Readers may be interested to know about the above publication received but not reviewed because of its limited relevance to the majority of readers of Experimental Agriculture.

Smallholders in south-east Tanzania grow the groundnut Red Mwitunde (Arachis hypogaea ssp. hypogaea), a long-season variety with seed dormancy, although earlier maturing varieties with no seed dormancy (ssp. hypogaea and fastigiata) usually yielded better in trials, particularly when late sown. Small-seeded, short-season varieties established better in the field than Red Mwitunde and other large-seeded varieties, especially under moisture stress. Trials with selective fungicides to estimate yield losses from leafspots (mainly Cercosporidium personatum) and rust (Puccinia arachidis), jointly and separately, showed no consistent varietal differences.

The response of cassava to CCC was investigated by applying concentrations of 0, 500, 1000, 1500 and 2000 ppm twice or four times as a foliar spray, which resulted in a significantly greater tuber yield than the control with most marked effects at the final harvest. CCC at 1500 ppm, applied four times at various growth stages, gave the best increase in tuber yield. Application of CCC tended to cause greater RGR and dry matter content (percentage) of tubers.

In recent years many economists have been posted to agricultural research stations in Africa but their roles and methodologies have not been clearly defined. Maize research in Nigeria has an exceptionally good structure, good facilities and highly trained manpower, yet the innovations recommended to farmers are not entirely satisfactory. Deficiencies are the result of inadequate attention to the way innovations fit into the farm-household system, identification of farmer's objectives, the uses made of maize and problems of resource shortage. Pilot studies demonstrated how these deficiencies may be rectified by an economist, and suggest changed production recommendations and research priorities.

Insect-proof net tunnels can help reduce virus infection of clean virus-tested sweetpotato seed produced by decentralized seed producers. However, optimal management is required to maintain both quality and quantity of seed produced. This study investigated the effect of the ratoon cropping technique on vine production in net tunnels and open fields. Virus-tested planting material of two varieties, Kabode and Mataya, were grown in net tunnels and open fields. Each variety had 80 plants per plot, with 40 following the ratooning technique and 40 a replanting technique. The ratooned crop was harvested six times, comprising the initial harvest and five regrowths. This covered 14 months representing six generations of vine production. The number of vines, number of nodes per vine, and vine length were recorded. The number of plants showing virus symptoms was also recorded. The ratoon cropping technique produced more vines compared with the replanting technique in both net tunnels and open fields. Cv. Kabode produced more vines in open fields compared with net tunnels regardless of cropping technique. On the other hand, cv. Mataya produced relatively equal numbers of vines in net tunnels and open fields. Despite ratooning leading to more vine production compared with replanting, the technique led to higher virus incidences on plants grown in the open. This also varied with variety with the highest virus disease incidences being recorded on cv. Mataya. We recommend the ratoon cropping technique for sweetpotato vine production in net tunnels. Replanting technique should be adopted for vine production in the open fields because it acts as a key control strategy for virus infections even for susceptible varieties.

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.

Nitrate content in the petiole of sugar beet (var. Polygrave) reaches its maximum three months after emergence of the seedling. There is a linear correlation between the final yields and the nitrate content of the petiole at the maximum stage. Nitrogen fertilization should be given in the first three months of the beet growth.

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.

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.