Last August 13, 2008, I happened to be invited through our office by the Security and Escort Battalio, HHSG, PA at Fort Bonifacio, Metro Manila. The intention is to lecture on proper use of fertilizer and procedures on Agricultural Production and train some of their personnel to carry out the said endeavor. It’s always a good opportunity for us working at the Department of Agriculture (DA) because through this kind of activity, we can continuously educate people on other field of discipline at the same time promote the DA program.
I prepared a lecture on Integrated Nutrient Management (INM) believing that INM is a wholistic approach that they can use in Agricultural Prodeuction. INM is a means of utilizing all the available fertilizer source inside and outside of the farm at the same time integrating available technologies. I started my lecture with the objectives of INM: I emphasized to them that with INM, we can sustainably manage our farm land; maintain the quality of the soil (physical, biological and chemical properties); promote a low cost management; and use envornmental friendly technologies.
In the use of INM, there are things to be considered:
- Technical applicability – that means asking ourselves whether we can just use manure or organic pertilizer? Can we avoid the use of inorganic fertilizer? Or do we need a combination? Will the nutrients from organic fertilizer be enough to sustain the needs of the plant and attain the yield we target?
- Economic returns – among the many available means of producing good crop, which is the most economical and affordable to the farmer, at the same time good for the environment as a whole not only for the soil.
- Practical fesibility – if ever the farmer decided to use a technology, say for example, organic fertilizer, do they have the capability to mix 10T of organic fertilizer or can they source out this volume in the farm or will enough labor force be available?
- Social acceptability – it’s always good to check on the social acceptability of the technology. We need to look at the effect on the enviroment (water, soil and air).
I went to explain to them that if ever they are decided to use the INM as technology, it’s always good to start to know whether the soil has enough nutrients to support plant growth or do they need to apply additional input, if ever what to apply and by how much. There are means to do that:
- Soil Analysis – this is done by simply taking soil samples and analysing it. It will give us the indication of the sufficiency and deficiency of a particular element, and what need to apply and by how much.
- Plant Tissue Analysis – this method complements the soil tissue analysis, instead of getting soil sample part of the plant is the one being analyse. With proper procedure, plant tissue analysis could give a good indication of nutrient sufficiency and deficiency.
- Field Experiment or Biological Test – setting up a simple experiment, for example what volume of crop residues can significantly increase yield; what combination of inorganic fertilizer; time of application and so on. This is always a good practice to do before adoption of any technology. We can start with small lot in the farm, then test the technology if it will work or not. Say the use of earthworm cast. We can apply this in a portion of the farm and then compare the effect on those without application. Farmer will have a first hand experience and at the same time familiarize themselves on the technology.
- Visual Diagnosis of Observing Difficiency Symptoms – this is done by daily observation of the crop stand, observing the plant of color abnormality or appearance like yellowing (defficent in nitrogen) , purpose color (defficent in phosphorus, scorching (defficient in K), stunted growth (N), curling of the leaves (Ca) , white strips (Mg) and others. By careful observation of deviation from the normal plant will give an indication of what particular element is defficient. There are some difficulty regarding the method because defficiency could be a combination of particular element. Further, defficiency could appear at the late stage and providing the necessary measure is a bit late.
Aside from what mentioned above, defficency of particular element can be assessed through general soil fertility evaluation. This can be done by answering questions such as: time of fertilizer application; is there enough moisture when fertilizers were applied; right kind of fertilizers were applied; right amount of fertilizers were applied; were fertilizers thoroughly mixed to the soil; used balanced fertilization; organic fertilizers were used and so on.
Then I provided them some options of managing the natural resources such as: recycling; nutrient budgetting; use of organic fertilizers (i.e. compost; liquid manures); use of crop rotation; use of conservation tillage; use of cover crop and proper intercropping; good cropping pattern; use of leguminous crop in the cropping pattern and others.
I also discussed several means in maintaining the fertility of the soil and minimize depletion at the same time maintaining the good soil quality: planting crops that are suitable to the inherent characteristics of the soil; minor alteration of the soil inerent fertility level through the use of organic fertilizer; and use of balanced fertilization.
I also mentioned a little on soil erosion and many other things which I will discuss in details in my next writting.