An Approach to the Study of Yearly and other Variation in Crop Yields

The effects of deep ploughing, shallow ploughing-with-subsoiling, shallow ploughing, and shallow rotary cultivation combined factorially with three manurial treatments on the yields of vegetable crops are described. Each of the five crops in the rotation was grown in each year from i960 to 1962 on a sandy loam at Wellesbourne.

Where a high level of fertility bad been built up by the use of farmyard manure (FYM), yields were subsequently maintained at a high level for a three-year period by the use of NPK fertilizers alone.

Plots which had received either FYM with NPK fertilizers for each crop from 1954 to 1962 (FYM -j- NPK), or FYM with NPK fertilizers from 1954 to 1959 but with NPK only from i960 to 1962 (residual FYM + NPK), gave much higher yields than plots which had received only nitrogenous fertilizers from 1954 to 1959 and NPK fertilizers from 1960 to 1962. The increases in yields from FYM + NPK over those from residual FYM + NPK were small, and significant only for autumn lettuce and leeks.

Although, on average, the differences between the yields from the three ploughing treatments were small (the largest was 10%) some of the differences were significant.

The ploughing treatments gave significantly higher yields of early peas, autumn lettuce, leeks and Brussels sprouts than shallow rotary cultivation ; with early summer cauliflowers, however, only shallow ploughing-with- subsoiling gave a higher yield than shallow rotary cultivation.     

The Effects of Different Manurial Treatments on The Yield and Mineral Composition of Red Beet

Red beet was grown in factorial manurial experiments at two sites: at Wellesbourne annually from 1954 to 1964 in a rotation of vegetable crops and at Efford in 1959 only.

At Wellesbourne applications of FYM (20 tons per acre per crop), together with NPK fertilizers, consistently gave much higher yields than mineral fertilizers alone, but the relative effect of FYM did not increase as the experiment proceeded.

In the presence of FYM, yields of red beet increased with increasing rates of application of Nitrochalk (up to 124 lb. N per acre), but applications of phosphate and potash fertilizers did not affect yields.

In the absence of FYM, phosphate fertilizers did not increase yields significantly after 1959; there was an important interaction between the effects of the applications of Nitrochalk and SUlphate of potash. Each fertilizer applied alone produced small increases in yield, but when they were applied together at the highest rates used (186 lb. Nand 192 lb. K₂O per acre) large increases in yield were obtained and there was some indication that an even higher rate of application would have given a further increase in yield. At Efford, nitrogenous fertilizers increased yields significantly.

Applications of FYM increased the potassium and decreased the calcium and magnesium contents of red beet leaves and had only small effects on the nitrogen and phosphorus contents; in the roots, only the potassium content was altered (increased) by the FYM applications.

In general, in the absenc~ of FYM only potash fertilizer applications had large, consistent and significant effects on the mineral composition of the leaves and roots. At both sites, applications of sulphate of potash increased the potassium content of the leaves and had a much smaller depressing effect on the calcium and magnesium contents of the leaves but not, in general, of the roots.

The effects of the nitrogenous fertilizers on the total nitrogen content of the roots were relatively small, but could be important in relation to the processing quality of the beet.

The marked differences between the responses of red beet and early potatoes to the manurial treatments are discussed in relation to the nutrient contents of the plants.     

The Effects of Manurial Treatments on The Yield and Quality of Carrot Seed

Seed crops of carrots were grown in 1962, 1963 and 1964, on plots of a 2⁴ N, P, K and farmyard manure factorial experiment. Significant seed yield responses were obtained to each of the fertilizers and to manure, as compared with the yields from the control plot with no manure or fertilizers.

Except when a seed-borne disease caused by Stemphylium radicinum was present, the germination of the ungraded seed was well above the statutory declarable minimum of 60% and there were no significant differences in germination caused by the manurial treatments.

The seed produced in 1963 and 1964 was of similar mean chemical composition to commercial seed and, although its composition was affected by the nitrogen and farmyard manure dressings, these variations in composition did not affect the yield of roots obtained from field sowings of the 1963 seed. The 1962 seed was exceptional in having a lower mean phosphorus concentration than commercial seed. The seed with the lowest phosphorus concentration was obtained from the plots which had received nitrogen but not phosphorus fertilizers, and the root yields from such seed were significantly lower than those from the seed containing higher concentrations of phosphorus.     

The Minimization of Variability in Apples Planted on the Site of a Previous Orchard

Following the grubbing of a mature orchard of Bramley’s Seedling apples an investigation was made into the effects of deep (18 in.) or shallow (9 in.) ploughing immediately after grubbing, and of rich or poor manuring during the ensuing seven-year period of arable cropping, on the restoration of uniformity of the soil and its suitability for further experimentation on apples.

