Tree crops require nutrients, but because of the amount of nutrient stored internally and the delay between application and uptake, the effects of fertiliser application are delayed

I agree with Paul that like annual crops perennials also require nutrients either in the form of inorganic, organic or as a combination of the two. In most cases, the integrated nutrient management approach is more preferred for tree crops for efficient and longer-term utilization of the applied input.

Plant nutrients are  harvested during crop harvesting, that means a replenishment is necessary for the next crop. Otherwise, over-exploitation of the soil  nutrient resource may may result in low yield, or even sometimes bineal bearing unless the plants are properly managed including fertilizing, particularly in times of heavy crop. Overall, soil testing is advisable to determine the status of plant nutrients in the soil and to recommend the appropriate type and rate of fertilizer application.

Hello. i recommend to take soil samples of the orchard for a lab analysis to see the nutrient output after each harvest. Perhaps the soil there is rich and you havent noticed yield reduction yet, but once it starts depleteing you will notice the yield reduction and will be necessary to add nutrient input to the produce.

All of these are good answers, what we do in Corn, Alfalfa, Soy Beans, Sugar cane, we have a crop log of biomass analysis and soil analysis. Since I have an XRF we can do all the elements in single sample, no manipulation of the sample. I am publishing a paper comparing XRF and ICP, the results in precision and accuracy are more 99%. The ICP has higher variability.

If natural forest like closed system  exists and if  there is no net removal of nutrients from the system, one can ignore fertilizer or manure application.Can you calculate the nutrients going out of the system through fruit harvest and other losses?At least that much nutrients have to be added or compensated.Other wise fertilization is desired as highlighted by  Dr.Agegnehu.  As mentioned by Dr.Paul,also there may  be delay in nutrient utilization by the crop as the nutrients have to reach the active roots, probably deeper in subsoil.

Tree crops do require annual fertilizer application to maintain the C/N ratio for a regular bearing, otherwise like the crops you mentioned it would be low quality and erratic bearing, while the perennial crops has the tendency to store the nutrients in vascular system for the rejuvenation and to withstand the environmental stresses, which is a confusion for most of the scientists leading to conclusion like your -not to apply fertilizers on annual basis.

Dr. Klavinan, all the presented answers are good and help to explain the causes of the situation but please do not forget the volume of soil (horizontally and the down soil horizon- the sub soil) used for up taking nutrients by the spreading of roots, especially active parts. Hence, the perennials meet their need even if fertilizers are not applied. They indicate no deficiency symptoms and nothing can be assessed in plant analysis after harvesting.  However, if these are applied they will definite be benefited and have lesser energy utilization in effort for search of nutrients. The saved energy can be used for increasing of fruit yield. For knowing nutrient deficiency, the leave samples of growing parts should be obtained.

If applied fertilisers not impacting crop growth for considerable period then there must be some factors intervening in between. We must also look at this angle.

For a perennial crop five years is too short  in my opinion. Therefore it is necessary to fertilize based on the chemical analysis of soil or foliar . There is no alchemy this process: it is the drain source relationship

Fertilization is required for perennial crops or fruit crops at regular intervals for sustainable yield. I do agree with Dr. Rao that we need to find out the removal of nutrients from the soil after harvesting of fruit and then nutrients may be applied through integrated approach (organic + inorganic). I also agree with Dr. Vicente that the soil physico-chemical characteristics need to be estimated at least once in 3 years for better soil management. Another point is of importance is the soil reaction. If the soil is acidic in nature you have to add lime on the basis of the soil pH and lime requirement as most of the macro and secondary nutrients are available from pH 6.5-7.5.

Circular bands (for young plants) to be prepared for application of lime (if soil is acidic pH < 6.5) and organic manures and oil cakes and then inorganic fertilizers may be added through bore hole method by digging holes up to the root depth (90 cm) using auger on two/four sides of the plant and then placing fertilizers over there. Fertilizer application should be done during dry season and little water to be added to make the soil moist. There will be response of fertilizers as the release rate of nutrients from the soil stores (mineralization) often could not match the demand of  the plants. Moreover split dose of fertilizer application especially for nitrogen, potassium and micronutrients during the fruiting stage may enhance the yield and quality of the fruit.

