Predicting in-season crop yield is a unique tool for drawing important crop management decisions for precision farming. Field experiments were conducted at two locations in northwestern India under different agro-climatic zones to predict and validate spring maize yield using various in-season spectral indices. The spectral properties measured with leaf color chart (LCC), chlorophyll meter (SPAD meter), and GreenSeeker optical sensor were used to predict grain yield. A power function based on the Normalized Difference Vegetative Index (NDVI) measured with GreenSeeker optical sensor at V9 growth stage (9th leaf with fully exposed collar) presented higher values of coefficient of determination and explained 61% of the variability in spring maize grain yield, whereas NDVI measured at early and late growth stages were not reliable for the purpose. The spectral properties recorded with the SPAD meter and LCC rendered better grain yield estimates at VT growth stage (tasseling) and were respectively able to explain 75 and 76% variability in grain yield. The developed models were validated on an independent data set from another field experiment on spring maize. The normalized root mean square error (NRMSE) was <10% for LCC and SPAD at all the growth stages and at V9 growth stage for NDVI. The LCC, SPAD, and NDVI values adjusted with cumulative growing degree day were not helpful to improve NRMSE.

In the past two decades, a growing body of work on research stations and farmers' fields in Southern Africa has provided evidence that fertilizer trees can improve the productivity of land, increase crop yields and contribute towards climate change mitigation and adaptation. In a recent issue of Experimental Agriculture, Coe et al. (2019) published analysis of risks associated with adopting agroforestry in Malawi. The article contains several factual inaccuracies about agroforestry and misinterpretations of earlier work. Our aim in this correspondence is, therefore, to point out the key problems, seek clarification from Coe and co-workers, and stimulate wider scientific debate on the perceived risks of adopting agroforestry.

Lusala (Dioscorea hirtiflora Benth. subsp. pedicellata Milne-Redh) is an important wild edible tuber foraged widely from natural forests in Southern Zambia, but at risk from overharvesting and deforestation. Its propagation was investigated in glasshouse studies to explore potential domestication and future in situ and ex situ genetic resources conservation. Almost all tubers planted with visible shoot buds produced vines, with no effect of tuber size on vine emergence or tuber yield. Few tubers without visible shoot buds at planting produced vines, but those that did not re-tuberized. The progeny provided good vine emergence and similar tuber yield, with vines from tubers produced by re-tuberization being more vigorous. Re-tuberization in the absence of vine emergence also occurred in other experiments. Minisetts cut from the proximal end of tubers provided better vine emergence (with more from 20-mm than 10-mm-long sections) and greater tuber yield than mid- or distal minisetts. Nodal stem cuttings rooted well, vined, and provided small tubers. This study shows that lusala can be propagated successfully from tubers, minisetts, nodal vine cuttings, or mini-tubers from nodal vine cuttings, for genetic resources conservation and/or domestication. Domestication is likely to be hampered by the long period required for vines to emerge and establish. More sustainable foraging, including re-planting in natural forests, is recommended to balance consumption of lusala in the region and promote its long-term conservation.

The ureides allantoic acid and allantoin form a bright pink compound with acidic p-dimethylamino cinnamaldehyde. It is possible to estimate the ureide content of a soyabean petiole segment by crushing it on filter paper and developing the colour with this reagent. There is a strong correlation between the spot test and estimates from colorimetric determination of ureides. In field grown soyabeans, there was a positive correlation between the petiole ureide content during pod fill and the integrated seasonal acetylene reduction activity. The spot test can be used to identify plants with low nitrogen fixation activity.

Mon O45 at rates of 4 and 6 kg./ha. was shown to increase total dry matter in the stem of the sugarcane variety M13/56, optimum response occurring at 9–12 weeks after application. The increase in dry matter was mainly due to an increase in sucrose, since the chemical had no effect on fibre and decreased reducing sugars. The site of action appears to be in the top 16 internodes. Possible modes of action of the chemical are discussed.

Soil analysis on samples taken from apple orchards in Khorasan and quince orchards in Esfahan, suggested that at a sampling depth of 20–45 cm., the critical soil concentration of calcium carbonate at which chlorosis might appear seems to be 14–15 per cent for apple and 39–40 per cent for quince. The incidence of lime-induced chlorosis was accompanied by lowered leaf Ca/K ratios. The application of various iron chelates to chlorotic trees not only benefited yield of apples but also exercised a residual effect in succeeding seasons.

Before an innovation can be judged as superior to existing technology, its relevance should be jointly evaluated by researchers and farmers by testing the proposed practice in a farm environment. Using a proposed maize technology as an example, it is demonstrated how site-related and management variables can be used to quantify the factors influencing actual yields on farmers' fields. Similarly, economic and management analysis of the practice provides an estimate of the probability of the farmer being better off by using the technology. The integrated analysis of the practice provide insights for the design of problem-oriented research projects.