The effects of these treatments were assessed through a study of the variation of an apple indicator crop planted at the end of the period of arable cropping and are discussed in the light of the results previously observed after only three years of arable cropping.

There was some indication of a “distance-from-former-tree-site” gradient in growth which was reduced by either deep ploughing or rich manuring.

The contribution of the residual-pattern effect ot the previous orchard to the total variability of the apple indicator crop was small in comparison with the random component of variability.

Random variation was slightly increased by deep ploughing or rich manuring, offsetting the reduction in intensity of residual pattern so that total variability in size of indicator plants was largely unaffected by cultural treatment.     

The Effects of Different Manurial Treatments on The Yield and Mineral Composition of Early Potatoes

The effects of different manurial treatments on the yield and mineral composition of early potatoes are described. The crops were grown annually from 1954 to 1964 in a rotation of vegetable crops in a factorial manurial experiment on a sandy loam at Wellesbourne and, in i960 only, on a very fine sandy loam at Efford.

At Wellesbourne, farmyard manure (20 tons per acre per crop) with fertilizers consistently produced much higher yields than mineral fertilizers alone, and the relative effect of FYM increased from 1954 to 1959 but not subsequently. In years when moisture supplies were adequate, the larger part of the increase in yield could be attributed to effects of FYM on the early growth of the plants, and a smaller part to the increased rate of bulking of the tubers on the FYM plots. In dry years, however, growth during the harvest period was much slower on the fertilizer plots than on the FYM plots and the additional relative increase in yield on the latter during this period caused the overall effect of FYM to be larger than in the wetter years.

In the absence of FYM, each of the major nutrients N, P and K gave significant yield increases, but the need for adequate applications of phosphate and potash fertilizers together was emphasized by a marked interaction between their effects on yield. Applications of phosphate fertilizers had a particularly important effect early in the bulking period, whereas the effects of the nitrogenous fertilizers were greater at the later stages. In the presence of FYM, the fertilizer applications had significant effects only at the later stages of bulking, but at this time the amounts needed to give maximum yields were similar to those needed in the absence of FYM (124 lb. N, 36 lb. P₂O₅ 144 lb. K₂O (estimated), each per acre).

At Efford, applications of up to 4 cwt. per acre of sulphate of ammonia and 2 cwt. per acre of superphosphate (18% P₂2O₅) gave significant increases in yield, and higher rates would probably have given still higher yields. Potash fertilizers did not affect yields although they markedly increased the potash contents of the plants. The differences between the responses at the two sites are discussed in relation to soil conditions.

The leaves of plants manured with FYM (Wellesbourne) contained much more potassium and slightly more phosphorus than leaves from unmanured plants and, while the differences in potassium content were larger towards the end of the bulking period than at the beginning, the reverse was true of the phosphorus contents. Thus, to use leaf composition data to indicate possible shortages of nutrients in the soil, the samples of leaves for chemical analysis must be taken at several different times during the growth of the crop. The value, if any, of extra nutrients for FYM-manured plants cannot at present be assessed.

At Efford, applications of sulphate of potash increased the potassium content of the leaves to levels approaching those found in the manured plants at Wellesbourne and higher than those in the unmanured plants. Because of marked interactions between the effects of the phosphate and potash fertilizers at Wellesbourne and indications that phosphate applications at Efford may have been too low to ensure maximum yields, it does not seem possible to combine the data from the two experiments in order to suggest levels of the major nutrients in the potato leaves, at any particular stage or stages, which may be considered adequate for maximal yield production.

At Wellesbourne the standard error per plot was smaller for the manured series (8·1%) than for the unmanured (12·9%), indicating that growth was more uniform on the former.     

Edge Effects in a Cocoa Shade and Manurial Experiment

The separate recording of “edges” and “cores” of the plots of a cocoa shade and manurial experiment has shown that the gross plot yield exceeds the guarded plot yield by about 17%. Previously published yields of this experiment have been based on unguarded plots and are presumably correspondingly in error, at least in recent years. (The edge effects may not have been so great in earlier years.)

At interfaces between manured and unmanured plots there was a substantial manurial edge effect, the edge rows of the unmanured plots apparently deriving almost as much benefit from the fertilizer as did the manured plots themselves.     

A Note on the Growth-Regulating Activity of 2:6-Dichlorophenoxyacetic Acid

During each of the four years 1957-60 the growth of the carrot crops in a long-term manurial experiment was studied. Significant increases in the yield of roots were produced by the application of farmyard manure and of potassic fertilizer but not by the application of nitrogenous or phosphatic fertilizers. The mean annual yields, and the responses to the applications of FYM and K, varied considerably from year to year.

