Crop Management AGN 32102 2024 PDF

CROP MANAGEMENT Course Code: AGN 32102 Lameck Vwalika 1 CROPPING SYSTEMS Unit 4: Cropping systems – Subunit 4.1: Shifting cultivation – Subunit 4.2: Mono-cropping (monoculture) – Subunit 4.3: Crop rotation – Subunit 4.4: Multiple cropping Unit 4: Cropping s...

CROP MANAGEMENT Course Code: AGN 32102 Lameck Vwalika 1 CROPPING SYSTEMS Unit 4: Cropping systems – Subunit 4.1: Shifting cultivation – Subunit 4.2: Mono-cropping (monoculture) – Subunit 4.3: Crop rotation – Subunit 4.4: Multiple cropping Unit 4: Cropping systems (cont’d) – Subunit 4.5: Agroforestry systems Alley cropping Biomass transfer Topic 4: Cropping Systems Objective By the end of this topic students should: Explain the main cultural practices and cropping systems used for crop production and the reasons for their use Recommended books 1. Bunting RH & Bunting E (1984). The Future of shifting cultivation in Africa and Task Universities. FAO, Rome 2. Nair PKR (1989). Agroforestry Systems in the Tropics. Klumer Academic Pub. 3. Rependeck RC, Sanchez PA & Tridett GB (1976). Multiple Cropping. American Society of Agronomy publications, Wisconsin 4. Journal articles (google search) Cropping systems are classified based on: 1. Distribution of crops in time whether shifting cultivation, crop rotation or monoculture is being practised 2. Distribution of crops in space on the field Whether intercropping or sole cropping is being practiced 3. Level of management & resources used to produce the crop Is production intensive or extensive? 4. Type of crop grown Whether arable cropping, orchard, agroforestry, pasture is being practiced Cropping systems The generic properties (relevant characteristics) to assess cropping system functions are : 1) Sustainability: This refers to the ability of a cropping system to maintain yield over a long period. 2) Productivity : This is an economic yield per unit area (e.g. 600 kg/ha) 3) Efficiency: This is an economic yield per unit input used Cropping systems 4) Stability: maintain production levels without degrading the environment (degree of variation in yield over time (years) 5) Effectiveness : capacity of a cropping system to achieve farmers objectives. E.g. weed control, pest control Soil: a major resource upon which sustainable cropping depends. Soil management is important in managing cropping systems for sustainability and productivity. What is a cropping system? Refers to all crops, crop sequences & management practices used on agricultural farm over a period of time (years). It describes a pattern in which crops are grown in a given area over a period of time and includes technical & managerial resources utilized Designed to maximize crop yields & promote environmental sustainability Involves complex interactions farm resources: enterprises, technological & social factors Physical factors: light, temperature, water etc. Biological factors: soil organisms, weeds, pathogens, insects etc. Why cropping systems? To meet various human needs: – food – feed – fibre such as cotton raw materials & wealth 10 Examples of cropping systems 1. Shifting cultivation 2. Mono-cropping 3. Crop rotation 4. Multiple cropping 5. Agroforestry 11 1. Shifting Cultivation Crops are grown on a piece of land for a short period and later abandoned (cultivation shifts within the area) Examples: Slash and burn type of farming: practiced by early people (broadcast seeds) Chitemene: in Zambia (pollarding trees) Nthemera : in Nthalire (Malawi) - heaping cut trees and burn them Example of crops Sorghum (originated from Sudan) Finger millet, cassava, beans etc. Characteristic of shifting cultivation 1. Vegetation is cleared (cutting down trees and burning them) 2. Crops are grown for a year, two or three 3. Low levels of inputs, technology & management 4. Low yields 5. High labour demand Shifting cultivation (cont’d) Importance of burning kills grass (weed) seeds A source of ash (potash & calcium for crop growth) Factors necessitated moving from one place to another Decline in soil fertility High pest and disease incidences Disadvantages of shifting cultivation No investment in permanent structures – irrigation, soil conservation measures, stores Low efficiency in land and labour utilization Requires a lot of land to maintain the system