Th bore hole method of fertilizer application to tree/ orchard crops is interesting.Dr. Mausumi,I think it is designed to reach the location of subsoil root activity of the crop It may vary among the crops but it is a  good attempt to reach active roots deep in the subsoil.In some coarse textured soils, nutrient ions like nitrate,Ca, Mg,sulphate may leach  down to lower depths even up to active root zone and taken up by plants.Is it possible/convenient to go for split application during the fruiting stage?Can they go for foliar application ?

Dr. Rao you are very right. Bore hole mehods are very effective for heavy soils and high rainfall areas. During fruiting stage foliar spray of micronutrients are recommended. I encouraged  split application of fertilizers but it totally depends on the soil characteristics, rainfall pattern and topography of the orchard. Otherwise foliar application of nutrients in splits is the best option.

Suggestions of Mauumi are good and workable.

Fertilizer must be applied. But it should be lower dose compared to recommended from your agricultural department if it is higher due to soil your region. However soil analysis is best thing for application of fertilizer. which major element is deficient then it should be corrected. Otherwise nutrient deficiency will cause low yield and quality of produce. Small doze of nitrogenous fertilizer application  through( fertigation) use of sprayer at direct tree plants will give important results.

I fail to understand  why such question comes to our mind to defer the any fertilizer application in the first five years of perennial fruits . There may not be any difference in yield for few years , it does not mean , there is no fertilizer application  need, which is again site specific , nothing to do with plant  physiological nutrient requirement   . As long as  perennial trees are in their peak orchard productive life , these effects might not be so distinctively visible , but as soon as such peak period is over , one can easily visualise the difference in productivity as well as orchard life both .  Perennial trees accumulate good amount of nutrients in their perennial framework, and they often continue to supplement nutritional requirement of crop through this means . But , again such attempts depletes the nutrient reserve of the plant and  exposes plant to various biotic factors , like diseases being one of them . In perennial crop , there is an established method of fertilizer application , called skirt belt application . Applying fertilizers within the perimeter of trees according to distribution of feeder roots is considered the best method of fertilization  , including the fertigation .  The perimeter  of trees for  fertilizer application  is usually considered 1.2 -1.3 times the perimeter of the canopy .  

Next question emerges , how do we fertilize these plants , and what methodologies  are we adopting to fertilize these plants.  It is usually said response of fertilization is as good as the diagnosis of nutrient constraints . Unless correct diagnosis of nutrient constraints is made , we will always fail to utilise the yield and quality incentives on fertilizer use . Therefore , crop- specific leaf nutrient standards or even soil test guidelines are used through proper sampling and analysis . I think we need to fertilize these trees on a long term basis , if we have to prolong the orchard life coupled  quality production plus shelf life of fruits . There could some orchard sites initially optimum in most of the nutrients , may not be that much critical during initial years of plantation , that does not mean , it should be invariably followed .This is still important to keep in mind that once a perennial trees enter into reproductive phase from long vegetative or juvenile phase , the nutrient dynamics of whole plant changes so abruptly , that in later years , it will be irreversible task to go for any remediation of such faulty  fertilizer practices.

We  are advised two types of recommendations for perennial tree crops-one based on feeder or lateral roots nearer to surface( Dr.Srivastava)and the bore hole method  based on active roots in subsoil at 90 cm( Dr.Mausumi).This implies that we should have some knowledge of root system of the crops -where root activity is more for nutrient uptake,surface soil or subsoil or relative proposition in both for fertilizer or manure application. Will it change with crop growth stage? will it be affected by management practices like fertilizer application and irrigation?Will some perennial trees survive on subsoil nutrients nutrients ,nutrients leached into subsoil or from mineralization of leaf litter ?Do you have separate recommendations before fruit bearing or after fruit bearing and harvesting?