The applications of FYM resulted in increases of 15-20% in the net assimilation rates and relative growth rates of the plants but these increases persisted for only 4-7 weeks when growth of the leaves on all plots was exponential. Subsequently net assimilation and relative growth rates of the plants on the FYM plots were slightly less than those on the no-FYM plots. It appeared that the initial differences in net assimilation rates were the main cause of the increased leafiness of the plants on the FYM plots, and hence of the increases in yields of roots.

Year-to-year differences in the total weight of leaves produced were related mainly to differences in the amount of rainfall during their growth. Yearly variation in root yields, however, was related both to the amount and to the distribution of the rainfall during growth.

The relative importance of variations in net assimilation rate and in leaf weight ratio are discussed.     

不同耕作方式对赤红壤甘蔗产量、糖分及效益的影响

通过设置纵横深耕松土、覆盖蔗叶;单向深耕松土、覆盖蔗叶;常规犁耕松土、覆盖蔗叶（CK）试验,研究不同耕作方式对酸性赤红壤春植糖料蔗产量与糖分及效益的影响。结果表明：纵横深耕松土、覆盖蔗叶栽培方式优于单向深耕松土、覆盖蔗叶栽培方式和常规犁耕松土、覆盖蔗叶栽培方式。     

冬闲田白菜薹免耕和翻耕栽培比较试验

利用水稻冬闲田对白菜薹进行免耕和翻耕栽培比较试验,设计了免耕留蔸15 cm、免耕留蔸35 cm和机械翻耕（CK）3个处理,比较了白菜薹的生产成本、移栽成活率、前期产量和总产量。试验结果表明,2种栽培方式下白菜薹总产量无显著差异;免耕栽培的生产成本高于机械翻耕栽培;综合来看,在面积较小或地形限制等不方便采用机械翻耕的条件下,可利用水稻冬闲田进行白菜薹免耕栽培。     

Stock and Scion Investigations: X. Influence of an Intermediate Stem-Piece Upon the Scion in Apple Trees

Cox’s Orange Pippin apples from a factorial N, P, K manurial trial, with superimposed cultivation and sward treatments, were stored at 37⁰ F. (3⁰ C.) and 32⁰ F. (o° C.) each year from 1953 to 1958 inclusive (except in 1953 when they were stored at 37⁰ F. only).

Consistent effects were observed of nitrogen increasing wastage due to Gloeosporium (mainly G. album) rots, and of sward in reducing this wastage. The effect of nitrogen was greatest in the presence of applied phosphate.

Consistent effects were observed of potash and of sward in reducing wastage due to low temperature breakdown. The effect of sward was most .marked in the absence of nitrogen.

These differences in wastage in store were not related to differences in maturity at picking as measured by the time of onset of the respiration climacteric. They also were not related to differences in cortical cell size.     

The effects of alternatives to soil residual herbicides on weed control,yield and quality of hops

Summary

Several non-chemical methods of weed control in hops (Humulus lupulus) were evaluated in a three-year study. The results show that the use of cultivation, grass and winter rye cover crops, straw and plastic mulches all gave satisfactory weed control in both alleyways and hop rows. Data are presented on the effects of the main treatment groups, on the yield, alpha-acid content and alpha yield of hops. The effects on other hop cone quality criteria are also reported. Cultivation to control weeds had to be timely, and by the end of the study, numbers of weeds germinating in the spring were increasing. The use of a winter rye cover crop was successful in reducing over-wintering weed populations in cultivated plots. Grass reduced yield but raised the alpha-acid content of the cones, resulting in no overall loss in yield of alpha-acid. Yield reductions were overcome by adding extra nitrogen as an early spring top dressing, but this tended to reduce alpha-acid content to give similar alpha yields. Analysis of soil mineral nitrogen contents of soils to 90 cm depth in spring and autumn indicated that extra spring nitrogen was readily taken up by grass swards, helping to overcome its competitive effect on the hop plants. Winter rye reduced soil mineral nitrogen levels although this failed to reach statistical significance (P>0.05) but this nitrogen was returned to the soil when the cover was cultivated out in spring. Straw mulches tended to raise alpha-acid levels enough to raise alpha yield one year by 5% compared with conventional residual herbicide, although this failed to reach statistical significance (P>0.05). The implications of the results to growers of hops are discussed.     

Pollination and Environmental Factors Affecting Fruit-Setting in Spencer Sweet Peas,Lathyrus Odoratus L.