Shifting Cultivation was possible due to: 1. Plenty of land for cultivation 2. No fixed boundaries - people moved from one land to another 3. Low human population 4. Food sources include bush collection hence no reliance on grown crops 2. Monocropping & Monoculture Monoculture : is an agricultural practice of growing of one crop on the farm at a time (season) Monocropping: a continuous planting of the same crop for several seasons (year after year) Examples of monocropping Sugarcane estates Tea estate Coffee estates 2. Mono-cropping (cont’d) Advantages A farmer is an expert in production of a particular crop Easy to set and use machinery Easy to use of herbicides and pesticides Easy planning of cultural practices Disadvantages of Monoculture Difficult to maintain soil cover High build-up of pests, diseases and weeds Depletes soil moisture and nutrients from the same depth High risk of total loss in case of pest/disease outbreak or bad weather Crop rotation A practice of growing different types of crops one at a time in a sequence on the same piece of land Fallow can be included in the crop rotation system Advantages of a good crop rotation 1. Improves soil productivity 2. Growing a mixture of crops provides a diversity of diet 3. Reduces market price risk 4. Controls weeds, pests & diseases (breaks life cycle) 5. It improves soil structure and fertility Principles of crop rotation Factors to consider when deciding sequence of crop rotation: Target crop (main crop) should be planted immediately after legumes or fallow period – Soil fertility is at its peak Crops with deep feeders (roots) should alternate shallow feeders – Allows uniform nutrient removal from different soil layer Crops of the same family should not follow each other in crop rotation – attacked by the same pests & diseases The number of years for which each cycle of rotation should run is determined by the number of crops in the rotation 20 Multiple Cropping Growing of two or more crops on the same piece of land in a year Examples of multiple cropping 1. Intercropping a) Mixed cropping b) Row intercropping 2. Relay cropping 3. Sequential cropping 4. Strip intercropping Intercropping Growing two or more crops in the same field simultaneously 1. Mixed Intercropping: No distinct row arrangement. 2. Row Intercropping: Rows assigned to particular crops 3. Strip intercropping: Narrow strips assigned to crops Row intercropping Mixed intercropping Strip intercropping Strip intercropping: Involves planting broad strips of several crops in a field E.G. Planting alternating strips of maize, soybean & finger millet Each strip is 3 - 9 m wide. On slopes, strips prevent erosion A farmer can rotate crops by planting each strip with a different crop Strip intercropping Relay cropping - form of intercropping Growing one crop then planting another crop (usually a cover crop) in the same field before harvesting the first crop Example Planting maize then sowing beans between the maize rows four weeks later Advantages Avoids competition between a main crop & an intercrop Longer soil cover Sequential cropping Refers to the growing of two crops in the same field one after the other in the same year Second crop is planted after harvesting the first crop It can be done under Residual moisture and extended rainy season Two rainy seasons in a year (in some countries) Irrigation Second crop planted after harvesting the first crop Use residual moisture & extended rainy season two rainy seasons or irrigation Agroforestry It integrates leguminous trees and crops on the same unit of land Leguminous trees or shrubs are grown to benefit crops) Advantages Improves soil fertility (crops benefit from the supply of N and other plant nutrients (BNF) Livestock feed (e.g. Leucaena) Improves soil health (source of soil organic matter) Provide fuelwood Source of fruits and food to human Alley cropping Crops grown in alleys formed by the trees (hedges 4-5 m apart with an interplant of 45 - 90 cm) Crop ridges are in the middle surrounded by the hedge Hedges can be Leucaena Gliricidia Leaves are pruned & applied on maize planting station before planting Alley cropping Agroforestry Direct roles Production of wood, fruits, fodder, green manure, construction materials (pole), wind breaks etc. Service roles – Soil conservation – erosion control, soil fertility maintenance – Aeration of the microclimate – Rehabilitation of degraded land Crops under Faidherbia albida trees Agroforestry Some known AF Tree/Shrub species Gliricidia sepium Tephrosia vogelii Cajanus cajan Acacia angustissima Acacia species Sesbania sesban Tithonia diversifolia Faidherbia albida 29 Gliricidia Sepium It leguminous plant produces a lot of litter. Advantages of Gliricidia species It is considered as a good soil improver, because of its deep roots and quick growth, it is used as a windbreak. It thrives on steep slopes and may be used to reclaim denuded land. It is also often used as shade for perennials (coffee, tea, cocoa) or as nurse-tree since it produces light shade and reduces soil temperatures. Gliricidia Sepium Seed – seed collection and nursery phase Pods are collected in February to March before they dehisce on the tree and dried in the sun for 3 to 4 days to separate the seeds. Good seeds should be well dried, insect-free, fungus-free, and weed- free. Gliricidia has from 6,000-13,000 seeds per kg, depending on variety. Keep seeds dry in a tightly-closed plastic bag or jar, and they will last for years, longer if refrigerated. Gliricidia seeds require no pretreatment, unlike most other leguminous trees. Just plant them. They will germinate in 7-10 days.  Gliricidia Sepium Nursery phase Its seeds can be directly, planted in well-prepared cropland or raised in a nursery for 6–8 weeks before transplanting Ensure you cover the seeds with light or thin soil and Water regularly. The seeds will germinate within 7-14 days of sowing. Once germinated, seedlings can be raised bare rooted or in containers, but regular watering  Gliricidia Sepium Use of Cuttings Large sized cuttings, 1 to 2.5 m in length and 6 cm in diameter, are made from branches 1.5 to 2.0 years old Small cuttings are 30 to 50 cm long and made from branches 6 to 12 months old. Branches used for cuttings should be straight and healthy, and without side branches. The top of the cutting should be cut on a slant to prevent water collection and subsequent rot. The bark on the lower portion of the cutting should be scarred through to the cambium with a sharp knife to encourage rooting. One-third of small cuttings can be buried. Trees established from cuttings will have a shallow root system. They are susceptible to uprooting by heavy winds. Gliricidia Sepium Management in the Field planting Gliricidia is managed by cutting, that is, by pollarding or coppicing. Pollarding (cutting off the top crown) It is done at 1.5–2 m above ground 18–24 months from planting. Pollarding is most appropriate when gliricidia is intercropped with perennial crops, such as coffee and tea, as a shade tree or when planted along boundaries or on soil-protection structures, such as terraces. Pollarding is also recommended for use in monocropping Gliricidia Sepium Management in the Field planting To improve soil fertility, the cuttings from coppicing or pollarding should be left in the field for two weeks to allow the leaves to completely detach from the branches Alternatively, the leaves can be removed from the branches by chopping and incorporating them into the soil as green manure The farmer can use the branches for Firewood. , The gliricidia trees can be pruned every 2–3 months from the first pruning. The procedure is then repeated regularly. After the harvest of seasonal crops, the gliricidia trees are left to grow as fallow when crops are not being grown. Biomass Transfer refers to cutting and carrying (“transferring”) nutrient-rich leaves of agroforestry species to fertilize fields for the production of crops such as maize and vegetables Biomass transfer offers smallholder farmers the opportunity to supplement their incomes by growing cash crops that fetch high prices in urban markets. In this system, nitrogen fixing trees or shrubs are planted on a separate plot and the leaves are regularly cut and used to fertilize neighbouring field plots in a cut-and-carry way, especially in the dambos Reading assignment Make your own notes on seed and seedling production, planting and all field management practices of the following Agroforestry species: 1. Cajanus cajan 2. Tithonia diversifolia  END OF CROPPING SYSTEMS 10/30/2024 38