Considering straw resource utilization and air pollution prevention, straw return has been commonly practiced in China. However, the practicability of plenty straw return in an emerging maize–rice rotation and their effects on soil C and N pools have not been extensively investigated. This study has been conducted to examine the effects of straw return on soil nutrients, soil functional C and N fractions, and then to figure out their relationships with yield and N use efficiency. Two treatments of straw return (S2Nck) and without straw return (S0Nck) were compared in 3-year field experiment, and subplots without N application were added in their respective plots in the third year. The results showed that, relative to the control (S0Nck), straw return significantly increased soil mineralized nitrogen (Nmin), available P, and exchange K content by 11.7%, 41.1%, and 17.4% averaged across 3-year experiments, respectively. Straw return substantially increased soil dissolved organic C, microbial biomass C, and microbial biomass N content by 73.0%, 25.2%, and 36.8%, respectively. Furthermore, straw return markedly increased C and N retention in particulate organic matter in microaggregates (iPOM) and mineral associated organic matter within microaggregates (intra-SC), but significantly reduced in free mineral associated organic matter (free-SC) fraction. The structural equation modeling analysis showed that yield and the partial factor productivity of N were positively correlated with labile and slow soil C and N fractions. Consequently, straw incorporation significantly increased grain yields of maize by 14.7% and rice by 15.1%. The annual potential reduction proportion in fertilizer-N induced by straw return was estimated to be 25.7% in the third year. This study suggests that the incorporation of straws is an effective way to enhance soil nutrients and regulate soil C and N pools to improve crop production and has the potential to reduce N fertilizer application under maize–rice rotation in subtropical regions.

The government of Thailand aims for sustainability of palm oil production in the Northeast for bioenergy and farmers’ income. This study investigated whether producers in Northeast Thailand managed their oil palm according to good agricultural practices (GAP) and if not, what effects this has on yield. A survey was conducted amongst 108 randomly selected farmers. For 25 selected plots, management and yields were monitored twice a month for two full years. Compliance to GAP was high for weeding, harvesting, pruning and pest and disease control but not for irrigation (40%) and fertiliser application (20–40%). GAP adoption scores per households positively correlated with income from other crops, tree age and degree of training. We showed that rainfall was insufficient for good oil palm growth between October and April. In the monitored group, use of irrigation and amounts of N, P, K and Mg applied were strongly correlated. The yield was significantly greater with irrigation and fertiliser, reaching similar levels as in the South of Thailand (up to 25–30 Mg Fresh Fruit Bunches: FFB ha−1), but did not differ with soil texture. This allows us to conclude that better application of GAP, especially including a combination of irrigation and fertilisers overcame the unsuitable soil and rainfall conditions in the Northeast of Thailand. However, the costs of fertilisers compared to the price of FFB affected the profitability of FFB production, which may affect farmers’ motivation to apply GAP, especially on unsuitable soils. When the government aims for sustainable palm oil production in the Northeast it needs to invest in frequent technical support, irrigation infrastructure and affordable fertilisers. Otherwise, farmers may not apply GAP because of low returns on investments and yields will remain very modest.

In sub-Saharan Africa (SSA), farmers intercrop common beans with maize but apply inorganic or organic fertilisers targeting only maize. Effects of this practice on bush bean yield have not been fully evaluated with respect to input use and compatibility when intercropped with maize. An on-farm trial managed by smallholder community members was conducted to assess the influence of various soil fertility management options and cropping systems on the yield of two bush bean genotypes (SER45 and SER83) in two agro-ecological zones of Malawi. The farmer-managed trials were laid out in split-plot design, with the bean genotypes as main plots and a combination of the soil fertility management options (i.e., no input, manure, fertiliser and fertiliser + manure) and cropping systems (i.e., sole crop and intercrop) as subplots. The trials were affected by terminal drought and dry spells, but results show that manure and fertiliser application enhanced the resilience of the drought-tolerant bean genotypes. The genotype SER45 was responsive to manure application in the sole crop, giving a 44.4% yield increase over no-manure application. In sole cropping with fertiliser plus manure, bean yields improved by 40.1% for SER45 and 78.3% for SER83 relative to the no-input control. Although sole cropping had higher bean yields, the treatment with manure and fertiliser had a higher land equivalence ratio for intercrop of 1.54 for SER45 and 1.32 for SER83 over sole cropping. These results show that, under smallholder farmer management, the climate adaptability of bush bean genotypes could be enhanced by the combined application of organic and inorganic fertilisers in maize–bean intercrop. The combined application also enhances whole-farm productivity of the common maize–bean intercrop practice than monocrop, hence is of benefit to most low-input smallholder farmers of SSA.