Dr Mausumi , bore hole method of fertilizer  application is usually not adopted for perennial trees established in areas where rainfall is not so heavy  ( 400-1200mm ) and orchards are established on flat physiography terrain .  Bore hole method of fertilizer application using  upper half moon of tree basin is utilised in orchards established on slopy lands having exceedingly high rainfall (  more than 2000-3000 mm) . This method of fertilizer application is not exactly the  bore hole , but deep trenches ( Dimension depending upon soil depth  , could be upto 20-50 cm ) inside the upper half of the canopy basin is dug  , and fertilizers , amendments etc are loaded in upper half trenches of trees , so that ferilizers are not leached out of the effective roortzone under the influence of both gravity as well as heavy rainfall (For example Northeastern region of India and elsewhere  having similar soil conditions). And following strictly the bore hole method  of fertilizer application on hilly terrain  will not  be so effective , since  you will be allowing surface area of the effective rootzone of trees , eventually leading to much reduced fertilizer use efficiency . Such practices on flat land orchards will be still less effective .

Dr Rao , in perennial trees , usually we follow two types of fertilizer recommendation s, one for pre-bearing trees  and  another  for bearing trees , because during pre-bearing years , every passing year will bring incremental growth in canopy area  , expanding the nutrient requirement in tandem with canopy volume. And during pre-bearing years , plants require nutrients basically for vegetative growth  building the perennial framework of the trees. While  with onset of reproductive phase of the plant i.e. when plants start bearing fruits , it will be an entirely different nutrient requirement of those trees  . Now onwards , plants need nutrients  for both continuous vegetative growth as well as nutrients  for developing fruits which are so heavily  diverted from the leaves of various growth stages. This fertilizer recommendation , we assume will be effective  as long as trees are in peak productive life , but once those trees attain  senility , probably nutrient requirement will again change  . For senile orchards , fertilizer recommendations will be on the  higher side over the same earlier  recommended doses,  since  trees will not be experiencing so heavy root flush ( both quantum and intensity ). In addition , much lesser amount of applied fertilizers will be effectively utilised  towards sustaining the same fruit yield expectancy  preceding of productive years , simply because of reduced fertilizer-use-efficiency . 

Dear Kalaivanan

I say it is required to apply RDF for harvesting good yields from any crop. After 5 years if you do not provide sufficient food to tree like plants the yield in terms of quality and size will reduce. It happens with Mango and Sapota, that I have seen.

Dear D. Kalaivanan,

Some research suggests that cashew trees respond positively to irrigation and fertilization. But it would be interesting to know the type of soil in which the studies you refer to were conducted. The natural fertility of the soil is of utmost importance. It is known that cashew trees have very extensive root systems and therefore explore a large volume of soil. In moderately fertile soils, nutrient recycling through litter can provide significant amounts of nutrients.

It is also possible that a micronutrient is limiting plant growth and, therefore, the tree will not respond to the application of macronutrients; or that the limiting factor is water, and then it would be necessary to water for the plant profiting from fertilizers applied.

Attached is an interesting article on the subject.

As for pH, moderately acid pH is adequate for cashew trees, which grow well in well drained, coarse-textured soils.

I thank Maria Luisa for providing excellent publication of Grundon on cashew nutrient requirement.If the cashew apple is not removed from field,we have to at least replace or apply the nutrients  equivalent to removal through kernels  and testa plus shell in case of N,P,K and S.Ca and Mg are provided in sufficient amount  by leaf litter.As advocated by some scientists ,one can apply fertilizers on research farm without  crop response but we can not convince the farmers to apply fertilizers for several years without any benefit .As we can not also starve the plants, certain critical nutrients need to be applied to support the normal growth and harvest the economic produce.

Let me extend the discussion on the subject further  Dr Kalaivanan . We often stress upon unnecessary stress on possibility  the sub-soil nutrient supply  . Infact during pre-years, these perennial tress do not have so much of canopy development that these trees will shed leaves,  undergoing mineralization , getting accumulated in the subsoil , and eventually exploited by the roots to meet  a part of nutrient requirement. In fully grown -up trees , there could be some possibility of contribution from sub-soil .    

