What are the possible causes of low yield of Maize in Nepal? Enlist the Maize research priorities of NMRP.
Diseases and Pests in Maize Fields and Stores
| eastern and midwestern/far-western midhills and highhills | Smut (Sphacelotheca reiliana) and turcicum blight (Helminthosporium turcicum) |
|---|---|
| central/western and mid-western/far-western midhills | ear rot |
| mid-western/far-western midhills, terai, and highhills | stalk rot |
| terai | downy mildew (Perona sclerospora spp.) and leaf firing |
Soil fertility and crop management
Primary soil fertility inputs fym and compost use is decreased due to unavailability and lack of using modern techniques. Because most fields are sloped and rains during the monsoon can be heavy, soil erosion causes large losses of productive topsoil. Traditional planting and weeding procedures are labor demanding, and weed management is challenging due to a labor scarcity (more adult males leaving the community for off-farm work and youngsters attending schools).
Weed competition is less of a limitation in this agro-ecology since weed development is slower in high hills. Lodging is a common issue with today's genotypes. In comparison to the maize-millet relay system, less research has been done on the maize-wheat system (mostly in the mid-western/far-western hills). As a result, specific input management strategies that improve this cropping system are rarely available.
Institutional Constraints
Although the DADO has offices in the district headquarters and satellite offices at the service center/ sub-center level, it has not been able to provide sufficient services to farmers, especially in remote hills. One of the problems is the relatively large area each extension personnel has to serve.
Information Constraints
Farmers in the highhills and rural parts of the midhills face the greatest lack of knowledge. Many farmers in these locations were unaware of whether enhanced cultivars were appropriate for their crops or where they could be obtained. While they did occasionally come across seeds labeled as better varieties, these kinds rarely produced as much as local variety, farmers are becoming less interested in adopting enhanced varieties as a result of this. Other issues include a lack of understanding about better crop management procedures such as spacing, fertilization, and variety selection.
Input Supply Constraints
The issues surrounding the availability of high-quality maize seeds vary by agro-ecology. Farmers in the eastern to western midhills frequently lamented the lack of superior maize varieties of their choice. While the DADO does provide some seeds through minikits and demonstration plots, the number distributed is insignificant in comparison to the requirement. Farmers in the midwestern and farwestern midhills and highhills claimed that the enhanced varieties available were not fit for their environment or taste.
As a result of the government's recent withdrawal of its subsidies, fertilizer prices have risen dramatically. In the lack of a solid government policy and a market that is still developing,the private sector has been hesitant to enter the input industry. Farmers also complained about the poor quality of fertilizers supplied by private traders (mostly from India) and the lack of quality control in the districts.
Other constraints
Excess maize output is difficult to sell at a profit due to a lack of marketing infrastructure, insufficient market infrastructure, and a scarcity of inputs.
Maize research priorities of NMRP are
⦁ Germplasm collection, exchange, evaluation and utilization.
⦁ Development of stress (drought, heat, cold and low nutrient) resilient high yielding hybrids and open pollinated varieties of maize.
⦁ Low cost resource conserving production technologies,
⦁ Development of quality protein maize for nutritional enhancement
Describe the water management techniques for maize.
- Vigorous plant require 2-3 litres of water per day during peak growing period.
- Moisture stress during seedlng stage delays tasseling by 3-5 days and silking by 5-8 days.
- Yield reduces by logging so water management is important.
- Summer maize is mostly grown under monsoon rain, spring maize may or maynot be grown under irrigation but winter maize is cultivated with irrigation.
- In case of summer maize drainage is important due to water logging.
Frequency and depth of irrigation depends on
- Climatic condition
- Soil type
- Types of crop grown
- Organic matter content
Critical growth stage for irrigation are
- Seedling Stage(V2)
- Knee high stage(V5)
- Flowering(VT)
- Grain filling(R2)
Enlist the major weed flora of (maize. Describe about herbicidal methods of weed control in maizė and rice.
Weeds of Maize
Abhijalo Drymaria cordata
Ratnaulo Plolygonum chinensis
Kodejhar Dactyloctenium aegypticum
Banso Echinochloa colonum
Mothe Cyperus rotundus
W6 Kanejhar Commelina spp
Gandhe Ageratum conyzoides
Chariamilo Oxalis spp
Dubo Cynodon dactylon
Siru Imperata cylindrica
Weed control at the early stage of maize growth is crucial for improving the maize yield.
Maize yield loss is influenced by weed species, densities, and interactions. Weed plants compete with maize for vital growth resources such as water, nutrients, and space, resulting in yield reductions of up to 65 percent when weed management measures are not implemented during critical crop growth phases. While some harmful weed species are difficult to distinguish because they are similar in nature and life cycle to maize.
To keep any potential yield loss under control. According to studies, as weed management was delayed, losses in kernel quantity per plant accounted for around 65 percent of the decline in grain output.When weeds emerged with maize, a 2% yield reduction was detected when weed control was postponed until the third-leaf stage of maize development. When early emerging weeds were controlled until the third to fifth-leaf tip stage, a 5% yield loss in maize was documented (V1 to V3).
Enlist the direct and indirect weed management practices for summer season maize. Explain the chemical weed management practices for winter maize.
For the control of weeds, direct control tactics include biological, chemical, cultural, and/or physical measures.
Indirect control measures include agronomic procedures such as cultivar selection, crop rotation, sowing season, and nutrient management, among other things, and are intended to improve a crop's competitive capacity.
Chemical control is a faster, more effective, more time and labor-saving way than other methods. Herbicides are used in the chemical approach.
Weed management techniques
Manual method
2 manual weedings 20 DAS and 30-35 days after sowing followed by earthing up(not after V5 stage.
Herbicidal method
Herbicidal method of weed control
Simazine/Atrazine | 1 to 1.25(light soil) 1.25-1.5(Heavy soil) In 800 to 1000 litres of water | Pre-emergence |
Alachlor | 2-3 litres | Pre-emergence |
Mesotrione | 1-1.5 kg a.i/ha(70g/lit | Post emergence, V2 to V8 stage |
2,4 D | 1.5-2 kg a.i./ha in 800 lit water | Post emergence |