FAQ

Recently mature leaf called “Index Leaf” can be collected. The age of the leaf varies depending upon the crop.

Generally the leaf samples may be collected before fertilization during pre-monsoon and post-monsoon periods. Depending up the crop and purpose, the period can vary.

If the leaf samples are tested, one will know the fertilizer that has been applied has been taken by the plant or not. You can also know the hidden hunger of the plant for correcting and to get good production.

If soil is analyzed for various nutrients, one will know the capacity of the soil to supply nutrients for the crop that is being grown.

Before fertilization or after 4 to 5 months of fertilizer application, the soil may be collected.

The soil should be dried in shade but not in sunlight.

Soil Augars, Spades, Crowbar etc.,

From a uniform field of 1 acre, 10-15 sub-samples can be collected in a zig-zag manner and can be made into a sample of 1 kg by quartering method.

In general, the soil samples can be collected from 0” – 9” depth or 0” – 12” depth for nutrient analysis purpose depending upon the corp.

The soil samples should be collected from the field by moving in a zig-zag manner.

Phosphorous is a relatively immobile fertilizer nutrient and suffers from instantaneous fixation if intimately mixed in the soil. Normally, the crop absorbs most of its P requirement during early vegetative stage and therefore one basal application is adequate. Keeping these points in view, banding of superphsophate 5cm below the seed/plant row led to the maximum utilization of the fertilizer in most crops except okra which performed when placed 10cm below the seed row. As a result in brinjal, a saving of 40% of P input and in tomato and onion, a saving of 20% was achieved without loss in yield. In other corps, any reduction in p-input reduced the yield.

The N use efficiency can be maximized by increasing the number of split applications. However, it is not advisable to exceed 3 split applications as the increased cost of fertilizer application makes it cost-prohibitive.

Among 6 popular cropping sequences practiced around Bangalore, the most efficient sequences were French bean-tomato-onion (38.37% utilization of N applied to first crop) and Okra-cabbage-brinjal (21.82%). Different combinations of crops in the same sequence also differed significantly. For instance, the sequence of Tomato-onion-French bean was the best (42.13%) in the former sequence while Cabbage-okra-brinjal (23%) was superior in the latter sequence.

The nutrient use efficiency of fertilizers can be enhanced by appropriate placement, method and time of application consistent with the behaviour of the fertilizer nutrient in soil. In the case of nitrogen which is a relatively mobile nutrient, banding and deep placement/incorporation in the soil will be helpful. The time of fertilizer application to synchronize with the period of high root activity and crop need will maximize its use efficiency. In the case of ‘Arka Vikas’ tomato (a semi-determinate type) for instance, a saving of 25% N-input was possible without loss in yield by postponing the basal application after planting and applying the fertilizer in 3 equal splits within 30-35 days of planting.

Efficiency of fertilizer nitrogen use was studied in 6 vegetables viz., tomato, onion, brinjal, okra, chilli and French bean using 15N-enriched fertilizer. The utilization of fertilizer N ranged from 13.9% in chilli to 44.8% in brinjal. Onion showed the highest N use efficiency ratio as well as physiological efficiency while brinjal showed the highest agronomic efficiency. Nitrogen balance studies showed that a large portion of applied N ranging from 31.7% in onion to 80% in French bean remained in the soil, most of it in the top 30cm of the soil. Loss of N fertilizer from the soil ranged from 0 in French bean to as high as 50.7% in onion. The relative dependence between soil and fertilizers differed considerably among different vegetables. However, in general, the vegetable crops depend more on fertilizer source during vegetative growth till flowering stage due superficial root growth. At later stages, they depend more on native source due to root proliferation at deeper depths. Any fertilizer applied at later stages, therefore, tends to go unutilized.