Hand pollination, flower-shaking or tripping of the keel petals, was necessary to obtain adequate self-pollination of Spencer type sweet peas in glasshouses.

The effect of low light intensities on fruit-setting was studied by growing plants under muslin of different weaves. During long days a small but significant increase in the fertility of a summer-flowering variety of sweet pea occurred on plants shaded by thin muslin, provided that high temperatures and minimal soil watering were maintained. The more intense the shading treatment, the greater was the amount of flower-bud abortion and this abortion was responsible for lower yields of fruits per plant. A significantly smaller number of flowers set fruit as a result of a heavy watering treatment that led to a slight waterlogging in the pots.

By comparing the fruit-setting rate with temperatures which prevailed in a series of five-day periods in spring and summer, it was found that, for unit rises of temperature, the setting rate increased exponentially. A regression equation was computed for the prediction of setting rates.

Low temperatures in the week before anther-dehiscence were found to depress fertility, no matter how favourable the post-pollination temperatures.     

The Influence of Light,Modified Atmospheres and Benzimidazole on Brussels Sprouts

Brussels sprouts held in 7% CO₂, light and 200 p.p.m. solutions of benzi-midazole at 21° C. for six days retained their original colour and maintained relatively high rates of respiration and photosynthesis after removal to air. Chlorophyll retention was greatest in the O₂-free atmospheres in both light and darkness but undesirable odours developed.     

Crown branching and cropping potential in strawberry (Fragaria ananassa Duch.) can be enhanced by daylength treatments

Summary

When strawberries (Fragaria ananassa Duch.) are produced in a greenhouse, usually two crops a year are obtained; in the fall and in the spring. To increase productivity, new cultivation techniques are needed. The aim of this study was to examine the effect of daylength treatments on the performance of strawberry plants to improve plant production protocols. The possibility of obtaining two successive crops during forcing was explored by exposing plants of cultivar Korona to two successive short day (SD) treatments followed by cold storage. The following daylength treatments were studied: 3 wk SD + 2 wk long day (LD) + 3 wk SD (3SD2LD3SD), 3 wk SD + 4 wk LD + 3 wk SD (3SD4LD3SD), and 10 wk SD (10SD). In addition, crown branching was studied in plants subjected to SD treatments. Two successive SD treatments enabled two successive flowering and cropping periods during greenhouse forcing after eight weeks of cold storage.The first SD treatment caused crown branching and induced flowering in the apical meristem of the main-crown and in the oldest axillary meristem(s), whereas younger axillary meristems were induced during the second SD treatment. Marketable yield and the number of inflorescences were comparable in 3SD4LD3SD and 10SD, but considerably lower in 3SD2LD3SD. However, this study demonstrated the high cropping potential of artificially SD treated plants, which makes them a potential alternative for greenhouse strawberry cultivation. Multi-crowned plants of ‘Korona’ can be produced by subjecting young plants to a three week SD treatment, and crown branches can be induced to flowering by a new SD treatment resulting in a very high cropping potential. Induced plants can be stored at –1°C for later forcing.     

The Effect of Different Irrigation Treatments on the Growth and Yield of Early Summer Cauliflowers

Lettuce were grown during the winter of 1957–58 on the plots of a long-term manurial experiment in which the treatments had been applied to each crop from 1954 to 1957. Three rates of each of the three nutrients N, P and K were applied either with or without farmyard manure (20 tons per acre per crop) in a 3³ × 2 factorial design.

The mean yield from the plots which received farmyard manure (FYM) together with fertilizers was more than twice that from the plots which received fertilizers alone; the extra yield came from the greater number of lettuces that reached marketable condition on the former plots and not from an increase in the size of the plants. The date by which 50% of the plants that eventually reached marketable condition had been cut was almost 8 days earlier for the FYM plots than for the no-FYM plots. The different rates and combinations of fertilizers, when applied with FYM, did not produce different yield effects.

In the absence of FYM, applications of sulphate of potash and superphosphate each increased yields significantly (P =.0·05); applications of Nitrochalk, however, reduced yields but the reduction just failed to reach significance (P = 0·05). The treatments did not affect the 50% cutting date.

Where FYM had been applied, the fertilizer applications did not have differential effects on the mineral composition of the lettuce plants but, on average, there was twice as much potassium in the dry matter of plants (7·8%) as in plants from the no-FYM plus fertilizer plots (3·9%). In the absence of FYM, the fertilizer applications had marked differential effects on the mineral composition of the plants and these effects are discussed in relation to yield.     