Phosphorus at the recommended dose of 10 kg P2O5 ha−1 divided between three equal applications, one on each of 0, 7 and 14 d after Azolla inoculation (DAI), increased biomass production but sporulation was invariably inhibited. Of the different options tested, lowering the phosphorus application rate to 4–8 kg P2O5 ha−1 significantly improved sporulation in A. microphylla (strain 202) but there was a substantial reduction in biomass production. On the other hand, changing the schedule of phosphorus application from 0, 7 and 14 DAI to 0, 3 and 6 DAI did not hamper biomass production and improved sporulation frequency and sporocarp number in A. microphylla (strain 202), A. caroliniana and A. pinnata. It was comparable to the no-P treatment for the number of sporocarps, with slightly lower sporulation frequency. In these species, the sporulation frequency and sporocarp number of Azolla enriched with 30 or 60 kg P2O5 ha−1 and then grown without any further added phosphorus were higher than those of unenriched Azolla grown with 10 kg P2O5 ha−1 and mostly comparable to those of Azolla grown without phosphorus. Foliar spray of 2.5 μg ml−1 gibberellic acid (GA) solution (7 DAI) along with the application of 10 kg P2O5 ha−1 (split between 0, 7 and 14 DAI) to unenriched Azolla increased the sporulation frequency and number of sporocarps in A. microphylla (strains 202 and 203), A. caroliniana and A. pinnata, not only over that of phosphorus application alone but also over the untreated control. Combining the use of P-enriched Azolla (A. microphylla strains 202 and 203) with application of GA was more effective for increasing sporulation than was the use of P-enriched Azolla without GA, or application of phosphorus plus GA to unenriched Azolla.

The importance of carotene supplements in the feeding of White Fulani Zebu cattle has been studied in three experiments. The live weight gains of heifers, with and without carotene on two planes of nutrition, showed 0·2 lb/head/day gain on the ‘high’ plane, but the ‘low’ plane group did not respond to carotene supplement. The association between cottonseed feeding and vitamin A deficiency, studied by comparing the rates of depletion of heifer calves on cottonseed supplements and on a sorghum/groundnut mixture, indicated that cottonseed can enhance the rate of carotene/vitamin A depletion in the liver. Carotene supplements equivalent to 2 oz red palm oil, to cows before and after calving failed to improve the vitamin A potency of milk. The total daily secretion of carotene and vitamin A in the milk was insufficient to maintain adequate liver stores in a suckled calf.

Obtaining yield–density relationships for perennials is difficult. Apart from the long time span involved, problems are also posed by the different types of uncertainty associated with field experimentation. Consequently researchers have explored alternative means. This study uses survey data as an alternative. The data show sufficient variability around the density which is regarded as optimal for Typica variety of coconut (158 palms ha−1) to be of value for estimating its yield–density function. A quadratic function gives a good fit to the data. Results suggest that the yield maximizing density of variety Typica form typica is relatively insensitive to the influence of fertilizer practices adopted by farmers and to variations by agroclimatic sub-regions.

Growth characteristics of dry bean genotypes of determinate (Type I), indeterminate small vine (Type II), and indeterminate large vine (Type III) types were evaluated over three spacings and two growing seasons. Important observations include: (1) Type I did not give increased yields in response to planting rows closer together in Trial II because there was a large decrease in harvest index, which did not occur for Types II and III; (2) accumulation of reproductive nodes prior to anthesis is important for high yields, as are biological yield, harvest index and leaf area; and (3) within-habit spacing combinations, factors such as flowering duration, branch-, leaf- and raceme-numbers, and stem length could not be used to predict yield.

The sugar cane ripener Mon O45, tested on three commercial sugar cane varieties, showed responses depending on variety, time of application, dosage rate and the interval between application and harvest. Age of crop at application appeared to have little influence on the response. The chemical was also shown to have growth inhibiting properties. The possible use of this chemical to increase sugar produced per unit area is discussed.

Leaf protein concentrate was prepared from the weed Parthenium hysterophorus L. and the nutritional properties of this preparation were studied in relation to its amino acid composition and digestibility. The product and the residual fibre closely resembled similar products made from conventional forage species.

