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Showing posts with the label Integrated nutrient management

Some notes on the soils and use of fertilizers and pesticides by vegetable farmers in Claveria, Misamis Oriental, Philippines

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The gently rolling topography which typifies a large portion of the volcanic landscape in Claveria makes it ideal for intensive large-scale vegetable production. The widely grown vegetables include cabbage, beans, tomato, sweet pepper and eggplant. The breathtaking volcanic landscape of Claveria, Misamis Oriental But the strongly weathered soils which range from Oxisols in the lower slopes (about 400 to 600 m above sea level or asl) to Ultisols in the upper slopes (about 600 to 900m asl) are a major constraint to vegetable production in the area. Oxisols (also called Ferralsols) and Ultisols (also called Alisols and Acrisols) are clayey, reddish, acidic and nutrient-poor soils although they generally have good physical properties like good structure and moderate to high porosity. As in other volcanic landscapes, the oldest and most infertile soils (Oxisols) are formed on the older and stable lower slopes. Dr. Apol & Nelds Gonzaga, Ruby Gabaca, Dr. Steve Harper & myself in fro...

Potassium availability in soils

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Potassium (K) is second to nitrogen in terms of the amount absorbed by higher plants. Optimum K level for plant growth ranges from 2 to 5% of plant dry weight (Marschner, 1995). Unlike P, K is present in relatively large quantities in soils coming from the weathering of primary minerals such as feldspars, mica and others. But it is commonly deficient in highly weathered or old soils. Total K contents of soils range between 3000 and 100,000 kg/ha in the upper 20 cm of the soil profile (Sparks, 2000). The behavior of K in the soil is influenced primarily by CEC and mineral weathering and not by biological processes. Interrelationship of various forms of soil K (modified from Sparks, 2000) K in the soil occurs in 4 forms: solution K, exchangeable K, nonexchangeable K, and mineral K (Sparks, 2000). a) Solution K . This is the K dissolved in the soil solution. It is the form of K that is readily available to plants and soil microorganisms and also is the form of K most subject to leaching ...

Challenges and opportunities in agriculture

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by Dr. Cezar P. Mamaril Senior Consulting Expert of Philippine Rice Research Institute (PhilRice) Los Ba ñ os, Laguna I would like to share my thoughts about current challenges and opportunities in agriculture that institutions like Visayas State University (VSU) should be concerned. I could not over emphasize the fact that we are facing the problem of producing sufficient food to feed the ever increasing population of our country. Last census reported that our population is increasing by 2.3 percent, while our food production (particularly rice) is increasing by about 2.5 percent. The minimal growth difference between population and food production is not sufficient to provide the other requirements of small farmers to live a decent life. I hope the current census will show a decline in population growth so that we will have a better breathing space. (If you have not yet been interviewed by the census takers, you better do so otherwise you may not get your ration of rice!). Further...