Cashew trees have a very extensive root system, especially horizontally. That is why large plantation frames are used, to avoid competition between trees. The roots explore a large volume of soil, not only in depth but especially horizontally.

Excellent discussion on fertilization of perennial tree plantations. As pointed out by Dr. A.K. Srivastava, two different recommendations  -- one for vegetative growth during establishment years and another for fruit-bearing trees -- are developed for each soil type. Trenches between rows of trees (coconut plantations) are dug and all crop wastes are dumped into the trenches for slow decomposition; the trenches also collect rainwater and let it penetrate deep into the soil. In some coconut plantations, intercropping of annuals and shade-loving perennials will be used to augment income and fertilization of intercrops will add some amount of nutrients to the main tree crops. In other areas, sheep penning is used to control weeds and to fertilize the soil. Overall, we need to establish how much nutrients are exported from the orchard in the form of fruits, nuts, etc. and how much organic matter (nutrients) is added to the soil from outside the orchard, and then we need to calculate and replenish the nutrient deficit with suitable fertilizers by an appropriate method. Foliar analysis is the best to indicate specific nutrient deficiency that can be corrected on a timely manner. Balanced use of both macro, secondary and micronutrients is critical for healthy trees and high yield of quality produce.  

Dr.Balasubramaniam and other colleagues ,I agree with you  that it as a good discussion.But one or two things are not clear to me .Are the crops like coconut,pomegranate and citrus are more cared for compared to mango , guava and cashew by the farmers.Root systems(depth and spread),return of leaf litter to soil and  availability of irrigation  water play a good role in managing nutrients in  perennial crops. In some orchards nearer to home  manures or house hold waste are applied .Irrigation is given in summer only.So we have to analyse the practices being followed by the farmers and intervene  appropriately with our technology or package.Even while planning research we have to look into these things.Is alternate year  or some years not bearing fruits in some crops like mango is related to water availability,nutrient reserves in plant or nutrient insufficiency in soil?Responses may also depend on rainfall received in a particular year.

Dr. Suba Rao, 

Really you have raised some good additional points despite the discussion already reached a very high level. Yes, I agree that all the factors, you pointed out, should be taken together while formulating a package of recommendations. The alternate fruiting or partial fruiting of mango in every alternate year can be partially regarded due to insufficient nutrient uptake because it has been observed that high application of nutrients could not cure this phenomenon. This problem still needs specific investigations and some good agronomic practices have to be brought forward in addition to some genetic considerations. 

Any research should use the set of farmers' current practices as the base or control for comparison of proposed packages; this must be in addition to zero fertilization control, if needed.

Jain irrigation has established closely planted drip-irrigated fertilized tree crops orchards in different parts of the country for demo purpose. Researchers close by can collaborate with Jain Irrigation company to develop mutually beneficial research projects on perennial crops that are optimally irrigated and fertilized. Anybody from Jain Irrigation can answer the question whether the alternate-year bearing of mango is a varietal trait or a nutrition-water problem. Do they observe this phenomenon of alternate-year bearing in closely planted irrigated and well fertilized mango orchards?

Dr Nazir , alternate bearing in mango has been investigated from various angles including the soil fertility and plant nutrition , but unfortunately none of them have been able nail the problem correctly . the biggest problem in these perennials is the correct diagnosis of nutrient constraints , which we have ben failing time and again . The entire performance  is hugely dependent  upon ,  how are we feeding these trees , whether or not according to plants nutritional  needs . And researches so far have revealed,  the problem is more a genetic trait driven  than any lacunae on account of insufficiency in fertilization . High density planting is also under evaluation in mango and citrus ( Citrus also tend to behave like mango , not true alternate bearing sense , but does experience on and off year cycle quite often)   at CISH , Lucknow and CCRI, Nagpur . But they have least  relation to throw any concrete line with regard to such behaviour( Dr Balasubramanian ). Rather there have been precocity in bearing , earliness in flowering , but no explanation for  so called elusive problem of alternate flowering . Another issue Dr Balasubrmanian , you raised  a very pertinent issue , what should be the basis of  annual fertilizer recommendation in perennials since w eneed to giv esome liverage about the  development of perennial framework of the plant . This is equally important   looking  at the perennial source   nutrient reserve ,  a major fraction of which is  diverted towards floral primordia formation during induction of flowering and subsequently fruit set as well .  .    