Both short- and long-term effects of fertilizers on crops and soils are often studied only in arid or paddy soils, whereas less is known about the long-term effects in paddy-upland rotations, particularly with multiple crops and frequent tillage in subtropical areas. Therefore, an 18-year field experiment was initialized to assess the effects of different types of fertilization (no fertilizer; chemical fertilizer (CF); and manure in combination with CF (MCF)) on yield and soil chemical and microbial properties in a crop rotation involving rice (Oryza sativa L., summer), rapeseed (Brassica campestris L., winter), tobacco (Nicotiana tabacum L., the following summer), and hairy vetch (Vicia villosa Roth, the following winter). MCF caused higher yields of rapeseed grains and tobacco leaves than CF after 3 or 4 years of implementing the experiment, while rice yields varied little between MCF and CF, with one exception in 2011. Compared with the initial soil properties, providing soil with MCF increased organic matter (OM), while the opposite trend was found with CF. Higher microbial biomasses, enzyme activities, bacterial operational taxonomic units, and richness and diversity indexes of bacterial communities were found in soils receiving MCF, implying the improvement of soil microbial properties in the paddy-upland rotation system with multiple crops and frequent tillage. The experimental soils under varying fertilization were dominated by four bacterial phyla (Proteobacteria, Acidobacteria, Actinobacteria, and unclassified groups), which accounted for approximately 70% of the 16S rDNA sequences. Among the top 20 predominant bacteria, 14 were commonly found in all soil samples irrespective of which fertilizer treatment was implemented. Thus, the presence of those bacteria was stable in the soil and to some extent was influenced by fertilization. Most of them were facultative anaerobic bacteria, which can adapt to both anaerobic paddy soil and aerobic drylands. The dominant bacteria at various taxonomic levels found in soils might reflect multiple soil processes such as OM turnover, nutrient cycling, physical structure formation, and xenobiotic detoxification.

The use of date palm (Phoenix dactylifera L.) has been closely connected with the survival of people in arid areas given their fruits´ high concentration of energy, fibre, minerals, vitamins and 16 amino acids. The arid climate and sandy or clayey loam soils in many parts of Pakistan are ideal for the cultivation of date palm, which contributes to feeding the country's rapidly growing population. To fill knowledge gaps on the effects of cultivar diversity and cultivation sites on the nutritional properties of dates, the present project studied dates and related physical and chemical soil properties across six districts in four provinces of Pakistan: Jhang, Muzaffargarh and Bahawalpur in Punjab; Dera Ismail Khan (D. I. Khan) in Khyber Pakhtunkhwa (KPK); Khairpur in Sindh and Panjgur in Baluchistan. To this end, during 2012–2013, a total of 170 households (HHs) were selected using a snowball sampling approach. Thirty-nine different date palm cultivars with diverse nutritional properties are grown in the study area. In these total soluble solids (TSS) were highest in Muzawati and Koharba cultivars, while cultivars and site conditions significantly affected TSS, minerals (calcium and magnesium), acidity, and firmness of dates. Concentration of CaCO3 and bulk density (BD) of soils varied widely, while hydraulic conductivity (HC) was similar across sites (p = 0.128). Mean soil pH was highest in Panjgur (8.3) and lowest in Muzaffargarh (7.6), soil organic matter content was highest in Jhang (0.8%) and lowest in D. I. Khan (0.6%) and plant available phosphorous (P) was highest in Muzaffargarh (7.8 mg kg−1) and lowest in Panjgur (6.0 mg kg−1). As indicated by correlation analysis BD and cation exchange capacity of soils seemed to affect TSS, whereas concentration of CaCO3 and available P were correlated with calcium concentration of dates. HC and electrical conductivity, however, seemed to have little effect on dates´ nutritional properties.

Large areas of rainfed lowlands of Asia annually experienced flash flooding during the rice-growing season, which is an important abiotic stress that adversely affect grain yield of rice (Oryza sativa L.) crop. Submergence stress is a common environmental challenge for agriculture sustainability in these areas because lack of high-yielding, flood-tolerant cultivars. In this study, IR64-Sub1 and IR64 were compared for their tolerance to submergence at active tillering (AT), panicle initiation (PI) and heading (H) stages with nitrogen and phosphorus application time. We evaluated the role of cultivars, stage of submergence and N and P application on phenology, leaf senescence (LS), photosynthetic (Pn) rate, yield attributes and yield. Under non-submerged conditions, no difference was observed in phenology, Pn rate and yield of both cultivars. Submergence substantially reduced biomass, Pn rate, yields attributes and yield across cultivars with more drastic reduction in IR64. Submergence at H stage proves to be most detrimental. Nitrogen application after desubmergence with basal P improved the Pn rate resulting in significantly higher yield and yield components. Nitrogen application before submergence resulted in increased LS and ethylene accumulation in shoots leading to drastic reduction in growth, Pn rate and yield. Crop establishment and productivity could therefore be enhanced in areas where untimely flooding is anticipated by avoiding N application before submergence and applying N after desubmergence with basal P (phosphorus).

