These textural differences in the surface soil did not generally cause noticeable variation in yields. Fortunately, the task is facilitated by the generally uniform condition of palms in the various fields. T he spear consisted of three unopened leaves in the center of the crown and was only cut from the trunk - after the palm had been cut down.
In the crown, the rachis was the dominant component, and the weight of the pinnae was about half that of the rachis. The summation curve is closely related to that of the stem in the mature phase of the palm. It is interesting to note that in the mature palms the roots constituted about 20-13% of the total dry matter in a decreasing trend from about the 80th month onwards.
On average, only about 15% of roots were found below a soil depth of 60 cm, even in the deep inland soil at Jerangao. In the canopy, the order of nitrogen levels was cabbage > feather > spear > rach. Average values for whole palms in the field were two to three times higher than those for nitrogen.
I F'inme '.-his Caibage Tmnk Trunk Tmnk
Within individual palms (Fig. 9b), auricle potassium levels clearly decreased with leaf age and the auricles of older leaves from the two older palms tended to have higher values. Phosphorus content was the largest of the major nutrients in absolute terms, generally being 10-20% that of nitrogen. As in the case of nitrogen and potassium, cabbage was the richest and the roots the poorest in phosphorus.
In the crown, the order of phosphorus concentration was cabbage > spear > pinnae > rachis;. It is interesting to note that the peaks occurring at 115 months in the curve of crown and stem coincide with those of stem potassium. Fosp a orus levels in general were less variable than those of nitrogen and potassium, thus consistent with findings on phosphorus content in leaf blades.
In the crown, feather and spear levels were generally comparable, but rachis had slightly lower values. In the trunk, the inner part had higher values in the early years, but the position was reversed in older palms. In the canopy, levels tended to decrease during the first 90 months and then increase, probably due to fertilizer application.
Except for palms up to 14 months in the field, magnesium in stem followed the pattern in crown. Within individual palms (Fig. l l b), magnesium concentration in pinnae increased from the first fully opened leaf blade to about leaf blades 7-10 and then decreased, markedly in the older palms. Crown values were greater than those of whole stem and again root levels were the lowest.
Apart from the first year, the calcium level in the components behaved in the same way as magnesium. It is interesting to note that while the concentration of phosphorus in cabbage exceeded the concentration of sulphur, the position was reversed in the case of other tissues of the crown.
Most palms also showed this trend for potassium and phosphorus, but this was not evident in the case of calcium. Since young plant tissue is known to generally contain higher concentrations of most key nutrients than older tissue, the results suggest that the palm's active root region probably extends beyond a radius of 1.2 m from the base of the palm.
I .76 Metre 0.68
In most palms, the softer, inner part of the stem, presumably the more physiologically active part, showed a concentration gradient for all the nutrients except magnesium. The highest concentrations were at the palm neck just below the cabbage as shown by nitrogen, potassium and phosphorus. The shapes of the curves are comparable to dry matter production, and this also applies to other nutrients.
In the first 70 months the crown accounted for the dominant part of the total, but after that the trunk became the dominant part and this dominance increased over time. The curves are exponential in nature and the summation curve was very similar to that of the trunk except in the few early years. So it took about half as long for the potassium, phosphorus and sulfur levels in the trunk to make up the bulk of the other nutrients in the whole palm.
At maturity, the curves of otasia and sulfur content in the trunk became more divergent than those in the crown, but this difference was smaller for other nutrients. This emphasizes the dominant position of the trunk in the distribution of potassium and sulfur throughout the palm. Within the crown, most of the potassium, magnesium, calcium and sulfur was located in the rachis.
As already mentioned, the content in the trunk represented the dominant share in the intermediate total from 2-6 years on in the field and it steadily increased with age. Excluding the early period of 2-4 years, the nitrogen content of pimas was second to the trunk, and in the case of potassium, the rachis content exceeded that of quills. While the proportion of nutrients in the trunk increased with age, the proportion of nutrients in the quills and feathers decreased.
Nutrient content in the roots of field palms generally accounted for less than 10% of the total in the palm. From the cumulative curves of different nutrient contents in the palm, the annual net increase in nutrient content for growth.
However, the differences between summary and additive values are generally on the order of less than 5%. In all cases except sulphur, growth for the whole palm was greatest in the third year. Also, while crown growth values were highest in the second year, except for sulfur, trunk growth peaked about one to two years later.
Each year in the field, the standing palm increased its nutrient content by a net amount because fronds were cut off during the harvest of fruit bunches. Net growth rate values for various nutrients in palms up to 15 years in the field are shown in Table 17. As previously pointed out, the growth rates were highest in the immature years, in articular the first two years of field planting.
These increases during this adult stage were accounted for by increases in the trunk. It suggests the dominance of crown content and its faster build-up in the first five years in the field. On the contrary, it continued to increase with age, albeit very little in the mature years.
While measurement of leaf length is useful in the absence of better indices, the present findings clearly indicate that quill weight. Thus, in the immature period, the feather weight of the 9th leaf will be a very useful index of the growth rate of the palm. Since feather weight is also related to leaf area, this index should be preferred over leaf length in order to evaluate the performance of palms, especially in the early years.
The total dry matter production of the palm increases the production of both vegetative tissue and reproductive organs in the palm. For comparison purposes, it is best to consider total dry matter production levels in mature palms that produce steady yields of fruit bars.
Given the fact that such a large proportion of roots were found within 2.4 m of the base of Malayan palms, further investigation is necessary to unequivocally determine the location of feeder roots in the palm. Such research should include the application of nutrients to the soil and the use of tracer techniques. For the palm as a whole, the order of nutrient concentration is K>N>S>Ca/Mg>P, being similar to that in the fresh fruit bunch and confirming the main position of potassium in palm oil nutrition. which trunk plays a vital role.
That the trunk is a storage organ is illustrated by the decrease in potassium and nitrogen levels in the inner trunk as the palm age increased. Although little is known about sulfur content in the oil palm, results show that sulfur Further checking is essential and this has already been shown in Part I of this series in the case of nutrients in fresh fruit bunches.
But by far the most important aspect concerns the role of nutrients, especially potassium, in the metabolism of the palm. During the first 60 months, the crown constituted the majority of the total plant dry matter in the palm, but thereafter stem tissue became the dominant component. In general, less than 20% of the roots in the sampling zone were found in the lower 60–90 cm soil layer, even in a deep, inner soil layer.
This suggests that pinnae weight of leaf blades 9 or 17 can be conveniently used as an index of growth rate, especially in the early growth stages of the palm. T he total vegetative as well as reproductive dry matter production of mature palms aged 8-15 years in the field is estimated as follows:-. In the case of potassium, its concentration in the stem actually increased with the first five.
This suggests that leaf analysis would not invariably detect a resen7 amount of potassium and nitrogen in the palm until a critical stage. It was shown that satisfactory cumulative nutrient content curves could be drawn through the nutrient content values of the main components of the palm. The cumulative curves showed that the accumulation of potassium content in the trunk was the fastest, followed closely by phosphorus and sulfur.
Scope of use of detailed soil maps in the planting industry in Malaya. iruit tufts and male inflorescences.
