摘要:

Cation‐exchange capacity (CEC) of 30 Alabama soils was estimated by two different methods based or routine soil‐test results consisting of soil‐water pH, Adams‐Evans buffer pH, and Mehlich‐1 extractable cations (K, Mg, and Ca), which were obtained automatically by a computerized data acquisition system. In one method, CEC was calculated by solving a quadratic equation involving soil‐water and buffer pH's; in the other, CEC was estimated as the summation of extractable cations and exchangeable acidity. The two estimated CEC's agreed well with each other and also had the same magnitude as CEC determined by the normal NaOAc, pH 8.2 method. By averaging the two calculated values, an even closer estimation of the measured CEC was found. These calculations and comparisons can be accomplished quickly and efficiently by a minicomputer via a simple FORTRAN program.

ISSN:0010-3624    

DOI:10.1080/00103628309367397

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Conventional redox potential measurements in the field frequently become erratic during the summer season due to low moisture contents in the surface soil. A KCl‐salt bridge which circumvents this problem was designed for in situ, long‐term, nondestructive redox determinations in the subsoil. Measurements are rapid, and redox values are not affected by the use of the salt bridge, irrespective of depth of measurement.

ISSN:0010-3624    

DOI:10.1080/00103628309367398

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The nutrition of cashew(Anacardium occidentaleL.), commercially grown on a large scale on infertile sandy Spodosols at Besut, Malaysia, was evaluated based on the major element of the leaves composition from two fertilizer trials and from an independent field nutritional survey (1979–1981). Except for the sampling periods which represented four physiological stages of the crop, commercial fertilizers applied even up to 1.4 kg/ tree/year did not show significant changes in the five major elements in cashew tree leaves. However, the organic matter levels within the top 32 cm of the surface soil did show consistent positive correlations with each of the five major elements in leaves sampled from a nutritional survey. The significance of these foliar data is discussed in relation to the overall nutrition of cashew grown extensively on sandy infertile soils of Malaysia.

ISSN:0010-3624    

DOI:10.1080/00103628309367399

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The growth pattern and element uptake during early years of production of durian(Durio zibethinusMurr.) was studied using various ages of trees growing at Serdang, Malaysia. Growth was rapid until the seventh year when the dry matter production was nearly at its maximum. The proportion of underground to above ground materials decreases as the tree ages and in a seven‐year old tree, 30% is roots and 70% tops. The elements (N, P, K, Ca and Mg) stored in the vegetative parts increases with the age of the tree in a similar manner to that of the total dry matter. However, the amount of elements stored in a seven‐year old tree exceeds that which, was applied as fertilizers suggesting that the once‐jungle tree obtains additional elements from the soil. The element removed in fruits during the first two years of production was low. In general, the growth and early production of durian on an Oxisol, using the agronomic practices adopted at Serdang, are satisfactory.

ISSN:0010-3624    

DOI:10.1080/00103628309367400

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Tomatoes (Lycoperscion esculentumMill.) were grown in the greenhouse to determine if excess water and/or N rates are involved with a nonbacterial “soft‐fruit”; problem which has been encountered in the Southeastern Coastal Plain. The treatments included flooding for 0, 5, or 8 days and three rates of N (245, 346, or 627 kg/ha). Flooding induced stomatal closure, hastened fruit maturation, and significantly reduced internal fruit firmness after 8 days of storage at 20°C, but N had no significant effect. Stomata closed approximately 3 days after plants were flooded and were permanently impaired in plants flooded for 8 days. These results suggest that for tomatoes grown on the Norfolk soil association (Typic Paleudults) irrigation applied during fruiting must be carefully managed to prevent excess soil‐water in the root zone which can cause stomatal closure and subsequently influence the storage quality of the fruit.

ISSN:0010-3624    

DOI:10.1080/00103628309367401

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Blackbeans(Phaseolus vulgaris(L.) var ‘Black Turtle') were grown on a Lakeland soil in a factorial growth chamber experiment with 0 and 8 ppm added Zn; 0, 20, 40, 80, and 160 ppm added P; and under two temperature regimes ‐ a 28°C/23°C (day/night) temperature and a 20°C/15°C (day/night) temperature. Blackbeans were also grown at two field sites in Southern Manitoba which were selected for their low supply of available zinc. Zinc, at 0 and 15 kg/ha, and phosphorus, at 0, 100, 200, 400, and 800 kg P205/ha vere disced into the soil in a factorial experiment.

ISSN:0010-3624    

DOI:10.1080/00103628309367402

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Ten soils from bench mark sites found in four different ecological zones of western Nigeria were enriched with 0, 50 and 100 ppm K and equilibrated for two weeks in the greenhouse. Three extractants: 0.01 M calcium chloride, IN ammonium acetate (pH 7.0), and 0.13 N HCl were used to determine K status of the soils after being cropped for three cycles of 17 days per cycle. The critical soil K level for optimum K in the plant was estimated graphically by Cate/Nelson technique.

ISSN:0010-3624    

DOI:10.1080/00103628309367403

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

Our prospect on direct application of polyacrylamide gel “PAMG”; without pre nor post treatments of soils for conditioning is realized. Seeds gemination, seedlings growth and cuttings propagation were investigated.

ISSN:0010-3624    

DOI:10.1080/00103628309367404

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

ISSN:0010-3624    

DOI:10.1080/00103628309367396

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor