Discuss the maize establishment and agronomic practices

1.Cropping system:
-Monoculture
-Crop rotation
-Intercropping

2.Land Preparation
-Early land preparation is recommended as this ensures timely sowing and good harvest. Land should be prepared before the onset of rains.
-Maize seeds require worm, moist, well aerated and fine enough soil to facilitate contact between seeds and soil.
-The practice for a long time has been to plough the soil to obtain fine tilth. However this is overworking the soil and is a harmful practice because a fine tilth is likely to seal the soil surface when it rains leading to increased erosion and runoff.
-Conservation tillage with good weed management option should be adopted.

3.Source of planting materials and sowing
-Propagation is done through seeds. Certified seeds are available from registered farm inputs stockists/ Agrovets or authorized agents of Seed Companies.
-The time of sowing is most critical factor as it determines the yields. There is a drop of expected
yields by 1-2% every day sowing are delayed.
-Maize should be sown in rows by drilling along the contours to minimize run-off and soil erosion losses on sloppy lands.
-The spacing should be 25 -30cm within the rows (Intra row spacing) and 75 -90 cm between the rows (inter row spacing).
-The standard spacing may change due to various factors such as soil fertility, rainfall availability etc.
-The normal sowing depth is 2.5 – 5 cm depending on soil condition and temperature. Where rainfall duration is short, dry sowing 2-3 weeks before the onset of rains is recommended. In case of dry sowing the seed are placed at 10 cm depth. Pre-germination by soaking can also be done

4.Fertilizer Application
-When other husbandry practices are properly done, the use of fertilizers increases yield. Fertilizer -recommendations are made when soil analysis has been done. The use of fertilizers in maize production is economic only where improved varieties are used.
-Phosphate fertilizers should be applied in the planting holes in the time of sowing while nitrogen fertilizers should be top dressed when maize is knee high (45-60 cm high).

Method of application
-To maximize yields of maize, a full dose of P and K and a half dose of N may be applied during planting to stimulate early growth.
-When planting manually, it is recommended to place a teaspoonful or soda bottle cap of fertilizer into each planting hole.
-Thoroughly mix the fertilizer with the soil and then place the seed.
-Under mechanical planting well calibrated planters with fertilizer hoppers are used.
N uptake is low during the first month after sowing and increases to amaximum at tasseling. Maxium N uptake takes place 10 days before tasseling.
-Increased N fertilizers usually increase protein contents of grains.
-Nitrogen can be lost through volatilization, leaching, as ammonia gas (NH3). Hence nitrogen fertilizers should not be applied once but in bands.
-The fertilizer applied as a top dress or side dressing when the crop is on the 4 -6th leaf stage (45cm high or knee high).This is the time of highest demand of N.
-In high rainfall areas this application is applied in two splits. 1st split is done 6 weeks after sowing and 2nd split is done 10-15 days later or just before tasseling.
-In low rainfall areas the application is applied once.
-This is done when the soils are moist; apply 1 teaspoonful of fertilizer at the base of each plant in a ring [approximately 15 cm radius] or along the row 15 cm away from the plant.

6.Weed control and management
-In Africa in general low average yields are caused by ineffective weed control
-The most effective period of weed control is when the crop is emerging and at tasseling stage.
-These are the periods when the crop is highly affected by weeds.

Generally there are four methods of controlling weeds:
i. Cultural
ii. Biological
iii. Chemical/ Herbicide
iv. Legislative measure

-Weeding tools are hoes or tractor mounted implements.
-The use of these may cause injury to the roots of the crop thus affect yields.
-The suitable method if yield is to be maximized and in pure stand is application of suitable pre-e-mergence and post-emergence herbicide.
-However in Africa hand weeding is mostly or commonly used. 1st weeding is done 3 weeks after sowing when crops are about 8cm high.
-Two other weedings are done at equal intervals thereafter.
-The field should be kept weed free till maize tasseling after which their presence might not cause crop loss.

7. Thinning and Gapping
Gapping is done to replace seeds that fail to germinate immediately after germination is complete.
Thinning is done when maize has grown to height of 15 cm by removing the weak and deformed seedlings to leave the desired number of seedlings per hole.

---

Titany answered the question on August 16, 2021 at 07:39