Excessive nutrients transported from agricultural fields into the environment are causing environmental and ecological problems. This study uses an integrated multi-media modeling system version 1 (IMMMS 1.0) linking air, land surface, and watershed processes to assess corn grain yield and nitrogen (N) losses resulting from changing fertilization conditions across the contiguous United States. Two fertilizer management scenarios (FMSs) were compared and evaluated: 2006 FMS, developed based on the 2006 fertilizer sales data; and 2011 FMS, developed based on 2011 fertilizer sales and manure. Corn grain yields captured historical reported values with average percent errors of 4.8% and 0.7% for the 2006 FMS and 2011 FMS, respectively. Increased nitrogen (N) application of 21.2% resulted in a slightly increased corn grain yield of 5% in the 2011 FMS, but the simulated total N loss (through denitrification, volatilization, water, and sediment) increased to 49.3%. A better correlation was identified between crop N uptake and N application in the 2006 FMS (R = 0.60) than the 2011 FMS (R = 0.51), indicating that applied N was better utilized by crops in the 2006 FMS. Animal manure could create nutrient surpluses and lead to greater N loss, as identified in the regions of the Pacific and Southern Plains in the 2011 FMS. Manure nutrient management is important and urgently needed to protect our air and water quality. The IMMMS 1.0 is responsive to different FMSs and can be utilized to address alternative management scenarios to determine their impact when addressing the sustainability of food production and environmental issues.

Private sector investment interventions serve as essential mechanisms for creating efficient, cost-effective financial solutions and technological support for emerging farmers in developing economies, yet their successful implementation is influenced by various contextual and socioeconomic factors. Using a quantitative research approach, this study examined the factors influencing participation in private sector investment interventions among 121 emerging commercial farmers in KwaZulu-Natal, South Africa, utilizing a Poisson regression model to analyze four key intervention areas: credit access, market access, technical support, and spot supply. The first-hurdle model revealed that age and training skills negatively influenced market access while the training period showed positive influence, and similarly, the second-hurdle equation demonstrated that employment status and training period positively influenced participation intensity levels, though age maintained its negative impact. The findings of the first-hurdle model reveal that age and training skills negatively influenced market participation. The study concludes that employment status and training period positively impacted technical support adoption, with household size and training period emerging as significant determinants of intervention success. The private sector needs to develop strategic partnership models that encourage emerging farmers to participate intensively in interventions that are designed to improve their production and productivity. There is a need for targeted capacity-building programmes and enhanced extension services to improve emerging commercial farmers' participation in private-sector initiatives.

The reliance on rainfed agriculture exposes southern Africa to low agricultural productivity and food and nutritional insecurity; yet, the region is endowed with vast irrigation potential. Extreme weather events including drought, floods, and heatwaves exacerbate the existing challenges, underscoring the need to improve agricultural water management as a climate change adaptation strategy. This mixed-methods review followed the Search, Appraisal, Synthesis, and Analysis (SALSA) framework to explore the irrigation opportunities and challenges in southern Africa by critically analysing the drivers and constraints of irrigation systems in southern Africa. The premise is to understand the reasons behind the abandonment of some of the areas equipped for irrigation. In cases where irrigation systems are present, the study assesses whether such technologies are effectively being used to generate the expected agricultural productivity gains, and what factors, in cases where that is not the case, constrain farmers from fully using the existing infrastructure. The review further discusses the enabling environment supporting irrigated agriculture and the role of gender in irrigation development. An assessment of the role of women in agriculture on the share of land equipped for irrigation to total cultivated land area, as well as on the proportion of the area equipped for irrigation versus the area that is actually irrigated is conducted. The review found a divergence between countries' land areas equipped for irrigation and actually irrigated areas. Specific to irrigation expansion, the review rebuts the notion that increasing the irrigated area increases crop production and ensures food security. This may not always be true as irrigation development needs to consider the impacts on other closely linked water and energy sectors through transformative approaches like the water-energy-food (WEF) nexus and scenario planning. If well-planned and implemented, sustainable irrigated agriculture could be catalytic to transforming southern Africa's food system to be inclusive, equitable, socially just, and resilient, benefiting people and the planet.

Indigenous crops have been proposed as part of a solution for household food security and sustainable farming systems. However, they have been overlooked and underutilised by households and farmers despite their potential contribution to household food security. The objective of this paper was to determine the association of socio-economic factors and indigenous crops with the household food security of farming households. About 260 farming households were selected using a simple random sampling procedure. The food security status was measured through the use of the Household Food Insecurity Access Scale (HFIAS). The Chi-square test and extended ordered probit regression model assessed the relationship of socio-economic factors and indigenous crops with household food security status. The results from the HFIAS showed that farming households were largely in the mildly and moderately food-insecure categories, with 34.2% and 36.2% of the sampled farmers found in these categories, respectively. The Chi-square test showed a statistically significant relationship between food security status and socio-economic factors. Young men and everyone were perceived to be the ones likely to consume indigenous crops. Consumption of indigenous crops was perceived to be associated with food security. The results also showed that farming experience is likely to positively contribute to the food security status of the farming households. Selling indigenous crops in a formal market is perceived to be associated with food security compared to selling in an informal market. This study concludes that consuming indigenous crops is likely associated with improved food security. Identifying an appropriate market for sales of indigenous crops is imperative. Government, extension officers, and nutritionists must conduct training workshops to encourage households to grow, market and buy indigenous crops. Government and policymakers need to include indigenous crops in the national food and nutrition security policy and create formal markets for indigenous crops.

