Studies have been carried out in Egypt to determine the most suitable time and proper method of fertilizer application for various crops. The following are some examples (Taha et al., 1996).
For broadcast seeded rice, recent work conducted by the Rice Research and Training Center (RRTC) indicated that the most effective treatment is the split application of fertilizer nitrogen in three equal doses: one third applied before planting, incorporated in dry soil; one third at the mid tillering stage and one third at panicle initiation.
For transplanted rice, using N15 labeled fertilizer, it was found that, comparing banding in dry soil, placement ten cm deep in the soil, two thirds top dressed 35 days after transplanting and one third at the primordial initiation of the panicle, the treatments gave roughly comparable results. The ten cm placement treatment was found to be the best (Table 14).
Effect of timing and method of N application on paddy
Banded in dry soil
Broadcast in water before leveling
Point placement 10 cm deep
2/3 band+1/3 at panicle initiation (p.i.)
2/3 top dress 15 d.a.t.+1/3 at p.i.
2/3 top dress 35 d.a.t.+1/3 at p.i.
d.a.t. = days after transplanting.
p.i. = panicle initiation
Studies were carried out to determine the most suitable time of nitrogen application for producing the highest yield of grain and protein. In a coordinated field trial, using N15 labeled fertilizer, it was found that splitting the amount of nitrogen into three equal doses to be applied at planting, early tillering and booting stages of growth were more effective than N fertilizer applied in two equal doses at planting and tillering or in one single dose at planting.
Data obtained from a coordinated programme on maize, using N15 labeled fertilizer, showed that the split application of N fertilizer in three equal doses applied at planting, at 50 cm plant height and at tasseling was more effective than N fertilizer applied in two equal doses.
About 22 field trials were conducted to study the most effective method and the suitable time of nitrogen application. The results indicated that:
Deep side dressing after thinning was the most effective treatment when compared with topdressing after thinning or banding in the bottom of the ridge.
Splitting the nitrogen dose into two equal doses, the first before the second watering (after thinning) and the second before the fourth watering was the most efficient treatment.
Data from different field experiments showed that the application of phosphate fertilizer in one single dose before planting or before the first or second watering were almost equal in their impact on crop production.
Conventional fertilization practice involves the application of phosphate, potassium and part of nitrogen requirements before planting and the application of one or two doses of N fertilizer during growth. Manual broadcasting and mechanical spreading or spraying are used.
Fertigation, the application of fertilizers with irrigation water, is used in Egypt on sandy soils and especially for vegetable production where the productivity of crops on these soils is lower than the potential yield of the recommended cultivars. Below optimum productivity is due to poor soil fertility, low water and fertilizer efficiency and unsuitable management practices. Fertigation permits improved efficiency of irrigation and nutrient use and reduces application costs. It improves plant growth and nutrient uptake and limits nutrient losses.
In Egypt, fertigation is practiced on only 13 percent of agricultural land, 87 percent of the fertilizer being applied to the soils. One of the main recommendations adopted at an FAO meeting in the year 2000 concerned the importance of fertigation in both pressurized systems (sprinkler and drip irrigation) and surface irrigation. Fertigation was shown to enhance overall root activity, improve the mobility of nutritive elements and their uptake, as well as reducing the contamination of surface and ground water. The fertigation technique is used mainly with N and K fertilizers (Taha, 1999).
Under Egyptian agricultural conditions, nitrogen is considered to be the most critical factor in crop production. The rate of nitrogen application in Egypt is one of the highest rates in the world. As a result, nitrogen contamination of drainage water reaches an average of 1.5 ppm N in the drains of the Nile Delta area. This results from the heavy application of nitrogenous fertilizers and the leaching out of the easily soluble nitrogen through the uncontrolled surface irrigation practices usually practiced by Egyptian farmers. Such losses of nitrogen are a substantial financial waste and pollution of the environment with nitrate.
Applying fertilizers through the irrigation system has several advantages:
Nutrients can be applied at any time during the season and according to plant requirements.
Placement of mobile nutrients such as nitrogen can be regulated in the soil profile by the amount of water applied.
Applied nutrients are readily available for rapid plant uptake.
Nutrients are applied uniformly over the field.
Ground water contamination is likely to be less since nitrogen may be applied at any given time. It is often applied when crop uptake and utilization are at their maximum.
Crop damage during fertilizer application is minimized.
The disadvantages of fertilizer application through the irrigation system are:
Uniformity of fertilizer distribution is only as good as the uniformity of water distribution.
Lower cost fertilizer materials often cannot be used.
Localized fertilizer placement such as banding cannot be achieved in a sprinkler irrigation system. To a limited extent, it can be achieved with drip irrigation.
Water source contamination can be significant if the injection system is not properly installed or is poorly maintained.
The following are two fertilization programmes, for maize and wheat grown on sandy soil in open fields.
