Six sugarcane varieties grown alone and in mixtures containing equal proportions of two or three varieties were evaluated for the economically important traits of the first crop and subsequent ratoon crops over a three year period. An increase in the yield of cane and sugar of up to 25% more than the average for the pure components was observed in some mixtures. The number of millable canes, sucrose content and cane yield in the mixtures was more stable than in the pure varieties. The advantages of growing varietal mixtures of sugarcane are discussed.

Preparation of small catchment areas on rainfed valley floor soils in highland Balochistan, Pakistan, is a low-cost method of generating run-off and increasing crop yields within the cropped areas. The effect of different proportions of water catchment area to cropped area were investigated by comparing a control treatment with the entire area planted to the crop (traditional rainfed agriculture); a 1:1 treatment, with one half of the area used for water catchment and one half for planting; and a 2:1 treatment, with two thirds of the area used for water catchment and one third for planting. Results from six seasons of trials using wheat (Triticum aestivum) showed that the 1:1 treatment had 23% higher net benefits than the control, with a 19% reduction in the coefficient of variation. The 2:1 treatment had 29% lower net benefits than the control and reduced the variation in net benefits by 8%. By contrast, four seasons of trials using barley (Hordeum vulgare) showed that the l: l treatment yielded 25% lower net benefits than the control but increased by 4% the variation in net benefits. Treatment 2:1 had 36% lower net benefits than the control and 18% more variation. Even though the gross revenue from wheat under the 1:1 treatment was less than that from the control, the reduction in total costs in the 1:1 treatment resulted in larger net benefits than the control. Water-harvesting in the valley floors is not a net yield-increasing technology. Land suitable for cultivation is limited and the increases in yields in the cropped area resulting from water-harvesting are offset by the opportunity costs of the catchment area. However, wheat grown in a 1:1 ratio of cropped to catchment area can increase farmers' income and decrease its variation. For barley, farmers are better off using their traditional management practice than giving up part of their cropped area to create water catchments.

In field experiments at Pantnagar, India during 1968–70, evapo-transpiration (ET) in wheat was significantly correlated with U.S.W.B. class A pan evaporation (E0) when the crop was in an active stage of growth and moisture was non-limiting (50 or 25% depletion of available moisture). The estimated ET was higher than E0, probably due to ‘oasis’ and ‘clothesline’ effects. When ET measurements were made at varying distances from the upwind side during the subsequent three years, it was found that ET decreased with increasing distance downwind with a conspicuous border effect up to about 25 m distance. In the absence of advective heating, i.e. in extreme downwind locations, the actual ET was 480, 533 and 530 mm during 1970–71, 1971–72 and 1972–73 respectively.

Ethephon substantially increased pod numbers of a rust-susceptible cultivar, by inducing leaf fall and a second flowering, but had no such effect on a rust-resistant cultivar. The treatment reduced seed number per pod in both cultivars. B-9 increased pod number in the rust-resistant cv. but reduced mean pod weight and seed number per pod.

A major problem faced by small-scale farmers in northern Ethiopia is reduced crop yield due to increasing soil degradation resulting from repeated tillage and inadequate agronomic management practices. These practices have left soils and rainfed crops susceptible to hazardous climatic events such as droughts. Sustainable farm practices such as minimum tillage and surface residue retention have been shown to improve soil health and crop productivity. The objectives of this field study were thus to evaluate the impacts of conservation agriculture (CA) practices on crop yield and economic productivity over 6 years in the eastern Tigray region of northern Ethiopia. Using a barley–wheat rotation from 2010 to 2016, the applied treatments were (i) permanent raised beds (PRB); (2) semi-permanent raised beds (SPB) and (3) conventional tillage (CT). Average barley and wheat biomass and grain yields in PRB and SPB treatments were consistently greater than yields under CT each year. In addition, the highest marginal rate of return was obtained in PRB and SPB compared to CT in all years (2010–2016). These results suggest that the CA practices of PRB and SPB can improve crop yield and profit compared to CT practices in the Tigray region.

The effects of water and nitrogen on growth, yield and yield components of tepary bean (Phaseolus acutifolius) were evaluated at Tucson, Arizona in 1987 and the effects of water and intercrop competition with Sonoran panicgrass (Panicum sonorum) in 1988. Total shoot biornass and reproductive yield were significantly reduced by lack of water in both seasons. Addition of nitrogen had no significant effect on total shoot biomass or reproductive yield in 1987. Intercrop competition significantly reduced total shoot biomass and reproductive yield of tepary bean in 1988. Yield component responses varied slightly depending on treatment and year.

An experiment at the University of Queensland studied the response of Crotalaria juncea to a single cut above node 4 or 10 at 6, 8 or 10 weeks after planting under long or short (inductive) daylengths. Initial deleterious effects of cutting on plant parts were in the sequence nodules > roots > shoots. Subsequent greater regrowth from plants cut earliest and at the higher node was associated with higher residual leaf area and negative growth rates were inferred below 90 cm2 pot−1. Redistribution of assimilate from stem to leaf production followed cutting; in inductive daylengths of 11.4 hours, flowering was delayed and the proportion of leaf increased from 21.0 to 32.4%. The high nitrogen content of leaf (3.5–5.3%) compared to stem (0.6–1.7%) indicated that early cutting was important in producing good quality hay.

Little is known about the adaptability of longan (Dimocarpus longan) to acidic soils high in aluminum (Al). A two-year field study was conducted to determine the effects of various levels of soil Al on dry matter production, plant growth and nutrient content in shoots of four cultivars of longan. Soil Al and cultivars were statistically different for all variables measured in the study. Total leaf, petiole, stem and root dry weights significantly decreased at soil Al concentrations ranging from 5.1 to 12.1 cmol kg−1 but this reduction was of a smaller magnitude in roots than in other organs. Increments in soil Al resulted in a significant reduction in the concentration of leaf Ca and a significant increase in leaf Al in all cultivars. Shoot content of N, P, K, Ca, Mg, Fe, Mn and Al declined with increase in soil Al. The result of this study demonstrates that longan is highly susceptible to acid soils.

Extracted leaf protein is now used regularly as human food in several places. For preliminary, or domestic, trials the equipment used is inconveniently large. A miniature extraction unit, which does not depend on electricity, is described.

Differences in the water and air regime of the germination environment may cause variations of 30% and over in the yield of barley, wheat and oats.

The yield and soil data are presented of four long-term experiments on sugarcane at Muzaffarnagar (Uttar Pradesh), Anakapalle (Andhra Pradesh), Padegaon (Maharashtra) and Shahjahanpur (Uttar Pradesh). On soils where phosphorus and potash were not limiting, application of ammonium sulphate over 14 years at Muzaffarnagar and Anakapalle gave higher yields than those obtained by application of farmyard manure, and the fertility status of ammonium sulphate plots was in no way inferior to plots treated with farmyard manure. When phosphorus was also limiting, the application of a basal dose of compost on black cotton soil maintained yield levels. There was a steady decline in yields of cane in plots which received a dressing of ammonium sulphate without any basal dose of compost, but when N.P.K. equivalent to the compost were added the yields were equal to those from plots receiving compost. Thus the effect of compost is explanable on its nutrient content rather than on its effect on physical properties of the soil. In Shahjahanpur there was a decrease in cane yield as the experiment progressed, but the decline in yield in ammonium sulphate treated plots was of the same magnitude as from the plots receiving no dressing of ammonium sulphate. By changing the cane variety and the rotation simultaneously, the yield from all plots went up but subsequently showed a declining tendency.

Ureaform, applied twice a year, in early spring and late summer, was compared with poultry manure and (NH4)2SO4 top dressings as nitrogen suppliers in a banana plantation. No significant differences between the treatments were obtained in any of the plant criteria, but nitrate concentrations in the soil were higher in the ureaform treatment at the standard nitrogen level than in the standard treatment, within the root zone as well as below it. The spring application of ureaform affected the nitrate concentration in soil for 8 months and was better utilized by the crop than the autumn application, which left a greater residual effect. It therefore seemed that one spring application might be sufficient to meet the banana's nitrogen requirement.