The use of ethephon, designed to stimulate nut detachment, initiates the release of ethylene, a well-established regulator of postharvest shelf-life in various agricultural products. This study aimed to assess the impact of ethephon application on individual fatty acids and dietary indicators in two macadamia nut cultivars, namely '788' and 'Beaumont,' during postharvest storage. Nuts that naturally abscised and those detached through ethephon treatment were divided into two groups: the ethylene-treated group (ED) and the control group (CD). Nuts were stored at 25 °C and sampled at 0, 36, and 72 days for fatty profile analysis. Our findings indicated a significant increase in stearic acid content in ED nuts (24,622 µg/g) compared to CD nuts (16,764 µg/g) at the end of the storage period for the 'Beaumont' cultivar. Additionally, unsaturated fatty acids (USFAs), such as eicosatrienoic acid + erucic acid (C20:3n + C22:1) and eicosatrienoic acid + alpha-linolenic acid (C20:1 + C18:3n), were notably reduced. Hierarchical clustering analysis revealed positive correlations between ethylene treatment and saturated fatty acids (SFAs) in both 'Beaumont' (0.78) and '788' (0.80) cultivars. This also coincided with an increase in atherogenic indices, thrombogenic index, and saturation index and a decrease in the hypocholesterolemic/hypercholesterolemic ratio and arachidonic acid (C20:4n) within the ED group of the 'Beaumont' cultivar, collectively potentially impacting nutritional quality negatively. Furthermore, our findings indicated that the PUFA:SFA ratio was higher in CD (0.51) compared to ED (0.45) on day 72 for the 'Beaumont' cultivar, revealing differences in fatty acid compositions between the two treatment groups. Conversely, for '788', both ED and CD had a PUFA:SFA ratio below 0.45, indicating an increased risk of cardiovascular diseases. These results suggest that ethephon treatment increases SFA levels and reduces USFA levels in the 'Beaumont' cultivar, while the response to ethylene varies between the two cultivars. Thus, the study provides insight into the significant role of modifying ethephon treatment methods and careful cultivar selection in the attainment of optimal nutritional value and shelf-life of macadamia nuts.

The importance of smallholder farming is increasingly recognized in rural areas where increased crop productivity and market participation can effectively improve their dietary diversity and nutrition quality. However, rural households are still faced with severe food insecurity and malnutrition. The study sought to assess the role of smallholder farming in crop productivity and market access on rural household dietary diversity. The secondary data were collected using a quantitative research method, and 1520 participants were selected using a stratified random sampling technique. The descriptive results showed that cereals were the most (98%) consumed food group, while vegetables and fruits were the least consumed food groups, at 37% and 23%, respectively. The results from the Household Dietary Diversity Score (HDDS) showed that 57% of smallholder farmers consumed highly diverse diets (more or equal to six food groups), whereas 25% and 18% of smallholder farmers consumed medium dietary diversity (four to five food groups) and low diverse diets (less or equal to three food groups), respectively. The findings from the Conditional Mixed Process (CMP) and Poisson endogenous treatment effect models showed that household size, ownership of livestock, wealth index, and involvement in crop production positively influenced household dietary diversity. On the other hand, output and access to market information showed a negative effect. Social grants had contradicting effects: they had a negative impact on the HDDS received from crop productivity while they had a positive effect on the HDDS from market participation. Providing different ways smallholder farmers can use their funds effectively can help improve household dietary diversity and nutrition quality. The study recommended that more workshops and training be conducted that cover all the sustainable production systems that smallholder farmers can undertake to produce different food groups. These will raise awareness among smallholder farmers about the requirements for balanced diets for food and nutrition security.

Addressing the disproportionate burden of food insecurity in South Africa requires targeted efforts to help smallholder farmers to access markets. The purpose of this study was to assess determinants of market participation and its contribution to household food security. The secondary data used in this study were collected from 1520 respondents; however, 389 smallholder farmers participated in the market. The Household Food Insecurity Access Scale revealed that out of the total sample size, 85% of the households were food insecure while 15% were food secure. Gender of household head, receiving social grants and higher wealth index positively impacted market participation. Having a family member with HIV had a negative impact on market participation among smallholder farmers. The results from the extended ordered probit regression model showed that household size, having a family member with HIV and agricultural assistance had a positive and significant contribution to the household food insecurity situation of the smallholder farmers. On the other hand, the educational level of household head, ownership of livestock, age of household head, gender of household head, and having access to social grants had a negative and significant effect on the food insecurity status. Access to education and the market can improve household food security. Linking smallholder farmers, particularly women and aged farmers, to markets should form an intrinsic part of the government's efforts to improve farming and food security and increase access to diversified food.