330 kg N/ha as ammonium nitrate. Twenty percent applied to the soil before planting and after thinning, the remainder being applied in irrigation water (fertigation).
70 kg P2O5/ha as single superphosphate applied to the soil in two equal doses before planting and after thinning.
130 kg K2O/ha as potassium sulphate applied in three doses, half applied to the soil before planting, one quarter after thinning and one quarter during the growing season in irrigation water.
285 kg N/ha as ammonium nitrate, ten percent applied to the soil before planting and at tillering, the remainder being applied in irrigation water.
70 kg P2O5/ha as single superphosphate applied to the soil in two equal doses before planting and at tillering.
115 kg K2O/ha as potassium sulphate applied in three doses (half applied to the soil before planting, one quarter at tillering and one quarter during the growing season in irrigation water).
Yields of maize 7.9 tonnes/ha and wheat 6.4 tonnes/ha indicated that it is possible to increase the crop productivity of sandy soils of low soil fertility with the use of fertigation.
The efficiency of the fertigation technique depends on many factors including:
Water quality, (pH, exchangeable cations, concentration of soluble cations and anions Na+, Ca++, Mg++, Cl-, SO4=).
The fertilizers and salts should be completely soluble to avoid problems in solution flow and to improve fertilizer efficiency.
The timing and concentrations of each type of fertilizer.
Avoidance of reaction between water and fertilizers leading to precipitation of salts in the irrigation system.
Cleaning the system by injecting diluted mineral acids periodically in order to dissolve precipitations in the system.
Extension is one of the main activities of the Ministry of Agriculture and Land Reclamation in Egypt. This sector has different "Central Departments", one of which is the Central Department of Soil Fertility and Soil Improvement.
In addition to the extension staff, there are national campaigns for different individual crops, involving research and extension staff and covering issues that include soil fertility and fertilizer application. Research staff at the Agriculture Research Center (ARC) must allocate 30 percent of their time to extension activities.
Recently there was a national campaign for recycling agricultural residues by composting, for use as organic manure.
In addition to the national campaigns, there are other collaborative activities between research and extension staff such as:
Training programs for agronomists and their assistants.
Extension meetings and lectures.
Farmers Field Sschools (FFS).
Farmers field schools involve four coordinated projects:
Egypt-Finland Agriculture Research Project in Ismailia Province (East Delta).
German Technical Cooperation in some provinces of North and Middle Egypt.
Integrated Pest Management Project in Fayoum.
Capacity building in land management and soil productivity/soil productivity improvement through FFS in Fayoum Governorate and Nubariya Region (TCP/EGY/2904, FAO).
The Egyptian/German assisted project started in 1976 with the objective of studying plant nutrition problems in Egypt, especially those related to micronutrients. Subsequently it covered almost all aspects of plant nutrition and foliar fertilization in the context of balanced fertilization and nutrient management. From the outset, the project involved on-farm research with farmers. In 1980, the study of new approaches for transferring the research results to farmers was initiated (Manning, 1980; Fritz, 1980).
This project was and still is primarily concerned with innovations in the field of plant nutrition and fertilizer use and in extension methodologies, all involving collaboration with farmers. It was in fact recognized that all aspects of growing the crop and not only nutrient management should be discussed with farmers. FFS specializing in nutrient management are indicated only in the early stages of developing new technology. Subsequently nutrient management should become a part of the crop FFS.
The Fayoum Integrated Pest Management Project is a Dutch assisted project that began in March 1999 with two cotton FFS on integrated pest management in two villages. In addition to cotton, these FFS cover problems of other crops cultivated by the farmers during the season. In June 1999 a tomato curriculum was introduced.
Rural schools for women were introduced on a pilot basis. Training subjects included integrated pest management, pesticides, processing of the products, basic agricultural practices, household animal husbandry, production of dairy products, literacy, hygiene and child care (EL-Fouly, 2000).
Project TCP/EGY/2904 (A) started in October 2003 and is designed to function at village level. The project aims to improve the productivity and fertility of degraded soils including salt affected soils through ISNM and farmers involvement through the FFS approach. One of the major objectives is to demonstrate appropriate ISNM methods for optimum sustainable production on selected pilot farms (farmers fields) in two Governorates (Fayoum and Nubariya).
The planned outputs of the project for enhancing the productivity of salt affected soils in relation to plant nutrition, soil fertility improvement, and fertilizer use include:
Improved ISNM technologies.
Integrated agronomic and soil, water and nutrient management practices.
Training material concerning soil, water, fertility and crop management.
Guidelines on integrated low cost, low risk techniques.
One of the major achievements, which reveals the importance of the interaction between researchers and extension staff in the area of soil fertility and plant nutrition, is the application of zinc fertilizers in rice fields. Twenty years ago zinc as a fertilizer was unknown to rice farmers in Egypt. Today the application of zinc fertilizers to paddy nurseries is one of the general fertilizer practices in rice cultivation.