROP ROTATION Year Crop Growing period Begin End 1 Carrot Oct-Nov (Feb) May-Jun (Jun-Jul) Chicory Jul Sept-Oct 2 Potato Mar Jul Bean Jun-Jul Aug-Sept 3 Catch crop Oct Mar Onion (or Leak) Mar Jun-Jul Cauliflower Aug Dec Year Crop Growing period Begin End 1 Carrot Oct-Nov (Feb) May-Jun (Jun-Jul) Chicory Jul Sept-Oct 2 Wheat Apr Jul-Aug Bean Jun-Jul Aug-Sept 3 Catch crop Oct Mar Onion (or Leak) Mar Jun-Jul Cauliflower Aug Dec

41 NORTH ITALY (VENETO): 4 YEARS CROP ROTATION Year Crop Growing period Begin End 1 Garlic Oct-Nov Jun-Jul Cabbage/Savoy Aug Dec 2 Tomato (canned) Apr Jul-Aug 3 Carrot Oct-Nov May-Jun Lettuce Jun-Jul Aug Cabbage/Savoy Sept Dec 4 Melon Apr Jul-Aug It is also reccommended to distribute an organic ammendment, after growing cauliflower or cabbage.

42 NORTH ITALY (VENETO): 4 YEARS CROP ROTATION Year Crop Growing period Begin End 1 Wheat Oct-Nov Jun-Jul Bean Jun-Jul Aug-Sept Catch crop Oct Mar 2 Melon Apr Jul-Aug 3 Carrot Oct-Nov May-Jun Lettuce Jun-Jul Aug Cabbage/Savoy Sept Dec 4 Tomato (canned) Mar-Apr Jul-Aug Year Crop Growing period Begin End 1 Garlic Oct-Nov Jun-Jul Cabbage/Savoy Aug Dec 2 Tomato (canned) Apr Jul-Aug 3 Wheat Oct-Nov Jun-Jul Bean Jun-Jul Aug-Sept Catch crop Oct Mar 4 Melon Apr Jul-Aug

43 NORTH ITALY (VENETO): 4 YEARS CROP ROTATION Year Crop Growing period Begin End 1 catch crop Oct Mar melon Apr Jul-Aug lettuce Ago Oct 2 potato Mar Jul crogette Ago Oct catch crop Oct Mar 3 eggplant Apr-May Ago cichory Ago Dic 4 celery Feb-Mar Jun bean Jun-Jul Aug-Sept It is reccomended to distribute an organic amendment after lettuce or cichory

Organic Crop Production: Crop Rotation

Organic Crop Production: Crop Rotation Annette Wszelaki Vegetable Specialist Well thought out crop rotation is worth 75% of everything else that might be done, including fertilization, tillage and pest