The root system of the weeds may have a greater effect than the shoot, and the opposite may be true, as the root system impedes the spread of agricultural crops, as well as competition for water and nutrients.
As for the shoots, they compete with agricultural crops for carbon dioxide and sunlight, and may help with disease infections
@ Nofel, I think the ratio is important . That means the ratio of the amount of plant tissues that have supportive functions to the amount of those that have growth functions. Plants with a higher proportion of roots can compete more effectively for soil nutrients, while those with a higher proportion of shoots can collect more light energy.
It is a nice question!
it is hard to answer it.
it depends on plant type, usage and climate, however we have to seen the whole plant at all.
I think both the roots and the shoot system. I would tend to think the root system is more important because the shoot system depends on soil nutrients and water drawn from the soil, but then nutrients and water are need driven of the shoot system, making the latter equally important. Like photosynthesis for example will not be complete when water is absent/limited. Taking this into consideration, the order of importance should be root system, then the shoots, for most crops, at least.
Good roots, good shoots... Bad roots, bad shoots. In agriculture we are all "root growers".
Of course, the best example of this is the Saad or galangal (cypeus rotundus) plant in sugar cane fields ... etc.
With regard to the root system, it certainly has a great impact on the growth and productivity of agricultural crops. In plants with a large root system, the number of root hairs is more, and the extension of the root in the soil horizontally and vertically is greater and therefore the surface area of the root in contact with the soil is greater, and the plant's ability to absorb nutrients from the soil increases. This is due to the large size of the rhizosphere, which is the arena of chemical and biological activities that occur between the soil and the plant. As for the vegetative system of the plant, by increasing the number of branches of the vegetative system, the number of plant leaves increases and the plant’s needs of nutrients and water increase, and this requires soils rich in nutrients and a large root system to meet a need Plant from soil
I think both are important and have a great impact on agricultural crops. These are depend on what type of crops and weeds are involved in the competition. Primarily root system impacts initially and then gradually increased at their growing stage. After germination, if the shoots of field crops are grown quickly the weeds become lag behind, or in the case of broad leaf crop the weeds become suppress.
Dear doctor
I do hope my choice from Blaha (2019) study gives a convincing and satisfactory answer.
"Importance of plant integrity in crop research, breeding, is extremely important. Plant integrity looks like a “very easy and expanded topic” but the reality is totally different. Thanks to the very high specialization of scientists, we are losing a holistic view of plants and are making mistakes in our research due to this drawback. It is necessary to sense a plant in their whole complexity-in both roots and shoot, as well as throughout their life cycles. Only such an integrated approach can allow us to reach correct interpretations of our experimental results [1-6]. Further as folloows from literal quotation (St?eda ):Especially development of root :Shoot ratio during vegetation period is important. As an advantage it seems to be such a ratio, when at the beginning of vegetation the growth of the roots predates the growth and the development of the above-ground part, ie., if the root system reaches its maximum before the above-ground part. The quality of the root is very important, but it is not only a question of the size of the root system. There is is also a question of the root system activity and the maximum development in optimal time during crop growth, type of root branching, root penetration to the soil. It is necessary to pay attention to individual species, crops cultivras and their phylogeny and ontogeny[7,8]. In general, agriculture accepts the fact that a 1% change of the root system size corresponded to a 2% change of the grain yield. It is known, that the seed traits also affect the filial generation root morphology at the beginning of the vegetation period (especially length, surface, depth of root penetration, and also root weight). In the biology of the seeds, roots, yield formation, stress tolerance, etc., attention needs to be paid to plant integrity and adaptability during variable environmental conditions. Most scientists study only half of the organism, namely the aerial parts of plants and are neglecting the underground parts of plants. So in this case, the question is whether the published results for crops are correct and have correct and explanatory information content. Analysis of the root system is desirable-lot of methods exist[9-13] etc. Based on subjective evaluation and scientific results, crop varieties can be divided into two groups, i.e., adaptive, plastic varieties that are tolerant to variable weather and varieties designated directly for specific conditions, especially for drought conditions, organic agriculture wit etc. There is a lot of literature evaluating these issues, but predominantly without information concerning to root system, which plays an important role in crop production. So far from a general perspective is knownthat 55% of the total root weight isusually found between 0 and 25 cm for most crops, about 18% is between 25 and 50 cm, 15% of the root mass is between 50 and 75 cm, and below 12% of the root mass, which is particularly important for drought. Influence of Rht genes, especially cereals on root shoot ratio is often discussed and analyzed. Interestingly, the Rht genes reduce plant height i.e., have a significant effect on the above-ground part habitus, thus often also modifying the described ratio. But the direct effect on the root traits is in some cases sporadic. Rather, there are improved plant metabolic transport conditions, etc.,“Dwarf genotypes” have in some cases a higher root weight and a ratio to the above-ground mass at the beginning of the vegetation-which is positively reflected later in yield. It is a metabolic advantage from a physiological point of view, especially at spring crops. [14-18]. As follows from so far obtained results, it exists little evidence of varietal differences in genotypes root growth with Rht genes, but there are some indications, that at depth the roots of the semi?dwarf varieties they take more phosphate from the soilthan those of the taller varieties."