The yield of ginger following different dates of planting and harvesting was investigated at Umudike. The largest yields of stem-tubers were obtained seven months after planting while maximum yield of shoots was attained five months after planting. The interaction of yield with time of planting and age at harvest was highly significant. Maximum yields were obtained from mid-April plantings harvested six or seven months later in two years with contrasting weather patterns.

Potassium, calcium and magnesium in coffee leaves are presented as total K + Ca + Mg in dry matter and as percentages (proportions) of this sum. Brazilian coffee and leaf samples collected in different parts of Kenya generally fell within the normal ranges of values reported from the Kivu area in the Congo Republic. Data for Kenya coffee leaves are examined for the influence of season, cultural treatments such as organic mulch and fertilizers, and cropping level, on the concentration and balance of the nutrients.

In NPK experiments over three seasons additional N gave highly significant increases in total yield, average bulb size and doubles, and decreased bolting. P application gave similar results but responses to K were negligible. The increases in onion yield due to N and P fertilization were accompanied by significant increases in the N and P contents of the leaves.

Tubers of white yam (Dioscorea cayenensis-rotundata) are often cut into segments for planting, so-called setts, whose weight and quality strongly influence yield. The effect of a post-harvest gibberellic acid treatment or manual desprouting of seed tubers on the quality of setts was investigated in a combined storage and field experiment over two years in central Ivory Coast. Although post-harvest losses were slightly reduced after four months of storage by both treatments, this had no effect on tuber yield. However, emergence and yield were significantly influenced by both the sprouting state at planting and the origin of a sett with respect to its position on the mother tuber. Limited resources should therefore be directed to apical setts and sprouted setts which have the highest yield potential. A GA3-derived distortion of the spatial distribution of sprouting loci leads to a more homogenous yield for setts of different origins.

Given the importance of irrigation for rice production, this study compared the technical efficiency of irrigated and rain-fed rice (Oryza sativa) farms in the Upper Niger River Basin and Rural Development Authority (UNRBDA), Nigeria. Primary data were collected from 300 irrigators and 325 rain-fed rice producers. Applying the stochastic frontier Cobb–Douglas production function, net income analysis and Likert scale rating techniques, the study found that irrigated scheme increased marginal factor productivity and profitability. The study revealed the existence of large technical inefficiency in rain-fed farms when compared with irrigated farms. This suggests that there is room for output gains through technical efficiency improvement in the rain-fed system. The mean value of the marginal physical product of inputs (VMPPX) in the irrigated farms (₦2.32) was more than that of rain-fed farm (₦1.67). Thus, if the average producers in the rain-fed are to achieve the technical efficiency level of the average producer in the irrigated farms, they can realize 38% output gains. Similarly, the mean net farm income (NFI) of ₦62,280.00 per ha in the irrigated farm was more than double of that of rain-fed farms ₦22,391.00. The partial regression coefficients for the individual production factors (β1) and (β3) for labour input (X1) and other variable inputs (X3), respectively, were positive and significant at 1% level, suggesting that the partial elasticity of crop output with respect to labour and other costs was higher in the irrigated farms than in the rain-fed farms. The Likert scale rating techniques showed that the poor knowledge of irrigation techniques, insufficient water for irrigation during the dry season, high cost of labour and lack of access to credit were the critical constraints preventing the rain-fed rice producer from joining the irrigation scheme. In view of this, rice irrigators should be encouraged to train more rain-fed farmers on some rudiments of irrigation techniques. They should also be linked to the sources of finance. Water Users Association (WUA) should be established in communities within the scheme areas for effective communication between farmers and the officials of the UNRBDA. Decision on the allocation of resources to Fadama sites including water should be given to WUA to strengthen the membership of the organization, while the government officials serve as supervisory and advisory body.

A two-year field experiment was conducted with fifteen varieties of cowpeas to evaluate responses to three different planting dates in relation to flowering and yield of beans. It appeared that most of the cowpea varieties required a day length of more than 12 hours to initiate flower formation. During both years 1962 and 1963, May plantings gave the best results, and July, August and September plantings failed to form flowers.

An investigation was carried out in 1964 to determine the effect of seed size on oil content and seedling emergence in safflower (Carthamus tinctorius L.). Small, medium and large seeds yielded 37·0, 36·6 and 35·7 per cent oil respectively, and this inverse relationship between seed size and oil percentage (r = −0·9635) was attributed to the increase in proportion of hull in large seeds. In a pot experiment, plants from large seeds emerged earlier than those from small seeds when sown at both 1 and 3 inches depth. Further, plants from large seeds had greater dry weights and leaf areas than the others. The same sort of correlation was also obtained between seed size and early emergence in a field experiment using small, medium and large seeds.