The response of the carrot to water supply and fertilizer on a gravel soil

Abstract

This experiment was carried out on the Gravel Pit Field of Gravel Hill Farm, Cambridge. The soil to 9 in. gave the following analysis: j?H, 7-83; lime requirement, nil; free CaCO 3 , 2-93 %; available P 2 O 6 , 0-102 %; available K 2 O, 0-028 %; loss on ignition (less CO 2 ), 4-96 %; total nitrogen, 0-171 %; and moisture, 1-17 %. It thus showed very good phosphate and potash contents.The treatments were all possible combinations of ft}"where F o and F 1 represented no fertilizer and fertilizer mixture, respectively, and W o , W v and TF 2 represented the three levels of water, W o = rainfall (4-55 in.), 1^! = rainfall plus 3 in. of extra waters 7-55 in., and TT 2 = rainfall plus 6in. of extra water = 10-55 in. They were assigned at random the labels A-F, as follows:

Plant growth with nutrient solutions: I. A brief review of existing work

“…In sand, growth increased with water content up to 80 % of the water-holding capacity, while in soil the maximum growth was at 60%. It is interesting to note in passing that a similar effect was obtained by Woodman & Johnson (1944) in the field with Ideal carrot, when increases in yield of over 100% were obtained by the addition of 6 in. water to the natural rainfall.…”

Plant growth with nutrient solutions: II. A comparison of pure sand and fresh soil as the aggregate for plant growth

“…The same quantities of solution were always used in all treatments, so that the only varying factor was the amounts of nutrients applied, and not the water supply, which might equally well have caused a variation in yield (Wolkoff, 1918;Woodman & Johnson, 1944). Had opportunity permitted, it would have been advantageous to carry out experiments to determine the effects of the amount of water supplied when a,U treatments were receiving the same absolute amounts of nutrients, and also tocompare plants grown in an optimum solution in sand with those grown in soil (in pots) when given a single application of a fertilizer mixture (such as would be given in normal horticultural practice) at the commencement of the experiment, followed by water only, identical in volume with that used in the solution with sand.…”

The composition and digestibility of Northern Irish hays: I. Unthreshed and threshed ryegrass and crested dogstail hays as saved for seed.

“…All of the hays examined had starch equivalents considerably less than the average quoted for seeds hay low in clover by Ferguson & Watson (1944). The data given by Woodman (1944) for perennial ryegrass hay would, by comparison with those now reported, appear to relate to leafy ryegrass hay cut at an early stage. While it is fully recognized that the present results relate to hays saved in two seasons only and that seasonal effects probably influence values for composition and digestibility, nevertheless the results suggest that unthreshed ryegrass hay saved for seed has a starch equivalent in the neighbourhood of 33 on a dry-matter basis, while threshed ryegrass hay has a starch equivalent in the neighbourhood of 28 on a dry-matter basis.…”

“…The figures quoted by Davies (1939) for perennial ryegrass straw are closely comparable to those now reported for threshed ryegrass hay. First-year seeds hay low in clover (Ferguson & Watson, 1944) First-year seeds hay, average (Ferguson & Watson, 1944) Perennial ryegrass straw (Davies, 1939) Perennial ryegrass hay (Woodman, 1944) Ferguson & Watson (1944), Davies (1939) and Woodman (1944) are included in Table 1. The samples of ryegrass hays examined in the present investigation were representative of such hays as they are grown in the principal ryegrass seed producing areas of Northern Ireland.…”

“…By arrangement with growers, samples of unthreshed and threshed ryegrass hay from the same crop were secured for digestibility trials in 1944 and for seed, threshed First-year seeds hay low in clover, (Ferguson & Watson, 1944) First-year seeds hay, average (Ferguson & Watson, 1944) Perennial ryegrass hay (Woodman, 1944) -35-3 29-3 -36-4 29-9 27-4 -28-4 -32-5 28-4 -43-5 43-3 a <3.…”