Dear Shampriti,

Yes, I think your experimentation explain (partly) your finding. The availability of certain nutrients can be crucial for a good reproduction for crop. Please investigate on this aspect. Other problems like pollen limitation is one of this issue (see Ashman et al, 2004, Ecology 85) 

Please provide some details of your experiment.Have you applied adequate P to the crop? Is it  rice crop?

Rao Sir, the crop I tested was Maize. Actually, I applied equal total N to the crop using digestates from different feedstock. But, in case of digestate with higher mineralized N, the vegetative growth (height, leaf area etc) were quite higher, but reproductive characters (grain yield, weight, cob weight etc) were lower than that of application from a digestate with lower mineralized N. But the reverse is true, i.e. lower vegetative growth and better reproductive growth  was obtained with digestate application having lower mineralized N.

This means, plant with better vegetative traits show lower reproductive traits! So sir, how can I explain this, can you please give some idea?

When one applies more fertilizer N or if more mineralized N is available(as in your case),the excess N encourages more vegetative growth.If other nutrients , especially P are available in adequate amounts the reproductive characters or yield attribute may not decrease.We have to see for balanced nutrition of the crop when we impose treatments.Yield potential of the crop/crop variety selected is also important.A crop variety with less yield potential when provided with more N,may not be able to utilize it for grain production and may put up more vegetative growth.Excess nitrogen can be translocated to reproductive parts and utilized provided that the P and other nutrients are not a limitation. In case of low nitrogen supply treatment(low mineralization), the availbe P may be just adequate to meet the reproductive phase requirement.So,Please check whether you applied adequate P .Have you analyzed the soil for different plant- available  nutrients?Analysis of the plant samples may also clarify whether other nutrients especially  P is adequate or not.

It optimize crop growth if one only considers Nitrogen the tendency is to stimulate the top growth and not stimulating as much the root growth. The tops and roots should be balanced with each other for optimized plant health. Phosphorus is needed for agressive early root growth in particular and needs attention for optimzing maize through starter nutrient. The nitrogen is most needed from knee high to flowering and the potassium is most needed at waste high to milky grain stages. The use of soil analysis and tissue analysis can be useful for finding the rich balance of nutrients for optimizing you maize crop. The best approach is targeting a full nutritional program based on soil and tissue results. 

Dr.Sampriti,have you checked/computed how much P and K are added through digestates from different sources in your experiments?Prior to this crop plant experiment (pot/field) have you conducted N mineralization study? It is desired to study P mineralization along with N. K is readily available to plants if the digestates contained sufficient K.

When the soil nutrients are more than the critical levels , additional sources of nutrients from fertilisers will lead to luxury consumption and the plants will continue to grow vegetatively and delay fruiting and maturity leading to low crop yields.For example, excess nitrogen in soils will lead to excessive vegetative growth of maize ,rice,sorghum and so forth,with taller height which make suspectible to wind attack-[lodging] ,loss of good number of plant population ,delayed maturity and low yields .Besides, the harvested crop yields will suffer quick deterioration with poor storage ability because excessive nitrogen increases water uptake. Therefore, there is a need to carry out soil analysis to determine the critical levels of nutrients which will determine the amount of nutrients to add from fertiliser sources to stabilise the soil equilibrium also nitogen fertilisers should be applied in phases to prevent luxury consumption and law of diminishing returns.Finally.destablisation of soil equilbrum through excessive nutrients will reduce uptake of other nutrients which is called nutrient antagonism as noted in K/Ca, P/Mg , K/Mg ,N/P interactions

I think yes, the rapid growth and too vegetated decrease significantly yield. This is the case of excess nitrogen in cereals.

I think you gave the plants excessive dose over its demand which encourage  vegetative growth and let  juvenile  phase takes along time so that it caused a little yield compared with the case of the fertilizer with less available N and slow N release  where N as i think was available to plants in adequate quantities during all of vegetative and reproductive stages so that it gave abetter yield .

the excessive supply of N encourage your plants to continue in the vegetative growth rather than start the reproductive growth and go in the "luxury" consumption of N.