In upland rice, seed soaked in CCC for 24 hours before sowing or sprayed with CCC 10, 21, 42 and 63 days after sowing, showed severe lodging. Effects of CCC on the number of paniclebearing tillers, number of good grains in 1000 grains, weight of 100 good grains and grain yield were not significant. On the other hand CCC prevented lodging in swamp rice, with the lowest percentage when foliar spray was given 21 days after transplanting. CCC failed to increase the number of panicle-bearing tillers and grain yield in swamp rice.

This paper reports the heterotic pod production of three different crosses between a Nigerian local selection (N38) and three Trinidad Introductions (CF47, CF56 and CF207). The hybrids consistently outyielded the inbreds throughout the first 19 years of pod production. N38 × CF56 hybrid produced the highest number of pods per tree, closely followed by N38 × CF47 hybrid; while N38 × CF47 hybrid showed the best heterotic response. Pod production figures of (CD207)2 and (CD302)2, both double inbreds of N38, support the hypothesis that N38 is a Trinitario × local selection hybrid which segregate for pod production.

One of the major research activities of the Mauritius Sugar Industry Research Institute (MSIRI) is the breeding and selection of sugarcane varieties adapted to the different agro-climatic environments. Most of the on-farm experimentation is carried out in the fields of miller-planters (planters who own the sugar mills), where resources in terms of land, labour and other inputs are usually easily available. The non-miller-planters are operating in environments which are not always similar to those of the miller-planters. There is a need for on-farm experimentation under these conditions in order to improve productivity. Variety trials, observation plots and industrial trials to compare commercial varieties with promising and newly released ones have been established on-farm in order to improve the adoption rate of new varieties. The paper elaborates on the objectives of this major extension activity during the last decade. A major inference is that the planters obtain first-hand information on promising varieties prior to their release for commercial plantation, hence influencing their decision for adoption or rejection. Moreover, additional information on the performance and behaviour of these promising varieties is made available to research staff.

The important interactions in a 2-year maize trial were population × location, location × year and population × year × location, and our analyses suggest that eight locations, two years and three replications will allow the detection of a 5% differential in yield. The most effective way of obtaining the true value of a variety is by increasing the number of years, and the least effective is by increasing the number of replications. Since locations can be effectively substituted for years, increasing the number of locations will expedite the release of improved cultivars.

The yields of extractable protein, and its rates of production, were measured with seven crops given large dressings of nitrogen, which produced lush plants with small fibre to juice ratios, increased the nitrogen content (as percentage of dry matter) in five species, improved the extractability of protein N in three, and gave significant increases in both dry matter and protein yields of non-legumes. However, yields were affected more by climate than by the N fertilizer. It is felt that non-legumes given large dressings of fertilizer N, as well as leguminous fodders, could be used efficiently if their excess protein was extracted and used for human consumption.

The potential was demonstrated of using sodium chloride and sodium metabisulphite as chemical preservatives during pre-drying storage of wet cassava chips, and during slow sun-drying under adverse weather conditions. Both chemicals permitted chips to maintain a good colour and texture and prevented gross microbial deterioration.

Two of the most common criticisms over the widely used Palmer Drought Severity Index (PDSI) is that it cannot be calculated at different time scales and it is not as spatially comparable as other Standardized Drought Indices (SDI), such as the Standardized Precipitation Index (SPI). Therefore, the hypothesis that the PDSI may be transformed into a multi-scalar index sharing the same normalized nature of others SDI has been proposed in the scientific literature. This hypothesis was extensively evaluated in this study by statistical methods largely used to assess and improve the performance of others standardized drought indices (e.g. SPI). In general terms, these methods evaluated the ability of the transformed/probability-based Palmer's Index to approach the standard normal distribution. The strategy of basing the selection of a distribution for calculating such an index on its performance within the range of typical drought and flood events was adopted. The testing region was the State of São Paulo, a tropical-subtropical region of Brazil. Time scales ranging from 1- to 12-month and Available Water Capacity equal to 50, 100 and 150 mm were also considered. A computational algorithm for calculating the new version of the Palmer's index is also provided. The Generalized Logistic distribution with parameters estimated by the maximum likelihood method is recommended to calculate the new index. The results of the normality tests are consistent with the above-mentioned strategy. From a scientific standpoint, the results support the hypothesis of this study. Therefore, we conclude that the new Standardized Palmer Drought Index (SPDI) is capable of meeting the normally assumption under tropical-subtropical climatic conditions of Brazil. In other words, the new SPDI has shown to be capable of representing floods and drought events in a similar probabilistic/normalized way. This conclusion holds true for time scales ranging from 1- to 12-month and Available Water Capacity equal to 50, 100 and 150 mm.