Agriculture

The ammonic nitrogen, referring to the ammonium ion which carries a positive electrical charge (NH4⁺), is one of two forms of nitrogen that can be absorbed by plants.

The other is the nitrate ion (NO3^–) which has a negative charge.

Most nitrogen fertilizers either belong to the pure ammonium type or contain nitrogen in both the ammonium and nitrate forms.

Each of the two forms of nitrogen has advantages and disadvantages over the other.

The same applies to fertilizers that supply nitrogen in either or both the ammonic and nitrate forms. It is therefore important to familiarize with such fertilizer types.

Below is a list of fertilizers grouped according to the form of nitrogen that they contain.

The list also provides information on common fertilizer grades, chemical formula, formulation, and other descriptions.

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Anyone can experiment in creating his own vertical garden or wall garden, subject to financial limitations depending on the chosen design and familiarity with adapted plants.

However, for those who do not enjoy the benefit of time in experimenting and where aesthetics is a consideration, it may be best to seek the help of an expert.

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3. Planting corn –  Seeds of a glyphosate-resistant variety of corn are sown at the onset of the rainy season, ideally after a heavy downpour or, at least, moderate rainfall.

This is to ensure that the soil has sufficient moisture which is needed in seed germination.

Regular rainfall in the coming days also favors vigorous growth in sloping lands. Likewise, it is important in the timely application of fertilizers.

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There are several methods of harvesting vermicompost.

Harvesting may be gradual or in bulk at one time. It is normally done during the daytime for ease in separating the earthworms.

The vermicompost is ripe and ready for harvest when the raw materials, except for a few, particularly pieces of a woody stem, are fully decomposed.

At this stage, the vermicomposting ingredients would have undergone both thermophilic and mesophilic processes of decomposition.

The height of the pile would have dropped down to about one-third to one-half of that of the original pile, and the pile temperature would be close to ambient temperature.

The organic substrates are no longer distinguishable and the vermicompost appears somewhat darkish brown, crumbly, and smells earthy, like that of freshly excavated fertile soil.

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Palm sugar is the sweet substance that is processed from the sap of plant species belonging to the family Arecaceae or Palmae.

The main product, a crude sugar that is also referred to by various terms such as jaggery, palm gur and muscovado sugar, is largely used for sweetening purposes.

This information is nothing new, except that the advent of sugarcane and sugar beet as commercial sources of sugar has tended to put so much awareness on these sugar crops.

The distribution of palms also favors the tropical world.

Nevertheless, according to Hill (1972), the juice of some palms ranks as the fourth source of commercial sugar.

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The citrus greening disease, also known as “Huanglongbing” or HLB, is presently considered as the most serious disease affecting the U.S. citrus industry.

In 2005, it devastated the citrus industry of Florida, causing damage and lost revenue amounting to millions of dollars.

Diseased plants produce fruits that turn green after ripening.

It is believed that the causal organism is the bacterium Candidatus Liberibacter asiaticus.

A few years back, the Asian citrus psyllid (ACP) which transmits the disease has been found in Texas and California.

Texas is the third-largest producer of citrus fruits in the United States, mostly in the Rio Grande Valley.

The Valley produces grapefruit as its top citrus crop, with some orange, tangerine, tangelo, and Meyer lemon.

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2. Partial or Incomplete Dominance.

This is a type of dominance in which the heterozygote exhibits a character that is intermediate to the alternative characters carried by the two alleles making up the heterozygous genotype.

In this case, both alleles equally but partially contribute to the phenotype of the heterozygote.

With reference to the parents of a cross that possess homozygous genotypes (s1s1 and s2s2; p1p1 and p2p2), it is the dominance relation in which the heterozygote (s1s2 and p1p2) exhibits a phenotype that is halfway or a 50-50 mixture (intermediate) of the two parental characters.

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Photoperiodism is the response of plants to the relative lengths of light and dark periods within a 24-hour cycle.

Plant growth and development processes that are affected by photoperiod include flowering, vegetative growth, internode elongation; tuber, rhizome and bulb formation, sex expression, the formation of pigments such as anthocyanin, the number and size of root nodules, fruit set, leaf fall, and dormancy.

However, the above definition is susceptible of misinterpretation.

As early as 1938, Hamner and Bonner demonstrated that it is the long dark period (16 hours) that elicits the flowering response in Xanthium.

By interrupting the dark period with a short light break, the plant remains vegetative and fails to flower.

But the flowering response is maintained with 16 hours of the dark period even though the light period (8 hours) is interrupted with a short period of darkness (Devlin 1975).

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This is an overview of the major stages of development in intact plants, particularly in the annual, terrestrial angiospermous crops in which growth habit is determinate.

The morphological changes associated with these stages are more distinctive and their occurence are quite easily predictable in this group of plants.

These developmental stages also occur in perennial crops such as fruit trees, but various stages are repetitive and it may take a long, indefinite time for natural death to set in.

One of the oldest living, erect and single-trunked tree in the world, a bristlecone pine (Pinus longaeva, syn. Pinus aristata var. longaeva) which was discovered by Edmund Schulman in California, USA in 1958 was then established to be 4,600 years old by ring count (Schulman 1958).

Also, according to Watada et al. (1984), overlapping of development stages is more pronounced in horticultural crops.

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