The Effects of Different Manurial Treatments on the Yield and Mineral Composition of Runner Beans (Phaseolus Multiflorus)

The effects of farmyard manure (FYM), peat, and fertilizers applied in 1957 on the yield and mineral composition of runner beans grown in 1957 and 1958 are described. The residual effects of the organic matter treatments were compared with the effects of further applications of fertilizers in 1959 and i960. No fertilizer was applied in 1958.

In the year of application, FYM produced more than twice the yield of bean pods than did a generous application of fertilizers, but in succeeding years the difference decreased and had disappeared by i960. Peat had a much smaller effect on yield than FYM, both in the presence and in the absence of fertilizers, and by 1959 its residual effect was negligible. Possible reasons for the difference between the yield responses to applications of FYM and peat are discussed.

The results of chemical analyses of whole plants (1957) and of leaves (1958-60) did not indicate any major nutrient deficiency in the plants from the fertilizer-only plots, as compared with those from the FYM-treated plots, such as might account for the observed yield differences.

The manurial treatments had relatively little differential effect on the nitrogen, phosphorus and calcium contents of the bean leaves but had a large effect on their potassium and magnesium contents. In the bean pods, only the concentration of potassium was markedly affected by the manurial treatments. While there was a negative K/Mg interaction in the leaves, this was not found in the pods, in which the concentration of magnesium was virtually constant.

Runner bean leaves were found to contain more magnesium than many other vegetable materials, but the amount in the pods was much lower than that in the leaves, with the result that the amount of magnesium removed by this crop was similar to that removed by other vegetables.     

Glucosinolate profiling of seeds and sprouts of B. oleracea varieties used for food

Consumption of plants of the species Brassica oleracea is related to a decreased incidence of certain cancer forms in humans, and this has been linked to the presence of glucosinolates in those vegetables. After ripe seeds, sprouts of some brassicaceous plants contain the highest concentration of these compounds and are therefore a good source of glucosinolates for chemoprotection. In the present experiments, the content and distribution of glucosinolates was determined in ripe seeds and sprouts (seedlings) of five varieties of B. oleracea (white cabbage, red cabbage, Savoy cabbage, broccoli and cauliflower) by high performance liquid chromatography. The type and concentration of individual glucosinolates varied according to variety of B. oleracea, plant parts in which they occurred and the sprouting period of the seed. Concentration of alkyl glucosinolates decreased whereas that of indol-3-ylmethylglucosinolates increased throughout the sprouting period. Roots had the highest glucosinolate concentration in four and seven day old sprouts whereas at both sprouting times, cotyledons had the highest concentration of alkylthio- and alkylsulphinylglucosinolates.     

春甘薯—秋白菜复种栽培技术规程

为了解决石家庄地区春甘薯—秋白菜生产中品种不配套、栽培技术不规范、病虫害较为严重等问题,充分发挥甘薯节水抗旱、营养均衡、祛病保健,白菜营养丰富、品质柔嫩、口味颇佳的独特优势,特编写了《春甘薯—秋白菜复种栽培技术规程》,详细规范了春甘薯—秋白菜复种栽培的基础条件、茬口安排、品种选择以及春甘薯栽培、秋白菜复种的技术要点。确保了每667 m^2春甘薯产量在2000 kg以上,大白菜产量在4000 kg以上,每667 m^2种植效益比传统模式增加1000元。为种植春甘薯、秋白菜的菜农和蔬菜生产企业提供了技术支撑。     

Yield and height response to anti-lodging treatments in peas

Five cultivars of peas (Pisum sativum L.), ‘New Season’, ‘Wis. 7107’, ‘Alsweet’, ‘Sprite’, and ‘Dark Skin Perfection’ were grown at the Arlington Agronomy Research Farm in 1973 and 1974 and at the Libby, McNeil, and Libby Research Farm at Janesville in 1974 only. Control plots were allowed to lodge naturally while anti-lodging treatments consisted of bamboo canes inserted between the rows of peas at 5 or 10% of the pea plant population, or a stiff-strawed experimental oat line grown between the rows of peas at 5, 10, or 20% of the pea plant population.Shelled pea yields from the 10% bamboo support ranged from 2 to 17% greater than from unsupported plants, and averaged 8% greater over the three trials. Shelled pea yields from the 5% bamboo treatments did not differ significantly from the unsupported control. Yields of peas interplanted with oats were less than the control and decreased with increasing oat populations.Plants supported with 10% bamboo were nearly twice as tall at harvest as those unsupported, while 5% bamboo resulted in a canopy about 50% higher than the control. Oats increased canopy height only slightly.Tenderometer differences among the two bamboo treatments and the control were minor, but there was a tendency for lower tenderometer with increasing oat population.