Agronomic and economic viability of intercropping onion and lettuce

The study aimed to evaluate the agronomic and economic performance of intercropping onion and lettuce on four plant densities of each species. The experiment was set up in completely randomized blocks, with four replications and treatments arranged in a 4 x 4 factorial. Treatments resulted from a combination of four (100, 80, 60, and 40% of recommended plant densities in monoculture) plant densities for both lettuce and onion. Intercropping did not affect the agronomic performance of onion or lettuce. Higher plant densities (100% for both vegetables) resulted in higher lettuce and onion yields. The best economic results were observed using (a) onion at 80% of plant density combined with lettuce at 40 and 100% and (b) onion at 100% and lettuce at all densities (40 to 100%).

Split-plot Analysis—Now and Then

Split-plot design is a very popular experimental design in analyzing factorial treatments in horticultural experiments. Two different sizes or types of experimental units are assigned to main plot and the split-plot treatments. The SAS procedure GLM with the TEST option is commonly used to analyze the split-plot data by assigning the correct error term to test the main plot factor. In SAS GLM, no option is available to compare the two main factors within a split-plot factor. The CONTRAST tests and LSMEAN comparisons are valid only for comparing split-plot factors within a main plot treatment. The main factor standard error provided by the LSMEAN option is also incorrect. The new PROC MIXED procedure available in SAS 8.08 or above can be used to correct these problems in split-plot analysis. The analysis of split-plot experiments using the PROC MIXED is presented here.

THE EFFECTS OF VINE SPACING, SHOOT DENSITY AND FOLIAR KNO3 ON NUTRIENT CONTENT OF SEYVAL GRAPEVINES

Factorial treatments of vine spacing, shoot density and foliar applications of KNO3 were imposed on 9-year-old Seyval grapevines during 1989. Rows were spaced 3.05 m apart; vines within the row were spaced 1.2, 1.8 or 2.4 m apart and trained to a bilateral cordon. Shoots were thinned to 10, 20 or 30/m of canopy. A solution containing 6 kg of KNO3/379 liters of water was applied as a foliar spray at 2-week intervals between June 1 and August 1, 1989 (5 applications). Each shoot was thinned to one cluster prior to full bloom. Vines spaced at 1.2, 1.8 and 2.4 m produced an average of 4.2, 5.9 and 7.3 kg/vine, respectively (11.3, 10.6 and 9.8 MT/ha). Cluster weight averaged .22 kg; fruit maturity averaged 19.7°Brix for all treatments. Applications of KNO3 increased foliar N, K, Fe, B, Cu and Na, but decreased P, Ca, Mg, Mn, and Zn. As vine spacing increased the concentration of foliar N, P, K decreased. As shoot density increased N, P, K, B, and Cu decreased, while Ca, Mg, Mn and Na increased. The experiment will be repeated in 1990.

THE EFFECTS OF VINE SPACING, SHOOT DENSITY AND FOLIAR KNO3 ON NUTRIENT CONTENT OF SEYVAL GRAPEVINES

Factorial treatments of vine spacing, shoot density and foliar applications of KNO3 were imposed on 9-year-old Seyval grapevines during 1989. Rows were spaced 3.05 m apart; vines within the row were spaced 1.2, 1.8 or 2.4 m apart and trained to a bilateral cordon. Shoots were thinned to 10, 20 or 30/m of canopy. A solution containing 6 kg of KNO3/379 liters of water was applied as a foliar spray at 2-week intervals between June 1 and August 1, 1989 (5 applications). Each shoot was thinned to one cluster prior to full bloom. Vines spaced at 1.2, 1.8 and 2.4 m produced an average of 4.2, 5.9 and 7.3 kg/vine, respectively (11.3, 10.6 and 9.8 MT/ha). Cluster weight averaged .22 kg; fruit maturity averaged 19.7°Brix for all treatments. Applications of KNO3 increased foliar N, K, Fe, B, Cu and Na, but decreased P, Ca, Mg, Mn, and Zn. As vine spacing increased the concentration of foliar N, P, K decreased. As shoot density increased N, P, K, B, and Cu decreased, while Ca, Mg, Mn and Na increased. The experiment will be repeated in 1990.

Water use efficiency of wheat in a Mediterranean-type environment. II. some limitations to efficiency

Evidence is presented that water use efficiency and yield of wheat are reduced by insufficient leaf area and by inadequate content of nutrients in the top growth. Yields from field trials are compared with the potential yield, and a review is made of the limitations caused by weeds, the incidence of diseases and the harvest index. The data highlight the need for field experiments to define the evaporation and transpiration components of water use in each environment. They also indicate the need for multi-factorial treatments to overcome all yield limitations and thereby attain the potential yield.

The laying performance of hens fed Uniwhite lupin seed and supplementary DL-methionine

Hens, aged 34 weeks, were fed diets containing 0, 10 or 20 per cent lupin seed (cv. Uniwhite) and sufficient DL-methionine to raise the level to either 1.23 or 2 per cent of the protein. (1.23 per cent was the proportion of methionine in the control diet containing wheat, barley and meat-meal but no lupin seed.) The hens were fed for 24 weeks and each diet had the same metabolizable energy to nutrient ratio for each of the following: crude protein, calcium, phosphorus, sodium, and supplementary vitamins and trace elements. Egg number, egg weight, graded quality of eggs and mortality were recorded daily. Feed consumption was recorded midway and at the end of the experiment. An average peak rate of lay of 76 per cent was reached at 34 weeks and held until hens were 39 weeks of age. At the end of the study (hens aged 58 weeks), the average rate of lay was 57 per cent. Feed consumption increased significantly (P < 0.05) with increased proportions of lupin seed in the diet. There was a significant difference in mean egg weight (58.1 v 58.6 g) between factorial treatments containing methionine at 1.23 and 2 per cent of the protein. There were no significant differences between factorial treatments in any other of the measurements analyzed, namely, hen-day egg production, consumption of metabolizable energy or of protein, or the metabolizable energy or protein required per kg of egg. Uniwhite lupin seed supplemented with methionine was included in a laying diet at 10 and 20 per cent without a subsequent loss of laying performance.

Effects of Ground Covers and Fertilizers on Establishment and Yield of Cocoa on Clear-Felled Land in Ghana

SUMMARYAn experiment is described on the establishment of cocoa on clear-felled land, using various ground covers on which 22 NP:KMg factorial treatments were later superimposed. Growth of cocoa was improved in mulched and clean-weeded plots and the unshaded trees began bearing two years after planting, which is exceptionally early for young cocoa in Ghana. In the third year responses to NP fertilizer were obtained and in the following year yields were very high, up to 2170 pounds dry cocoa per acre. This was partly responsible for K deficiency, particularly in plots without mulch and KMg, which led to declining yields especially on the NP plots. Significant increases were thence obtained from the KMg fertilized plots. Mulching at the rates used in this experiment is too expensive and uneconomic, but K fertilizer applied at rates higher than the present rate of 75 lb K2O/acre/annum may be needed on Ghanaian forest soils if they are clear-felled for growing unshaded cocoa.