Yes Sir,

Trees also require nutrition. Mango or any other fruit tree will give good yield if you provide better nutrition.  As Anoop sir told alternate bearing in Mango, it is the inherent character rather nutritional. In sapota I have seen small fruits because of  no feeding.

In perennial trees, i is difficult to whole plant (tree) analysis. It is therefore important to develop a nutrients inputs-Nutrients outputs balance method once the trees reach maturity and bears fruiting at optimum level. Another way is to identify an index plant part that reflects the true tree nutrition level for optimum bearing and then analyze that plant part to determine nutrient deficiency, if any, and correct it on a timely manner. For micronutrients, foliar application is the best.

In short yes, otherwise your yield and fruit quality will be affected.

In short yes, otherwise your yield and fruit quality will be affected.

I endorse the views of Dr. Balasubramaniam

In Bangladesh fertilizer recommendation is done based on research results, considering both agronomic and economic performance. If it is true also for your country using fertilizers in recommended dose should increase both agronomic and economic benefits.

Yes, Abdus Sattar, economic performance is the deciding factor for a farmer, may not be for a researcher because he thinks mining and replenishing mechanism as well. However, a farmer will always be thinking like that how much he will get if he put in expenditure on application of certain fertilizer. 

Dear Dr. Nazir Hussain

Your answer is quite convincing but Dr. Md. Abdus Satter 's point is still valid as most of the research studies  in the government institutes are farmers' interest oriented

In fruitcrops  is essential to apply fertilizers for good vegetative growth,  appropriate yield and fruit quality. I recommend soil and leaves  analysis, If you no met differences it is possible that soil  had adequate amounts of nutrients. I agreed with Bhadu.

Let me expend this discussion further as to why such question comes to our mind , whether or not recommended doses of fertilizers is necessary , especially during the vegetative years  ( Pre-bearing stage ) while dealing with perennial trees. Let me cite a classical example of northeast India , where  new perennial orchards are established by cutting the forest ( Often called slash and burn , known as Jhooming as a part of shifting cultivation ) . This site would be a  rich source of different nutrients , and there will much favourable soil pH also after burning and turning the burnt plant ashes into the soil . Under such condition , one can expect that fertilization need not to be so aggressive . On the contrary , on a soil site where re-palnting or another cycle of perennial crop is to raised , probably here we need to adhere to recommended doses of fertilizers. So , fertilizer application eventually comes to initial nutrient profile of  soil  as a function of soil test value to decide whether or not fertilizer should be applied  during per-bearing years of perennial trees.  

For me, the answer is very simple and straight forward. First determine the crop requirement and analysis the soil supporting capacity. Decide whether you need to apply or not. Now, you might argue that recommended dose is based on crop requirements. Unfortunately, in mamy of the cases it is not. In many cases people make fertilizer trial with different rates of one nutrient keeping all other fertilizer nutrients constant. This types of experiment might not menifest potential yield as nutrients maintain stoichiometric relationship. I mean if you apply increased rate of N, you must apply increased rate of P. Otherwise, this will just lead to loss of  N. Therefore, in many cases recommendations are not justified and valid. Follow your own analysis and take your decision.

Dear Mr.Mia,In addition to variable rates of one nutrient   at constant level of other essential nutrients,now we are using combination of nutrients in balanced way at lower as well as at higher rates of application in partial factorial design in Indian soil test crop response correlation project( ICAR ). Even other factorial designs may be available which can be tried.

Dear Rao,

Thanks for your answer.

Unfortunately, in Bangladesh it has not been started in many cases. 

Thanks!

I agree with Shamim Mia answer

Let it be any fertilizer application strategy , it has to based on our experimental results -based recommendation , later fine tuned to field application in a  much larger perspective . But once , we have calibration data , we can adjust our fertilizer recommendation suiting to different fields and crops , instead of sticking to strategy of  application of minimum doses of fertilizers.  And  the recommended doses of fertilizers will undergo certain changes as per crop age , distinctly varying from  vegetative phase to reproductive phase   .  The recommended doses of fertilizers will also undergo changes as per soil  types , alot depends upon the initial soil test value , yield target and the stage of the crop , all collectively conditioned by the nature and properties of soils , in addition to irrigation method being followed, since drip irrigation -based fertgation imparts much higher fertilizer use efficiency than basin method of irrigation .

All plants and trees do require nutrients. The level of nutrients available controls the growth and development as well as the production. Tree crops mentioned too do not deviate from that. 

If the soil does not provide nutrients, the roots should explore deeper soils, provided that the soil physical properties such aeration porosity do not restrict root growth and penetrability. Application of fertilizers in the short supply of key nutrients from the soil (after determining with a soil test and tissue analysis) would always be beneficial.

If the crop is irrigated, the nutrient contents in the irrigation water should also be added to nutrient availability. Then the balance can be supplied after considering the percent availability of nutrients in the media/fertilizer, etc.

Hope this will provide some assistance in addition to what has been mentioned by the above persons.

The law of the minimum implies that yield is constrained by the nutrient with lower bioavailability (remember that plants take up nutrients from soil and not from fertilizers. Nutrient availability in the soil is what is changed by fertilization).

I suggest you to carry on a soil test to evaluate the limiting factors; try to correct them and to then monitor the nutrient status of your cashew crop by yearly leaf analysis (beginning of rainy season).

Cashew is a quite rustic crop, so high responses to fertilizer application are less expected than other crops.

You can find practical information in IFA’s World Fertilizer Use Manual that is available for free in the internet (http://www.fertilizer.org/ItemDetail?iProductCode=7351Pdf&Category=AGRI&WebsiteKey=411e9724-4bda-422f-abfc-8152ed74f306)

http://www.fertilizer.org/ItemDetail?iProductCode=7351Pdf&Category=AGRI&WebsiteKey=411e9724-4bda-422f-abfc-8152ed74f306

It is really interesting to to be a part of such an excellent discussion on the subject . In these perennial crops , another very important  part is missing . Do we need to apply fertilizers in increasing doses  , with increasing age of the trees? . Is there any  effective mechanism to monitor the fate of application of fertilizers in preceding years? , And , using this as a base, subsequent fertilizer doses are to be downscaled or upscaled , keeping in mind,  the perennial framework ( Some additional fertilizers are needed for development of their framework  , until peak productive life of trees ) of these crops .

The question brought by Dr. Srivstava is very important and the idea of incresing fertilizer dose as crops grows depends very much on the type of nutrient we are talking about, to my point of view.

For example, N is extremaly dynamic in the soil-plant-atmosphere system, so it is very unlike to build up a N stocks. On the other hand, P is quite immobile in the soil and the plant uptake is mostly by root interception. Hence, we see often an increase in soil P avaliability in orchards along the years, mainly because the root system is still small in the initial development phase of the crop.

In my opinion, the best available mechanism to assess the bioavailability of nutrients to perennial crops is regular leaf analysis.

In perennial crops nutrients application takes place at same place. There may be nutrients build up in course of time . Therefore, based  on rhozospheric soil nutrients status, doses of nutrients  should be fixed. In such case 50 per cent nutritional requirement should be met from organic sources and rest from inorganic. 

Irrespective of age of the tree or the natural nutrient availability, some amount of additional supplementary nutrient supply is essential.

Nutrients are required by all plant species regardless of their growth habits. the differences are in the dose, time of application and recipe of the applied fertilizers. for fruit trees, fertilizers will differ in the amount for the first few year but later on it should be continued regularly for best growth and production. the results may differ from one grower to another also because of the fertilizer placement and how close it is from the most active root zone.

Assuming that your soil are fertile, you still have to add some fertilizers to keep this fertility. otherwise, the continues depletion of nutrients due to plant uptake will reduce this fertility resulting in yield reduction and symptoms of nutrient deficiency.